MAX3212 Datasheet, PDF (1/12 Pages) Maxim Integrated Products – +2.7V to+3.6V-Powered, 1μA Supply Current, 3-Driver/5-Receiver, True RS-232Transceiver

19-0312; Rev 0; 9/94
+2.7V to +3.6V-Powered, 1µA Supply Current,
3-Driver/5-Receiver, True RS-232 Transceiver
_______________General Description
The MAX3212 uses Maxim’s new proprietary Auto-
Shutdown mode to reduce supply current to 1µA. 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 1µA with Maxim’s 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.
________________________Applications
Notebook and Palmtop Computers
Peripherals
Instruments
Battery-Powered Equipment
______________Ordering Information
PART
MAX3212CWI
MAX3212CAI
MAX3212EWI
MAX3212EAI
TEMP. RANGE
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 Wide SO
28 SSOP
28 Wide SO
28 SSOP
Pin Configuration appears at end of data sheet.
* Patent pending
____________________________Features
BETTER THAN BIPOLAR!
o 1µA Supply Current Using AutoShutdown
o Operates from Single +2.7V to +3.6V Supply
o 28-Pin SSOP or Wide SO Packages
o Meets All EIA/TIA-232E & EIA/TIA-562 Specifications
o Mouse Driveability–Guaranteed
o Low-Cost, Surface-Mount External Components
o 235kbps Guaranteed Data Rate–
LapLink™ Compatible
o +5V Logic Compatible
o Complementary Receiver Output Always Active
o Flow-Through Pinout
__________Typical Operating Circuit
+3.0V
0.33µF
+3.0V
0.68µF 1N6050 15µH 1N6050
3 27 1
V_CC V+ LN
26 _FORCEON
2 16
LP V-
25 _FORCEOFF
5 _TRAN
6 _INVALID
MAX3212
13 T1IN
T1
T1OUT 19
14 T2IN
15 T3IN
8 R1OUT
T2
T2OUT 18
T3
T3OUT 17
R1
R1IN 24
5k
9 R2OUT
10 _R3OUT
11 R4OUT
12 R5OUT
R2
R2IN 23
5k
R3
R3IN ²²
5k
R4
R4IN ²¹
5k
R5
R5IN 20
+3.0V
7 R5OUTB
R5
5k
EN GND
4 28
AUTOSHUTDOWN OPERATION
FORCEOFF = HIGH, FORCEON = LOW
RS-232 Present
Yes
No
Status
On
Shut Down
0.33µF
________________________________________________________________ Maxim Integrated Products 1
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