General Description
The MAX3224E/MAX3225E/MAX3226E/MAX3227E/
MAX3244E/MAX3245E are 3V-powered EIA/TIA-232 and
V.28/V.24 communications interfaces with automatic shut-
down/wakeup features, high data-rate capabilities, and
enhanced electrostatic discharge (ESD) protection. All
transmitter outputs and receiver inputs are protected to
±15kV using IEC 1000-4-2 Air-Gap Discharge, ±8kV using
IEC 1000-4-2 Contact Discharge, and ±15kV using the
Human Body Model.
All devices achieve a 1μA supply current using Maxim’s
revolutionary AutoShutdown Plus™ feature. These devic-
es automatically enter a low-power shutdown mode when
the RS-232 cable is disconnected or the transmitters of
the connected peripherals are inactive, and the UART
driving the transmitter inputs is inactive for more than 30
seconds. They turn on again when they sense a valid
transition at any transmitter or receiver input.
AutoShutdown Plus saves power without changes to the
existing BIOS or operating system.
The MAX3225E/MAX3227E/MAX3245E also fea-
ture MegaBaud™ operation, guaranteeing 1Mbps for
high-speed applications such as communicating with
ISDN modems. The MAX3224E/MAX3226E/MAX3244E
guarantee 250kbps operation. The transceivers have a
proprietary low-dropout transmitter output stage enabling
true RS-232 performance from a +3.0V to +5.5V supply
with a dual charge pump. The charge pump requires only
four small 0.1μF capacitors for operation from a 3.3V
supply. The MAX3224E–MAX3227E feature a logic-level
output (READY) that asserts when the charge pump is
regulating and the device is ready to begin transmitting.
All devices are available in a space-saving TQFN,
SSOP, and TSSOP (MAX3224E/MAX3225E/MAX3244E/
MAX3245E) packages.
Applications
●Notebook, Subnotebook, and Palmtop Computers
●Cellular Phones
●Battery-Powered Equipment
●Hand-Held Equipment
●Peripherals
●Printers
●Automotive
Next Generation Device Features
● For Space-Constrained Applications:
MAX3228E/MAX3229E: ±15kV ESD-Protected,
+2.5V to +5.5V, RS-232 Transceivers in UCSP™
MAX3222E/MAX3232E/MAX3241E/MAX3246E:
±15kV ESD-Protected, Down to 10nA, +3.0V to
+5.5V, Up to 1Mbps, True RS-232 Transceivers
(MAX3246E Available in UCSP)
● For Low-Voltage or Data Cable Applications:
MAX3380E/MAX3381E: +2.35V to +5.5V, 1μA,
2Tx/2Rx RS-232 Transceivers with ±15kV
ESD-Protected I/O and Logic Pins
Ordering Information continued at end of data sheet.
19-1339; Rev 11; 11/18
AutoShutdown Plus, MegaBaud, and UCSP are trademarks of
Maxim Integrated Products, Inc.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
PART TEMP RANGE PIN-PACKAGE
MAX3224ECTP+ 0°C to +70°C 20 TQFN-EP*
MAX3224ECUP+ 0°C to +70°C 20 TSSOP
MAX3224ECAP+ 0°C to +70°C 20 SSOP
MAX3224ECPP+ 0°C to +70°C 20 Plastic DIP
MAX3224EETP+ -40°C to +85°C 20 TQFN-EP*
MAX3224EEUP+ -40°C to +85°C 20 TSSOP
MAX3224EEAP+ -40°C to +85°C 20 SSOP
MAX3224EEPP+ -40°C to +85°C 20 Plastic DIP
MAX3224EAAP+ -40°C to +125°C 20 SSOP
PART
NO. OF
DRIVERS/
RECEIVERS
GUARANTEED
DATA RATE
(bps)
READY
OUTPUT
Auto-
Shutdown
Plus
MAX3224E 2/2 250k ü ü
MAX3225E 2/2 1M ü ü
MAX3226E 1/1 250k ü ü
MAX3227E 1/1 1M ü ü
MAX3244E 3/5 250k — ü
MAX3245E 3/5 1M — ü
Ordering Information
Selector Guide
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Click here for production status of specific part numbers.
VCC to GND ............................................................-0.3V to +6V
V+ to GND (Note 1) ................................................. -0.3V to +7V
V- to GND (Note 1) .................................................. +0.3V to -7V
V+ +│V-│(Note 1) ................................................................+13V
Input Voltages
T_IN, FORCEON, FORCEOFF to GND .............. -0.3V to +6V
R_IN to GND ...................................................................±25V
Output Voltages
T_OUT to GND .............................................................±13.2V
R_OUT, INVALID, READY to GND ...... -0.3V to (VCC + 0.3V)
Short-Circuit Duration
T_OUT to GND ...................................................... Continuous
Continuous Power Dissipation (TA = +70°C)
16-Pin SSOP (derate 7.10mW/°C above +70°C) .....571.4mW
16-Pin TSSOP (derate 9.4 mW/°C above +70°C) .... 754.7mW
16-Pin TQFN (derate 20.8mW/°C above +70°C) ...1666.7mW
20-Pin TQFN (derate 21.3mW/°C above +70°C) ....1702.1mW
20-Pin Plastic DIP
(derate 11.11mW/°C above +70°C) ............................889mW
20-Pin SSOP (derate 8.00mW/°C above +70°C) ........640mW
20-Pin TSSOP (derate 11mW/°C above +70°C) .....879.1 mW
28-Pin Wide SO (derate 12.5mW/°C above +70°C) ..........1W
28-Pin SSOP (derate 9.1mW/°C above +70°C) .......727.3mW
28-Pin TSSOP (derate 14mW/°C above +70°C) .... 1025.6mW
36-Pin TQFN (derate 26.3mW/°C above +70°C) ..... 2105.3mW
Operating Temperature Ranges
MAX32_ _EC_ _ .................................................0°C to +70°C
MAX32_ _EE_ _ ............................................. -40°C to +85°C
MAX32_ _EAA_ ............................................ -40°C to +125°C
Storage Temperature Range ............................ -65°C to +160°C
Lead Temperature (soldering, 10s) ................................. +300°C
Soldering Temperature (reflow) ....................................... +260°C
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
16-SSOP
16-TSSOP
PACKAGE CODE A16+2
Outline Number 21-0056
Land Pattern Number 90-0106
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 140
Junction to Case (θJC) 34
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 86
Junction to Case (θJC) 33
PACKAGE CODE U16+1
Outline Number 21-0066
Land Pattern Number 90-0117
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 106
Junction to Case (θJC) 27
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 90
Junction to Case (θJC) 27
Absolute Maximum Ratings
Package Information
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.
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
2
16-TQFN-EP
20-SSOP
20-DIP
PACKAGE CODE T1655+2
Outline Number 21-0140
Land Pattern Number 90-0072
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 48
Junction to Case (θJC) 2
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 30
Junction to Case (θJC) 2
PACKAGE CODE A20+1
Outline Number 21-0056
Land Pattern Number 90-0094
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 125
Junction to Case (θJC) 32
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 84
Junction to Case (θJC) 33
PACKAGE CODE P20+3
Outline Number 21-0043
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 90
Junction to Case (θJC) 30
Package Information (continued)
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
3
20-TQFN-EP
28-WIDE SO
20-TSSOP
PACKAGE CODE T2055+5
Outline Number 21-0140
Land Pattern Number 90-0010
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 47
Junction to Case (θJC) 2
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 29
Junction to Case (θJC) 2
PACKAGE CODE W28+6
Outline Number 21-0042
Land Pattern Number 90-0109
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 80
Junction to Case (θJC) 18
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 59
Junction to Case (θJC) 18
PACKAGE CODE U20+2
Outline Number 21-0066
Land Pattern Number 90-0116
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 91
Junction to Case (θJC) 20
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 73.8
Junction to Case (θJC) 20
Package Information (continued)
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
4
28-TSSOP
36-TQFN
28-SSOP
PACKAGE CODE U28+2
Outline Number 21-0066
Land Pattern Number 90-0171
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 78
Junction to Case (θJC) 13
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 71.6
Junction to Case (θJC) 13
PACKAGE CODE T3666+3
Outline Number 21-0141
Land Pattern Number 90-0050
Thermal Resistance, Single layer board:
Junction to Ambient (θJA) 38
Junction to Case (θJC) 1
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 28
Junction to Case (θJC) 1
PACKAGE CODE A28+1
Outline Number 21-0056
Land Pattern Number 90-0095
Thermal Resistance, Single layer board:
Junction to Ambient (θJA)110
Junction to Case (θJC) 25
Thermal Resistance, Four-layer board:
Junction to Ambient (θJA) 67.1
Junction to Case (θJC) 25
Package Information (continued)
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.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.
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
5
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
DC CHARACTERISTICS (VCC = 3.3V or 5.0V, TA = +25°C)
Supply Current,
AutoShutdown Plus
FORCEON = GND, FORCEOFF = VCC,
all R_IN idle, all T_IN idle 1 10 μA
Supply Current, Shutdown FORCEOFF = GND 1 10 μA
Supply Current,
AutoShutdown Plus Disabled FORCEON = FORCEOFF = VCC, no load 0.3 1 mA
LOGIC INPUTS AND RECEIVER OUTPUTS
Input Logic Threshold Low T_IN, FORCEON, FORCEOFF 0.8 V
Input Logic Threshold High T_IN, FORCEON,
FORCEOFF
VCC = 3.3V 2 V
VCC = 5.0V 2.4
Transmitter Input Hysteresis 0.5 V
Input Leakage Current T_IN, FORCEON, FORCEOFF ±0.01 ±1 μA
Output Leakage Current R_OUT (MAX3244E/MAX3245E),
receivers disabled ±0.05 ±10 μA
Output Voltage Low IOUT = 1.6mA 0.4 V
Output Voltage High IOUT = -1.0mA VCC
- 0.6
VCC
- 0.1 V
RECEIVER INPUTS
Input Voltage Range -25 +25 V
Input Threshold Low TA = +25°C VCC = 3.3V 0.6 1.2 V
VCC = 5.0V 0.8 1.5
Input Threshold High TA = +25°C VCC = 3.3V 1.5 2.4 V
VCC = 5.0V 1.8 2.4
Input Hysteresis 0.5 V
Input Resistance TA = +25°C 3 5 7 kΩ
TRANSMITTER OUTPUTS
Output Voltage Swing All transmitter outputs loaded with 3kΩ
to ground ±5 ±5.4 V
Output Resistance
VCC = V+ = V- = 0V, transmitter outputs = ±2V
300 10M Ω
Output Short-Circuit Current ±60 mA
Output Leakage Current VCC = 0V or 3V to 5.5V, VOUT = ±12V,
Transmitters disabled ±25 µA
Electrical Characteristics
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
6
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MOUSE DRIVEABILITY (MAX3244E/MAX3245E)
Transmitter Output Voltage
T1IN = T2IN = GND, T3IN = VCC,
T3OUT loaded with 3kΩ to GND,
T1OUT and T2OUT loaded with
2.5mA each
±5 V
ESD PROTECTION
R_IN, T_OUT
IEC 1000-4-2 Air Discharge ±15
kVIEC 1000-4-2 Contact Discharge ±8
Human Body Model ±15
AutoShutdown Plus (FORCEON = GND, FORCEOFF = VCC)
Receiver Input Threshold to
INVALID Output High Figure 4a Positive threshold 2.7 V
Negative threshold -2.7
Receiver Input Threshold to
INVALID Output Low Figure 4a -0.3 +0.3 V
INVALID, READY
Output Voltage Low
(MAX3224E–MAX3227E)
IOUT = -1.6mA 0.4 V
INVALID, READY
Output Voltage Low
(MAX3224E–MAX3227E)
IOUT = -1.0mA VCC - 0.6 V
Receiver Positive or Negative
Threshold to INVALID High tINVH VCC = 5V, Figure 4b 1μs
Receiver Positive or Negative
Threshold to INVALID Low tINVL VCC = 5V, Figure 4b 30 μs
Receiver or Transmitter Edge
to Transmitters Enabled tWU VCC = 5V, Figure 5b (Note 2) 100 μs
Receiver or Transmitter Edge
to Transmitters Shutdown
tAUTOSHDN
VCC = 5V, Figure 5b (Note 2) 15 30 60 s
Electrical Characteristics (continued)
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
7
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
(VCC = +3V to +5.5V, C1–C4 = 0.1μF, tested at 3.3V ±10%; C1 = 0.047μF, C2–C4 = 0.33μF, tested at 5.0V ±10%; TA = TMIN to TMAX,
unless otherwise noted. Typical values are at TA = +25°C.)
Note 2: A transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic thresholds.
Note 3: Transmitter skew is measured at the transmitter zero cross points.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Maximum Data Rate RL = 3kΩ, CL = 1000pF,
one transmitter switching 250 kbps
Receiver Propagation Delay tPHL R_IN to R_OUT, CL = 150pF 0.15 μs
tPLH 0.15
Receiver Output Enable Time Normal operation (MAX3244E only) 200 ns
Receiver Output Disable Time Normal operation (MAX3244E only) 200 ns
Transmitter Skew │tPHL - tPLH│ (Note 3) 100 ns
Receiver Skew │tPHL - tPLH│50 ns
Transition-Region Slew Rate
VCC = 3.3V, TA = +25°C,
RL = 3kΩ to 7kΩ,
measured from +3V to -3V
or -3V to +3V, one
transmitter switching
CL = 150pF
to 1000pF 6 30 V/μs
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Maximum Data Rate
RL = 3kΩ, CL = 1000pF,
one transmitter switching 250
kbps
VCC = 3.0V to 4.5V, RL = 3kΩ,
CL = 250pF, one transmitter switching 1000
VCC = 4.5V to 5.5V, RL = 3kΩ,
CL = 1000pF, one transmitter switching 1000
Receiver Propagation Delay tPHL R_IN to R_OUT, CL = 150pF 0.15 μs
tPLH 0.15
Receiver Output Enable Time Normal operation (MAX3245E only) 200 ns
Receiver Output Disable Time Normal operation (MAX3245E only) 200 ns
Transmitter Skew │tPHL - tPLH│ (Note 3) 25 ns
Receiver Skew │tPHL - tPLH│50 ns
Transition-Region Slew Rate
VCC = 3.3V, TA = +25°C,
RL = 3kΩ to 7kΩ, CL = 150pF to 1000pF,
measured from +3V to -3V or -3V to +3V,
one transmitter switching
24 150 V/μs
Timing Characteristics—MAX3224E/MAX3226E/MAX3244E
Timing Characteristics—MAX3225E/MAX3227E/MAX3245E
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
8
(VCC = +3.3V, 250kbps data rate, 0.1μF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
0 1000 2000 3000 4000 5000
MAX3224E/MAX3226E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-01
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
T1 TRANSMITTING AT 250kbps
T2 (MAX3224E) TRANSMITTING AT 15.6kbps
VOUT+
VOUT-
-7.5
0
-2.5
-5.0
2.5
5.0
7.5
0 1000500 1500 2000 2500
MAX3225E/MAX3227E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-04
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
2Mbps
2Mbps
1.5Mbps
1.5Mbps
1Mbps
1Mbps
1 TRANSMITTER AT FULL DATA RATE
1 TRANSMITTER AT 1/16 DATA RATE
(MAX3225E)
LOAD = 3kΩ + CL
0
15
10
5
20
25
30
35
40
45
50
0 1000500 1500 2000 2500
3000
MAX3225E/MAX3227E
TRANSMITTER SKEW
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-07
LOAD CAPACITANCE (pF)
TRANSMITTER SKEW (ns)
AVERAGE: 10 PARTS
1 TRANSMITTER AT 512kbps
1 TRANSMITTER AT 30kbps
(MAX3225E)
LOAD = 3kΩ + CL
0
2
4
6
8
10
12
14
16
0 1000 2000 3000 4000 5000
MAX3224E/MAX3226E
SLEW RATE vs. LOAD CAPACITANCE
MAX3224-7/44/45E-02
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
-SLEW
+SLEW
FOR DATA RATES UP TO 250kbps
0
80
70
60
50
40
30
20
10
0 500 1000 1500 2000 2500
MAX3225E/MAX3227E
SLEW RATE vs. LOAD CAPACITANCE
MAX3224-7/44/45E-05
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
1 TRANSMITTER AT 1Mbps
1 TRANSMITTER AT 62.5kbps (MAX3225E)
-SLEW
+SLEW
20
24
22
30
28
26
36
34
32
38
-40 0 20-20 40 60 80 100
MAX3224E–MAX3227E
READY TURN-ON TIME
vs. TEMPERATURE
MAX3224-7/44/45E-08
TEMPERATURE (°C)
READY TURN-ON TIME (µs)
0
5
10
15
20
25
30
35
40
45
0 20001000 3000 4000 5000
MAX3224E/MAX3226E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-03
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
250kbps
120kbps
20kbps
T1 TRANSMITTING AT 250kbps
T2 (MAX3224E) TRANSMITTING AT 15.6kbps
0
20
10
40
30
60
50
70
90
80
100
0 500 1000 1500 2000 2500
MAX3225E/MAX3227E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-06
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
2Mbps
1.5Mbps
1Mbps
1 TRANSMITTER AT FULL DATA RATE
1 TRANSMITTER AT 1/16 DATA RATE
(MAX3225E)
LOAD = 3kΩ + CL
0
200
180
160
140
120
100
80
60
40
20
-40 0 20-20 40 60 80 100
MAX3224E–MAX3227E
READY TURN-OFF TIME
vs. TEMPERATURE
MAX3224-7/44/45E-09
TEMPERATURE (°C)
READY TURN-OFF TIME (ns)
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Maxim Integrated
│
9
www.maximintegrated.com
(VCC = +3.3V, 250kbps data rate, 0.1μF capacitors, all transmitters loaded with 3kΩ and CL, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
0 1000 2000 3000 4000 5000
MAX3244E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-10
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
VOUT+
VOUT-
-7.5
0
-2.5
-5.0
2.5
5.0
7.5
0 800400 1200 1600 2000
MAX3245E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-13
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
2Mbps
2Mbps
1.5Mbps
1.5Mbps
1Mbps
1Mbps
1 TRANSMITTER AT FULL DATA RATE
2 TRANSMITTERS AT 1/16 DATA RATE
0
20
10
40
30
60
50
70
0 400 800 1200 1600 2000
MAX3245E
SLEW RATE vs. LOAD CAPACITANCE
MAX3224-7/44/45E-14
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
1 TRANSMITTER AT 1Mbps
2 TRANSMITTERS AT 62.5kbps
0
20
10
40
30
60
50
70
90
80
100
0 400 800 1200 1600 2000
MAX3245E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-15
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
2Mbps
1.5Mbps
1Mbps
1 TRANSMITTER AT FULL DATA RATE
2 TRANSMITTERS AT 1/16 DATA RATE
0
15
10
5
20
25
30
35
40
45
50
0 1000 2000 3000
MAX3245E
TRANSMITTER SKEW
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-16
LOAD CAPACITANCE (pF)
TRANSMITTER SKEW (ns)
0
4
2
8
6
12
10
14
0 1000 2000 3000 4000 5000
MAX3244E
SLEW RATE vs. LOAD CAPACITANCE
MAX3224-7/44/45E-11
LOAD CAPACITANCE (pF)
SLEW RATE (V/µs)
0
30
20
10
40
50
60
0 20001000 3000 4000 5000
MAX3244E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3224-7/44/45E-12
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
250kbps
120kbps
20kbps
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
Maxim Integrated
│
10
www.maximintegrated.com
PIN
NAME FUNCTION
MAX3224E
MAX3225E
MAX3226E
MAX3227E MAX3244E
MAX3245E
SO/ SSOP/ TSSOP
MAX3245E
TQFN
TQFN
DIP/
SSOP/
TSSOP
TQFN SSOP/
TSSOP
19 1 14 1 — — READY
Ready to Transmit Output,
active-high. READY is enabled
high when V- goes below
-4V and the device is ready
to transmit.
1 2 16 2 28 31 C1+
Positive Terminal of
Voltage-Doubler Charge-Pump
Capacitor
20 3 15 3 27 30 V+ +5.5V generated by the charge
pump
2 4 1 4 24 26 C1-
Negative Terminal of
Voltage-Doubler Charge-Pump
Capacitor
3 5 2 5 1 33 C2+ Positive Terminal of Inverting
Charge-Pump Capacitor
4 6 3 6 2 34 C2- Negative Terminal of Inverting
Charge-Pump Capacitor
5 7 4 7 3 35 V- -5.5V Generated by the Charge
Pump
6, 15 8, 17 10 13 9, 10, 11 7, 8, 9 T_OUT RS-232 Transmitter Outputs
7, 14 9, 16 5 8 4-8 1-5 R_IN RS-232 Receiver Inputs
8, 13 10, 15 6 9 15-19 15, 16, 17,
19, 20 R_OUT TTL/CMOS Receiver Outputs
911 7 10 21 23 INVALID
Valid Signal Detector Output,
active low. A logic high indicates
that a valid RS-232 level is
present on a receiver input.
10, 11 12, 13 8 11 12-14 11, 12, 13 T_IN TTL/CMOS Transmitter Inputs
12 14 9 12 23 25 FORCEON
Force-On Input, Active-
High. Drive high to override
AutoShutdown Plus, keeping
transmitters and receivers on
(FORCEOFF must be high)
(Table 1).
Pin Description
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
11
Detailed Description
Dual Charge-Pump Voltage Converter
The MAX3224E–MAX3227E/MAX3244E/MAX3245E’s
internal power supply consists of a regulated dual charge
pump that provides output voltages of +5.5V (doubling
charge pump) and -5.5V (inverting charge pump), over
the +3.0V to +5.5V range. The charge pump operates in
discontinuous mode: if the output voltages are less than
5.5V, the charge pump is enabled; if the output voltages
exceed 5.5V, the charge-pump is disabled. Each charge
pump requires a flying capacitor (C1, C2) and a reservoir
capacitor (C3, C4) to generate the V+ and V- supplies.
The READY output (MAX3224E–MAX3227E) is low when
the charge pumps are disabled in shutdown mode. The
READY signal asserts high when V- goes below -4V.
PIN
NAME FUNCTION
MAX3224E
MAX3225E
MAX3226E
MAX3227E MAX3244E
MAX3245E
SO/ SSOP/ TSSOP
MAX3245E
TQFN
TQFN
DIP/
SSOP/
TSSOP
TQFN SSOP/
TSSOP
16 18 11 14 25 27 GND Ground
17 19 12 15 26 29 VCC
+3.0V to +5.5V Single Supply
Voltage
18 20 13 16 22 24 FORCEOFF
Force-O󰀨 Input, Active-Low.
MAX3225E, MAX3227E:
When Force-O󰀨 input is
low, transmitters are in high
impedance, charge pumps are
shutdown, and receivers are
active.
MAX3244E, MAX3245E:
When Force-O󰀨 input is low,
transmitters and receivers are
in high impedance, charge
pumps are shutdown, and only
R2OUTB is active. Force-O󰀨
overrides AutoShutdown Plus
and FORCEON (Table 1).
— — — — 20 21 R2OUTB
TTL/CMOS Noninverting
Complementary Receiver
Outputs. Always active.
— — — — — 6, 10, 14, 18,
22, 28, 32, 36 N.C. No Connection. Not internally
connected.
— — — — — — EP
Exposed Pad. Solder the
exposed pad to the ground
plane or leave unconnected.
Pin Description (continued)
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
12
LapLink is a registered trademark of Laplink Software, Inc.
RS-232 Transmitters
The transmitters are inverting level translators that con-
vert CMOS-logic levels to 5.0V EIA/TIA-232 levels. The
MAX3224E/MAX3226E/MAX3244E guarantee a 250kbps
data rate (1Mbps, for the MAX3225E/MAX3227E/
MAX3245E) with worst-case loads of 3kΩ in parallel with
1000pF, providing compatibility with PC-to-PC communi-
cation software (such as LapLink®). Transmitters can be
paralleled to drive multiple receivers. Figure 1 shows a
complete system connection.
When FORCEOFF is driven to ground or when the Auto-
Shutdown Plus circuitry senses that all receiver and
transmitter inputs are inactive for more than 30s, the
transmitters are disabled and the outputs go into a high-
impedance state. When powered off or shut down, the
outputs can be driven to ±12V. The transmitter inputs do
not have pullup resistors. Connect unused inputs to GND
or VCC.
Figure 1. Interface Under Control of PMU
Figure 2. The MAX3244E/MAX3245E detect RS-232 activity
when the UART and interface are shut down.
MAX3244E
MAX3245E
T1OUT
R2OUTB
Tx
5kΩ
UART
VCC
T1IN
THREE-STATED
LOGIC
TRANSITION
DETECTOR
R2IN
PROTECTION
DIODE
R2OUT
FORCEOFF = GND
VCC
TO
µP
Rx
PREVIOUS
RS-232
Tx
UART
SHDN = GND
VCC
VCC
GND
Rx
5kΩ
a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM ACTIVE
RECEIVER OUTPUT IN SHUTDOWN.
b) NEW MAX3244E/MAX3245E: IN SHUTDOWN, R2OUTB IS USED TO MONITOR
EXTERNAL DEVICES AND R2OUT IS THREE STATED, ELIMINATING A
CURRENT PATH THROUGH THE UART'S PROTECTION DIODE.
GND
PROTECTION
DIODE
I
I
MAX3244E
MAX3245E
I/O
CHIP
WITH
UART
CPU
RS-232
POWER-
MANAGEMENT
UNIT OR
KEYBOARD
CONTROLLER
FORCEOFF
FORCEON
INVALID
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
13
RS-232 Receivers
The receivers convert RS-232 signals to CMOS-logic
output levels. The MAX3224E–MAX3227E feature
inverting outputs that always remain active (Table 1). The
MAX3244E/MAX3245E have inverting three-state outputs
that are high impedance when shut down (FORCEOFF =
GND) (Table 1).
The MAX3244E/MAX3245E feature an extra, always
active, noninverting output, R2OUTB. R2OUTB output
monitors receiver activity while the other receivers are
high impedance, allowing ring indicator applications
to be monitored without forward biasing other devices
connected to the receiver outputs. This is ideal for
systems where VCC is set to ground in shutdown to
accommodate peripherals such as UARTs (Figure 2).
The MAX3224E–MAX3227E/MAX3244E/MAX3245E
feature an INVALID output that is enabled low when no
valid RS-232 voltage levels have been detected on all
receiver inputs. Because INVALID indicates the receiver
input’s condition, it is independent of FORCEON and
FORCEOFF states (Figures 3 and 4).
AutoShutdown Plus Mode
The MAX3224E–MAX3227E/MAX3244E/MAX3245E
achieve a 1μA supply current with Maxim’s AutoShutdown
Plus feature, which operates when FORCEOFF is high
and a FORCEON is low. When these devices do not
sense a valid signal transition on any receiver and trans-
mitter input for 30s, the on-board charge pumps are
shut down, reducing supply current to 1μA. This occurs
if the RS-232 cable is disconnected or if the connected
Table 1. Output Control Truth Table
X = Don’t care
* INVALID connected to FORCEON
** INVALID connected to FORCEON and FORCEOFF
OPERATION
STATUS FORCEON FORCEOFF
VALID
RECEIVER
LEVEL
RECEIVER OR
TRANSMITTER
EDGE WITHIN
30s
T_OUT
R_OUT
(MAX3224E/
MAX3225E/
MAX3226E/
MAX3227E)
R_OUT
(MAX3244E/
MAX3245E)
R2OUTB
(MAX3244E/
MAX3245E)
Shutdown
(Forced O󰀨) X 0 X X High-Z Active High-Z Active
Normal
Operation
(Forced On)
1 1 X X Active Active Active Active
Normal
Operation
(AutoShutdown
Plus)
0 1 X Yes Active Active Active Active
Shutdown (Auto-
Shutdown Plus) 0 1 X No High-Z Active Active Active
Normal
Operation INVALID*1Ye s X Active Active Active Active
Normal
Operation INVALID* 1 X Ye s Active Active Active Active
Shutdown INVALID*1 No No High-Z Active Active Active
Normal
Operation
(AutoShutdown)
INVALID* INVALID** Yes X Active Active Active Active
Shutdown
(AutoShutdown) INVALID* INVALID** No X High-Z Active High-Z Active
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
14
peripheral transmitters are turned off, and the UART
driving the transmitter inputs is inactive. The system turns
on again when a valid transition is applied to any RS-232
receiver or transmitter input. As a result, the system saves
power without changes to the existing BIOS or operating
system.
Figures 3a and 3b depict valid and invalid RS-232
receiver voltage levels. INVALID indicates the receiver
input’s condition, and is independent of FORCEON and
FORCEOFF states. Figure 3 and Tables 1 and 2 summa-
rize the operating modes of the MAX3224E–MAX3227E/
MAX3244E/MAX3245E. FORCEON and FORCEOFF
override AutoShutdown Plus circuitry. When neither
control is asserted, the IC selects between these states
automatically based on the last receiver or transmitter
input edge received.
When shut down, the device’s charge pumps turn off, V+
is pulled to VCC, V- is pulled to ground, the transmitter
outputs are high impedance, and READY (MAX3224E–
MAX3227E) is driven low. The time required to exit shut-
down is typically 100μs (Figure 8).
By connecting FORCEON to INVALID, the MAX3224E–
MAX3227E/MAX3244E/MAX3245E shut down when no
valid receiver level and no receiver or transmitter edge is
detected for 30s, and wake up when a valid receiver level
or receiver or transmitter edge is detected.
Table 2. INVALID Truth Table
Figure 3a. INVALID Functional Diagram, INVALID Low
Figure 3b. INVALID Functional Diagram, INVALID High
Figure 3c. AutoShutdown Plus Logic
Figure 3d. Power-Down Logic
Figure 4a. Receiver Positive/Negative Thresholds for INVALID
RS-232 SIGNAL
PRESENT AT ANY
RECEIVER INPUT
INVALID OUTPUT
Yes High
No Low
+0.3V
-0.3V
INVALID
R_IN
INVALID ASSERTED IF ALL RECEIVER INPUTS ARE BETWEEN +0.3V AND -0.3V FOR
AT LEAST 30µs.
30µs
TIMER
R
AUTOSHDN
R_IN
T_IN
R
S
30s
TIMER
EDGE
DETECT
EDGE
DETECT
FORCEOFF
FORCEON
+2.7V
-2.7V
INVALID
R_IN
INVALID DEASSERTED IF ANY RECEIVER INPUT HAS BEEN BETWEEN +2.7V AND -2.7V
FOR LESS THAN 30µs.
30µs
TIMER
R
POWERDOWN*
AUTOSHDN
FORCEOFF
FORCEON
* POWERDOWN IS ONLY AN INTERNAL SIGNAL.
IT CONTROLS THE OPERATIONAL STATUS OF
THE TRANSMITTERS AND THE POWER SUPPLIES.
RECEIVER INPUT LEVELS
-2.7V
-0.3V
+2.7V
+0.3V
0
INDETERMINATE
INVALID HIGH
INVALID LOW
INVALID HIGH
INDETERMINATE
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
15
By connecting FORCEON and FORCEOFF to INVALID,
the MAX3224E–MAX3227E/MAX3244E/MAX3245E shut
down when no valid receiver level is detected and wake
up when a valid receiver level is detected (same function-
ality as AutoShutdown feature on MAX3221E/MAX3223E/
MAX3243E).
A mouse or other system with AutoShutdown Plus may
need time to wake up. Figure 5 shows a circuit that
forces the transmitters on for 100ms, allowing enough
time for the other system to realize that the MAX3244E/
MAX3245E is awake. If the other system outputs valid
RS-232 signal transitions within that time, the RS-232
ports on both systems remain enabled.
Software-Controlled Shutdown
If direct software control is desired, use INVALID to indi-
cate DTR or ring indicator signal. Tie FORCEOFF and
FORCEON together to bypass the AutoShutdown Plus so
the line acts like a SHDN input.
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures are
incorporated on all pins to protect against electrostatic
discharges encountered during handling and assembly.
The driver outputs and receiver inputs of the MAX3224E–
MAX3227E/MAX3244E/MAX3245E have extra pro-
tection against static electricity. Maxim’s engineers
have developed state-of-the-art structures to protect
Figure 4b. AutoShutdown Plus, INVALID, and READY Timing Diagram
Figure 5. AutoShutdown Plus Initial Turn-On to Wake Up a
Mouse or Another System
VCC
0
0
V+
V-
VCC
0
INVALID
OUTPUT
READY
TRANSMITTER
INPUTS
RECEIVER
INPUTS }INVALID
REGION
*MAX3224E–MAX3227E
TRANSMITTER
OUTPUTS
*VCC
tAUTOSHDN tWU tWU
tINVL tINVH tAUTOSHDN
FORCEON
MASTER SHDN LINE
0.1µF 1MΩ
FORCEOFF
MAX3224E
MAX3225E
MAX3226E
MAX3227E
MAX3244E
MAX3245E
POWER-
MANAGEMENT
UNIT
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
16
these pins against ESD of ±15kV without damage. The
ESD structures withstand high ESD in all states: normal
operation, shutdown, and powered down. After an ESD
event, Maxim’s E versions keep working without latchup,
whereas competing RS-232 products can latch and must
be powered down to remove latchup.
ESD protection can be tested in various ways; the
transmitter outputs and receiver inputs of this product
family are characterized for protection to the following
limits:
1) ±15kV using the Human Body Model
2) ±8kV using the Contact-Discharge Method specied
in IEC 1000-4-2
3) ±15kV using IEC 1000-4-2’s Air-Gap Method.
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
Human Body Model
Figure 6a shows the Human Body Model and Figure
6b shows the current waveform it generates when
discharged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
1.5kΩ resistor.
Figure 6a. Human Body ESD Test Model
Figure 6b. Human Body Current Waveform
Figure 7a. IEC 1000-4-2 ESD Test Model
Figure 7b. IEC 1000-4-2 ESD Generator Current Waveform
CHARGE-CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
100pF
RC 1MΩRD 1500Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
IP 100%
90%
36.8%
tRL TIME
tDL
CURRENT WAVEFORM
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
Ir
10%
0
0
AMPERES
CHARGE CURRENT
LIMIT RESISTOR
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Cs
150pF
RC 50MΩ to 100MΩRD 330Ω
HIGH-
VOLTAGE
DC
SOURCE
DEVICE
UNDER
TEST
tr = 0.7ns to 1ns
30ns
60ns
t
100%
90%
10%
IPEAK
I
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
17
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and
performance of finished equipment; it does not specifically
refer to integrated circuits. The MAX3224E–MAX3227E,
MAX3244E/MAX3245E help you design equipment that
meets Level 4 (the highest level) of IEC 1000-4-2, without
the need for additional ESD-protection components.
The major difference between tests done using the
Human Body Model and IEC 1000-4-2 is higher peak
current in IEC 1000-4-2, because series resistance is
lower in the IEC 1000-4-2 model. Hence, the ESD with-
stand voltage measured to IEC 1000-4-2 is generally
lower than that measured using the Human Body Model.
Figure 7a shows the IEC 1000-4-2 model and Figure 7b
shows the current waveform for the 8kV, IEC 1000-4-2,
Level 4, ESD Contact-Discharge Method.
The Air-Gap Method involves approaching the device
with a charged probe. The Contact-Discharge Method
connects the probe to the device before the probe is
energized.
Machine Model
The Machine Model for ESD tests all pins using a 200pF
storage capacitor and zero discharge resistance. Its
objective is to emulate the stress caused by contact that
occurs with handling and assembly during manufacturing.
Of course, all pins require this protection during manu-
facturing, not just RS-232 inputs and outputs. Therefore,
after PC board assembly, the Machine Model is less
relevant to I/O ports.
Applications Information
Capacitor Selection
The capacitor type used for C1–C4 is not critical for
proper operation; polarized or nonpolarized capacitors
can be used. The charge pump requires 0.1μF capaci-
tors for 3.3V operation. For other supply voltages,
see Table 3 for required capacitor values. Do not use
values smaller than those listed in Table 3. Increasing
the capacitor values (e.g., by a factor of 2) reduces ripple
on the transmitter outputs and slightly reduces power
consumption. C2, C3, and C4 can be increased without
changing C1’s value. However, do not increase C1
without also increasing the values of C2, C3, C4, and
CBYPASS, to maintain the proper ratios (C1 to the other
capacitors).
When using the minimum required capacitor values,
make sure the capacitor value does not degrade exces-
sively with temperature. If in doubt, use capacitors with
a larger nominal value. The capacitor’s equivalent series
resistance (ESR), which usually rises at low tempera-
tures, influences the amount of ripple on V+ and V-.
Power-Supply Decoupling
In most circumstances, a 0.1μF VCC bypass capacitor
is adequate. In applications that are sensitive to power-
supply noise, use a capacitor of the same value as
charge-pump capacitor C1. Connect bypass capacitors
as close to the IC as possible.
Transmitter Outputs
when Exiting Shutdown
Figure 8 shows two transmitter outputs when exiting
shutdown mode. As they become active, the two transmit-
ter outputs are shown going to opposite RS-232 levels
(one transmitter input is high, the other is low). Each
Table 3. Required Minimum Capacitance
Values
Figure 8. Transmitter Outputs when Exiting Shutdown or
Powering Up
VCC
(V)
C1, CBYPASS
(μF)
C2, C3, C4
(μF)
3.0 to 3.6 0.22 0.22
3.15 to 3.6 0.1 0.1
4.5 to 5.5 0.047 0.33
3.0 to 5.5 0.22 1
5µs/div
T1OUT
FORCEON = FORCEOFF
T2OUT
READY
5V/div
0
2V/div
0
5V/div
0
VCC = 3.3V
C1–C4 = 0.1µF
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
18
transmitter is loaded with 3kΩ in parallel with 1000pF.
The transmitter outputs display no ringing or undesirable
transients as they come out of shutdown. Note that the
transmitters are enabled only when the magnitude of
V- exceeds approximately -3V.
High Data Rates
The MAX3224E/MAX3226E/MAX3244E maintain the
RS-232 ±5.0V minimum transmitter output voltage even
at high data rates. Figure 9 shows a transmitter loop-
back test circuit. Figure 10 shows a loop-back test result at
120kbps, and Figure 11 shows the same test at 250kbps.
For Figure 10, all transmitters were driven simultaneously
at 120kbps into RS-232 loads in parallel with 1000pF. For
Figure 11, a single transmitter was driven at 250kbps, and
all transmitters were loaded with an RS-232 receiver in
parallel with 250pF.
The MAX3225E/MAX3227E/MAX3245E maintain the
RS-232 ±5.0V minimum transmitter output voltage at data
rates up to 1Mbps (MegaBaud). Figure 12 shows a loop-
back test result with a single transmitter driven at 1Mbps
and all transmitters loaded with an RS-232 receiver in
parallel with 250pF.
Figure 10. MAX3224E/MAX3226E/MAX3244E Loopback Test
Result at 120kbps
Figure 9. Loopback Test Circuit
Figure 11. MAX3224E/MAX3226E/MAX3244E Loopback Test
Result at 250kbps
Figure 12. MAX3225E/MAX3227E/MAX3245E Loopback Test
Result at 1Mbps
2µs/div
T1IN
T1OUT
R1OUT
5V/div
5V/div
5V/div
VCC = 3.3V
2µs/div
T1IN
T1OUT
R1OUT
5V/div
5V/div
5V/div
VCC = 3.3V
MAX3224E
MAX3225E
MAX3226E
MAX3227E
MAX3244E
MAX3245E
5kΩ
R_ IN
R_ OUT
FORCEON
C2-
C2+
C1-
C1+
V-
V+
VCC
C4
C3*
C1
C2
CBYPASS
VCC
FORCEOFF
*C3 CAN BE RETURNED TO VCC OR GND.
T_ OUT
T_ IN
GND
VCC
1000pF
200ns/div
T1IN
T1OUT
R1OUT
5V/div
5V/div
5V/div
VCC = 3.3V
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
19
Figure 13a. Mouse Driver Test Circuit
+V
COMPUTER SERIAL PORT
+V
-V
GND
Tx
SERIAL
MOUSE
MAX3244E
MAX3245E
FORCEOFF
23
R5OUT
15
R4OUT
16
R3OUT
17
R2OUT
18
R1OUT
19
R2OUTB
20
LOGIC
OUTPUTS
5kΩ
5kΩ
5kΩ
5kΩ
5kΩ
R5IN 8
R4IN 7
R3IN 6
R2IN 5
R1IN 4
RS-232
INPUTS
GND
25
LOGIC
INPUTS
T3IN
12
T2IN
13
T1IN
14
C2-
2
C2+
1
C1-
24
C1+
28
T3OUT 11
T2OUT 10
T1OUT 9
V-
3
V+
27
VCC
VCC
C4
0.1µF
C3
0.1µF
0.1µF 26
C1
0.1µF
C2
0.1µF
FORCEON
INVALID
22
21
TO POWER-
MANAGEMENT
UNIT
+3.3V
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
20
Mouse Driveability
The MAX3244E/MAX3245E are specifically designed
to power serial mice while operating from low-voltage
power supplies. They have been tested with leading
mouse brands from manufacturers such as Microsoft and
Logitech. The MAX3244E/MAX3245E successfully drove
all serial mice tested and met their respective current and
voltage requirements. The MAX3244E/MAX3245E dual
charge pump ensures the transmitters supply at least
±5V during worst-case conditions. Figure 13b shows the
transmitter output voltages under increasing load current.
Figure 13a shows a typical mouse connection.
Interconnection with 3V and 5V Logic
The MAX3224E–MAX3227E/MAX3244E/MAX3245E can
directly interface with various 5V logic families, including
ACT and HCT CMOS. See Table 4 for more information
on possible combinations of interconnections.
Table 5 lists other Maxim ESD-powered transceivers.
Figure 13b. MAX324_E Transmitter Output Voltage vs. Load
Current per Transmitter
Table 4. Logic Family Compatibility with Various Supply Voltages
Table 5. ±15kV ESD-Protected, 3.0V to 5.5V Powered RS-232 Transceivers from Maxim
SYSTEM
POWER-SUPPLY
VOLTAGE (V
VCC SUPPLY
VOLTAGE
(V)
COMPATIBILITY
3.3 3.3 Compatible with all CMOS families
5 5 Compatible with all TTL and CMOS families
5 3.3 Compatible with ACT and HCT CMOS, and with AC, HC, or CD4000 CMOS
PART
SUPPLY
VOLTAGE
RANGE
(V)
NO.
OF
Tx/Rx
SUPPLY
CURRENT
(μA)
Auto-
Shutdown
Plus
Auto-
Shutdown
Human
Body
Model
(kV)
IEC 1000-4-2
Contact
Discharge
(kV)
IEC 1000-4-2
Air-Gap
Discharge
(kV)
GUARANTEED
DATA RATE
(kbps)
MAX3241E +3.0 to +5.5 3/5 300 — — ±15 ±8 ±15 250
MAX3243E +3.0 to +5.5 3/5 1 — Yes ±15 ±8 ±15 250
MAX3244E +3.0 to +5.5 3/5 1 Yes — ±15 ±8 ±15 250
MAX3245E +3.0 to +5.5 3/5 1 Yes — ±15 ±8 ±15 1Mbps
MAX3232E +3.0 to +5.5 2/2 300 — — ±15 ±8 ±15 250
MAX3222E +3.0 to +5.5 2/2 300 — — ±15 ±8 ±15 250
MAX3223E +3.0 to +5.5 2/2 1 — Yes ±15 ±8 ±15 250
MAX3224E +3.0 to +5.5 2/2 1 Yes — ±15 ±8 ±15 250
MAX3225E +3.0 to +5.5 2/2 1 Yes — ±15 ±8 ±15 1Mbps
MAX3221E +3.0 to +5.5 1/1 1 — Yes ±15 ±8 ±15 250
MAX3226E +3.0 to +5.5 1/1 1 Yes — ±15 ±8 ±15 250
MAX3227E +3.0 to +5.5 1/1 1 Yes — ±15 ±8 ±15 1Mbps
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
012345678910
MAX2343E-FIG15
LOAD CURRENT PER TRANSMITTER (mA)
VOUT+
VOUT-
VOUT+
VOUT-
VCC
VCC = 3.0V
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
21
MAX3244E***
MAX3245E
FORCEON
23
R5OUT
15
R4OUT
16
R3OUT
17
R2OUT
18
R1OUT
19
R2OUTB
20
FORCEOFF
22
R5IN 8
R4IN 7
R3IN 6
R2IN 5
R1IN 4
GND
25
T3IN
12
T2IN
13
T1IN
14
C2-
2
C2+
1
C1-
24
C1+
28
T3OUT 11
T2OUT 10
T1OUT 9
V- 3
V+
27
V
CC
C4
0.1µF
C3
0.1µF
C1
0.1µF
C
BYPASS
0.1µF
C2
0.1µF
+3.3V
26
INVALID
21
MAX3226E*
MAX3227E
FORCEON
READY AutoShutdown
Plus
12
1
R1OUT9
FORCEOFF 16
INVALID 10
GND
14
T1IN
11
C2-
6
C2+
5
C1-
4
C1+
2
R1IN 8
T1OUT 13
V- 7
V+
3
V
CC
V
CC
C4
0.1µF
C3
0.1µF
0.1µF 15
C1
0.1µF
C2
0.1µF
C
BYPASS
C
BYPASS
+3.3V
TO POWER-
MANAGEMENT
UNIT
5kΩ
MAX3224E**
MAX3225E
FORCEON
READY
14
1
R2OUT10
R1OUT15
FORCEOFF 20
INVALID 11
R2IN 9
GND
18
RS-232
OUTPUTS
TTL/CMOS
INPUTS T2IN
12
T1IN
13
C2-
6
C2+
5
C1-
4
C1+
2
R1IN 16
T2OUT 8
T1OUT 17
V- 7
V+
3
V
CC
V
CC
C4
0.1µF
C3
0.1µF
0.1µF 19
C1
0.1µF
C2
0.1µF
+3.3V
RS-232
INPUTS
TO POWER-
MANAGEMENT
UNIT
TTL/CMOS
OUTPUTS 5kΩ
5kΩ
AutoShutdown
Plus
AutoShutdown
Plus
*MAX3226E/MAX3227E PIN OUT REFERS TO SSOP/TSSOP PACKAGES.
**MAX3224E/MAX3225E PIN OUT REFERS TO DIP/ SSOP/TSSOP PACKAGES.
***MAX3244E/MAX3245E PIN OUT REFERS TO SO/SSOP/TSSOP PACKAGES.
Typical Operating Circuits
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
22
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
READY
C1+
V+
C1-
C2+
C2-
V-
R1IN
FORCEOFF
VCC
GND
T1OUT
FORCEON
T1IN
INVALID
R1OUT
MAX3226E
MAX3227E
SSOP/TSSOP
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
C1+
V+
VCC
GND
C1-
FORCEON
FORCEOFF
INVALID
R2OUTB
R1OUT
R2OUT
R3OUT
R4OUT
R5OUT
C2+
C2-
V-
R1IN
R2IN
R3IN
R4IN
R5IN
T1OUT
T2OUT
T3OUT
T3IN
T2IN
T1IN
SO/SSOP/TSSOP
MAX3244E
MAX3245E
20
19
18
17
16
15
14
13
1
2
3
4
5
6
7
8
FORCEOFF
VCC
GND
T1OUT
C1-
V+
C1+
READY
R1IN
R1OUT
FORCEON
T1IN
T2OUT
V-
C2-
C2+
12
11
9
10
T2IN
INVALIDR2OUT
R2IN
DIP/SSOP/TSSOP
MAX3224E
MAX3225E
GND
C1-
FORCEOFF
INVALID
R1OUT
R2OUT
N.C.
R2OUTB
FORCEON
R3IN
R4IN
R5IN
T1OUT
T2OUT
T3OUT
R1IN 1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18
27
26
25
24
23
22
21
20
19
N.C.
R5OUT
R4OUT
N.C.
T1IN
T2IN
T3IN
N.C.
V-
C2-
C2+
N.C.
C1+
V+
VCC
N.C.
N.C.
TQFN
MAX3245E
TOP VIEW
*EP
N.C.
R3OUT
R2IN
36 35 34 33 32 31 30 29 28
15
16
14
13
6
5
7
C2+
V-
8
C1-
GND
FORCEON
VCC
1 2
READY
4
12 11 9
V+
C1+
T1IN
INVALID
R1OUT
R1IN
MAX3226E
MAX3227E
C2- T1OUT
3
10
*EP
*CONNECT EP TO GND.
TQFN
TOP VIEW
MAX3224E
MAX3225E
TQFN
TOP VIEW
19
20
18
17
7
6
8
C1-
C2-
V-
9
C1+
R1IN
FORCEON
T1IN
T1OUT
1 2
FORCEOFF
4 5
15 14 12 11
READY
V+
INVALID
R2OUT
R2IN
T2OUT
C2+ R1OUT
3
13
VCC
16 10 T2IN
GND
*EP
FORCEOFF
+
+
+
+
++
Pin Congurations
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
23
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
/V denotes an automotive qualified part.
PART TEMP RANGE PIN-PACKAGE
MAX3225ECUP+ 0°C to +70°C 20 TSSOP
MAX3225ECTP+ 0°C to +70°C 20 TQFN-EP*
MAX3225ECAP+ 0°C to +70°C 20 SSOP
MAX3225ECPP+ 0°C to +70°C 20 Plastic DIP
MAX3225EETP+ -40°C to +85°C 20 TQFN -EP*
MAX3225EEUP+ -40°C to +85°C 20 TSSOP
MAX3225EEUP/V+
-40°C to +85°C 20 TSSOP
MAX3225EEAP+ -40°C to +85°C 20 SSOP
MAX3225EEPP+ -40°C to +85°C 20 Plastic DIP
MAX3225EAAP+ -40°C to +85°C 20 SSOP
MAX3226ECTE+ 0°C to +70°C 16 TQFN-EP*
MAX3226ECUE+ 0°C to +70°C 16 TSSOP
MAX3226ECAE+ 0°C to +70°C 16 SSOP
MAX3226EEAE+ -40°C to +85°C 16 SSOP
MAX3226EETE+ -40°C to +85°C 16 TQFN-EP*
MAX3226EEUE+ -40°C to +85°C 16 TSSOP
MAX3226EAAE+ -40°C to +125°C 16 SSOP
MAX3227ECAE+ 0°C to +70°C 16 SSOP
MAX3227ECTE+ 0°C to +70°C 16 TQFN-EP*
MAX3227ECUE+ 0°C to +70°C 16 TSSOP
MAX3227EEAE+ -40°C to +85°C 16 SSOP
MAX3227EEAE/V+ -40°C to +85°C 16 SSOP
PART TEMP RANGE PIN-PACKAGE
MAX3227EETE+ -40°C to +85°C 16 TQFN-EP*
MAX3227EEUE+ -40°C to +85°C 16 TSSOP
MAX3227EAAE+ -40°C to +125°C 16 SSOP
MAX3244ECWI+ 0°C to +70°C 28 Wide SO
MAX3244ECAI+ 0°C to +70°C 28 SSOP
MAX3244ECUI+ 0°C to +70°C 28 TSSOP
MAX3244EEWI+ -40°C to +85°C 28 Wide SO
MAX3244EEAI+ -40°C to +85°C 28 SSOP
MAX3244EEUI+ -40°C to +85°C 28 TSSOP
MAX3245ECWI+ 0°C to +70°C 28 Wide SO
MAX3245ECAI+ 0°C to +70°C 28 SSOP
MAX3245ECTX+ 0°C to +70°C 36 TQFN- EP*
MAX3245EEAI+ -40°C to +85°C 28 SSOP
MAX3245EEWI+ -40°C to +85°C 28 WIDE SO
MAX3245EEUI+ -40°C to +85°C 28 TSSOP
MAX3245EETX+ -40°C to +85°C 36 TQFN- EP*
Chip Information
PROCESS: BiCMOS
Ordering Information (continued)
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
www.maximintegrated.com Maxim Integrated
│
24
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
10 3/11 Added an automotive qualied part to the Ordering Information; changed all
the parts listed in the Ordering Information to lead free 1, 20
11 11/18 Updated Applications, Absolute Maximum Ratings, Package Information,
Electrical Characteristics, Pin Description, and Ordering Information 1–5, 12, 24
Revision History
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
MAX3224E/MAX3225E/
MAX3226E/MAX3227E/
MAX3244E/MAX3245E
±15kV ESD-Protected, 1μA, 1Mbps,
3.0V to 5.5V, RS-232 Transceivers
with AutoShutdown Plus
© 2018 Maxim Integrated Products, Inc.
│
25
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.