19-1144; Rev 0; 9/96
+3.0V to +5.5V, 1µA, up to 250kbps, True
RS-232 Transceiver with AutoShutdown Plus™
_______________General Description
The MAX3238 true RS-232 transceiver achieves a
1µA supply current with Maxim’s revolutionary
AutoShutdown Plus feature. When the device does not
sense a valid signal transition on either the receiver or
transmitter inputs within 30sec, the on-board power
supply and drivers shut down. This occurs if the RS-232
cable is disconnected or if the transmitters of the con-
nected peripheral are inactive. The system turns on
again when a valid transition is applied to any RS-232
receiver or transmitter input, saving power without
changes to the existing BIOS or operating system.
The MAX3238 5-driver/3-receiver complete serial port is
a 3V-powered EIA/TIA-232 and V.28/V.24 communica-
tions interface intended for notebook or subnotebook
computer applications. A proprietary, high-efficiency,
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 popu-
lar software for communicating with personal comput-
ers. The MAX3238 requires only 0.1µF capacitors in
3.3V operation. It is ideal for 3.3V-only systems, mixed
3.3V and 5.0V systems, or 5V-only systems that require
true RS-232 performance.
Receiver R1 has an extra, always-active output (in addi-
tion to its standard output), which allows external
devices, such as a modem, to be monitored without for-
ward biasing the protection diodes in circuitry that may
have V
CC
completely removed.
The MAX3238 is available in a space-saving SSOP
package.
____________________________Features
o
1µA Supply Current Achieved with
AutoShutdown Plus
o
Guaranteed Data Rate: 250kbps
o
1µA Low-Power Shutdown
o
Receivers Active in AutoShutdown Plus Mode
o
Flow-Through Pinout
o
Meets EIA/TIA-232 Specifications Down to 3.0V
o
Guaranteed 6V/µs Slew Rate
MAX3238*
______________Ordering Information
PART
MAX3238CAI
MAX3238EAI
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
28 SSOP
28 SSOP
__________________Pin Configuration
TOP VIEW
C2+
GND
C2-
V-
T1OUT
T2OUT
T3OUT
R1IN
R2IN
1
2
3
4
5
6
7
8
9
28 C1+
27 V+
26 V
CC
25 C1-
________________________Applications
Notebook, Subnotebook, and Palmtop
Computers
High-Speed Modems
Battery-Powered Equipment
Hand-Held Equipment
Peripherals
Printers
MAX3238
24 T1IN
23 T2IN
22 T3IN
21 R1OUT
20 R2OUT
19 T4IN
18 R3OUT
17 T5IN
16 R1OUTB
15 INVALID
T4OUT 10
R3IN 11
Typical Operating Circuit appears at end of data sheet.
T5OUT 12
FORCEON 13
FORCEOFF 14
AutoShutdown Plus
is
a trademark of Maxim Integrated Products.
*Patents
Pending
SSOP
1
________________________________________________________________
Maxim Integrated Products
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
