5

LTC1487

DI (Pin 4): Driver Input. If the driver outputs are enabled

(DE HIGH) then a LOW on DI forces the outputs A LOW and

B HIGH. A HIGH on DI with the driver outputs enabled will

force A HIGH and B LOW.

GND (Pin 5): Ground.

A (Pin 6): Driver Output/Receiver Input.

B (Pin 7): Driver Output/Receiver Input.

RO (Pin 1): Receiver Output. If the receiver output is

enabled (RE LOW), and A > B by 200mV, RO will be HIGH.

If A < B by 200mV, then RO will be LOW.

RE (Pin 2): Receiver Output Enable. A LOW enables the

receiver output, RO. A HIGH input forces the receiver

output into a high impedance state.

DE (Pin 3): Driver Outputs Enable. A HIGH on DE enables

the driver output. A and B and the chip will function as a line

driver. A LOW input will force the driver outputs into a high

impedance state and the chip will function as a line

receiver. If RE is HIGH and DE is LOW, the part will enter

a low power (1

µA) shutdown state.

Figure 3. Driver/Receiver Timing Test Circuit

Figure 4. Driver Timing Test Load

OUTPUT

UNDER TEST

S1

S2

500

Ω

LTC1487 • F04

3V

DE

A

B

DI

RO

15pF

A

B

RE

LTC1487 • F03

Figure 1. Driver DC Test Load

Figure 2. Receiver Timing Test Load

A

B

R

R

LTC1487 • F01

RECEIVER

OUTPUT

1k

S1

S2

TEST POINT

1k

LTC1487 • F02

TEST CIRCUITS

LTC1487 Transmitting

INPUTS

OUTPUTS

RE

DE

DI

B

A

X11

0

1

X10

1

0

00

X

Z

Z

1

0

X

Z*

Z*

*Shutdown mode

LTC1487 Receiving

INPUTS

OUTPUTS

RE

DE

A – B

RO

00

≥0.2V

1

00

≤–0.2V

0

0

0

Inputs Open

1

10

X

Z*

*Shutdown mode

FU CTIO TABLES