19-1298; Rev 3a; 1/00
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
________________General Description
The MAX3222E/MAX3232E/MAX3237E/MAX3241E are
3V-powered EIA/TIA-232 and V.28/V.24 communications
interfaces with low power requirements, 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 Dis-
charge, and ±15kV using the Human Body Model. The
MAX3237E’s logic and receiver I/O pins are protected to
the above standards, while the transmitter output pins are
protected to ±15kV using the Human Body Model.
The transceivers have a proprietary low-dropout transmit-
ter output stage, delivering 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. Each device is guaran-
teed to run at data rates of 250kbps while maintaining RS-
232 output levels. The MAX3237E is guaranteed to run at
data rates of 250kbps in the normal operating mode and
1Mbps in the MegaBaud™ operating mode while main-
taining RS-232-compliant output levels.
The MAX3222E/MAX3232E have two receivers and two
drivers. The MAX3222E features a 1µA shutdown mode
that reduces power consumption and extends battery
life in portable systems. Its receivers can remain active
in shutdown mode, allowing external devices such as
modems to be monitored using only 1µA supply current.
Both the MAX3222E and MAX3232E are pin, package,
and functionally compatible with the industry-standard
MAX242 and MAX232, respectively.
The MAX3241E is a complete serial port (three drivers/five
receivers) designed for notebook and subnotebook com-
puters. The MAX3237E (five drivers/three receivers) is ideal
for peripheral applications that require fast data transfer.
Both devices feature a shutdown mode in which all
receivers can remain active while using a supply cur-
rent of only 1µA (MAX3241E) or 10nA (MAX3237E). The
MAX3237E/MAX3241E have additional receiver outputs
that always remain active.
The MAX3222E and MAX3232E are available in space-
saving SO, SSOP, and TSSOP packages. The MAX3241E
is available in SO and SSOP packages. The MAX3237E is
available in an SSOP package.
____________________________Features
o
ESD Protection for RS-232 I/O Pins
(MAX3222E/MAX3232E/MAX3241E)
±15kV—Human Body Model
±8kV—IEC 1000-4-2, Contact Discharge
±15kV—IEC 1000-4-2, Air-Gap Discharge
o
ESD Protection for All Logic and Receiver I/O
Pins (MAX3237E)
±15kV—Human Body Model
±8kV—IEC 1000-4-2, Contact Discharge
±15kV—IEC 1000-4-2, Air-Gap Discharge
o
ESD Protection for Transmitter Output Pins
(MAX3237E)
±15kV—Human Body Model
o
Guaranteed Data Rate
250kbps (MAX3222E/MAX3232E/MAX3241E
and MAX3237E, normal operation)
1Mbps (MAX3237E, MegaBaud operation)
o
Latchup Free
o
Low-Power Shutdown with Receivers Active
1µA (MAX3222E/MAX3241E)
10nA (MAX3237E)
o
Flow-Through Pinout (MAX3237E)
o
Guaranteed Mouse Driveability (MAX3241E)
o
Meets EIA/TIA-232 Specifications Down to 3.0V
MAX3222E/MAX3232E/MAX3237E/MAX3241E
†
_______________Ordering Information
PART
MAX3222ECUP
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
20 TSSOP
MAX3222ECAP
0°C to +70°C
20 SSOP
Ordering Information continued at end of data sheet.
___________________________Selector Guide
PART
MAX3222E
MAX3232E
MAX3237E
(Normal)
MAX3237E
(MegaBaud)
MAX3241E
NO. OF
DRIVERS/
RECEIVERS
2/2
2/2
5/3
5/3
3/5
LOW-
POWER
SHUTDOWN
✔
—
✔
✔
✔
GUARANTEED
DATA RATE
(kbps)
250
250
250
1M
250
________________________Applications
Notebooks, Subnotebooks,
and Palmtop Computers
Battery-Powered Equipment
Cell-Phone Data Cables
Smart Phones
XDSL Modems
Printers
Cell Phones
Pin Configurations appear at end of data sheet.
Typical Operating Circuits appear at end of data sheet.
MegaBaud is a trademark of Maxim Integrated Products.
†
Covered by U.S. Patent numbers 4,636,930; 4,679,134; 4,777,577; 4,797,899; 4,809,152; 4,897,774; 4,999,761; and other patents pending.
________________________________________________________________
Maxim Integrated Products
1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
MAX3222E/MAX3232E/MAX3237E/MAX3241E
ABSOLUTE MAXIMUM RATINGS
V
CC
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,
EN, SHDN,
MBAUD to GND ........................-0.3V to +6V
R_IN to GND .....................................................................±25V
Output Voltages
T_OUT to GND...............................................................±13.2V
R_OUT, R_OUTB (MAX3241E)................-0.3V to (V
CC
+ 0.3V)
Short-Circuit Duration, T_OUT to GND.......................Continuous
Continuous Power Dissipation (T
A
= +70°C)
16-Pin SSOP (derate 7.14mW/°C above +70°C) ..........571mW
16-Pin Wide SO (derate 9.52mW/°C above +70°C) .....762mW
18-Pin Wide SO (derate 9.52mW/°C above +70°C) .....762mW
18-Pin PDIP (derate 11.11mW/°C above +70°C)..........889mW
20-Pin TSSOP (derate 7.0mW/°C above +70°C) ..........559mW
20-Pin SSOP (derate 8.00mW/°C above +70°C) ..........640mW
28-Pin SSOP (derate 9.52mW/°C above +70°C) ..........762mW
28-Pin Wide SO (derate 12.50mW/°C above +70°C) .............1W
Operating Temperature Ranges
MAX32_ _EC_ _ ...................................................0°C to +70°C
MAX32_ _EE_ _.................................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
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.
ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +5.5V, C1–C4 = 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
PARAMETER
CONDITIONS
MAX3222E, MAX3232E,
MAX3241E
MAX3237E
Shutdown Supply Current
LOGIC INPUTS
Input Logic Low
Input Logic High
Transmitter Input Hysteresis
Input Leakage Current
RECEIVER OUTPUTS
Output Leakage Current
Output Voltage Low
Output Voltage High
RECEIVER INPUTS
Input Voltage Range
Input Threshold Low
T
A
= +25°C
V
CC
= 3.3V
V
CC
= 5.0V
-25
0.6
0.8
1.1
1.5
+25
V
V
R_OUT (MAX3222E/MAX3237E/MAX3241E),
EN
= V
CC
,
receivers disabled
I
OUT
= 1.6mA (MAX3222E/MAX3232E/MAX3241E)
I
OUT
= 1.0mA (MAX3237E)
I
OUT
= -1.0mA
V
CC
-
0.6
V
CC
-
0.1
±0.05
±10
0.4
0.4
µA
V
V
T_IN,
EN, SHDN
T_IN,
SHDN,
MBAUD
MAX3222E, MAX3232E,
MAX3241E
MAX3237E (Note 3)
T_IN,
EN, SHDN,
MBAUD
T_IN,
EN, SHDN,
MBAUD
V
CC
= 3.3V
V
CC
= 5.0V
2.0
2.4
0.5
±0.01
9
±1
18
0.8
V
V
V
µA
SHDN
= GND
SHDN
= R_IN = GND, T_IN = GND or V
CC
(MAX3237E)
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
(V
CC
= +3.3V or +5.0V, T
A
= +25°C)
Supply Current
SHDN
= V
CC
, no load
0.3
0.5
1
10
1
2.0
10
300
µA
nA
mA
2
_______________________________________________________________________________________
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +5.5V, C1–C4 = 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
PARAMETER
RECEIVER INPUTS
Input Threshold High
Input Hysteresis
Input Resistance
TRANSMITTER OUTPUTS
Output Voltage Swing
Output Resistance
Output Short-Circuit Current
Output Leakage Current
V
CC
= 0 or 3V to 5.5V, V
OUT
= ±12V, transmitters disabled
(MAX3222E/MAX3232E/MAX3241E)
All transmitter outputs loaded with 3kΩ to ground
V
CC
= 0, transmitter output = ±2V
±5
300
±5.4
50k
±60
±25
V
Ω
mA
µA
T
A
= +25°C
3
T
A
= +25°C
V
CC
= 3.3V
V
CC
= 5.0V
1.5
2.0
0.5
5
7
2.4
2.4
V
V
kΩ
CONDITIONS
MIN
TYP
MAX
UNITS
MAX3222E/MAX3232E/MAX3237E/MAX3241E
MOUSE DRIVEABILITY
(MAX3241E)
Transmitter Output Voltage
ESD PROTECTION
Human Body Model
R_IN, T_OUT
IEC 1000-4-2 Air-Gap Discharge (except MAX3237E)
IEC 1000-4-2 Contact Discharge (except MAX3237E)
T_IN, R_IN, R_OUT,
EN, SHDN,
MBAUD
Human Body Model
MAX3237E
IEC 1000-4-2 Air-Gap Discharge
IEC 1000-4-2 Contact Discharge
±15
±15
±8
±15
±15
±8
kV
kV
T1IN = T2IN = GND, T3IN = V
CC
, T3OUT loaded with 3kΩ
to GND, T1OUT and T2OUT loaded with 2.5mA each
±5
V
TIMING CHARACTERISTICS—MAX3222E/MAX3232E/MAX3241E
(V
CC
= +3.0V to +5.5V, C1–C4 = 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Maximum Data Rate
Receiver Propagation Delay
Receiver Output Enable Time
Receiver Output Disable Time
Transmitter Skew
Receiver Skew
t
PHL
- t
PLH
t
PHL
- t
PLH
V
CC
= 3.3V,
T
A
= +25°C,
R
L
= 3kΩ to 7kΩ,
measured from +3V
to -3V or -3V to +3V
C
L
= 150pF to
1000pF
C
L
= 150pF to
2500pF
6
4
t
PHL
t
PLH
R
L
= 3kΩ, C
L
= 1000pF,
one transmitter switching
Receiver input to receiver output,
C
L
= 150pF
Normal operation (except MAX3232E)
Normal operation (except MAX3232E)
(Note 4)
250
0.15
0.15
200
200
100
50
30
V/µs
30
kbps
µs
ns
ns
ns
ns
Transition-Region Slew Rate
Note 2:
MAX3222E/MAX3232E/MAX3241E: C1–C4 = 0.1µF tested at 3.3V ±10%; C1 = 0.047µF, C2–C4 = 0.33µF tested at 5.0V
±10%. MAX3237E: C1–C4 = 0.1µF, tested at 3.3V ±5%; C1–C4 = 0.22µF tested at 3.3V ±10%; C1 = 0.047µF, C2–C4 =
0.33µF tested at 5.0V ±10%.
Note 3:
The MAX3237E logic inputs have an active positive feedback resistor. The input current goes to zero when the inputs are at
the supply rails.
Note 4:
Transmitter skew is measured at the transmitter zero crosspoints.
_______________________________________________________________________________________
3
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
MAX3222E/MAX3232E/MAX3237E/MAX3241E
TIMING CHARACTERISTICS—MAX3237E
(V
CC
= +3.0V to +5.5V, C1–C4 = 0.1µF, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 2)
PARAMETER
CONDITIONS
R
L
= 3kΩ, C
L
= 1000pF, one transmitter switching,
MBAUD = GND
Maximum Data Rate
V
CC
= 3.0V to 4.5V, R
L
= 3kΩ, C
L
= 250pF,
one transmitter switching, MBAUD = V
CC
V
CC
= 4.5V to 5.5V, R
L
= 3kΩ, C
L
= 1000pF,
one transmitter switching, MBAUD = V
CC
Receiver Propagation Delay
Receiver Output Enable Time
Receiver Output Disable Time
Transmitter Skew
Receiver Skew
R_IN to R_OUT, C
L
= 150pF
Normal operation
Normal operation
t
PHL
t
PLH
MIN
250
1000
1000
0.15
0.15
2.6
2.4
100
100
50
C
L
= 150pF
to 1000pF
MBAUD =
GND
MBAUD =
V
CC
6
24
4
30
150
30
V/µs
µs
µs
µs
ns
ns
ns
kbps
TYP
MAX
UNITS
|
t
PHL
- t
PLH
|
, MBAUD = GND
|
t
PHL
- t
PLH
|
, MBAUD = V
CC
|
t
PHL
- t
PLH
|
Transition-Region Slew Rate
V
CC
= 3.3V, R
L
= 3kΩ to
7kΩ, +3V to -3V or -3V to
+3V, T
A
= +25°C
C
L
= 150pF to 2500pF,
MBAUD = GND
__________________________________________Typical Operating Characteristics
(V
CC
= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and C
L
, T
A
= +25°C, unless otherwise noted.)
MAX3222E/MAX3232E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
0
MAX3237E toc01
MAX3222E/MAX3232E
SLEW RATE vs. LOAD CAPACITANCE
MAX3237E toc02
MAX3222E/MAX3232E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
40
SUPPLY CURRENT (mA)
35
250kbps
30
25
20
15
10
20kbps
120kbps
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
MAX3237E toc03
16
14
12
SLEW RATE (V/µs)
10
8
6
4
+SLEW
-SLEW
45
TRANSMITTER OUTPUT VOLTAGE (V)
V
OUT+
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
V
OUT-
2
FOR DATA RATES UP TO 250kbps
0
5
0
4000
5000
0
1000
2000
3000
4000
5000
1000
2000
3000
4000
5000
0
1000
2000
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
4
_______________________________________________________________________________________
±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
Typical Operating Characteristics (continued)
(V
CC
= +3.3V, 250kbps data rate, 0.1µF capacitors, all transmitters loaded with 3kΩ and C
L
, T
A
= +25°C, unless otherwise noted.)
MAX3241E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3237E to04
MAX3222E/MAX3232E/MAX3237E/MAX3241E
MAX3241E
SLEW RATE vs. LOAD CAPACITANCE
MAX3237E toc05
MAX3241E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
250kbps
40
30
20kbps
20
10
0
120kbps
MAX3237E toc06
TRANSMITTER OUTPUT VOLTAGE (V)
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
0
1000
2000
3000
14
12
SLEW RATE (V/µs)
10
8
6
4
60
50
SUPPLY CURRENT (mA)
V
OUT+
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
V
OUT-
4000
5000
2
0
0
1000
2000
3000
4000
5000
0
1000
2000
3000
4000
5000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
0
MAX3238E toc01
MAX3237E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE (MBAUD = V
CC
)
MAX3237E toc08
MAX3237E
SLEW RATE vs. LOAD CAPACITANCE
(MBAUD = GND)
MAX3237E toc09
7.5
1Mbps
TRANSMITTER OUTPUT VOLTAGE (V)
5.0
2.5
0
-2.5
-5.0
-7.5
2Mbps
1.5Mbps
1Mbps
0
500
1000
1500
1 TRANSMITTER AT FULL DATA RATE
4 TRANSMITTERS AT 1/16 DATA RATE
3kΩ + C
L
LOAD, EACH OUTPUT
2Mbps
1.5Mbps
12
10
SR-
SLEW RATE (V/µs)
8
SR+
6
4
2
0
1 TRANSMITTER AT 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3kΩ + C
L
0
500
1000
1500
2000
2500
TRANSMITTER OUTPUT VOLTAGE (V)
V
OUT
+
FOR DATA RATES UP TO 250kbps
1 TRANSMITTER 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3kΩ + C
L
V
OUT-
500
1000
1500
2000
2500
300
2000
3000
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
MAX3237E
SLEW RATE vs. LOAD CAPACITANCE
(MBAUD = V
CC
)
MAX3237E toc10
MAX3237E
SUPPLY CURRENT vs. LOAD CAPACITANCE
WHEN TRANSMITTING DATA (MBAUD = GND)
MAX3237E toc11
MAX3237E
TRANSMITTER SKEW vs. LOAD CAPACITANCE
(MBAUD = V
CC
)
MAX3237E toc12
70
60
SLEW RATE (V/µs)
50
40
30
20
10
0
0
500
1000
1500
-SLEW, 1Mbps
+SLEW, 1Mbps
-SLEW, 2Mbps
+SLEW, 2Mbps
50
250kbps
40
SUPPLY CURRENT (mA)
120kbps
20kbps
30
100
80
TRANSMITTER SKEW (ns)
60
20
1 TRANSMITTER AT 20kbps, 120kbps, 250kbps
4 TRANSMITTERS AT 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3kΩ + C
L
0
500
1000
1500
2000
2500
3000
40
|t
PLH
-
t
PHL
|
1 TRANSMITTER AT 500kbps
4 TRANSMITTERS AT 1/16 DATA RATE
ALL TRANSMITTERS LOADED
WITH 3kΩ + C
L
0
500
1000
1500
2000
LOAD CAPACITANCE (pF)
1 TRANSMITTER AT FULL DATA RATE
4 TRANSMITTERS AT 1/16 DATA RATE
3kΩ + C
L
LOAD EACH OUTPUT
2000
10
20
0
LOAD CAPACITANCE (pF)
LOAD CAPACITANCE (pF)
0
_______________________________________________________________________________________
5
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