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Two Phase Dynamic Logic with Enhancement Depletion Technology

IP.com Disclosure Number: IPCOM000082814D
Original Publication Date: 1975-Feb-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 38K

Publishing Venue

IBM

Related People

Falcoz, A: AUTHOR [+2]

Abstract

Technologies of switching circuits where a field-effect transistor (FET) operating in depletion mode is used as a load for active devices operating in enhancement mode, provides a number of advantages over linear loading technologies. The depletion load is a current source which provides a better power delay product.

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Two Phase Dynamic Logic with Enhancement Depletion Technology

Technologies of switching circuits where a field-effect transistor (FET) operating in depletion mode is used as a load for active devices operating in enhancement mode, provides a number of advantages over linear loading technologies. The depletion load is a current source which provides a better power delay product.

As a metal-oxide semiconductor (MOS)FET operating in a depletion mode is 0N with V(gs) = 0, the gate and source of such a device are tied together and, therefore, the V(gg) power supply is no longer needed.

However, when such switching circuits are used to operate in a 2-phase dynamic logic, an additional power source is required for the clock signals driving the transmission gate FETs. An important parameter is the amplitude of these clocks which must be larger than the uplevel of the logic signal. A nominal level of 8.5 volts is convenient to operate properly. This value of 8.5 volts is the value of the V(gg) power supply used in linear load technology. As this source does not exist anymore when using a load FET operating in the depletion mode, it seems troublesome to require that the clock level remain at 8.5 volts.

To overcome this drawback, a depletion mode FET is used as the transmission gate. To turn it ON, a positive level of the same amplitude as the up logic level is necessary. To turn it OFF, a negative voltage is required. A nominal value for such a turnoff voltage would then b...