3Mbps RS-232 Transceivers with

Low-Voltage Interface

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9

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.

21

16

C1+

Positive Terminal of the Voltage Doubler Charge-Pump

Capacitor

3

20

15

V+

+5.5V Generated by the Charge Pump

42

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

10

8

—

R2OUT

11

9

7

Logic-Level Supply. All CMOS inputs and outputs are related

to this supply.

—

—

8

TIN

12

10

—

T2IN

13

11

—

T1IN

14

12

9

FORCEON

FORCEON high to override automatic circuitry keeping

transmitters on (

FORCEOFF must be high).

See Table 1.

15

13

—

R1OUT

—

—

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

+3V to +5.5V Supply Voltage

20

18

13

FORCEOFF

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.