MAX13234E–MAX13237E
3Mbps RS-232 Transceivers with
Low-Voltage Interface
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Pin Descriptions
PIN
MAX13234E/
MAX13235E
MAX13236E/
MAX13237E
TSSOP TQFN-EP TQFN-EP
NAME FUNCTION
1 19 14 READY
Ready to Transmit Output, Active-High. READY is enabled
high when V- goes below -4V and the device is ready to
transmit.
2 1 16 C1+
Positive Terminal of the Voltage Doubler Charge-Pump
Capacitor
3 20 15 V+ +5.5V Generated by the Charge Pump
4 2 1 C1-
Negative Terminal of the Voltage Doubler Charge-Pump
Capacitor
5 3 2 C2+ Positive Terminal of the Inverting Charge-Pump Capacitor
6 4 3 C2- Negative Terminal of the Inverting Charge-Pump Capacitor
7 5 4 V- -5.5V Generated by the Charge Pump
8 6 — T2OUT RS-232 Transmitter Output 2
— — 5 RIN RS-232 Receiver Input
9 7 — R2IN RS-232 Receiver Input 2
— — 6 ROUT CMOS Receiver Output. V
L
referred logic.
10 8 — R2OUT CMOS Receiver Output 2. V
L
referred logic.
11 9 7 V
L
Logic-Level Supply. All CMOS inputs and outputs are related
to this supply.
— — 8 TIN CMOS Transmitter Input. V
L
referred logic.
12 10 — T2IN CMOS Transmitter Input 2. V
L
referred logic.
13 11 — T1IN CMOS Transmitter Input 1. V
L
referred logic.
14 12 9 FORCEON
FORCEON Input, Active-High. V
L
referenced logic. Drive
FORCEON high to override automatic circuitry keeping
transmitters on (FORCEOFF must be high).
See Table 1.
15 13 — R1OUT CMOS Receiver Output 1. V
L
referred logic.
— — 10 TOUT RS-232 Transmitter Output
16 14 — R1IN RS-232 Receiver Input 1
17 15 — T1OUT RS-232 Transmitter Output 1
18 16 11 GND Ground
19 17 12 V
CC
+3V to +5.5V Supply Voltage
20 18 13 FORCEOFF
FORCEOFF Input, Active-Low. V
L
referenced logic. Drive
FORCEOFF low to shut down transmitters and on-board
charge pumps. All receiver and transmitter outputs are tri-
stated. This overrides all automatic circuitry and FORCEON
(Table 1).
— — — EP Exposed Pad. Connect EP to GND or leave unconnected.
