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High Speed Sense Amplifier With Low Impedance Input

IP.com Disclosure Number: IPCOM000089099D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Malaviya, SD: AUTHOR

Abstract

This is a high speed bipolar sense amplifier with low input impedance that operates essentially as an ideal current meter to read bit line current.

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High Speed Sense Amplifier With Low Impedance Input

This is a high speed bipolar sense amplifier with low input impedance that operates essentially as an ideal current meter to read bit line current.

In one form, the circuit, as illustrated in Fig. 1, consists of two Schottky barrier diode clamped transistors Q1 and Q2 with their emitters connected to a source of potential such as ground. The clamping diodes are D1 and D2. The collector of Q1 acts as the input terminal, and the collector of Q2 as the output terminal. Resistor RB, connected between +V and the bases of Q1 and Q2, is a base resistor, while resistor RC, connected between +V and the collector of Q2, is a collector resistor. Frequently, it is desired to collector-dot the outputs of a number of sense amplifiers in a memory array. In that case, resistor RC and diode D2 are eliminated. When this circuit is used as a memory sense amplifier, the input terminal is connected to a bit/sense line.

A high speed low impedance sense amplifier may also be implemented without Schottky barrier diodes, as illustrated in Fig. 2. Transistors Q11 and Q12, with their emitters connected to a source of potential such as ground, have their base electrodes connected to a current source 1. A third transistor Q13 has its collector also connected to the current source, its base connected to another source of potential such as +V, and its emitter connected to the collector of Q11. The collector of Q11 acts as the input terminal, and the collector of Q12 acts as the output terminal. Constant current source I...