Signal Paths

1-3

Introduction

Figure 1 - 2. SN65HVD22 Evaluation Module (EVM)

Note that the EVM printed circuit board includes a location (U1) for a full-duplex

transceiver. This allows for future EVM configurations using the same board.

1.2

Signal Paths

The signal paths on this EVM include coaxial connectors (J7 and J8) for

connecting to test equipment, and differential connection points (W17 and

W18) for connecting to an RS-485 bus. Two banana jacks (J17 and J18)

provide for power and ground connections. Jumpers (W3 and W4) in the circuit

can be used to set the transceiver enabling. Jumper W11 is used to select the

provided in the circuit to facilitate measurements of critical signals.

Table 1 - 1 lists the EVM connections.

Table 1 - 1. HVD22 EVM Connections

Connection

Label

Description

J17

Vcc2

Power supply for HVD22 device

J18

GND2

Power supply ground

J7

RECEIVER

Receiver output, R (pin 1)

J8

DRIVER INPUT

Driver input, D (pin 4)

P3, W17, W18

TRANSCEIVER I/O

RS-485 BUS I/O (pins 6 and 7)

TP3

R

Receiver output (pin 1)

TP4

Driver input, D (pin 4)

TP6

EXT_V2

Externally applied Vcm

W3

RECEIVER

Receiver enable, RE, (pin 2)

W4

DRIVER

Driver enable, DE, (pin 3)

W11

TRANSCEIVER VCM SELECT

Select between Vcm choices:

None, GND2, External