• www.maxlinear.com• Rev 1.0.7
SP3222EB / SP3232EB
Data Sheet
True +3.0V to +5.5V RS-232 Transceivers
General Description
The SP3222EB and SP3232EB series are RS-232
transceiver solutions intended for portable or hand-held
applications such as notebook or laptop computers. The
SP3222EB / SP3232EB series has a high-efficiency,
charge-pump power supply that requires only 0.1µF
capacitors in 3.3V operation. This charge pump allows the
SP3222EB / SP3232EB series to deliver true RS-232
performance from a single power supply ranging from
3.0V to 5.5V. The SP3222EB / SP3232EB are 2-driver /
2-receiver devices. The ESD tolerance of the SP3222EB /
SP3232E devices is over ±15kV for both Human Body
Model and IEC61000-4-2 Air discharge test methods. The
SP3222EB device has a low-power shutdown mode
where the devices’ driver outputs and charge pumps are
disabled. During shutdown, the supply current falls to less
than 1µA.
Features
■Meets true EIA / TIA-232-F standards from a 3.0V to
5.5V power supply
■250kbps transmission rate under load
■1μA low power shutdown with receivers active
(SP3222EB)
■Interoperable with RS-232 down to a 2.7V power source
■Enhanced ESD specifications:
 ±15kV Human Body Model
 ±15kV IEC61000-4-2 Air Discharge
 ±8kV IEC61000-4-2 Contact Discharge
Ordering Information - page 18
Selection Table
Pinouts
Figure 1: SP3222EB and SP3232EB Pinouts
Table 1: Selection Table
Device Power Supplies RS-232
Drivers
RS-232
Receivers
External
Components Shutdown TTL
3-State # of Pins
SP3222EB 3.0V to 5.5V 2 2 4 Capacitors Yes Yes 20
SP3232EB 3.0V to 5.5V 2 2 4 Capacitors No No 16
V-
1
2
3
417
18
19
20
5
6
7
16
15
14
SHDN
C1+
V+
C1-
C2+
C2-
N.C.
EN
R1IN
GND
V
CC
T1OUT
N.C.
8
9
10 11
12
13
R2IN
R2OUT
SP3222EB
T2OUT T1IN
T2IN
R1OUT
SSOP / TSSOP
V-
1
2
3
413
14
15
16
5
6
7
12
11
10
C1+
V+
C1-
C2+
C2-
R1IN
R2IN
GND
V
CC
T1OUT
T2IN
89
SP3232EB
T1IN
R1OUT
R2OUT
T2OUT
SSOP / NSOIC / TSSOP
SP3232EB
QFN
1
2
3
4
12
11
10
9
16 15 14 13
5678
C1-
V-
C2+
C2-
R2IN
T2OUT
T2IN
R2OUT
R1IN
T1OUT
T1IN
R1OUT
C1+
V+
GND
V
CC
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Revision History
1/24/20 Rev 1.0.7 ii
Revision History
Revision Release Date Change Description
-- 11/2/05 Legacy Sipex Datasheet
1.0.0 9/9/09 Convert to Exar Format. Update ordering information and change revision to 1.0.0.
1.0.1 6/7/11 Remove obsolete devices per PDN 110510-01 and change ESD rating to IEC-61000-4-2..
1.0.2 3/14/13 Correct ype error to RX input voltage range and TX transition region slew rate condition.
1.0.3 8/14/14 Add Max Junction temperature and package thermal information.
1.0.4 5/28/15 Update Absolute Max Rating for RxIN input voltage to ±25V, update logo.
1.0.5 10/27/15 Add SP3232EBER (QFN 16) preliminary package option.
1.0.6 2/23/16 Remove preliminary status of QFN 16 package option.
1.0.7 1/24/20
Update to MaxLinear template and logo. Update Ordering Information. Remove obsolete
WSOIC references. Move ESD tolerance levels to new ESD Ratings section located on
page 1.
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Table of Contents
1/24/20 Rev 1.0.7 iii
Table of Contents
General Description............................................................................................................................................. i
Features............................................................................................................................................................... i
Selection Table ................................................................................................................................................... i
Pinouts.................................................................................................................................................................. i
Specifications ..................................................................................................................................................... 1
Absolute Maximum Ratings...........................................................................................................................................1
ESD Ratings..................................................................................................................................................................1
Operating Conditions.....................................................................................................................................................2
Electrical Characteristics ...............................................................................................................................................2
Typical Performance Characteristics................................................................................................................ 4
Pin Information ................................................................................................................................................... 5
Pin Configurations ........................................................................................................................................................ 5
Pin Descriptions ............................................................................................................................................................5
Typical Operating Circuits ................................................................................................................................. 6
Description.......................................................................................................................................................... 7
Theory of Operation ..................................................................................................................................................... 7
Drivers ..................................................................................................................................................................7
Receivers .............................................................................................................................................................8
Charge Pump .......................................................................................................................................................8
ESD Tolerance ...................................................................................................................................................10
Mechanical Dimensions ................................................................................................................................... 12
SSOP20 ......................................................................................................................................................................12
SSOP16 ......................................................................................................................................................................13
TSSOP16 ....................................................................................................................................................................15
TSSOP20 ....................................................................................................................................................................16
QFN16 5x5 ..................................................................................................................................................................17
Ordering Information........................................................................................................................................ 18
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet List of Figures
1/24/20 Rev 1.0.7 iv
List of Figures
Figure 1: SP3222EB and SP3232EB Pinouts ....................................................................................................... i
Figure 2: Transmitter Output Voltage vs. Load Capacitance................................................................................ 4
Figure 3: Slew Rate vs. Load Capacitance........................................................................................................... 4
Figure 4: Supply Current vs. Load Capacitance When Transmitting Data ........................................................... 4
Figure 5: Supply Current vs. Supply Voltage........................................................................................................ 4
Figure 6: Transmitter Output Voltage vs. Supply Voltage..................................................................................... 4
Figure 7: Pinout Configurations for the SP3222EB and SP3232EB..................................................................... 5
Figure 8: SP3222EB Typical Operating Circuit..................................................................................................... 6
Figure 9: SP3232EB Typical Operating Circuit..................................................................................................... 6
Figure 10: SP3222EB / SP3232EB Driver Loopback Test Circuit ........................................................................ 7
Figure 11: Loopback Test Results at 120kbps ..................................................................................................... 7
Figure 12: Loopback Test Results at 250kbps ..................................................................................................... 8
Figure 13: Charge Pump — Phase 1.................................................................................................................... 9
Figure 14: Charge Pump — Phase 2.................................................................................................................... 9
Figure 15: Charge Pump Waveforms ................................................................................................................... 9
Figure 16: Charge Pump — Phase 3.................................................................................................................... 9
Figure 17: Charge Pump — Phase 4.................................................................................................................... 9
Figure 18: ESD Test Circuit for Human Body Model .......................................................................................... 10
Figure 19: ESD Test Circuit for IEC61000-4-2 ................................................................................................... 10
Figure 20: ESD Test Waveform for IEC61000-4-2 ............................................................................................. 11
Figure 21: Mechanical Dimensions, SSOP20..................................................................................................... 12
Figure 22: Mechanical Dimensions, SSOP16..................................................................................................... 13
Figure 23: Mechanical Dimensions, NSOIC16 ................................................................................................... 14
Figure 24: Mechanical Dimensions, TSSOP16 .................................................................................................. 15
Figure 25: Mechanical Dimensions, TSSOP20 .................................................................................................. 16
Figure 26: Mechanical Dimensions, QFN16 5x5 ................................................................................................ 17
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet List of Tables
1/24/20 Rev 1.0.7 v
List of Tables
Table 1: Selection Table........................................................................................................................................ i
Table 1: Absolute Maximum Ratings .................................................................................................................... 1
Table 2: ESD Ratings ........................................................................................................................................... 1
Table 3: Operating Conditions.............................................................................................................................. 2
Table 4: Electrical Characteristics ....................................................................................................................... 2
Table 5: Pin Descriptions...................................................................................................................................... 5
Table 6: SP3222EB Truth Table Logic for Shutdown and Enable Control ........................................................... 8
Table 7: Ordering Information............................................................................................................................. 18
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Specifications
1/24/20 Rev 1.0.7 1
Specifications
Absolute Maximum Ratings
Important: These are stress ratings only and functional operation of the device at these ratings or any other above those
indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating
conditions for extended periods of time may affect reliability and cause permanent damage to the device.
1. V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
2. Driver input hysteresis is typically 250mV.
ESD Ratings
Table 1: Absolute Maximum Ratings
Parameter Minimum Maximum Units
VCC –0.3 6.0 V
V+(1) –0.3 7.0 V
V-(1) –7.0 0.3 V
V+ + |V-|(1) 13 V
ICC (DC VCC or GND current) –100 100 mA
Input Voltages
TxIN, EN –0.3 6.0 V
RxIN –25 25 V
Output Voltages
TxOUT –13.2 13.2 V
RxOUT –0.3 VCC + 0.3 V
Short-Circuit Duration
TxOUT Continuous
Temperature
Storage temperature -65 150 °C
Table 2: ESD Ratings
Parameter Value Units
HBM (Human Body Model), driver outputs and receiver inputs ±15 kV
IEC61000-4-2 Air Discharge, driver outputs and receiver inputs Level 4 ±15 kV
IEC61000-4-2 Contact Discharge, driver outputs and receiver inputs Level 4 ±8 kV
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Operating Conditions
1/24/20 Rev 1.0.7 2
Operating Conditions
Electrical Characteristics
Unless otherwise noted, the following specifications apply for VCC = 3.0V to 5.5V with TAMB = TMIN to TMAX,
C1 - C4 = 0.1µF.
Table 3: Operating Conditions
Parameter Value Units
Temperature
Maximum junction temperature 125 °C
Power Dissipation Per Package
20-pin SSOP (derate 9.25mW/°C above 70°C) 750 mW
20-pin TSSOP (derate 11.1mW/°C above 70°C) 890 mW
16-pin SSOP (derate 9.69mW/°C above 70°C) 775 mW
16-pin TSSOP (derate 10.5mW/°C above 70°C) 850 mW
16-pin NSOIC (derate 13.57mW/°C above 70°C) 1086 mW
Thermal Resistance
16-pin TSSOP ѲJA 100.4 °C/W
16-pin TSSOP ѲJC 19.0 °C/W
16-pin QFN ѲJA 44.0 °C/W
16-pin QFN ѲJC 7.3 °C/W
Table 4: Electrical Characteristics
Parameter Test Condition Minimum Typical Maximum Units
DC Characteristics
Supply current No load, VCC = 3.3V, TAMB= 25°C,
TxIN = GND or VCC
0.3 1.0 mA
Shutdown supply current SHDN = GND, VCC = 3.3V, TAMB= 25°C,
TxIN = VCC or GND 1.0 10 µA
Logic Inputs and Receiver Outputs
Input logic threshold LOW TxIN, EN, SHDN(1) GND 0.8 V
Input logic threshold HIGH VCC = 3.3V(1) 2.0 VCC V
Input logic threshold HIGH VCC = 5.0V(1) 2.4 VCC V
Input leakage current TxIN, EN, SHDN, TAMB= 25°C, VIN = 0V to VCC ±0.01 ±1.0 µA
Output leakage current Receivers disabled, VOUT = 0V to VCC ±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
Driver Outputs
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Electrical Characteristics
1/24/20 Rev 1.0.7 3
1. Driver input hysteresis is typically 250mV.
Output voltage swing All driver outputs loaded with 3kΩ to GND,
TAMB= 25°C ±5.0 ±5.4 V
Output resistance VCC = V+ = V- = 0V, to VOUT = ±2V 300 Ω
Output Short-circuit current VOUT = 0V ±35 ±60 mA
Output leakage current VCC = 0V or 3.0V to 5.5V, VOUT = ±12V, drivers
disabled ±25 µA
Receiver Inputs
Input voltage range –15 15 V
Input threshold LOW VCC = 3.3V 0.6 1.2 V
Input threshold LOW VCC = 5.0V 0.8 1.5 V
Input threshold HIGH VCC = 3.3V 1.5 2.4 V
Input threshold HIGH VCC = 5.0V 1.8 2.4 V
Input hysteresis 0.3 V
Input resistance 3 5 7 kΩ
Timing Characteristics
Maximum data rate RL = 3kΩ, CL = 1000pF, one driver active 250 kbps
Receiver propagation delay, tPHL Receiver input to receiver output, CL = 150pF 0.15 µs
Receiver propagation delay, tPLH Receiver input to receiver output, CL = 150pF 0.15 µs
Receiver output enable time 200 ns
Receiver output disable time 200 ns
Driver skew |tPHL- tPLH|, TAMB= 25°C 100 ns
Receiver skew |tPHL- tPLH|50 ns
Transition-region slew rate
VCC = 3.3V, RL = 3kΩ, CL = 1000pF,
TAMB= 25°C, measurements taken from –3.0V
to +3.0V or +3.0V to –3.0V
30 V/µs
Table 4: (Continued) Electrical Characteristics
Parameter Test Condition Minimum Typical Maximum Units
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Typical Performance Characteristics
1/24/20 Rev 1.0.7 4
Typical Performance Characteristics
Figure 2: Transmitter Output Voltage
vs. Load Capacitance
Figure 3: Slew Rate vs. Load Capacitance
6
4
2
0
-2
-4
-6 0 1000 2000 3000 4000 5000
TxOUT +
TxOUT -
Transmitter Output
Voltage (V)
Load Capacitance (pF)
T1 at 250Kbps
T2 at 15.6Kbps
All TX loaded 3K // CLoad
30
25
20
15
10
5
00 500 1000 2000 3000 4000 5000
Slew rate (V/μs)
Load Capacitance (pF)
- Slew
+ Slew
T1 at 250Kbps
T2 at 15.6Kbps
All TX loaded 3K // CLoad
Figure 4: Supply Current vs. Load Capacitance
When Transmitting Data Figure 5: Supply Current vs. Supply Voltage
35
30
25
20
15
10
5
0
Supply Current (mA)
Load Capacitance (pF)
0 1000 2000 3000 4000 5000
250Kbps
125Kbps
20Kbps
T1 at Full Data Rate
T2 at 1/16 Data Rate
All TX loaded 3K // CLoad
16
14
12
10
8
6
4
2
02.7 3 3.5 4 4.5 5
Supply Current (mA)
Supply Voltage (V)
1 Transmitter at 250Kbps
1 Transmitter at 15.6Kbps
All transmitters loaded with 3K // 1000pf
Figure 6: Transmitter Output Voltage vs. Supply Voltage
6
4
2
0
-2
-4
-6 2.7 3 3.5 4 4.5 5
Supply Voltage (V)
Transmitter Output
Voltage (V)
TxOUT -
TxOUT +
T1 at 250Kbps
T2 at 15.6Kbps
All TX loaded 3K // 1000 pF
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Pin Information
1/24/20 Rev 1.0.7 5
Pin Information
Pin Configurations
Figure 7: Pinout Configurations for the SP3222EB and SP3232EB
Pin Descriptions
Table 5: Pin Descriptions
Pin
Name Function / Description
Pin Number
SP3222EB SP3232EB
SSOP
TSSOP
SSOP
TSSOP
NSOIC
QFN
EN Receiver enable. Apply logic LOW for normal operation.
Apply logic HIGH to disable the receiver outputs (high-Z state). 1 - -
C1+ Positive terminal of the voltage doubler charge-pump capacitor. 2 1 15
V+ 5.5V output generated by the charge pump. 3 2 16
C1- Negative terminal of the voltage doubler charge-pump capacitor. 4 3 1
C2+ Positive terminal of the inverting charge-pump capacitor. 5 4 2
C2- Negative terminal of the inverting charge-pump capacitor. 6 5 3
V- –5.5V output generated by the charge pump. 7 6 4
T1OUT RS-232 driver output. 17 14 12
T2OUT RS-232 driver output. 8 7 5
R1IN RS-232 receiver input. 16 13 11
R2IN RS-232 receiver input. 9 8 6
R1OUT TTL / CMOS receiver output. 15 12 10
V-
1
2
3
417
18
19
20
5
6
7
16
15
14
SHDN
C1+
V+
C1-
C2+
C2-
N.C.
EN
R1IN
GND
VCC
T1OUT
N.C.
8
9
10 11
12
13
R2IN
R2OUT
SP3222EB
T2OUT T1IN
T2IN
R1OUT
SSOP / TSSOP
V-
1
2
3
413
14
15
16
5
6
7
12
11
10
C1+
V+
C1-
C2+
C2-
R1IN
R2IN
GND
VCC
T1OUT
T2IN
89
SP3232EB
T1IN
R1OUT
R2OUT
T2OUT
SSOP / NSOIC / TSSOP
SP3232EB
QFN
1
2
3
4
12
11
10
9
16 15 14 13
5678
C1-
V-
C2+
C2-
R2IN
T2OUT
T2IN
R2OUT
R1IN
T1OUT
T1IN
R1OUT
C1+
V+
GND
VCC
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Typical Operating Circuits
1/24/20 Rev 1.0.7 6
Typical Operating Circuits
Figure 8: SP3222EB Typical Operating Circuit Figure 9: SP3232EB Typical Operating Circuit
.
R2OUT TTL / CMOS receiver output. 10 9 7
T1IN TTL / CMOS driver input. 13 11 9
T2IN TTL / CMOS driver input. 12 10 8
GND Ground. 18 15 13
VCC 3.0V to 5.5V supply voltage. 19 16 14
SHDN
Shutdown control Input. Drive HIGH for normal device operation.
Drive LOW to shutdown the drivers (high-Z output) and the on-board
power supply.
20 - -
N. C. No connect. 11, 14 - -
Table 5: Pin Descriptions
Pin
Name Function / Description
Pin Number
SP3222EB SP3232EB
SSOP
TSSOP
SSOP
TSSOP
NSOIC
QFN
SP3222EB
2
4
6
5
3
7
19
GND
T1IN
T2IN
T1OUT
T2OUT
C1+
C1-
C2+
C2-
V+
V-
V
CC
13
12
0.1μF
0.1μ F
0.1μF
+
C2
C5
C1
+
+
*C3
C4
+
+
0.1μ F
0.1μF
8
17
RS-232
OUTPUTS
RS-232
INPUTS
LOGIC
INPUTS
V
CC
18
1
5kΩ
R1IN
R1OUT
15
9
5kΩ
R2IN
R2OUT
10
16
LOGIC
OUTPUTS
EN 20
SHDN
*can be returned to
either V
CC
or GND
SSOP
TSSOP
SP3232EB
1
3
5
4
2
6
16
GND
T1IN
T2IN
T1OUT
T2OUT
C1+
C1-
C2+
C2-
V+
V-
V
CC
11
10
0.1μF
+
C2
C5
C1
+
+*C3
C4
+
+
14
7RS-232
OUTPUTS
RS-232
INPUTS
LOGIC
INPUTS
V
CC
15
5k Ω
R1IN
R1OUT
12 13
5k Ω
R2IN
R2OUT
98
LOGIC
OUTPUTS
*can be returned to
either V
CC
or GND
0.1μF
0.1μF
0.1μF
0.1μF
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Description
1/24/20 Rev 1.0.7 7
Description
The SP3222EB / SP3232EB transceivers meet the
EIA / TIA-232 and ITU-T V.28/V.24 communication
protocols and can be implemented in battery-powered,
portable, or hand-held applications such as notebook or
palmtop computers. The SP3222EB / SP3232EB devices
feature MaxLinear’s proprietary on-board charge pump
circuitry that generates ±5.5V for RS-232 voltage levels
from a single 3.0V to 5.5V power supply. This series is ideal
for 3.3V-only systems, mixed 3.3V to 5.5V systems, or
5.0V-only systems that require true RS-232 performance.
The SP3222EB / SP3232EB devices can operate at a data
rate of 250kbps when fully loaded.
The SP3222EB and SP3232EB are 2-driver / 2-receiver
devices ideal for portable or hand-held applications. The
SP3222EB features a 1µA shutdown mode that reduces
power consumption and extends battery life in portable
systems. Its receivers remain active in shutdown mode,
allowing external devices such as modems to be monitored
using only 1µA supply current.
Theory of Operation
The SP3222EB/SP3232EB series is made up of three
basic circuit blocks:
1. Drivers
2. Receivers
3. The MaxLinear proprietary charge pump
Drivers
The drivers are inverting level transmitters that convert TTL
or CMOS logic levels to 5.0V EIA / TIA-232 levels with an
inverted sense relative to the input logic levels. Typically,
the RS-232 output voltage swing is ±5.4V with no load and
±5V minimum fully loaded. The driver outputs are
protected against infinite short-circuits to ground without
degradation in reliability. Driver outputs will meet
EIA / TIA-562 levels of ±3.7V with supply voltages as low
as 2.7V.
The drivers can guarantee a data rate of 250kbps fully
loaded with 3kΩ in parallel with 1000pF, ensuring
compatibility with PC-to-PC communication software.
The slew rate of the driver is internally limited to a
maximum of 30V/µs in order to meet the EIA standards
(EIA RS-232D 2.1.7, Paragraph 5). The transition of the
loaded output from HIGH to LOW also meet the
monotonicity requirements of the standard.
Figure 10 shows a loopback test circuit used to test the
RS-232 Drivers. Figure 11 shows the test results of the
loopback circuit with all drivers active at 120kbps with RS-
232 loads in parallel with a 1000pF capacitor. Figure 12
shows the test results where one driver was active at
250kbps and all drivers loaded with an RS-232 receiver in
parallel with 1000pF capacitors. A solid RS-232 data
transmission rate of 250kbps provides compatibility with
many designs in personal computer peripherals and LAN
applications.
Figure 10: SP3222EB / SP3232EB
Driver Loopback Test Circuit
Figure 11: Loopback Test Results at 120kbps
SP3222EB
SP3232EB
GND
TxIN TxOUT
C1+
C1-
C2+
C2-
V+
V-
V
CC
0.1μF
0.1μF
0.1μF
+
C2
C5
C1
+
+
C3
C4
+
+
0.1μF
0.1μF
LOGIC
INPUTS
V
CC
5kΩ
RxIN
RxOUT
LOGIC
OUTPUTS
EN* *SHDN
1000pF
V
CC
* SP3222EB only
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Theory of Operation
1/24/20 Rev 1.0.7 8
Figure 12: Loopback Test Results at 250kbps
The SP3222EB driver’s output stages are turned off (tri-
state) when the device is in shutdown mode. When the
power is off, the SP3222EB device permits the outputs to
be driven up to ±12V. The driver’s inputs do not have pull-
up resistors. Designers should connect unused inputs to
VCC or GND.
In the shutdown mode, the supply current falls to less than
1µA, where SHDN = LOW. When the SP3222EB device is
shut down, the device’s driver outputs are disabled (tri-
stated) and the charge pumps are turned off with V+ pulled
down to VCC and V- pulled to GND. The time required to
exit shutdown is typically 100µs. Connect SHDN to VCC if
the shutdown mode is not used.
Receivers
The receivers convert EIA / TIA-232 levels to TTL or CMOS
logic output levels. The SP3222EB receivers have an
inverting tri-state output. These receiver outputs (RxOUT)
are tri-stated when the enable control EN = HIGH. In the
shutdown mode, the receivers can be active or inactive. EN
has no effect on TxOUT. The truth table logic of the
SP3222EB driver and receiver outputs can be found in
Table 6.
Since receiver input is usually from a transmission line
where long cable lengths and system interference can
degrade the signal, the inputs have a typical hysteresis
margin of 300mV. This ensures that the receiver is virtually
immune to noisy transmission lines. Should an input be left
unconnected, an internal 5kΩ pulldown resistor to ground
will commit the output of the receiver to a HIGH state.
Charge Pump
The charge pump is an MaxLinear-patented design (U.S.
5,306,954) and uses a unique approach compared to older
less-efficient designs. The charge pump still requires four
external capacitors, but uses a four-phase voltage shifting
technique to attain symmetrical 5.5V power supplies. The
internal power supply consists of a regulated dual charge
pump that provides output voltages of ±5.5V regardless of
the input voltage (VCC) over the 3.0V to 5.5V range.
In most circumstances, decoupling the power supply can
be achieved adequately using a 0.1µF bypass capacitor at
C5 (refer to Figure 8 and Figure 9).
In applications that are sensitive to power-supply noise,
decouple VCC to ground with a capacitor of the same value
as charge-pump capacitor C1. Physically connect bypass
capacitors as close to the IC as possible.
The charge pump operates in a discontinuous mode using
an internal oscillator. If the output voltages are less than a
magnitude of 5.5V, the charge pump is enabled. If the
output voltages exceed a magnitude of 5.5V, the charge
pump is disabled. This oscillator controls the four phases
of the voltage shifting. A description of each phase follows.
Phase 1: VSS charge storage
During this phase of the clock cycle, the positive side of
capacitors C1 and C2 are initially charged to VCC. Cl+ is
then switched to GND and the charge in C1– is transferred
to C2–. Since C2+ is connected to VCC, the voltage
potential across capacitor C2 is now 2 times VCC.
Phase 2: VSS transfer
Phase two of the clock connects the negative terminal of C2
to the VSS storage capacitor and the positive terminal of C2
to GND. This transfers a negative generated voltage to C3.
This generated voltage is regulated to a minimum voltage
of –5.5V. Simultaneous with the transfer of the voltage to
C3, the positive side of capacitor C1 is switched to VCC and
the negative side is connected to GND.
Table 6: SP3222EB Truth Table Logic
for Shutdown and Enable Control
SHDN EN TxOUT RxOUT
0 0 Tri-state Active
0 1 Tri-state Tri-state
1 0 Active Active
1 1 Active Tri-state
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Theory of Operation
1/24/20 Rev 1.0.7 9
Phase 3: VDD charge storage
The third phase of the clock is identical to the first phase;
the charge transferred in C1 produces –VCC in the negative
terminal of C1, which is applied to the negative side of
capacitor C2. Since C2+ is at VCC, the voltage potential
across C2 is 2 times VCC.
Phase 4: VDD transfer
The fourth phase of the clock connects the negative
terminal of C2 to GND, and transfers this positive
generated voltage across C2 to C4, the VDD storage
capacitor. This voltage is regulated to 5.5V. At this voltage,
the internal oscillator is disabled. Simultaneous with the
transfer of the voltage to C4, the positive side of capacitor
C1 is switched to VCC and the negative side is connected to
GND, allowing the charge pump cycle to begin again. The
charge pump cycle will continue as long as the
operational conditions for the internal oscillator are
present.
Since both V+ and V- are separately generated from VCC,
in a no-load condition V+ and V- will be symmetrical. Older
charge pump approaches that generate V- from V+ will
show a decrease in the magnitude of V- compared to V+
due to the inherent inefficiencies in the design.
The clock rate for the charge pump typically operates at
greater than 250kHz. The external capacitors can be as
low as 0.1µF with a 16V breakdown voltage rating.
Figure 13: Charge Pump — Phase 1
Figure 14: Charge Pump — Phase 2
Figure 15: Charge Pump Waveforms
Figure 16: Charge Pump — Phase 3
Figure 17: Charge Pump — Phase 4
V
CC
= +5V
–5V –5V
+5V
V
SS
Storage Capacitor
V
DD
Storage Capacitor
C
1
C
2
C
3
C
4
+
+
++
–
–
––
VCC = +5V
VSS Storage Capacitor
VDD Storage Capacitor
C1C2
C3
C4
+
+
++
–
–
––
-5.5V
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Theory of Operation
1/24/20 Rev 1.0.7 10
ESD Tolerance
The SP3222EB / SP3232EB Series incorporates
ruggedized ESD cells on all driver output and receiver input
pins. The ESD structure is improved over our previous
family for more rugged applications and environments
sensitive to electro-static discharges and associated
transients. The improved ESD tolerance is at least ±15kV
without damage nor latch-up.
There are different methods of ESD testing applied:
a. MIL-STD-883, Method 3015.7
b. IEC61000-4-2 Air-Discharge
c. IEC61000-4-2 Direct Contact
The Human Body Model has been the generally accepted
ESD testing method for semiconductors. This method is
also specified in MIL-STD-883, Method 3015.7 for ESD
testing. The premise of this ESD test is to simulate the
human body’s potential to store electro-static energy and
discharge it to an integrated circuit. The simulation is
performed by using a test model as shown in Figure 18.
This method will test the IC’s capability to withstand an
ESD transient during normal handling such as in
manufacturing areas where the IC’s tend to be handled
frequently.
Figure 18: ESD Test Circuit for Human Body Model
The IEC61000-4-2, formerly IEC801-2, is generally used
for testing ESD on equipment and systems. System
manufacturers must guarantee a certain amount of ESD
protection since the system itself is exposed to the outside
environment and human presence. The premise with
IEC61000-4-2 is that the system is required to withstand an
amount of static electricity when ESD is applied to points
and surfaces of the equipment that are accessible to
personnel during normal usage. The transceiver IC
receives most of the ESD current when the ESD source is
applied to the connector pins. The test circuit for
IEC61000-4-2 is shown on Figure 19. There are two
methods within IEC61000-4-2, the Air Discharge method
and the Contact Discharge method.
Figure 19: ESD Test Circuit for IEC61000-4-2
With the Air Discharge Method, an ESD voltage is applied
to the equipment under test (EUT) through air. This
simulates an electrically charged person ready to connect a
cable onto the rear of the system only to find an unpleasant
zap just before the person touches the back panel. The
high energy potential on the person discharges through an
arcing path to the rear panel of the system before he or she
even touches the system. This energy, whether discharged
directly or through air, is predominantly a function of the
discharge current rather than the discharge voltage.
Variables with an air discharge such as approach speed of
the object carrying the ESD potential to the system and
humidity will tend to change the discharge current. For
example, the rise time of the discharge current varies with
the approach speed.
The Contact Discharge Method applies the ESD current
directly to the EUT. This method was devised to reduce the
unpredictability of the ESD arc. The discharge current rise
time is constant since the energy is directly transferred
without the air-gap arc. In situations such as hand held
systems, the ESD charge can be directly discharged to the
equipment from a person already holding the equipment.
The current is transferred on to the keypad or the serial port
of the equipment directly and then travels through the PCB
and finally to the IC.
The circuit model in Figure 18 and Figure 19 represent the
typical ESD testing circuit used for all three methods. The
CS is initially charged with the DC power supply when the
first switch (SW1) is on. Now that the capacitor is charged,
the second switch (SW2) is on while SW1 switches off.The
voltage stored in the capacitor is then applied through RS,
the current limiting resistor, onto the device under test
(DUT). In ESD tests, the SW2 switch is pulsed so that the
device under test receives a duration of voltage.
R
C
Device
Under
Test
DC Power
Source
C
S
R
S
SW1 SW2
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Theory of Operation
1/24/20 Rev 1.0.7 11
For the Human Body Model, the current limiting resistor
(RS) and the source capacitor (CS) are 1.5kΩ and 100pF,
respectively. For IEC-61000-4-2, the current limiting
resistor (RS) and the source capacitor (CS) are 330Ω and
150pF, respectively.
The higher CS value and lower RS value in the
IEC61000-4-2 model are more stringent than the Human
Body Model. The larger storage capacitor injects a higher
voltage to the test point when SW2 is switched on. The
lower current limiting resistor increases the current charge
onto the test point.
Figure 20: ESD Test Waveform for IEC61000-4-2
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Mechanical Dimensions
1/24/20 Rev 1.0.7 12
Mechanical Dimensions
SSOP20
Figure 21: Mechanical Dimensions, SSOP20
Drawing No:
Revision: A
Side View
Top View
Front View
POD-00000119
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet SSOP16
1/24/20 Rev 1.0.7 13
SSOP16
Figure 22: Mechanical Dimensions, SSOP16
Drawing No:
Revision: A
Side View
Top View
Front View
POD-00000116
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet SSOP16
1/24/20 Rev 1.0.7 14
NSOIC16
Figure 23: Mechanical Dimensions, NSOIC16
Drawing No:
Revision: A
Side View
Top View
Front View
POD-00000114
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet TSSOP16
1/24/20 Rev 1.0.7 15
TSSOP16
Figure 24: Mechanical Dimensions, TSSOP16
Drawing No:
Revision: A
Side View
Top View
Front View
POD-00000117
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet TSSOP20
1/24/20 Rev 1.0.7 16
TSSOP20
Figure 25: Mechanical Dimensions, TSSOP20
Drawing No:
Revision: A
Side View
Top View
Front View
POD-00000120
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet QFN16 5x5
1/24/20 Rev 1.0.7 17
QFN16 5x5
Figure 26: Mechanical Dimensions, QFN16 5x5
SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Ordering Information
1/24/20 Rev 1.0.7 18
Ordering Information
1. Refer to www.maxlinear.com/SP3222EB and www.maxlinear.com/SP3232EB for most up-to-date Ordering Information.
2. Visit www.maxlinear.com for additional information on Environmental Rating.
Table 7: Ordering Information(1)
Ordering Part Number Operating Temperature Range Package Packaging Method Lead-Free(2)
SP3222EB
SP3222EBEA-L/TR –40°C to 85°C 20 Pin SSOP Reel Yes
SP3222EBEY-L/TR –40°C to 85°C 20 Pin TSSOP Reel Yes
SP3232EB
SP3232EBCA-L/TR 0°C to 70°C 16 Pin SSOP Reel Yes
SP3232EBCN-L 0°C to 70°C 16-pin NSOIC Tube Yes
SP3232EBCN-L/TR 0°C to 70°C 16-pin NSOIC Reel Yes
SP3232EBCY-L/TR 0°C to 70°C 16 Pin TSSOP Reel Yes
SP3232EBEA-L/TR –40°C to 85°C 16 Pin SSOP Reel Yes
SP3232EBEN-L/TR –40°C to 85°C 16-pin NSOIC Reel Yes
SP3232EBEY-L/TR –40°C to 85°C 16 Pin TSSOP Reel Yes
SP3232EBER-L/TR –40°C to 85°C 16 Pin QFN Reel Yes
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SP3222EB / SP3232EB True +3.0V to +5.5V RS-232 Transceivers Data Sheet Disclaimer
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