ADM3251E

Rev. 0 | Page 8 of 16

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

20

V+

19

C1+

18

C1–

17

16

15

C2+

14

C2–

13

V–

12

11

NC = NO CONNECT

ADM3251E

TOP VIEW

(Not to Scale)

Figure 2. Pin Configuration

Table 8. Pin Function Descriptions

Pin No.

Mnemonic

Description

1

NC

No Connect. This pin should always remain unconnected.

2, 3

lowered to between 3.0 V and 3.7 V, the integrated dc-to-dc converter is disabled.

4, 5, 6, 7, 10

GND

Ground Pin.

8

Receiver Output. This pin outputs CMOS logic levels.

9

Transmitter (Driver) Input. This pin accepts TTL/CMOS levels.

11

Ground Reference for Isolator Primary Side.

12

V−

Internally Generated Negative Supply.

13, 14

C2−, C2+

Positive and Negative Connections for Charge Pump Capacitors. External Capacitor C2 is connected between

these pins; a 0.1 μF capacitor is recommended, but larger capacitors up to 10 μF can be used.

15

Receiver Input. This input accepts RS-232 signal levels.

16

Transmitter (Driver) Output. This outputs RS-232 signal levels.

17, 18

C1−, C1+

Positive and Negative Connections for Charge Pump Capacitors. External Capacitor C1 is connected between

these pins; a 0.1 μF capacitor is recommended, but larger capacitors up to 10 μF can be used.

19

V+

Internally Generated Positive Supply.

20

circuitry. If the integrated dc-to-dc converter is disabled, power the secondary side by applying a voltage in the

range of 3.0 V to 5.5 V to this pin.