Browse Prior Art Database

Impedance Adjusting Active Terminator

IP.com Disclosure Number: IPCOM000122335D
Original Publication Date: 1991-Nov-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 29K

Publishing Venue

IBM

Related People

Dorler, JA: AUTHOR [+2]

Abstract

Devices R2, R3, T5, and T6 show a means of providing suitable bias at nodes 3 & 4. By adjusting these bias points any desired voltage swing, at the terminator, can be achieved. In the example below, a constant voltage difference between nodes 3 & 4 equal to .9 V is achieved thru R2, R3, T5, and T6.

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

Impedance Adjusting Active Terminator

      Devices R2, R3, T5, and T6 show a means of providing suitable
bias at nodes 3 & 4.  By adjusting these bias points any desired
voltage swing, at the terminator, can be achieved.  In the example
below, a constant voltage difference between nodes 3 & 4 equal to .9
V is achieved thru R2, R3, T5, and T6.

      T1, T2, and R1 form a reflective current source.

      When the input is at a low level, T4 turns on; when the input
is at an up level, T3 conducts, thus turning on T1.

      Both T3 and T5 are lateral PNPs, T3 requirement is to conduct
Ib of T1 and Ie of T2 which is less than 200uA.  PNP T5 has
similar low current requirements.

      The impedance of the terminator is proportional to 26 mV/Ie.

      Disclosed anonymously.