________________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 0.1F 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 MegaBaudTM operating mode while main-
taining RS-232-compliant output levels.
The MAX3222E/MAX3232E have two receivers and two
drivers. The MAX3222E features a 1A 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 1A 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 1A (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.
________________________Applications
Notebooks, Subnotebooks,
Smart Phones
and Palmtop Computers
XDSL Modems
Battery-Powered Equipment
Printers
Cell-Phone Data Cables
Cell Phones
____________________________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
1A (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
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
________________________________________________________________ Maxim Integrated Products
1
19-1298; Rev 3a; 1/00
_______________Ordering Information
Ordering Information continued at end of data sheet.
___________________________Selector Guide
Typical Operating Circuits appear at end of data sheet.
Pin Configurations appear at end of data sheet.
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.
MegaBaud is a trademark of Maxim Integrated Products.
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.
PART
MAX3222E
MAX3232E
MAX3237E
(Normal)
MAX3237E
(MegaBaud)
MAX3241E
3/5
5/3
5/3
2/2
2/2
NO. OF
DRIVERS/
RECEIVERS
LOW-
POWER
SHUTDOWN
--
250
1M
250
250
250
GUARANTEED
DATA RATE
(kbps)
MAX3222ECAP
MAX3222ECUP
PART
TEMP. RANGE
0C to +70C
0C to +70C
20 SSOP
20 TSSOP
PIN-PACKAGE
MAX3222E/MAX3232E/MAX3237E/MAX3241E
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +5.5V, C1C4 = 0.1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.) (Note 2)
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
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
= +70C)
16-Pin SSOP (derate 7.14mW/C above +70C) ..........571mW
16-Pin Wide SO (derate 9.52mW/C above +70C) .....762mW
18-Pin Wide SO (derate 9.52mW/C above +70C) .....762mW
18-Pin PDIP (derate 11.11mW/C above +70C)..........889mW
20-Pin TSSOP (derate 7.0mW/C above +70C) ..........559mW
20-Pin SSOP (derate 8.00mW/C above +70C) ..........640mW
28-Pin SSOP (derate 9.52mW/C above +70C) ..........762mW
28-Pin Wide SO (derate 12.50mW/C above +70C) .............1W
Operating Temperature Ranges
MAX32_ _EC_ _ ...................................................0C to +70C
MAX32_ _EE_ _.................................................-40C to +85C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
Note 1: V+ and V- can have maximum magnitudes of 7V, but their absolute difference cannot exceed 13V.
V
CC
= 5.0V
V
CC
= 3.3V
V
CC
= 3.3V
V
CC
= 5.0V
SHDN = V
CC
, no load
T_IN, EN, SHDN
T
A
= +25C
I
OUT
= 1.6mA (MAX3222E/MAX3232E/MAX3241E)
R_OUT (MAX3222E/MAX3237E/MAX3241E), EN = V
CC
,
receivers disabled
A
T_IN, EN, SHDN, MBAUD
T_IN, EN, SHDN, MBAUD
I
OUT
= -1.0mA
CONDITIONS
0.01
1
Input Leakage Current
SHDN = GND
A
1
10
Shutdown Supply Current
V
0.8
1.5
Input Threshold Low
0.6
1.1
V
-25
+25
Input Voltage Range
V
V
CC
-
V
CC
-
0.6
0.1
Output Voltage High
mA
0.3
1
Supply Current
V
0.4
Output Voltage Low
A
0.05
10
Output Leakage Current
V
0.5
Transmitter Input Hysteresis
V
0.8
Input Logic Low
2.0
V
2.4
Input Logic High
UNITS
MIN
TYP
MAX
PARAMETER
MAX3222E, MAX3232E,
MAX3241E
MAX3237E
0.5
2.0
SHDN = R_IN = GND, T_IN = GND or V
CC
(MAX3237E)
nA
10
300
MAX3222E, MAX3232E,
MAX3241E
T_IN, SHDN, MBAUD
9
18
MAX3237E (Note 3)
I
OUT
= 1.0mA (MAX3237E)
0.4
DC CHARACTERISTICS (V
CC
= +3.3V or +5.0V, T
A
= +25C)
LOGIC INPUTS
RECEIVER OUTPUTS
RECEIVER INPUTS
MAX3222E/MAX3232E/MAX3237E/MAX3241E
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
_______________________________________________________________________________________
3
Note 2: MAX3222E/MAX3232E/MAX3241E: C1C4 = 0.1F tested at 3.3V 10%; C1 = 0.047F, C2C4 = 0.33F tested at 5.0V
10%. MAX3237E: C1C4 = 0.1F, tested at 3.3V 5%; C1C4 = 0.22F tested at 3.3V 10%; C1 = 0.047F, C2C4 =
0.33F 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.
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +5.5V, C1C4 = 0.1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.) (Note 2)
T
A
= +25C
IEC 1000-4-2 Contact Discharge (except MAX3237E)
IEC 1000-4-2 Air-Gap Discharge (except MAX3237E)
Human Body Model
T
A
= +25C
V
CC
= 0 or 3V to 5.5V, V
OUT
= 12V, transmitters disabled
(MAX3222E/MAX3232E/MAX3241E)
T1IN = T2IN = GND, T3IN = V
CC
, T3OUT loaded with 3k
to GND, T1OUT and T2OUT loaded with 2.5mA each
CONDITIONS
V
0.5
Input Hysteresis
V
1.5
2.4
Input Threshold High
8
R_IN, T_OUT
15
kV
15
k
3
5
7
Input Resistance
A
25
Output Leakage Current
V
5
Transmitter Output Voltage
UNITS
MIN
TYP
MAX
PARAMETER
TIMING CHARACTERISTICS--MAX3222E/MAX3232E/MAX3241E
(V
CC
= +3.0V to +5.5V, C1C4 = 0.1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.) (Note 2)
V
CC
= 0, transmitter output = 2V
300
50k
Output Resistance
TRANSMITTER OUTPUTS
mA
60
Output Short-Circuit Current
2.0
2.4
All transmitter outputs loaded with 3k
to ground
V
5
5.4
Output Voltage Swing
V
CC
= 3.3V
V
CC
= 5.0V
MAX3237E
8
T_IN, R_IN, R_OUT, EN, SHDN,
MBAUD
15
kV
15
RECEIVER INPUTS
MOUSE DRIVEABILITY (MAX3241E)
ESD PROTECTION
Human Body Model
IEC 1000-4-2 Air-Gap Discharge
IEC 1000-4-2 Contact Discharge
Transition-Region Slew Rate
4
30
V/s
C
L
= 150pF to
2500pF
C
L
= 150pF to
1000pF
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Receiver Skew
t
PHL
- t
PLH
50
ns
Transmitter Skew
t
PHL
- t
PLH
100
ns
Receiver Output Disable Time
200
ns
Receiver Output Enable Time
200
ns
6
30
Maximum Data Rate
250
kbps
t
PHL
0.15
Receiver Propagation Delay
t
PLH
0.15
s
CONDITIONS
(Note 4)
Normal operation (except MAX3232E)
Normal operation (except MAX3232E)
V
CC
= 3.3V,
T
A
= +25C,
R
L
= 3k
to 7k,
measured from +3V
to -3V or -3V to +3V
R
L
= 3k
, C
L
= 1000pF,
one transmitter switching
Receiver input to receiver output,
C
L
= 150pF
__________________________________________Typical Operating Characteristics
(V
CC
= +3.3V, 250kbps data rate, 0.1F capacitors, all transmitters loaded with 3k
and C
L
, T
A
= +25C, unless otherwise noted.)
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
0
1000
2000
3000
4000
5000
MAX3222E/MAX3232E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3237E toc01
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
V
OUT+
V
OUT-
0
6
2
4
10
8
14
12
16
0
1000
2000
3000
4000
5000
MAX3222E/MAX3232E
SLEW RATE vs. LOAD CAPACITANCE
MAX3237E toc02
LOAD CAPACITANCE (pF)
SLEW RATE (V/
s)
+SLEW
FOR DATA RATES UP TO 250kbps
-SLEW
0
25
20
15
5
10
35
30
40
45
0
2000
1000
3000
4000
5000
MAX3222E/MAX3232E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3237E toc03
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
250kbps
120kbps
20kbps
T1 TRANSMITTING AT 250kbps
T2 TRANSMITTING AT 15.6kbps
MAX3222E/MAX3232E/MAX3237E/MAX3241E
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
4
_______________________________________________________________________________________
TIMING CHARACTERISTICS--MAX3237E
(V
CC
= +3.0V to +5.5V, C1C4 = 0.1F, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.) (Note 2)
24
150
MBAUD =
V
CC
Transition-Region Slew Rate
V
CC
= 3.3V, R
L
= 3k
to
7k
, +3V to -3V or -3V to
+3V, T
A
= +25C
MBAUD =
GND
C
L
= 150pF
to 1000pF
t
PLH
t
PHL
V/s
6
30
Receiver Skew
50
ns
|
t
PHL
- t
PLH
|
Transmitter Skew
100
ns
|
t
PHL
- t
PLH
|
, MBAUD = V
CC
R_IN to R_OUT, C
L
= 150pF
Maximum Data Rate
1000
kbps
V
CC
= 4.5V to 5.5V, R
L
= 3k
, C
L
= 1000pF,
one transmitter switching, MBAUD = V
CC
1000
V
CC
= 3.0V to 4.5V, R
L
= 3k
, C
L
= 250pF,
one transmitter switching, MBAUD = V
CC
PARAMETER
MIN
TYP
MAX
UNITS
Receiver Output Enable Time
2.6
s
Receiver Propagation Delay
0.15
s
250
0.15
100
ns
|
t
PHL
- t
PLH
|
, MBAUD = GND
Receiver Output Disable Time
2.4
s
Normal operation
CONDITIONS
Normal operation
R
L
= 3k
, C
L
= 1000pF, one transmitter switching,
MBAUD = GND
4
30
C
L
= 150pF to 2500pF,
MBAUD = GND
MAX3222E/MAX3232E/MAX3237E/MAX3241E
15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
Up to 1Mbps, True RS-232 Transceivers
_______________________________________________________________________________________
5
-6
-2
-4
2
0
4
6
-5
-3
1
-1
3
5
0
1000
1500
500
2000
2500
300
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3238E
toc01
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
V
OUT-
V
OUT
+
FOR DATA RATES UP TO 250kbps
1 TRANSMITTER 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3k
+ C
L
0
10
20
30
50
40
60
70
0
MAX3237E
SLEW RATE vs. LOAD CAPACITANCE
(MBAUD = V
CC
)
MAX3237E toc10
LOAD CAPACITANCE (pF)
SLEW RATE (V/
s)
500
1000
1500
2000
-SLEW, 1Mbps
+SLEW, 1Mbps
1 TRANSMITTER AT FULL DATA RATE
4 TRANSMITTERS AT 1/16 DATA RATE
3k
+ C
L
LOAD EACH OUTPUT
-SLEW, 2Mbps
+SLEW, 2Mbps
-7.5
-5.0
-2.5
0
2.5
5.0
7.5
0
MAX3237E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE (MBAUD = V
CC
)
MAX3237E toc08
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
500
1000
1500
2000
1 TRANSMITTER AT FULL DATA RATE
4 TRANSMITTERS AT 1/16 DATA RATE
3k
+ C
L
LOAD, EACH OUTPUT
2Mbps
1.5Mbps
1Mbps
2Mbps
1Mbps
1.5Mbps
0
2
4
6
8
10
12
0
MAX3237E
SLEW RATE vs. LOAD CAPACITANCE
(MBAUD = GND)
MAX3237E toc09
LOAD CAPACITANCE (pF)
SLEW RATE (V/
s)
1000
1500
500
2000
2500
3000
SR+
SR-
1 TRANSMITTER AT 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3k
+ C
L
0
10
20
30
40
50
0
MAX3237E
SUPPLY CURRENT vs. LOAD CAPACITANCE
WHEN TRANSMITTING DATA (MBAUD = GND)
MAX3237E toc11
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
1000
1500
500
2000
2500
3000
250kbps
120kbps
20kbps
1 TRANSMITTER AT 20kbps, 120kbps, 250kbps
4 TRANSMITTERS AT 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3k
+ C
L
0
20
60
40
80
100
0
MAX3237E
TRANSMITTER SKEW vs. LOAD CAPACITANCE
(MBAUD = V
CC
)
MAX3237E toc12
LOAD CAPACITANCE (pF)
1000
1500
500
2000
TRANSMITTER SKEW (ns)
|t
PLH
-
t
PHL
|
1 TRANSMITTER AT 500kbps
4 TRANSMITTERS AT 1/16 DATA RATE
ALL TRANSMITTERS LOADED
WITH 3k
+ C
L
Typical Operating Characteristics (continued)
(V
CC
= +3.3V, 250kbps data rate, 0.1F capacitors, all transmitters loaded with 3k
and C
L
, T
A
= +25C, unless otherwise noted.)
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
0
1000
2000
3000
4000
5000
MAX3241E
TRANSMITTER OUTPUT VOLTAGE
vs. LOAD CAPACITANCE
MAX3237E to04
LOAD CAPACITANCE (pF)
TRANSMITTER OUTPUT VOLTAGE (V)
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
V
OUT+
V
OUT-
0
30
20
10
40
50
60
0
2000
1000
3000
4000
5000
MAX3241E
OPERATING SUPPLY CURRENT
vs. LOAD CAPACITANCE
MAX3237E toc06
LOAD CAPACITANCE (pF)
SUPPLY CURRENT (mA)
250kbps
120kbps
20kbps
1 TRANSMITTER AT 250kbps
2 TRANSMITTERS AT 15.6kbps
0
4
2
8
6
12
10
14
0
1000
2000
3000
4000
5000
MAX3241E
SLEW RATE vs. LOAD CAPACITANCE
MAX3237E toc05
LOAD CAPACITANCE (pF)
SLEW RATE (V/
s)
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