_______________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
General Description
The MAX15500/MAX15501 analog output conditioners
provide a programmable current up to Q24mA, or a volt-
age up to Q12V proportional to a control voltage signal.
The control voltage is typically supplied by an external
DAC with an output voltage range of 0 to 4.096V for the
MAX15500 and 0 to 2.5V for the MAX15501. The output
current and voltage are selectable as either unipolar or
bipolar. In the unipolar configuration, a control voltage
of 5% full-scale (FS) produces a nominal output of 0A or
0V to achieve underrange capability. A control voltage
of 100%FS produces one of two programmable levels
(105%FS or 120%FS) to achieve overrange capability.
The outputs of the MAX15500/MAX15501 are protected
against overcurrent conditions and a short to ground or
supply voltages up to Q35V. The devices also monitor for
overtemperature and supply brownout conditions. The
supply brownout threshold is programmable.
The MAX15500/MAX15501 are programmed through an
SPIK interface capable of daisy-chained operation. The
MAX15500/MAX15501 provide extensive error reporting
through the SPI interface and an additional open-drain
interrupt output. The devices include an analog output to
monitor load conditions.
The MAX15500/MAX15501 operate over the -40NC to
+105NC temperature range. The devices are available in
a 32-pin, 5mm x 5mm TQFN package.
Applications
Programmable Logic Controllers (PLCs)
Distributed I/Os
Embedded Systems
Industrial Control and Automation
Features
S Supply Voltage Up to Q32.5V
S Output Protected Up to Q35V
S Programmable Output (Plus Overrange)
±10V
0 to 10V
0 to 5V
±20mA
0 to 20mA
4 to 20mA
S Current Output Drives 0 to 1kI
S Voltage Output Drives Loads Down to 1kI
S HART Compliant
S 2ppm Gain Error Drift Over Temperature
S SPI Interface, with Daisy-Chain Capability
S Supports +4.096V (MAX15500) or +2.5V
(MAX15501) Full-Scale Input Signals
S Extensive Error Reporting
Short-Circuit and Overcurrent Protection
Open-Circuit Detection
Brownout Detection
Overtemperature Protection
S Fast, 40µs Settling Time
19-4602; Rev 1; 2/11
Ordering Information
Note: All devices are specified over the -40NC to +105NC oper-
ating temperature range.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
SPI is a trademark of Motorola, Inc.
EVALUATION KIT
AVAILABLE
SPI
INTERFACE
DIN
SCLK
CS1
DOUT
READY
ERROR
MON
REFIN
AIN
DVDD
AVSS
AVDD
FSMODE FSSEL AGND DGND
OUT
SENSERN
COMP
CS2
OUTDIS
AVSSO
AVDDO
ERROR
HANDLING
BIDIRECTIONAL
CURRENT
DRIVER
BIDIRECTIONAL
VOLTAGE
DRIVER
ERROR
HANDLING
OVER-
CURRENT
PROTECTION
SENSERP
SENSEVP
SENSEVN
MAX15500
MAX15501
Pin Configuration
MAX15500
MAX15501
TQFN
TOP VIEW
29
30
28
27
12
11
13
DIN
READY
ERROR
DVDD
DGND
14
SCLK
SENSEVN
SENSERP
AVDDO
N.C.
OUT
COMP
1 2
AVSS
4 5 6 7
2324 22 20 19 18
MON
CS1
AIN
REFIN
AGND
FSMODE
DOUT SENSERN
3
21
31 10
CS2 FSSEL
32 9
N.C. OUTDIS
EP*
+
*EXPOSED PAD.
AGND
26 15 AGND
AVDD
25 16 N.C.
N.C. AVSSO
8
17
SENSEVP
Simplified Block Diagram
PART PIN-PACKAGE REFERENCE
MAX15500GTJ+ 32 TQFN-EP* +4.096V
MAX15501GTJ+ 32 TQFN-EP* +2.5V
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
2 ______________________________________________________________________________________
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
AVDD to AGND .....................................................-0.3V to +35V
AVSS to AGND ......................................................-35V to +0.3V
AVDD to AVSS ............................................................. 0 to +70V
AVDD to AVDDO ........................................................... 0 to +4V
AVSS to AVSSO ............................................................ -4V to 0V
DGND to AGND ...................................................-0.3V to +0.3V
AVDD to DVDD .........................................................-6V to +35V
DVDD to DGND ....................................................-0.3V to +6.0V
CS1, CS2, SCLK, DIN, DOUT, READY, ERROR, FSMODE,
MON, OUTDIS, FSSEL to DGND ......................-0.3V to +6.0V
AIN, REFIN to AGND ............................................-0.3V to +6.0V
SENSEVP, SENSEVN, SENSERP,
SENSERN to AGND the higher of -35V and (VAVSS - 0.3V) to
the lower of (VAVDD + 0.3V) and +35V
OUT, COMP to AGND .. the higher of -35V and (VAVSS - 0.3V) to
the lower of (VAVDD + 0.3V) and +35V
Maximum Current on Pin ............................................... ±100mA
Continuous Power Dissipation (derate 34.5mW/NC above +70NC)
32-Pin TQFN (TA = +70NC, multilayer board) .........2758.6mW
Operating Temperature Range ........................ -40NC to +105NC
Storage Temperature Range ............................ -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow) ......................................+260NC
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VAVDD = +24V, VAVSS = -24V, VDVDD = 5.0V, CLOAD = 1nF, CCOMP = 0nF, VREFIN = 4.096V for the MAX15500, VREFIN = 2.5V for
the MAX15501. All specifications for TA = -40NC to +105NC. Typical values are at TA = +25NC, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
POWER SUPPLY (Note 1)
Analog Positive Supply Voltage VAVDD 5% overrange (FSMODE = DVDD) 15 24 32.5 V
20% overrange (FSMODE = DGND) 18.5 24 32.5
Analog Negative Supply
Voltage VAVSS 5% overrange (FSMODE = DVDD) -32.5 -24 -15 V
20% overrange (FSMODE = DGND) -32.5 -24 -18.5
AVDD to AVDDO Voltage
Difference VAVDDO (Note 1) 2.5 V
AVSS to AVSSO Voltage
Difference VAVSSO (Note 1) 2.5 V
Digital Supply Voltage VDVDD 2.7 5.25 V
Analog Positive Supply Current IAP IAP = IAVDD + IAVDDO, ILOAD = 0A 5 7 mA
Analog Negative Supply Current IAN IAN = IAVSS + IAVSSO, ILOAD = 0A -7 -4.5 mA
Digital Supply Current IDVDD VDVDD = 5V 0.1 0.4 mA
Analog Positive Standby Current ISTBYP ISTBYP = IAVDD + IAVDDO, OUTDIS =
DGND or software standby mode 1 mA
Analog Negative Standby Current ISTBYN ISTBYN = IAVSS + IAVSSO, OUTDIS =
DGND or software standby mode -0.5 mA
ANALOG INPUT (AIN, REFIN)
Input Impedance RIN 10 kI
Input Capacitance CIN 10 pF
Analog Input Full Scale VAIN FSSEL = DVDD, MAX15500 4.0 4.096 4.2 V
FSSEL = DGND, MAX15501 2.4 2.5 2.6
REFIN Full-Scale Input VREFIN FSSEL = DVDD, MAX15500 4.0 4.096 4.2 V
FSSEL = DGND, MAX15501 2.4 2.5 2.6
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = +24V, VAVSS = -24V, VDVDD = 5.0V, CLOAD = 1nF, CCOMP = 0nF, VREFIN = 4.096V for the MAX15500, VREFIN = 2.5V for
the MAX15501. All specifications for TA = -40NC to +105NC. Typical values are at TA = +25NC, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
CURRENT OUTPUT (Note 2)
Maximum Load Resistance RLOAD VAVDD = +24V, VAVSS = -24V 750 I
VAVDD = +32.5V, VAVSS = -32.5V 1000
Maximum Load Inductance LLOAD CCOMP = 100nF (Note 3) 15 mH
Maximum Load Capacitance CLOAD CCOMP = 4.7nF 100 FF
Maximum Settling Time
Full-scale step
from 0 to 20mA or
-20mA to + 20mA,
RLOAD = 750I
To 0.1% accuracy,
LLOAD = 20FH,
CCOMP = 0nF
40
Fs
To 0.1% accuracy,
LLOAD = 1mH,
CCOMP = 0.15nF
500
To 0.1% accuracy,
LLOAD = 10mH,
CCOMP = 0.15nF
500
To 0.01% accuracy,
LLOAD = 20FH,
CCOMP = 0nF
60
To 0.01% accuracy,
LLOAD = 10mH,
CCOMP = 0.15nF
600
1% full-scale step,
RLOAD = 750I
To 0.1% accuracy,
LLOAD = 20FH,
CCOMP = 0nF
20
To 0.1% accuracy,
LLOAD = 1mH,
CCOMP = 0.15nF
100
To 0.1% accuracy,
LLOAD = 10mH,
CCOMP = 0.15nF
100
To 0.01% accuracy,
LLOAD = 20FH,
CCOMP = 0nF
40
To 0.01% accuracy,
LLOAD = 10mH,
CCOMP = 0.15nF
200
Full-Scale Output Current IOUT VFSMODE = VDVDD Q21 mA
VFSMODE = VDGND Q24
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
4 ______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = +24V, VAVSS = -24V, VDVDD = 5.0V, CLOAD = 1nF, CCOMP = 0nF, VREFIN = 4.096V for the MAX15500, VREFIN = 2.5V for
the MAX15501. All specifications for TA = -40NC to +105NC. Typical values are at TA = +25NC, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Offset Error VAIN = 5% of VREFIN (unipolar mode),
VAIN = 50% of VREFIN (bipolar mode) Q0.1 Q0.5 %FS
Offset-Error Drift Q5 ppm/NC
Gain Error GE
0.01% precision
RSENSE, tested
according to the
ideal transfer
functions shown in
Table 8
MAX15500 Q0.1 Q0.51
%FS
MAX15501 Q0.1 Q0.5
Gain-Error Drift No RSENSE drift Q2 ppm/NC
Integral Nonlinearity Error INL 0.05 %FS
Output Conductance
(dIOUT/dVOUT), IOUT = 24mA, RLOAD =
750I to 0I, FSMODE = DGND, unipolar
mode
1.0 FA/V
Power-Supply Rejection Ratio PSRR
At DC, VAVDD = +24V to +32.5V, VAVSS
= -24V to -32.5V, VAIN = VREFIN, unipolar
mode, FSMODE = DVDD
1.6 FA/V
Overcurrent Limit RSENSE shorted 25 30 40 mA
Output Current Noise 0.1Hz to 10Hz 20 nARMS
At 1kHz 2.6 nA/√Hz
Output Slew Rate 1.5 mA/Fs
Small-Signal Bandwidth 30 kHz
Maximum OUT Voltage to
AVDDO VAVDDO - VOUT 2.0 V
Minimum OUT Voltage to
AVSSO VOUT - VAVSSO 2.0 V
VOLTAGE OUTPUT (RLOAD = 1kI)
Minimum Resistive Load RLOAD 1kI
Maximum Capacitive Load CLOAD CCOMP = 4.7nF 100 FF
Maximum Settling Time (Full-
Scale Step)
To 0.1% accuracy, load = 1kI in parallel
with 1nF, CCOMP = 0nF 20
Fs
To 0.1% accuracy, load = 1kI in parallel
with 1FF, CCOMP = 4.7nF 1000
To 0.01% accuracy, load = 1kI in parallel
with 1nF, CCOMP = 0nF 30
To 0.01% accuracy, load = 1kI in parallel
with 1FF, CCOMP = 4.7nF 1300
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
_______________________________________________________________________________________ 5
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = +24V, VAVSS = -24V, VDVDD = 5.0V, CLOAD = 1nF, CCOMP = 0nF, VREFIN = 4.096V for the MAX15500, VREFIN = 2.5V for
the MAX15501. All specifications for TA = -40NC to +105NC. Typical values are at TA = +25NC, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Maximum Settling Time
(1% Full-Scale Step)
To 0.1% accuracy, load = 1kI in parallel
with 1nF, CCOMP = 0nF 10
Fs
To 0.1% accuracy, load = 1kI in parallel
with 1FF, CCOMP = 4.7nF 300
To 0.01% accuracy, load = 1kI in parallel
with 1nF, CCOMP = 0nF 20
To 0.01% accuracy, load = 1kI in parallel
with 1FF, CCOMP = 4.7nF 600
Gain Error Tested according to the ideal transfer
functions shown in Table 9 Q0.1 Q0.5 %FS
Gain-Error Drift Q2 ppm/NC
Full-Scale Output Voltage VOUT
FSMODE = DVDD
5V range 5.25
V
10V range 10.5
FSMODE = DGND
5V range 6
10V range 12
Offset Error VAIN = 5% of VREFIN (unipolar mode),
VAIN = 50% of VREFIN (bipolar mode) Q0.1 Q0.5 %FS
Offset-Error Drift Q2 ppm/NC
Integral Nonlinearity Error INL 0.05 %FS
Power-Supply Rejection PSRR At DC, VAVDD = +18.5V to +32.5V, VAVSS
= -18.5V to -32.5V, VAIN = VREFIN 30 FV/V
Output-Voltage Noise 0.1Hz to 10Hz 16.3 FVRMS
1kHz 250 nV/√Hz
Output-Voltage Slew Rate 1.5 V/Fs
Short-Circuit Current 20 30 45 mA
Maximum OUT Voltage to
AVDDO VAVDDO - VOUT 2.0 V
Minimum OUT Voltage to
AVSSO VOUT - VAVSSO 2.0 V
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
6 ______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = +24V, VAVSS = -24V, VDVDD = 5.0V, CLOAD = 1nF, CCOMP = 0nF, VREFIN = 4.096V for the MAX15500, VREFIN = 2.5V for
the MAX15501. All specifications for TA = -40NC to +105NC. Typical values are at TA = +25NC, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUTPUT MONITOR (MON)
Maximum Output Voltage
Current mode, see the Output Monitor
section for VMON equations 3
V
Voltage mode, see the Output Monitor
section for VMON equations 3
Output Resistance 35 kI
OVERTEMPERATURE DETECTION
Overtemperature Threshold +150 NC
Overtemperature Threshold
Hysteresis 10 NC
DIGITAL INPUTS (CS1, CS2, SCLK, DIN, OUTDIS, FSSEL, FSMODE)
Input High Voltage VIH 0.7 x
VDVDD V
Input Low Voltage VIL 0.3 x
VDVDD V
Input Hysteresis VIHYST 300 mV
Input Leakage Current IIN VINPUT = 0V or VDVDD Q0.1 Q1.0 FA
Input Capacitance CIN 10 pF
DIGITAL OUTPUT (DOUT, READY)
Output Low Voltage VOL ISINK = 4mA 0.4 V
Output High Voltage VOH ISOURCE = 4mA VDVDD -
0.5 V
Output Three-State Leakage IOZ DOUT only Q0.1 Q10 FA
Output Three-State Capacitance COZ DOUT only 15 pF
Output Short-Circuit Current IOSS VDVDD = 5.25V Q150 mA
DIGITAL INTERRUPT (ERROR)
Interrupt Active Voltage VINT ISINK = 5.0mA 0.4 V
Interrupt Inactive Leakage IINTZ Q0.1 Q1.0 FA
Interrupt Inactive Capacitance CINTZ 15 pF
Interrupt Short-Circuit Current IINTSS VDVDD = 2.7V 5 30 mA
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
_______________________________________________________________________________________ 7
Note 1: Use diodes as shown in the Typical Operating Circuit/Functional Diagram to ensure a voltage difference of 2V to 3.5V
from AVDD to AVDDO and from AVSS to AVSSO.
Note 2: RLOAD = 750I. For the MAX15500, RSENSE = 48.7I for FSMODE = DVDD and RSENSE = 42.2I for FSMODE = DGND.
For the MAX15501, RSENSE = 47.3I for FSMODE = DVDD and RSENSE = 41.2I for FSMODE = DGND. See the Typical
Operating Circuit/Functional Diagram.
Note 3: Condition at which part is stable.
Note 4: The maximum clock speed for daisy-chain applications is 10MHz.
Note 5: tCSH is applied to CS_ falling to determine the 1st SCLK falling edge in a free-running SCLK application. It is also applied
to CS_ rising with respect to the 15th SCLK falling edge to determine the end of the frame.
Note 6: After the 14th SCLK falling edge, the MAX15500/MAX15501 outputs are high impedance and DOUT data is ignored.
ELECTRICAL CHARACTERISTICS (continued)
(VAVDD = +24V, VAVSS = -24V, VDVDD = 5.0V, CLOAD = 1nF, CCOMP = 0nF, VREFIN = 4.096V for the MAX15500, VREFIN = 2.5V for
the MAX15501. All specifications for TA = -40NC to +105NC. Typical values are at TA = +25NC, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
TIMING CHARACTERISTICS
Serial-Clock Frequency fSCLK (Note 4) 0 20 MHz
SCLK Pulse-Width High tCH 40% duty cycle 20 ns
SCLK Pulse-Width Low tCL 60% duty cycle 20 ns
CS_ Fall to SCLK Fall Setup Time tCSS To 1st SCLK falling edge 15 ns
SCLK Fall to CS_ Fall Hold Time tCSH (Note 5) 0 ns
DIN to SCLK Fall Setup Time tDS 15 ns
DIN to SCLK Fall Hold Time tDH 0 ns
SCLK Fall to DOUT Settle Time tDOT CLOAD = 20pF 30 ns
SCLK Fall to DOUT Hold Time tDOH CLOAD = 0pF 2 ns
SCLK Fall to DOUT Disable tDOZ 14th SCLK deassertion (Note 6) 30 ns
SCLK Fall to READY Fall tCR 16th SCLK assertion, CLOAD = 0pF or 20pF 2 30 ns
CS_ Fall to DOUT Enable tDOE Asynchronous assertion 1 35 ns
CS_ Rise to DOUT Disable tCSDOZ Asynchronous deassertion 35 ns
CS_ Rise to READY Rise tCSR Asynchronous deassertion, CLOAD = 20pF 35 ns
CS_ Pulse-Width High tCSW 15 ns
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
8 ______________________________________________________________________________________
Typical Operating Characteristics
(VAVDD = +24V, VDVDD = +5V, VAVSS = -24V, CLOAD = 1nF, 5% overrange mode, unipolar current output or bipolar voltage-output
mode, VREFIN = +4.096V, TA = +25NC, unless otherwise specified.)
SUPPLY CURRENT vs. TEMPERATURE
MAX15500 toc01
TEMPERATURE (NC)
SUPPLY CURRENT (mA)
958050 65-10 5 20 35-25
-8
-6
-4
-2
0
2
4
6
8
10
10
-40 105
IAVDD
IAVSS
NO LOAD
VOLTAGE-MODE OUTPUT SLEW
RATE vs. TEMPERATURE
MAX15500 toc02
TEMPERATURE (NC)
OUTPUT SLEW RATE (V/Fs)
9580655035205-10-25
0.5
1.0
1.5
2.0
2.5
3.0
0
-40 105
NO LOAD
CURRENT-MODE OUTPUT SLEW
RATE vs. TEMPERATURE
MAX15500 toc03
TEMPERATURE (NC)
OUTPUT SLEW RATE (mA/Fs)
9580655035205-10-25
0.5
1.0
1.5
2.0
2.5
3.0
0
-40 105
RLOAD = 750I
CLOAD = 1FF
VOLTAGE-MODE OUTPUT NOISE
vs. FREQUENCY
MAX15500 toc04
FREQUENCY (Hz)
OUTPUT NOISE (FV/ Hz)
1k100
100
200
300
400
500
600
700
800
900
1000
0
10 10k
VAIN = 0V
UNIPOLAR
VOLTAGE
MODE (0 to 5V)
CURRENT-MODE OUTPUT NOISE
vs. FREQUENCY
MAX15500 toc05
FREQUENCY (Hz)
OUTPUT NOISE (FV/ Hz)
1k100
100
200
300
400
500
600
700
800
900
1000
0
10 10k
VAIN = 200mV
UNIPOLAR
CURRENT MODE
(0 to 20mA)
MAX15500 toc06
2V/div
VOUT (AC-COUPLED)
1mV/div
400ns/div
DIGITAL FEEDTHROUGH
SCLK
SCLK = DIN
SCLK = 1MHz
CS_ = HIGH
VAIN = 0.5 x VREFIN
VOLTAGE-MODE PSRR
vs. SUPPLY VOLTAGE
MAX15500 toc07
SUPPLY VOLTAGE (V)
PSRR (FV/V)
302826
10
20
30
40
50
60
70
80
90
100
0
24 32
VAIN = 4.096V
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
_______________________________________________________________________________________ 9
Typical Operating Characteristics (continued)
(VAVDD = +24V, VDVDD = +5V, VAVSS = -24V, CLOAD = 1nF, 5% overrange mode, unipolar current output or bipolar voltage-output
mode, VREFIN = +4.096V, TA = +25NC, unless otherwise specified.)
CURRENT-MODE PSRR vs.
SUPPLY VOLTAGE
MAX15500 toc08
SUPPLY VOLTAGE (V)
PSRR (FA/V)
313028 2926 2725
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
24 32
MAX15500 toc09
VOUT (AC-COUPLED)
20mV/div
40Fs/div
LOAD TRANSIENT (VOLTAGE MODE)
IOUT
10mA/div
OmA
MAX15500 toc10
IOUT
10mA/div
40Fs/div
0mA
LOAD TRANSIENT (CURRENT MODE)
VOUT
10V/div
O
FULL-SCALE OUTPUT VOLTAGE
vs. TEMPERATURE
MAX15500 toc11
TEMPERATURE (NC)
FULL-SCALE OUTPUT VOLTAGE (ppm/NC)
958050 65-10 5 20 35-25
-16
-12
-8
-4
0
4
8
12
16
20
-20
-40
VAIN = 4.096V
958050 65-10 5 20 35-25-40
OUTPUT CURRENT DRIFT
vs. TEMPERATURE
MAX15500 toc12
TEMPERATURE (NC)
OUTPUT CURRENT DRIFT (ppm/NC)
-6
-2
2
6
10
-10
VAIN = 4.096V
STANDBY SUPPLY CURRENT
vs. TEMPERATURE
MAX15500 toc13
TEMPERATURE (NC)
SUPPLY CURRENT (mA)
9580-25 -10 5 35 5020 65
-1.5
-1.0
-0.5
0
0.5
1.0
1.5
2.0
-2.0
-40
IAVDD
IAVSS
NO LOAD
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
10 _____________________________________________________________________________________
Typical Operating Characteristics (continued)
(VAVDD = +24V, VDVDD = +5V, VAVSS = -24V, CLOAD = 1nF, 5% overrange mode, unipolar current output or bipolar voltage-output
mode, VREFIN = +4.096V, TA = +25NC, unless otherwise specified.)
WAKEUP FROM STANDBY
(VOLTAGE MODE)
MAX15500 toc14
50Fs/div
5V/div
VOUT
2V/div
OUTDIS
0V
0V
FULL-SCALE INPUT
BIPOLAR VOLTAGE MODE
5% OVERRANGE
MAX15500 toc15
IOUT
10mA/div
40Fs/div
WAKEUP FROM STANDBY
(CURRENT MODE)
OUTDIS
2V/div
GAIN vs. FREQUENCY
(HART COMPLIANT)
MAX15500 toc16
FREQUENCY (Hz)
GAIN (dB)
10k1k100
-16
-12
-8
-4
0
-20
10 100k
UNIPOLAR
CURRENT MODE
BIPOLAR
CURRENT MODE
VAIN = 40mVP-P
MAX15500 toc17
IOUT
100FA/div
5Fs/div
SMALL-SIGNAL STEP RESPONSE
(CURRENT MODE)
VAIN
20mV/div
MAX15500 toc18
VOUT
(AC-COUPLED)
100mV/div
1Fs/div
SMALL-SIGNAL STEP RESPONSE
(VOLTAGE MODE)
VAIN
(AC-COUPLED)
50mV/div
OUTPUT SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
MAX15500 toc19
TEMPERATURE (NC)
SHORT-CIRCUIT CURRENT (mA)
958050 65-10 5 20 35-25
30.5
31.0
31.5
32.0
32.5
33.0
33.5
34.0
34.5
35.0
30.0
-40
VAIN = 4.096V
VOLTAGE-MODE MON TRANSFER
CURVE vs. OUTPUT CURRENT
MAX15500 toc20
IOUT (mA)
MON (V)
10987654321
1.4
1.8
2.2
2.6
3.0
1.0
0 11
VAIN = 4.096V
NO LOAD ON MON
CURRENT-MODE MON TRANSFER
CURVE vs. OUTPUT VOLTAGE
MAX15500 toc21
VOUT (V)
MON (V)
1284
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
1.0
0 16
VAIN = 4.096V
NO LOAD ON MON
VOLTAGE-MODE MAXIMUM OUT TO
AVDDO VOLTAGE vs. TEMPERATURE
MAX15500 toc22
TEMPERATURE (NC)
MAXIMUM INTERNAL VOLTAGE DROP (V)
958050 65-10 5 20 35-25
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
-40
VAIN = 4.096V
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 11
Typical Operating Characteristics (continued)
(VAVDD = +24V, VDVDD = +5V, VAVSS = -24V, CLOAD = 1nF, 5% overrange mode, unipolar current output or bipolar voltage-output
mode, VREFIN = +4.096V, TA = +25NC, unless otherwise specified.)
CURRENT-MODE OUTPUT
CONDUCTANCE vs. OUTPUT VOLTAGE
MAX15500 toc23
OUTPUT VOLTAGE (V)
OUTPUT CONDUCTANCE (FA/V)
14128 104 62
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0
0 16
MAX15500 toc24
VOUT
5V/div
100Fs/div
LARGE-SIGNAL SETTLING TIME
(VOLTAGE MODE, RISING EDGE)
VAIN
5V/div
RL = 1kI
CL = 1nF, CCOMP = 0nF
CL = 470nF, CCOMP = 4.7nF
CL = 47nF, CCOMP = 0nF
0
MAX15500 toc25
VOUT
5V/div
100
F
s/div
LARGE-SIGNAL SETTLING TIME
(VOLTAGE MODE, FALLING EDGE)
VAIN
5V/div
RL = 1kI
CL = 1nF, CCOMP = 0nF
CL = 470nF, CCOMP = 4.7nF
CL = 47nF, CCOMP = 0nF
MAX15500 toc26
VOUT
10ms/div
LARGE-SIGNAL SETTLING TIME
(VOLTAGE MODE, RISING EDGE)
VAIN
5V/div
RL = 1kI
CL = 1FF, CCOMP = 4.7nF
CL = 10FF,
CCOMP = 4.7nF
CL = 100FF,
CCOMP = 4.7nF
MAX15500 toc27
VOUT
5V/div
10ms/div
LARGE-SIGNAL SETTLING TIME
(VOLTAGE MODE, RISING EDGE)
VAIN
5V/div
RL = 1kI
CL = 10FF,
CCOMP = 4.7nF
CL = 100FF,
CCOMP = 4.7nF
CL = 1FF, CCOMP = 4.7nF
MAX15500 toc28
IOUT
4mA/div
200Fs/div
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, RISING EDGE)
VAIN
5V/div
RL = 750I
LL = 220FH, CCOMP = 0nF
LL = 1mH, CCOMP = 1nF
LL = 22FH, CCOMP = 0nF
MAX15500 toc29
IOUT
4mA/div
200Fs/div
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, FALLING EDGE)
VAIN
5V/div
RL = 750I
LL = 220FH, CCOMP = 0nF
LL = 1mH, CCOMP = 1nF
LL = 22FH, CCOMP = 0nF
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, RISING EDGE)
MAX15500 toc30
IOUT
4mA/div
20Fs/div
VAIN
5V/div
RL = 20I
LL = 220FH,
CCOMP = 0.47nF
LL = 1mH, CCOMP = 1nF
LL = 22FH, CCOMP = 0.15nF
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, FALLING EDGE)
MAX15500 toc31
IOUT
4mA/div
20Fs/div
VAIN
RL = 20I
LL = 220FH,
CCOMP = 0.47nF
LL = 1mH, CCOMP = 1nF
LL = 22FH, CCOMP = 0.15nF
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
12 _____________________________________________________________________________________
Typical Operating Characteristics (continued)
(VAVDD = +24V, VDVDD = +5V, VAVSS = -24V, CLOAD = 1nF, 5% overrange mode, unipolar current output or bipolar voltage-output
mode, VREFIN = +4.096V, TA = +25NC, unless otherwise specified.)
CURRENT-MODE INL
MAX15500 toc36
VAIN (V)
INL (%FS)
3.63.00.6 1.2 1.8 2.4
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
-0.04
0 4.2
VOLTAGE-MODE INL
MAX15500 toc37
VAIN (V)
INL (%FS)
3.63.00.6 1.2 1.8 2.4
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
-0.04
0 4.2
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, RISING EDGE)
MAX15500 toc32
IOUT
4mA/div
100ms/div
VAIN
5V/div
RL = 750I
LL = 80mH, CCOMP = 470nF
LL = 50mH, CCOMP = 100nF
LL = 10mH, CCOMP = 10nF
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, FALLING EDGE)
MAX15500 toc33
IOUT
4mA/div
100ms/div
VAIN
5V/div
RL = 750I
LL = 50mH, CCOMP = 100nF
LL = 80mH, CCOMP = 470nF
LL = 10mH, CCOMP = 10nF
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, RISING EDGE)
MAX15500 toc34
IOUT
4mA/div
10ms/div
VAIN
5V/div
RL = 20I
LL = 80mH,
CCOMP = 470nF
LL = 50mH, CCOMP = 100nF
LL = 10mH, CCOMP = 10nF
LARGE-SIGNAL SETTLING TIME
(CURRENT MODE, FALLING EDGE)
MAX15500 toc35
IOUT
4mA/div
10ms/div
VAIN
20V/div
LL = 80mH, CCOMP = 470nF
LL = 50mH, CCOMP = 100nF
LL = 10mH, CCOMP = 10nF
RL = 20I
VOLTAGE-MODE
SHORT-CIRCUIT DETECTION
MAX15500 toc38
100ms/div
2V/div
50mA/div
ERROR
IOUT
0mA
CURRENT-MODE
OPEN-CIRCUIT DETECTION
MAX15500 toc39
100ms/div
2V/div
50mA/div
ERROR
IOUT
0mA
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 13
Pin Description
PIN NAME FUNCTION
1 SCLK SPI Clock Input. Activate SCLK only when CS_ is low to minimize noise coupling.
2 DIN SPI Data Input. Data is clocked into the serial interface on the falling edge of SCLK.
3 DOUT SPI Data Output. Data transitions at DOUT on the falling edge of SCLK. DOUT is high impedance
when either CS1 or CS2 is high.
4READY
Active-Low Device Ready Output. READY is an active-low output that goes low when the device
successfully completes processing an SPI data frame. READY returns high at the next rising edge
of CS_. In daisy-chain applications, the READY output typically drives the CS_ input of the next
device in the chain or a GPIO of a microcontroller.
5ERROR
Active-Low Flag Output. ERROR is an open-drain output that pulls low when output short circuit,
output open circuit, overtemperature, or brownout conditions occur. ERROR typically drives an
interrupt input of a microcontroller. The ERROR output is cleared after the internal error register is
read through the SPI interface. Connect a 10kΩ pullup resistor from ERROR to DVDD.
6 DVDD
Digital Power-Supply Voltage Input. Apply either a 3V or 5V nominal voltage supply to DVDD.
DVDD powers the digital portion of the MAX15500/MAX15501. Bypass DVDD to DGND with a 0.1FF
capacitor as close as possible to the device.
7 DGND Digital Ground
8, 16,
24, 32 N.C. No Connection. Not internally connected.
9OUTDIS
Active-Low Output Disable Input. OUTDIS is an active-low logic input that forces the analog output
to 0A or 0V and puts the device in standby mode when connected to DGND. Connect OUTDIS to
DVDD for normal operation.
10 FSSEL
Full-Scale Select Input. Connect FSSEL to DVDD for the MAX15500 when applying a +4.096V
reference at REFIN. Connect FSSEL to DGND for the MAX15501 when applying a +2.50V reference
at REFIN.
11 FSMODE
Overrange Mode Select Input. Connect FSMODE to DVDD to set the output voltage to 105%FS
when the input voltage is equal to the full-scale value. Connect FSMODE to DGND to set the output
voltage to 120%FS when the input voltage is equal to the full-scale value. FSMODE has no effect in
current mode.
12, 15, 27 AGND Analog Ground
13 REFIN Reference Voltage Input. Connect REFIN to an external +4.096V reference for the MAX15500 or
+2.5V reference for the MAX15501. REFIN is used to set the offset for unipolar and bipolar modes.
14 AIN Analog Signal Input. The analog input signal range at AIN is from 0V to the nominal full scale of
+4.096V for the MAX15500 and +2.5V for the MAX15501.
17 AVSSO
Negative Output Driver Supply Voltage Input. AVSSO provides power to the driver output stage.
Bypass AVSSO to AVSS with a 0.1FF capacitor. Use diodes as shown in the Typical Operating
Circuit/Functional Diagram to ensure a voltage difference of 2V to 3.5V between AVSS and AVSSO.
18 COMP Output Amplifier Compensation Feedback Node. Connect a compensation capacitor from COMP to
OUT. See Table 10 for the recommended compensation capacitor values.
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
14 _____________________________________________________________________________________
Pin Description (continued)
PIN NAME FUNCTION
19 OUT Analog Output. The analog voltage or current output range at OUT is programmable. See Tables
1 to 4 for possible output range settings.
20 AVDDO
Positive Output Driver Supply Voltage Input. AVDDO provides power to the driver output stage.
Bypass AVDDO to AVDD with a 0.1FF capacitor. Use diodes as shown in the Typical Operating
Circuit/Functional Diagram to ensure a voltage difference of 2V to 3.5V between AVDD and
AVDDO.
21 SENSERP Sense Resistor Positive Connection. See the Typical Operating Circuit/Functional Diagram for the
typical connection.
22 SENSERN Sense Resistor Negative Connection. See the Typical Operating Circuit/Functional Diagram for the
typical connection.
23 SENSEVN Kelvin Sense Voltage Negative Input. See the Typical Operating Circuit/Functional Diagram for the
typical connection.
25 SENSEVP Kelvin Sense Voltage Positive Input. See the Typical Operating Circuit/Functional Diagram for the
typical connection.
26 AVDD Positive Analog Supply Voltage Input. Bypass AVDD to AGND with a 0.1FF capacitor.
28 AVSS Negative Analog Supply Voltage Input. Bypass AVSS to AGND with a 0.1FF capacitor.
29 MON Load Monitoring Output. MON provides an analog 0 to 3V output. See the Output Monitor section.
30 CS1 Active-Low SPI Chip-Select Input 1. See the SPI Interface section.
31 CS2 Active-Low SPI Chip-Select Input 2. See the SPI Interface section.
— EP Exposed Pad. Internally connected to AVSS. Connect to AVSS. Connect to a large copper area to
maximize thermal performance. Do not connect ground or signal lines through EP.
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 15
Typical Operating Circuit/Functional Diagram
10kI
10kI
PGA
OFFSET
GENERATOR
DAC
2.5V/4.096V
REF
OUTPUT STAGE
SPI INTERFACE/
LOGIC I/O
SENSEVP
SENSERP
OUT
SENSERN
SENSEVN
AIN
REFIN
BROWNOUT
TEMP
MONITOR
DIN
SCLK
CS1
CS2
DOUT
DVDD
READY
OUTDIS
FSSEL*
FSMODE
AGND DGND
MON
AVDD AVDDODVDD
0.1FF0.1FF
0.1FF
POR
C
COMP
R
LOAD
R
SENSE
COMP
CABLE1
CABLE2
CABLE3
WRITE
SCLK
CS
READ
GPIO
INT
FC
5V
DVDD
*FSSEL IS CONNECTED TO DGND FOR THE MAX15501.
C
LOAD
ADC
24V
AVSS AVSSO
0.1FF
0.1FF
-24V
MAX15500
MAX15501
ERROR
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
16 _____________________________________________________________________________________
Detailed Description
The MAX15500/MAX15501 output a programmable cur-
rent up to Q24mA or a voltage up to Q12V proportional to
a control signal at AIN. The devices operate from a dual
15V to 32.5V supply. The control voltage applied at AIN
is typically supplied by an external DAC with an output
voltage range of 0 to 4.096V for the MAX15500 and 0
to 2.5V for the MAX15501. The MAX15500/MAX15501
are capable of both unipolar and bipolar current and
voltage outputs. In current mode, the devices produce
currents of -1.2mA to +24mA or -24mA to +24mA. In
voltage mode, the devices produce voltages of -0.3V
to +6V, -0.6V to +12V, or Q12V. To allow for overrange
and underrange capability in unipolar mode, the transfer
function of the MAX15500/MAX15501 is offset such that
when the voltage at AIN is 5% of full scale, IOUT is 0mA
and VOUT is 0V. Once VAIN attains full scale, VOUT or
IOUT becomes full scale +5% or +20% depending on
the state of FSMODE. The MAX15500/MAX15501 are
protected against overcurrent and short-circuit condi-
tions when OUT goes to ground or a voltage up to
Q32.5V. The devices also monitor for overtemperature
and supply brownout conditions. The supply brownout
threshold is programmable between ±10V and ±24V in
2V increments.
The MAX15500/MAX15501 are programmed through an
SPI interface with daisy-chain capability. A device ready
logic output (READY) and two device select inputs (CS1
and CS2) facilitate a daisy-chain arrangement for multiple
device applications. The MAX15500/MAX15501 provide
extensive error reporting of short-circuit, open-circuit,
brownout, and overtemperature conditions through the
SPI interface and an additional open-drain interrupt
output (ERROR). The MAX15500/MAX15501 include an
analog 0 to 3V output (MON) to monitor the load condi-
tion at OUT.
Analog Section
The MAX15500/MAX15501 support two output modes:
current and voltage. Each mode has different full-scale
output values depending on the state of FSMODE as
detailed in Tables 1 to 4 and Figures 1 and 2. Use the
device configuration register in Table 6 to select the
desired voltage or current output range.
Startup
During startup, the MAX15500/MAX15501 output is set
to zero and all register bits are set to zero. The devices
remain in standby mode until they are configured
through the SPI interface.
Input Voltage Range
The input voltage full-scale level is selectable between
2.5V and 4.096V using logic input FSSEL. The MAX15500
is specified for a 0 to 4.096V input voltage range, while
the MAX15501 is specified for a 0 to 2.500V input volt-
age range. Connect FSSEL to DVDD to set the input
range to 0 to 4.096V for the MAX15500. Connect FSSEL
to DGND to set the input range to 0 to 2.500V for the
MAX15501.
Table 1. Output Values for FSMODE =
DVDD, Unipolar 5% Overrange
OUTPUT RANGE OUTPUT VALUES
VAIN = 5%FS VAIN = FS
0 to 20mA
(4mA to 20mA) 0mA 21mA
0 to 5V 0V 5.25V
0 to 10V 0V 10.5V
Table 2. Output Values for FSMODE =
DGND, Unipolar 20% Overrange
OUTPUT RANGE OUTPUT VALUES
VAIN = 5%FS VAIN = FS
0 to 20mA
(4mA to 20mA) 0mA 24mA
0 to 5V 0V 6V
0 to 10V 0V 12V
Table 3. Output Values for FSMODE =
DVDD, Bipolar 5% Overrange
OUTPUT RANGE OUTPUT VALUES
VAIN = 0V VAIN = FS
Q20mA -21mA +21mA
Q10V -10.5V +10.5V
Table 4. Output Values for FSMODE =
DGND, Bipolar 20% Overrange
OUTPUT RANGE OUTPUT VALUES
VAIN = 0V VAIN = FS
Q20mA -24mA +24mA
Q10V -12V +12V
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 17
Output Monitor
The MON output provides an analog voltage signal
proportional to the output voltage in current mode and
proportional to the output current in voltage mode. Use
this signal to measure the system load presented to the
output. The full-scale signal on MON is 3V with a typical
accuracy of 10%. The signal range is typically 1.5V to 3V
in unipolar mode and 0 to 3V in bipolar mode.
In current mode, the MAX15500/MAX15501 program IOUT
and monitor the voltage at SENSERN.
VMON = 1.425V + (VSENSERN/20)
RLOAD = ((VMON - 1.425V) x 20)/IOUT(PROGRAMMED)
In voltage mode, the MAX15500/MAX15501 program
VOUT and monitor IOUT.
VMON = 1.521V + 62.4 x ILOAD
RLOAD = VOUT(PROGRAMMED)/((VMON - 1.521V)/62.4)
Error Handling
Many industrial control systems require error detection
and handling. The MAX15500/MAX15501 provide exten-
sive error status reporting.
An open-drain interrupt flag output, ERROR, pulls low
when an error condition is detected. An error register
stores the error source. Reading the error register once
resets the ERROR pin but not the error register itself,
allowing the system to determine the source of the error
and take steps to fix the error condition. After the error
condition has been fixed, read the error register for the
second time to allow the device to clear the error reg-
ister. Read the error register for the third time to verify
if the error register has been cleared. If another error
occurs after the first read, ERROR goes low again. More
information on reading and clearing the error register is
described in the SPI Interface section.
When an output short-circuit or output open-load error
occurs and disappears before the error register is read,
the intermittent bit is set in the error register. The intermit-
tent bit does not assert for brownout and overtempera-
ture error conditions.
Error Conditions
Output Short Circuit
The output short-circuit error bit asserts when the output
current exceeds 30mA (typ) for longer than 260ms. In
current mode, this error occurs when the sense resistor
is shorted and the sense voltage is not equal to 0V. In
voltage mode, this error occurs when the load is shorted
to the supply or ground. The short-circuit error activates
the intermittent bit in the error register if the error goes
away before the error register is read.
V
AIN
V
OUT
OR I
OUT
FS + 20%
FS + 5%
FS
FS
5%FS
FSMODE = DGND
FSMODE = DVDD
Figure 1. Unipolar Transfer Function
V
AIN
V
OUT
OR I
OUT
FS + 20%
FS + 5%
-FS - 20%
-FS - 5%
FSMODE = DGND
FSMODE = DVDD
50%FS
FS
FS
-FS
Figure 2. Bipolar Transfer Function
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
18 _____________________________________________________________________________________
Output Open Load
The open-circuit error bit activates when VOUT is within
30mV of AVDDO or AVSSO and there is no short-circuit
current in current mode for longer than 260ms. This error
activates the intermittent bit in the error register if the
error goes away before the error register is read.
Internal Overtemperature
The MAX15500/MAX15501 enter standby mode if the die
temperature exceeds +150NC and the overtemperature
protection is enabled as shown in Table 6. When the die
temperature cools down below +140NC, the error regis-
ter must be read back twice to resume normal operation.
The devices provide a 10NC hysteresis.
Brownout
The brownout-error bit activates when the supply voltage
(VAVDD or VAVSS) falls below the brownout threshold.
The threshold is programmable between Q10V to Q24V
in 2V steps. See Table 6 for details. The MAX15500/
MAX15501 provide a 2% hysteresis for the brownout
threshold. The accuracy of the threshold is typically
within 10%. During power-up, ERROR can go low and
the brownout register is set. Users need to read out the
error register twice to clear all the error register bits and
reset ERROR to high.
Output Protection
The MAX15500/MAX15501 supply inputs (AVDD, AVDDO,
AVSS, and AVSSO) and sense inputs (SENSERN,
SENSERP, SENSEVN, and SENSEVP) are protected
against voltages up to Q35V with respect to AGND. See
the Typical Operating Circuit/Functional Diagram for the
recommended supply-voltage connection.
SPI Interface
Standard SPI Implementation
The MAX15500/MAX15501 SPI interface supports daisy-
chaining. Multiple MAX15500/MAX15501 devices can
be controlled from a single 4-wire SPI interface. The
MAX15500/MAX15501 feature dual CS_ inputs and
an added digital output, READY, that signals when
the devices finish processing the SPI frame. CS1 and
CS2 are internally OR-ed. Pull both CS1 and CS2 to
logic-low to activate the MAX15500/MAX15501. For a
daisy-chained application, connect the CS1 input of
all of the devices in the chain to the CS driver of the
microcontroller. Connect the CS2 input of the first device
to ground or to the CS driver of the microcontroller.
Connect CS2 of the remaining devices to the READY
output of the preceding device in the chain. The READY
output of the last device in the chain indicates when
all slave devices in the chain are configured. Connect
the READY output of the last device in the chain to the
microcontroller. Use the open-drain ERROR output as a
wired-OR interrupt. See Figures 3 to 6.
Figure 3. Single Connection (Compatible with Standard SPI)
CS
DWRITE
SCLK
DREAD
CS1
DOUT
SCLK
DIN
ERROR
INT
FC
CS1
CSn
TO OTHER CHIPS/CHAINS
READY
MONITOR
OPTIONAL CONNECTION
CS2
R
PULLUP
MAX15500
MAX15501
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 19
Figure 4. Alternate Single Connection (Compatible with Standard SPI)
Figure 5. Daisy-Chain Connection (Compatible with Standard SPI)
CS
DWRITE
SCLK
DREAD
CS1
DOUT
SCLK
DIN
ERROR
INT
FC
CS1
CSn
TO OTHER CHIPS/CHAINS
READY
MONITOR
OPTIONAL CONNECTION
CS2
R
PULLUP
MAX15500
MAX15501
CS
DWRITE
SCLK
DREAD
CS1
DOUT
SCLK
DIN
ERROR
INT
FC
CS1
CSn
TO OTHER CHIPS/CHAINS
READY
MONITOR
OPTIONAL CONNECTION
CS2
R
PULLUP
MAX15500
MAX15501
CS1
DOUT
SCLK
DIN
ERROR
READY
CS2
MAX15500
MAX15501
CS1
DOUT
SCLK
DIN
ERROR
READY
CS2
MAX15500
MAX15501
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
20 _____________________________________________________________________________________
Modified SPI Interface Description
The SCLK, DIN, and DOUT of the MAX15500/MAX15501
assume standard SPI functionality. While the basic func-
tion of the MAX15500/MAX15501 CS_ inputs is similar
to the standard SPI interface protocol, the management
of the CS_ input within the chain is modified. When both
CS_ inputs are low, the MAX15500/MAX15501 assume
control of the DOUT line and continue to control the line
until the data frame is finished and READY goes low
(Figure 9). Once a complete frame is processed and the
READY signal is issued, the devices do not accept any
data from DIN, until either CS1 or CS2 rises and returns
low. A new communication cycle is initiated by a sub-
sequent falling edge on CS1 or CS2. When either CS1
or CS2 is high, the MAX15500/MAX15501 SPI interface
deactivates, DOUT returns to a high-impedance mode,
READY (if active) clears, and any partial frames not yet
processed are ignored.
READY asserts once a valid frame is processed allowing
the next device in the chain to begin processing the sub-
sequent frame. A valid frame consists of 16 SCLK cycles
following the falling edge of CS_. Once READY asserts,
it remains asserted until either CS_ rises, completing the
programming of the chain.
Figure 6. Daisy-Chain Terminating (Compatible with Standard SPI)
CS
DWRITE
SCLK
DREAD
CS1
DOUT
SCLK
DIN
ERROR
INT
FC
CS1
CSn
TO OTHER CHIPS/CHAINS
SPI DEVICE
READY
CS2
R
PULLUP
MAX15500
MAX15501
CS1
DOUT
SCLK
DIN
ERROR
READY
CS2
MAX15500
MAX15501
CS
DOUT
SCLK
DIN
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 21
The MAX15500/MAX15501 relinquish control of DOUT
once the devices process the frame(s). DOUT remains
high impedance when the SPI interface continues to hold
CS_ low beyond the required frame(s). Install a pullup/
puldown resistor at the DOUT line to maintain the desired
state when DOUT goes high impedance.
Single Device SPI Connection
For applications using a single MAX15500 or MAX15501,
connect both CS1 and CS2 inputs to the device-select
driver of the host microcontroller. Alternatively, connect
one of the CS_ inputs to the device-select driver of the
host microcontroller and the other CS_ to DGND. Both
methods allow standard SPI interface operation. See
Figures 3 and 4.
Daisy-Chain SPI Connection
The MAX15500/MAX15501-modified SPI interface allows
a single SPI master to drive multiple devices in a daisy-
chained configuration, saving additional SPI channels for
other devices and saving cost in isolated applications.
Figure 5 shows multiple MAX15500/MAX15501 devices
connected in a daisy chain. The chain behaves as a
single device to the microcontroller in terms of timing
with an expanded instruction frame requiring 16 SCLK
cycles per device for complete programming. No timing
parameters are affected by the READY propagation as
all devices connect to the microcontroller chip-select
through the CS1 inputs.
A chain of MAX15500/MAX15501 devices can be termi-
nated with any standard SPI-compatible single device
without a READY output. The MAX15500/MAX15501 por-
tion of the chain continues to display timing parameters
comparable to a single device. See Figure 6.
When using the MAX15500/MAX15501 with mixed
chains, the connections could require some modification
to accommodate the interfaces of the additional devices
in the chain. Construct the daisy chain as shown in
Figure 7 when using devices with similar READY outputs
but without dual CS_ inputs such as the MAX5134 quad
16-bit DAC. The chain is subject to timing relaxation for
parameters given with respect to CS_ rising edges to
accommodate READY propagation to and through con-
secutive MAX5134 devices.
The chain can begin and terminate with either device
type. Each MAX5134 or MAX15500/MAX15501 device
in the chain could be replaced by a subchain of similar
devices. If the chain is terminated with a standard SPI
device, omit the optional connection from READY to the
monitor input on the microcontroller. The MAX15500/
MAX15501 portion of the chain continues to display tim-
ing parameters comparable to a single device.
SPI Digital Specifications and Waveforms
Figures 8, 9, and 10 show the operation of the modified
SPI interface. The minimum programming operation
typically used in single device applications is 16 SCLK
periods, the minimum for a valid frame. This cycle can
also represent the operation of the final device in a chain.
The extended programming operation is typically used
for devices in daisy-chained applications. In this case,
READY drives the chip-select input of the subsequent
device in the chain. The next device in the chain
begins its active frame on the 16th SCLK falling edge in
response to READY falling (latching DIN[13] on the 17th
SCLK falling edge, if present).
Aborted SPI Operations
Driving a CS_ input high before a valid SPI frame is
transmitted to the device can cause an erroneous com-
mand. Avoid driving CS_ high before a valid SPI frame is
transmitted to the device. See Figures 9 and 10 for valid
SPI operation timing.
SPI Operation Definitions
Input data bits DIN[13:11] represent the SPI command
address while DIN[9:0] represent the data written to
or read from the command address. The command
address directs subsequent input data to the proper
internal register for setting up the behavior of the device
and selects the correct status data for readback through
DOUT. Command address 0h points to a no-op com-
mand and does not impact the operation of the device.
DOUT is active during this operation and reads back
00h. Command address 1h points to the configuration
register used to program the MAX15500/MAX15501.
Device configuration takes effect following the 14th
SCLK falling edge. DOUT activates and remains low dur-
ing this operation. Command addresses 4h and 5h point
to readback commands of the MAX15500/MAX15501.
Readback commands provide configuration and error
register status through DOUT[9:0] and do not affect the
internal operation of the device. Command addresses
2h, 3h, 6h, and 7h are reserved for future use. Table 5
shows the list of commands.
Device Configuration Operation
Table 6 shows the function of each bit written to the con-
figuration register 1h. Table 7 shows the data readback
registers.
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
22 _____________________________________________________________________________________
Figure 7. Mixed MAX15500/MAX15501 and MAX5134 Daisy-Chain Connections
Figure 8. Minimum SPI Programming Operation (Typically for Single Device Applications)
CS
DWRITE
SCLK
DREAD
CS1
DOUT
SCLK
DIN
ERROR
INT
FC
CS1
CSn
TO OTHER CHIPS/CHAINS
READY
MONITOR
OPTIONAL CONNECTION
CS2
R
PULLUP
MAX15500
MAX15501
CS1
DOUT
SCLK
DIN
ERROR
READY
CS2
MAX15500
MAX15501
SCLK
DIN
READY
CS
MAX5134
12345678910 11 12 13 14 15 16
DIN13 DIN12 DIN11 DIN9 DIN8 DIN7 DIN6 DIN5 DIN4 DIN3 DIN2 DIN1X
Z
X X X
X
HIGH-Z
ACTIVE FRAME
CS_
DOUT
SCLK
DIN
t
CSH
t
CSH
t
CSW
t
CSS
t
DOE
t
DOH
t
DOT
t
DOZ
t
DS
t
CH
t
CP
t
CL
t
CH
COMMAND EXECUTED
DIN10 DIN0
DOUT9 DOUT8 DOUT7 DOUT6 DOUT5 DOUT4 DOUT3 DOUT2 DOUT1 DOUT0
ERROR REGISTER UPDATED,
ERROR RE-EVALUATED
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 23
Readback Operations
Write to the command addresses 4h or 5h to read back the
configuration register data or the internal error information
through DOUT[9:0]. For error readback operations, each
bit corresponds to a specific error condition, with multiple
bits indicating multiple error conditions present.
Intermittent Errors
An intermittent error is defined as an error that is detected
and is resolved before the error register is read back.
When the error is resolved without intervention, the inter-
mittent bit (bit 9) is set. The output short-circuit and output
open-load errors trigger the intermittent bit. Internal over-
temperature and supply voltage brownout do not trigger
the intermittent bit.
Error Reporting Applications
The ERROR output is typically connected to an inter-
rupt input of the system microcontroller. The MAX15500/
MAX15501 only issue an interrupt when a new error con-
dition is detected. The devices do not issue interrupts
when errors (either individual or multiple) are resolved
or when already reported errors persist. The system
microcontroller resets ERROR when the system micro-
controller reads back the error register. ERROR does not
assert again unless a different error occurs.
Figure 9. Extended SPI Programming Operation (Daisy-Chained Applications)
Figure 10. Aborted SPI Programming Operation (Invalid, Showing tCSDOZ and Internal Activity)
12345678910 11 12 13 14 15 16 17
DIN13 DIN12 DIN11 DIN9 DIN8 DIN7 DIN6 DIN5 DIN4 DIN3 DIN2 DIN1X
Z
X X X
X
HIGH-Z
ACTIVE FRAME
CS_
DOUT
SCLK
DIN
t
CSH
t
CSV
t
CSR
t
CSS
t
DOE
t
DOH
t
DOT
t
DOZ
t
DS
t
CH
t
CP
t
CL
t
CH
t
CR
DIN10 DIN0
DOUT9 DOUT8 DOUT7 DOUT6 DOUT5 DOUT4 DOUT3 DOUT2 DOUT1 DOUT0
READY
12345678910 11 12 13 14 15 16
Z
X
HIGH-Z
CS_
DOUT
SCLK
t
CSH
t
CSS
t
DOE
t
CSDOZ
ERROR REGISTER UPDATED,
ERROR RE-EVALUATED
OPERATION ABORTED
DOUT9
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
24 _____________________________________________________________________________________
Table 5. SPI Commands
Table 6. Configuration Register
Note: Modes 2h and 3h are functionally identical.
Table 7. Readback Operations and Formatting
LOCATION FUNCTION DESCRIPTION
DIN[9:7] Mode[2:0]
Sets device operating mode.
000 Mode[0]: Standby 100 Mode[4]: Standby
001 Mode[1]: Bipolar current: Q20mA 101 Mode[5]: Bipolar voltage: Q10V
010 Mode[2]: Unipolar current: 0 to 20mA 110 Mode[6]: Unipolar voltage: 0 to 10V
011 Mode[3]: Unipolar current: 4mA to 20mA 111 Mode[7]: Unipolar voltage: 0 to 5V
DIN[6:4] VBOTH[2:0]
Sets supply voltage brownout threshold for error reporting.
000: Q10V 100: Q18V
001: Q12V 101: Q20V
010: Q14V 110: Q22V
011: Q16V 111: Q24V
DIN[3] Thermal
shutdown 0 = thermal protection off. 1 = thermal protection on.
DIN[10],
DIN[2:0] — Reserved
DOUT BITS DESCRIPTION
COMMAND ADDRESS DIN[13:11] = 101. READBACK DEVICE CONFIGURATION REGISTER
DOUT[9:0] See configuration register details in Table 6.
COMMAND ADDRESS DIN[13:11] = 100. READBACK ERROR REGISTER
DOUT[9] Output intermittent fault. For details, see the Error Handling section.
DOUT[8] Output short circuit. This bit asserts when IOUT > 30mA in voltage and current modes for longer than 260ms.
DOUT[7] Output open load. This bit asserts when VOUT is within 30mV of AVDDO or AVSSO and there is no short-circuit
condition for longer than 260ms.
DOUT[6] Internal overtemperature. This bit asserts when the die temperature exceeds +150NC.
DOUT[5] Supply brownout. This bit asserts when either supply has entered the brownout limits. See Table 6 for details.
DOUT[4:0] Reserved
COMMAND
ADDRESS
DIN[13:11]
NAME DESCRIPTION
000 No-op No operation.
001 Write configuration Write device configuration register. See Table 6 for details.
010 Reserved Reserved, no operation.
011 Reserved Reserved, no operation.
100 Read error Read error register status. See Table 7 for details.
101 Read configuration Read device configuration register. See Table 6 for details.
110 Reserved Reserved, no operation.
111 Reserved Reserved, no operation.
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 25
Since the MAX15500/MAX15501 do not use a continuous
clock signal, the SPI read cycles are used to cycle the
error detection and reporting logic. Continue to poll the
device until the error readback reports an all clear status
when resolving single or multiple errors. See below for
examples of typical error handling situations and the
effects of the SPI read operations.
1) Error resolved by the system.
a) The MAX15500/MAX15501 detect an error condi-
tion and ERROR asserts.
b) The host controller reads the error register for the
first time. This has the effect of resetting ERROR.
The data indicates to the host processor which
error is active.
c) The host processor resolves the error successfully.
d) The host processor reads the error register for the
second time. The data still shows that the error is
present as the error persisted for some time after
step b and before step c. If the error is either an
open load or short circuit, the intermittent bit is set.
An overtemperature or a brownout does not set the
intermittent bit. Reading the register a second time
resets the register.
e) The host reads the error register for a third time.
The data now shows the error is resolved and
future occurrences of this error will trigger ERROR
assertion.
2) Error resolved before the host processor reads error
register.
a) The MAX15500/MAX15501 detect an error condi-
tion and ERROR asserts, but the error resolves
itself.
b) The host controller reads the error register for the
first time resetting ERROR. The data indicates to
the host processor which error is active. The data
also indicates to the host that the error has been
resolved since the intermittent bit is set.
c) The host processor reads the error register for the
second time. The data still shows that the error is
active. If the error is for an output fault, the data
also indicates to the host that the error has been
resolved since the intermittent bit is set. Reading
the register a second time resets the register.
3) An error that cannot be resolved.
a) The MAX15500/MAX15501 detect an error condi-
tion and ERROR asserts.
b) The host controller reads the error register for the
first time and resets ERROR. The data indicates to
the host processor which error is active.
c) The host processor takes action to resolve the
error unsuccessfully.
d) The host processor reads the error register for the
second time. The data still shows that the error is
present.
e) The host processor reads the error for the third
time. The data show the error to be unresolved.
ERROR does not respond to the same error until
the error is resolved and reported. ERROR asserts
if different errors occur.
Applications Information
Setting the Output Gain in Current Mode
In current mode, there is approximately 1.0V across the
current-sensing resistors at full scale. The current sens-
ing resistor sets the gain and is calculated as follows:
RSENSE = VSENSE_FS/IMAX
where VSENSE_FS is the full-scale voltage across the
sense resistor.
See Table 8 for values of VSENSE_FS.
Output Gain in Voltage Mode
The output gain in voltage mode is fixed as shown in
Table 9.
Selection of the Compensation
Capacitor (CCOMP)
Use Table 10 to select the compensation capacitor.
Layout Considerations
In the current-mode application, use Kelvin and a short
connection from SENSERN and SENSERP to the RSENSE
terminals to minimize gain-error drift. Balance and mini-
mize all analog input traces for optimum performance.
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
26 _____________________________________________________________________________________
Table 8. Recommended Current Setting Components
Table 9. Full-Scale Output Voltages
VREFIN
(V)
OVERRANGE
(%)
BIPOLAR/
UNIPOLAR MODE VSENSE_FS
(V)
RSENSE
(I)
IOUT
(mA)
IDEAL
GAIN
IDEAL TRANSFER
FUNCTION
4.096
+20
Unipolar 2 1.02144 42.2 24.205 0.2625/42.2 IOUT = 0.2625 x (VAIN -
0.05 x VREFIN)/42.2
Bipolar 1 Q1.024 42.2 Q24.27 0.5/42.2 IOUT = 0.5 x (VAIN - 0.5 x
VREFIN)/42.2
+5
Unipolar 2 1.02144 48.7 20.97 0.2625/48.7 IOUT = 0.2625 x (VAIN -
0.05 x VREFIN)/48.7
Bipolar 1 Q1.024 48.7 Q21.03 0.5/48.7 IOUT = 0.5 x (VAIN - 0.5 x
VREFIN)/48.7
2.500
+20
Unipolar 2 1.009375 41.2 24.5 0.425/41.2 IOUT = 0.425 x (VAIN -
0.05 x VREFIN)/41.2
Bipolar 1 Q141.2 Q24.27 0.8/41.2 IOUT = 0.8 x (VAIN - 0.5 x
VREFIN)/41.2
+5
Unipolar 2 1.009375 47.5 21.25 0.425/47.5 IOUT = 0.425 x (VAIN -
0.05 x VREFIN)/47.5
Bipolar 1 Q147.5 Q21.05 0.8/47.5 IOUT = 0.8 x (VAIN - 0.5 x
VREFIN)/47.5
VREFIN
(V)
OVERRANGE
(%)
BIPOLAR/
UNIPOLAR MODE IDEAL
GAIN
IDEAL
TRANSFER FUNCTION
IDEAL VOUT
(V)
4.096
+20 Unipolar 7 1.5625 VOUT = 1.5625 x (VAIN - 0.05 x VREFIN) 6.08
6 3.125 VOUT = 3.125 x (VAIN - 0.05 x VREFIN) 12.16
Bipolar 5 6.0 VOUT = 6.0 x (VAIN - 0.5 x VREFIN)Q12.288
+5 Unipolar 7 1.375 VOUT = 1.375 x (VAIN - 0.05 x VREFIN) 5.3504
6 2.75 VOUT = 2.75 x (VAIN - 0.05 x VREFIN) 10.7008
Bipolar 5 5.25 VOUT = 5.25 x (VAIN - 0.5 x VREFIN)Q10.752
2.500
+20 Unipolar 7 2.5125 VOUT = 2.5125 x (VAIN - 0.05 x VREFIN) 5.96719
6 5.0625 VOUT = 5.0625 x (VAIN - 0.05 x VREFIN) 12.0234
Bipolar 5 9.6 VOUT = 9.6 x (VAIN - 0.5 x VREFIN)Q12
+5 Unipolar 7 2.175 VOUT = 2.175 x (VAIN - 0.05 x VREFIN) 5.16563
6 4.425 VOUT = 4.425 x (VAIN - 0.05 x VREFIN) 10.5094
Bipolar 5 8.4 VOUT = 8.4 x (VAIN - 0.5 x VREFIN)Q10.5
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
______________________________________________________________________________________ 27
Table 10. Recommended Compensation Capacitor for Various Load Conditions
Chip Information
PROCESS: BiCMOS
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
CL = Load capacitance.
RL = Load resistance.
LL = Load inductance.
CCOMP = Compensation capacitance.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
32 TQFN-EP T3255+4 21-0140 90-0012
MODE CL (F) RL (kI)LL (H) CCOMP (F)
Voltage 0 to 1n 1 0 0
Voltage 1n to 100n 1 0 1n
Voltage 100n to 1F1 0 2.2n
Voltage 1F to 100F1 0 4.7n
Current 0 to 1n 20 to 750 0 to 20F0
Current 0 to 1n 20 to 750 20F to 1m 2.2n
Current 0 to 1n 20 to 750 1m to 50m 100n
Current 1n to 100n 20 to 750 0 to 20F1n
Current 1n to 100n 20 to 750 20F to 1m 2.2n
Current 1n to 100n 20 to 750 1m to 50m 100n
Current 100n to 1F20 to 750 0 to 20F2.2n
Current 100n to 1F20 to 750 20F to 1m 2.2n
Current 100n to 1F20 to 750 1m to 50m 100n
Current 1F to 100F20 to 750 0 to 20F2.2n
Current 1F to 100F20 to 750 20F to 1m 2.2n
Current 1F to 100F20 to 750 1m to 50m 100n
Industrial Analog Current/
Voltage-Output Conditioners
MAX15500/MAX15501
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time.
28 Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 7/09 Initial release —
1 2/11 Corrected description of DOUT pin in Pin Description section 13
