Complete, Isolated, 3.3V

RS-485/RS-422 Data Interface

8

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Note: For DE

_________________________________________________Pin Description (continued)

Isolated Driver-Enable Drive Input. The driver outputs, A and B, are enabled by bringing DE

The driver outputs are high impedance when DE

functions as a line driver. While the driver outputs are high impedance, the device functions as a line

normal operation (Table 1 of Figure 2).

ISO DE

DRV

17

ISO RO

LED

15

Isolated-Supply Common Input. Connect to ISO COM1.

ISO COM2

16

PIN

FUNCTION

NAME

18

Isolated Driver-Input Drive. With DE

a high on DI

ISO DI DRV

19

Isolated-Supply Common Output. Connect to ISO COM2. If RS-485 wires have a shield, connect ISO

COM1 to shield via 100

Ω resistor.

ISO COM1

20

Isolated Receiver-Output LED Anode (input). If A > B by 200mV, ISO RO LED will be high; if A < B by

200mV, ISO RO LED will be low.

Isolated Driver-Enable Input. Connect to ISO DE DRV for normal operation.

ISO DE IN

21

Noninverting Driver Output and Noninverting Receiver Input.

A

23

Inverting Driver Output and Inverting Receiver Input

B

25

Isolated Driver Input. Connect to ISO DI DRV for normal operation.

ISO DI IN

22

Isolated Receiver-Output Drive. Connect to ISO RO LED through R6 (Table 1 of Figure 2).

ISO RO

DRV

24

26

Internal Connections. Leave these pins unconnected.

AC2, AC1

27, 28

PINS ON THE ISOLATED RS-485/RS-422 SIDE