Philips Semiconductors

Product specification

74ABTL3205

10-bit BTL transceiver with registers

2

1995 Jun 16

853-1802 15352

FEATURES

impedances down to 10 ohms

power consumption

thresholds and improved noise immunity

bounce

and 200V per Machine Model

DESCRIPTION

This transceiver is a 10 bit bidirectional transceiver and is intended

to provide the electrical interface to a high performance wired-OR

bus.

The B-port drivers are Low-capacitance open collectors with

controlled ramp and are designed to sink 100mA. Precision band

gap references on the B-port insure very good margins by limiting

the switching threshold to a narrow region centered at 1.55V.

The B-port interfaces to “Backplane Transceiver Logic” (See the

IEEE 1194.1 BTL standard). BTL features low power consumption

by reducing voltage swing (1V p-p, between 1V and 2V) and

reduced capacitive loading (<6pF) by placing an internal series

diode on the drivers. BTL also provides incident wave switching, a

necessity for high performance backplanes.

To support live insertion, OEB is held Low during power on/off cycles

to insure glitch free B port drivers. Proper bias for B port drivers

during live insertion is provided by the BIAS V pin when at a 5V level

reverse bias the BTL driver series Schottky diode, and also bias the

B port output pins to a voltage between 1.62V and 2.1V. This bias

function is in accordance with IEEE BTL standard 1194.1. If live

insertion is not a requirement, the BIAS V pin should be tied to a

The LOGIC GND and BUS GND pins are isolated inside the

package to minimize noise coupling between the BTL and TTL

sides. These pins should be tied to a common ground external to the

internally to minimize noise and may be externally decoupled

separately or simply tied together.

This transceiver function is intended to operate in a half-duplex

mode. Low current in standby mode is obtained by powering down

unused circuitry. Likewise, transmit circuitry is powered down when

in receive mode and receive circuitry is powered down while in

transmit mode.

QUICK REFERENCE DATA

SYMBOL

PARAMETER

TYPICAL

UNIT

Propagation delay

3.3

ns

An to Bn

3.7

ns

Propagation delay

3.6

ns

Bn to An

3.5

ns

Output capacitance (B0 - B8) only)

6

pF

Output current (B0 - B8) only)

100

mA

Standby

1

Supply current

An to Bn

7

mA

Bn to An

18

ORDERING INFORMATION

PACKAGES

TEMPERATURE RANGE

OUTSIDE NORTH AMERICA

NORTH AMERICA

DWG NUMBER

52-PIN PQFP

–40

°C to +85°C

74ABTL3205 BB

74ABTL3205 BB

SOT379-1