________________________________________________________________ Maxim Integrated Products
1
General Description
The MAX3238E/MAX3248E transceivers use Maxim's
revolutionary AutoShutdown PlusTM feature to achieve
10nA supply current. These devices shut down the on-
board power supply and drivers when they do not sense
a valid signal transition on either the receiver or transmit-
ter inputs. This occurs if the RS-232 cable is disconnect-
ed or if the transmitters of the connected peripheral are
turned off. The devices turn on again when a valid transi-
tion is applied to any RS-232 receiver or transmitter input.
AutoShutdown Plus automatically achieves this power
savings through its on-board circuitry, as no changes are
required to the existing BIOS or operating system.
All RS-232 inputs and outputs, as well as the logic I/O
pins, have enhanced ESD protection to 15kV. The addi-
tional ESD protection on the logic I/O pins makes the
MAX3238E/MAX3248E ideal for cell phone data cable
applications because it eliminates the need for costly
external TransZorbTM or protection schemes.
The MAX3238E/MAX3248E contain five drivers and three
receivers and are 3V-powered EIA/TIA-232 and V.28/V.24
communication interfaces intended for cell phones, data
cables, and modem applications. A proprietary, high-effi-
ciency, dual charge-pump power supply and a low-
dropout transmitter combine to deliver true RS-232
performance from a single +3.0V to +5.5V supply. A
guaranteed data rate of 250kbps provides compatibility
with popular software for communicating with personal
computers.
The MAX3238E and the MAX3248E differ only in their
input logic thresholds. The MAX3238E has standard logic
thresholds, while the MAX3248E has low-level logic
thresholds of 0.6V to 1.2V, which are ideal for 1.8V sys-
tems.
The transmitter inputs, FORCEON, and FORCEOFF have
a 400k
active positive feedback resistor. Once driven to
a valid logic level, they will retain this level if the driving
signal is removed or goes high impedance. Unused
transmitter and logic inputs may be left unconnected. The
MAX3238E/MAX3248E can operate with supply voltages
ranging from +3.0V to +5.5V.
Applications
Features
o Enhanced ESD Protection on RS-232 I/O Pins and
All Logic Pins
15kV--Human Body Model
8kV--IEC 1000-4-2 Contact Discharge
15kV--IEC 1000-4-2 Air-Gap Discharge
o Guaranteed Data Rate: 250kbps
o 10nA Low-Power Shutdown with Receivers Active
o Schmitt Triggers on All Inputs
o Flow-Through Pinout
o Meets EIA/TIA-232 Specifications Down to 3.0V
o Guaranteed 6V/s Slew Rate
o Low-Level Logic Thresholds (MAX3248E)
o RS-232-Compatible Outputs to 2.7V
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with 15kV ESD-Protected I/O and Logic Pins
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+
V
CC
C1-
T1IN
T2IN
INVALID
T3IN
R1OUT
R2OUT
T4IN
R3OUT
T5IN
R1OUTB
FORCEOFF
FORCEON
T5OUT
R3IN
T4OUT
R2IN
R1IN
T3OUT
T2OUT
T1OUT
V-
C2-
GND
C2+
SSOP
TOP VIEW
MAX3238E
MAX3248E
___________________Pin Configuration
19-1632; Rev 1; 6/01
Ordering Information
AutoShutdown Plus is a trademark of Maxim Integrated Products.
TransZorb is a trademark of General Semiconductor Industries, Inc.
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.
Cellular Data Cables
Modems
Battery-Powered Equipment
Peripherals
Data Cradles
Printers
Typical Operating Circuit appears at end of data sheet.
28 SSOP
28 SSOP
28 SSOP
28 SSOP
PIN-PACKAGE
TEMP. RANGE
0C to +70C
-40C to +85C
0C to +70C
-40C to +85C
MAX3248EEAI
MAX3248ECAI
MAX3238EEAI
MAX3238ECAI
PART
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
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.
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with 15kV ESD-Protected I/O and Logic Pins
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +5.5V, C1C4 = 0.1F (tested at 3.3V 5%), C1C4 = 0.22F (tested at 3.3V 10%), C1 = 0.047F, and
C2C4 = 0.33F (tested at 5.0V 10%), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
V
CC
...........................................................................-0.3V to +6V
V+ (Note 1) ...............................................................-0.3V to +7V
V- (Note 1) ................................................................+0.3V to -7V
V+ + |V-| (Note 1) .................................................................+13V
Input Voltages
T_IN, FORCEOFF, FORCEON ..............................-0.3V to +6V
R_IN .................................................................................25V
Output Voltages
T_OUT...........................................................................13.2V
R_OUT, INVALID ....................................-0.3V to (V
CC
+ 0.3V)
Short-Circuit Duration
T_OUT (one at a time) ............................................Continuous
Continuous Power Dissipation (T
A
= +70C)
28-Pin SSOP (derate 9.52mW/C above +70C) .........762mW
Operating Temperature Ranges
MAX3238ECAI/MAX3248ECAI ...........................0C to +70C
MAX3238EEAI/MAX3248EEAI .........................-40C to +85C
Storage Temperature Range ............................-65C to +150C
Lead Temperature (soldering, 10s) ................................+300C
Note 1: V+ and V- can have a maximum magnitude of +7V, but their absolute difference can not exceed +13V.
1.10
1.2
1.15
1.6
0.95
1.2
MAX3248E
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 5.0V
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 3.3V
T_IN (active)
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 5.0V
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 3.3V
T_IN (active)
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 5.0V
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 3.3V
T_IN (active)
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 5.0V
FORCEON, FORCEOFF, and T_IN
wake-up threshold; V
CC
= 3.3V
T_IN (active)
PARAMETER
MIN
TYP
MAX
UNITS
Input Logic Threshold Low
0.8
1.20
V
Supply Current, AutoShutdown Plus
Disabled
0.5
2.0
mA
Supply Current, AutoShutdown Plus
Input Logic Threshold High
1.60
2.0
0.75
6
A
V
10
300
2.10
2.4
1.30
2.0
MAX3238E
0.6
0.7
0.8
1.45
0.6
1.0
0.6
0.85
0.8
1.00
MAX3248E
Supply Current, Shutdown
10
300
nA
CONDITIONS
FORCEOFF = GND, R_IN = GND, T_IN = V
CC
or GND
MAX3238E
FORCEON = FORCEOFF = V
CC
, no load
Receivers idle, T_IN = V
CC
or GND, FORCEON =
GND, FORCEOFF = V
CC
R_IN = FORCEON = GND, FORCEOFF = V
CC,
T_IN = V
CC
or GND
nA
DC CHARACTERISTICS (V
CC
= +3.3V or +5.0V, T
A
= +25C)
LOGIC INPUTS AND RECEIVER OUTPUTS
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with 15kV ESD-Protected I/O and Logic Pins
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +5.5V, C1C4 = 0.1F (tested at 3.3V 5%), C1C4 = 0.22F (tested at 3.3V 10%), C1 = 0.047F, and
C2C4 = 0.33F (tested at 5.0V 10%), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
Figure 4a
Figure 4a
Figure 4b
V
CC
= 5V, Figure 4b (Note 3)
V
CC
= 5V, Figure 4b
I
OUT
= 1.0mA
I
OUT
= -1.0mA
V
CC
= 5V, Figure 4b
V
-0.3
0.3
Receiver Input Threshold to
INVALID Output Low
V
2.7
Receiver Input Threshold to
INVALID Output High
s
15
30
60
Receiver or Transmitter Edge to
Shutdown (t
AUTOSHDN
)
s
25
Receiver or Transmitter Edge to
Transmitters Enabled (t
WU
)
s
60
Receiver Positive or Negative
Threshold to INVALID Low (t
INVL
)
V
0.4
INVALID Output Voltage Low
V
V
CC -
0.6
INVALID Output Voltage High
s
0.3
Receiver Positive or Negative
Threshold to INVALID High (t
INVH
)
Positive threshold
Negative threshold
-2.7
V
-25
25
I
OUT
= -1.0mA
I
OUT
= 1.0mA
Input Voltage Range
V
CC
= 3.3V
Receivers disabled
T_IN, FORCEON, FORCEOFF (Note 2)
0.6
1.0
CONDITIONS
V
CC
= 5.0V
V
0.8
1.4
Input Threshold Low
V
CC
= 3.3V
1.5
2.4
V
CC
= 5.0V
V
2.0
2.4
Input Threshold High
V
0.6
Input Hysteresis
T
A
= +25C
k
3
5
7
Input Resistance
V
V
CC
-
V
CC
-
0.6
0.1
Output Voltage High
V
0.4
Output Voltage Low
A
0.05
10
Output Leakage Current
A
9
18
Input Leakage Current
UNITS
MIN
TYP
MAX
PARAMETER
All transmitter outputs loaded with 3k
to ground
V
5.0
5.4
Output Voltage Swing
V
CC
= 0, T
OUT
= 2V
300
50k
Output Resistance
V
CC
3.6V
35
60
V
CC
> 3.6V
mA
40
100
Output Short-Circuit Current
IEC 1000-4-2 Air-Gap Discharge Method
15
IEC 1000-4-2 Contact Discharge Method
8
Human Body Model
kV
15
ESD Protection (R_IN, T_IN, R_OUT,
T_OUT, FORCEON, FORCEOFF,
INVALID, R_OUTB)
RECEIVER INPUTS
AutoShutdown (FORCEON = GND, FORCEOFF = V
CC
)
TRANSMITTER OUTPUTS
ESD PROTECTION
-6
-2
-4
2
0
4
6
-5
-3
1
-1
3
5
0
1000
1500
500
2000
2500
3000
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
4
2
8
6
10
12
0
1000
1500
500
2000
2500
3000
SLEW RATE vs. LOAD CAPACITANCE
MAX3238E toc02
LOAD CAPACITANCE (pF)
SLEW RATE (V/
s)
SR+
SR-
1 TRANSMITTER 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3k
+ C
L
50
20
10
0
0
1000
500
2000
3000
SUPPLY CURRENT vs. LOAD CAPACITANCE
WHEN TRANSMITTING DATA
30
MAX3238 TOC-03
SUPPLY CURRENT (mA)
LOAD CAPACITANCE (pF)
1500
2500
40
250kbps
20kbps
120kbps
1 TRANSMITTER 20kbps, 120 kbps, 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3k
+ C
L
__________________________________________Typical Operating Characteristics
(V
CC
= +3.3V, 250kbps data rate, 0.1F capacitors, all transmitters loaded with 3k
, T
A
= +25C, unless otherwise noted.)
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with 15kV ESD-Protected I/O and Logic Pins
4
_______________________________________________________________________________________
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +3.0V to +5.5V, C1C4 = 0.1F (tested at 3.3V 5%), C1C4 = 0.22F (tested at 3.3V 10%), C1 = 0.047F, and
C2C4 = 0.33F (tested at 5.0V 10%), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25C.)
Note 2: The transmitter inputs have an active positive feedback resistor. The input current goes to zero when the inputs are at the
supply rails.
Note 3: During AutoShutdown only, a transmitter/receiver edge is defined as a transition through the transmitter/receiver input logic
wake-up thresholds.
CONDITIONS
UNITS
MIN
TYP
MAX
PARAMETER
| t
PHL
- t
PLH
|
4
30
t
PHL
R_IN to R_OUT,
C
L
= 150pF
t
PLH
C
L
= 150pF to 1000pF
R
L
= 3k
, C
L
= 1000pF, one transmitter switching
C
L
= 150pF to 2500pF
0.15
V
CC
= 3.3V,
T
A
= +25C,
R
L
= 3k
to 7k,
measured from +3V to
-3V or -3V to +3V
Normal operation
Normal operation
| t
PHL
- t
PLH
|
s
0.15
Receiver Propagation Delay
kbps
250
Maximum Data Rate
V/s
6
30
Transition-Region Slew Rate
s
2.6
Receiver Output Enable Time
s
2.4
Receiver Output Disable Time
ns
50
ns
50
Receiver Skew
Transmitter Skew
TIMING CHARACTERISTICS
MAX3238E/MAX3248E
+3.0V to +5.5V, 10nA, 250kbps RS-232 Transceivers
with 15kV ESD-Protected I/O and Logic Pins
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(V
CC
= +3.3V, 250kbps data rate, 0.1F capacitors, all transmitters loaded with 3k
, T
A
= +25C, unless otherwise noted.)
______________________________________________________________Pin Description
Output of the Valid Signal Detector. A logic 1 indicates if a valid RS-232 level is present on
receiver inputs.
INVALID
15
Noninverting Complementary Receiver Output. Always active.
R1OUTB
16
TTL/CMOS Transmitter Inputs (T5INT1IN). This pin has an active positive feedback resis-
tor. Once driven to a valid logic level, the pin retains that level if left unconnected until
power is cycled.
T_IN
17, 19, 22, 23, 24
TTL/CMOS Receiver Outputs (R3OUTR1OUT)
R_OUT
18, 20, 21
Negative Terminal of Voltage-Doubler Charge-Pump Capacitor
C1-
25
RS-232 Transmitter Outputs (T1OUTT5OUT)
T_OUT
5, 6, 7, 10, 12
RS-232 Receiver Inputs (R1INR3IN)
R_IN
8, 9, 11
Force-On Input. Drive high to override AutoShutdown Plus, keeping transmitters and
receivers on (FORCEOFF must be high) (Table 1). This pin has an active positive feedback
resistor. Once driven to a valid logic level, the pin retains that level if left unconnected until
power is cycled.
FORCEON
13
Force-Off Input. Drive low to shut down transmitters, receivers (except R1OUTB), and on-
board supply. This overrides AutoShutdown Plus and FORCEON (Table 1). This pin has an
active positive feedback resistor. Once driven to a valid logic level, the pin retains that
level if left unconnected until power is cycled.
FORCEOFF
14
-5.5V Generated by the Charge Pump
V-
4
Negative Terminal of Inverting Charge-Pump Capacitor
C2-
3
PIN
Ground
GND
2
Positive Terminal of Inverting Charge-Pump Capacitor
C2+
1
FUNCTION
NAME
26
V
CC
+3.0V to +5.5V Supply Voltage
27
V+
+5.5V Generated by the Charge Pump
28
C1+
Positive Terminal of Voltage-Doubler Charge-Pump Capacitor
-6
-2
-4
2
0
4
6
-3
-5
1
-1
3
5
2.0
3.0
3.5
2.5
4.0
4.5
5.0
TRANSMITTER OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX3238E toc04
SUPPLY VOLTAGE (V)
TRANSMITTER OUTPUT VOLTAGE (V)
V
OUT-
V
OUT
+
1 TRANSMITTER 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3k
+1000pF
0
20
10
30
40
50
2.0
3.0
3.5
2.5
4.0
4.5
5.0
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX3238E toc05
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
1 TRANSMITTER 250kbps
4 TRANSMITTERS 15.6kbps
ALL TRANSMITTERS LOADED
WITH 3k
+1000pF
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