DS1776

PI-Bus Transceiver

General Description

The DS1776 is an octal PI-bus Transceiver. The A to B path

is latched. B outputs are open collector with series Schottky

diode, ensuring minimum B output loading. B outputs also

have ramped rise and fall times (2.5 ns typical), ensuring

minimum PI-bus ringing. B inputs have glitch rejection cir-

cuitry, 4 ns typical.

Designed using National’s Bi-CMOS process for both low

operating and disabled power. AC performance is optimized

for the PI-Bus inter-operability requirements.

The DS1776 is an octal latched transceiver and is intended

to provide the electrical interface to a high performance

wired-or bus. This bus has a loaded characteristic imped-

ance range of 20

Ω to 50Ω and is terminated on each end

with a 30

Ω to 40Ω resistor.

The DS1776 is an octal bidirectional transceiver with open

function is provided for the A port signals. The B port output

driver is designed to sink 100 mA from 2V and features a

controlled linear ramp to minimize crosstalk and ringing on

the bus.

A separate high level control voltage (V

vent the A side output high level from exceeding future high

density processor supply voltage levels. For 5V systems, V

X

is tied to V

Features

n Mil-Std-883C qualified

n Similar to BTL

n B output controlled ramp rate

n B input noise immunity, typically 4 ns

n Available in 28-pin DIP, Flatpak and CLCC

n Pin and function compatible with Signetics 54F776

Pin Configurations

Logic Symbol

Pin Configuration

DS010875-1

Order Number DS1776E/883 or DS1776J/883

See NS Package E28A or J28B

Pin Configuration

DS010875-2

DS010875-3

January 1996

© 1999 National Semiconductor Corporation

DS010875

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