19-0312; Rev 0; 9/94
+2.7V to +3.6V-Powered, 1碌A Supply Current,
3-Driver/5-Receiver, True RS-232 Transceiver
_______________General Description
The MAX3212 uses Maxim鈥檚 new proprietary Auto-
Shutdown mode to reduce supply current to 1碌A. The
MAX3212, with 3 RS-232 drivers and 5 RS-232 receivers,
is intended for 2.7V to 3.6V-powered EIA/TIA-232E and
V.28/V.24 serial interface. True RS-232 levels are main-
tained across the operating range. A guaranteed data
rate of 235kbps provides compatibility with popular soft-
ware for communicating with personal computers.
Supply current is reduced to 1碌A with Maxim鈥檚 new
AutoShutdown feature. When the MAX3212 does not
sense a valid signal level on the receiver inputs, the on-
board power supply and drivers shut down. This occurs
if the RS-232 cable is disconnected or if the transmit-
ters of the connected peripheral are turned off. The sys-
tem turns on again when a valid level is applied to any
RS-232 receiver input. As a result, the system saves
power without changes to the existing software.
A second power-management feature is incorporated to
permit automatic shutdown when the RS-232 connection
is valid but inactive. In this case, a transition detector
facilitates shutdown when the receivers are presented
with stationary RS-232 levels for long periods.
Three-state drivers are provided on receiver outputs so
that multiple receivers, generally of different interface
standards, can be wire-ORed at the UART. The
MAX3212 is available in 28-pin SO and SSOP packages.
____________________________Features
BETTER THAN BIPOLAR!
o
o
o
o
o
o
o
1碌A Supply Current Using AutoShutdown
Operates from Single +2.7V to +3.6V Supply
28-Pin SSOP or Wide SO Packages
Meets All EIA/TIA-232E & EIA/TIA-562 Specifications
Mouse Driveability鈥揋uaranteed
Low-Cost, Surface-Mount External Components
235kbps Guaranteed Data Rate鈥?/div>
LapLink鈩?Compatible
o
+5V Logic Compatible
o
Complementary Receiver Output Always Active
o
Flow-Through Pinout
MAX3212*
__________Typical Operating Circuit
0.68碌F 1N6050 15碌H
+3.0V
0.33碌F
3 27
1
V
CC
V+ LN
26 FORCEON
+3.0V
25 FORCEOFF
5 TRAN
6
INVALID
T1
T2
T3
R1
5k
9 R2OUT
R2
5k
10 R3OUT
R3
5k
11 R4OUT
R3IN 22
R2IN 23
T1OUT 19
T2OUT 18
T3OUT 17
R1IN 24
13 T1IN
14 T2IN
15 T3IN
1N6050
2 16
LP
V-
0.33碌F
MAX3212
________________________Applications
Notebook and Palmtop Computers
Peripherals
Instruments
Battery-Powered Equipment
8 R1OUT
______________Ordering Information
PART
MAX3212CWI
MAX3212CAI
MAX3212EWI
MAX3212EAI
TEMP. RANGE
0掳C to +70掳C
0掳C to +70掳C
-40掳C to +85掳C
-40掳C to +85掳C
PIN-PACKAGE
28 Wide SO
28 SSOP
28 Wide SO
28 SSOP
+3.0V
EN
4
12 R5OUT
7 R5OUTB
R4
5k
R5
R5
5k
GND
28
R4IN 21
R5IN 20
AUTOSHUTDOWN OPERATION
FORCEOFF = HIGH, FORCEON = LOW
Pin Configuration appears at end of data sheet.
* Patent pending
RS-232 Present
Yes
No
Status
On
Shut Down
________________________________________________________________
Maxim Integrated Products
1
Call toll free 1-800-998-8800 for free samples or literature.
1
2
3
4
5
6
7
8
9
10
11
12
