Browse Prior Art Database

High Noise Immunity Receiver Circuit

IP.com Disclosure Number: IPCOM000060605D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Reedy, DC: AUTHOR [+2]

Abstract

The disclosed circuit produces high noise immunity performance and exhibits a flexible threshold setting. High noise immunity is particularly necessary in very large scale integrated circuits which have large current changes in high simultaneous switching environments.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

High Noise Immunity Receiver Circuit

The disclosed circuit produces high noise immunity performance and exhibits a flexible threshold setting. High noise immunity is particularly necessary in very large scale integrated circuits which have large current changes in high simultaneous switching environments.

The receiver circuit, shown below, includes transistors T1-T3, diodes D1-D6, and biasing resistors as shown. The re ceiver input is at the emitter of transistor T1 and the output is at the collector of transistor T3. Schottky diodes D4-D6 provide anti-saturation protection for transistors T1-T3, respectively, and diode D1 provides electrostatic discharge protection to the receiver input. Clamping Schottky diode D3 connected to the base of transistor T1 provides the high noise margin capability by establishing the input threshold voltage which is derived from 1.7 volts and providing temperature tracking of the T1 base emitter junction. With the cathode of diode D3 biased to 1.7 volts, the anode is clamped to 2.3 volts, which provides a 600 mV up-level noise margin. The input must reach
1.38 volts from a down-level in order to switch the output to a logic "0", which provides 680 mV of down-level noise margin.

These noise margins are achieved without adversely affecting the receiver circuit delays and DC loading characteristics.

Disclosed anonymously.

1