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Very High Speed CCD Clock-Pulse Driver Circuit

IP.com Disclosure Number: IPCOM000037628D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Giordano, FP: AUTHOR [+2]

Abstract

The circuit diagram shown in the Figure contains component identifications of a specific embodiment for a CCD clock-pulse driver but the circuit may also be embodied for use as an MOS memory clock pulse driver.

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Very High Speed CCD Clock-Pulse Driver Circuit

The circuit diagram shown in the Figure contains component identifications of a specific embodiment for a CCD clock-pulse driver but the circuit may also be embodied for use as an MOS memory clock pulse driver.

The components function as follows:

Voltage amplifier: raises 5V logic amplitude to clock amplitude, 8.5V in the example shown. The 68 ohm load resistor value is small enough to maintain short delay and rise times, with approximately equal rise and fall delays. The VN1304N6 is an N-channel enhancement-made DMOS device made by SUPERTEX, INC.

Predriver: push-pull bipolar emitter followers provide the substantial charging and discharging currents required by the driver input. The ZN4401 and ZN4403 are made, for example, by Motorola Corp.

Driver: complementary push-pull saturating switches alternately pull the output to the power supply level and to ground. Two P-channel VP0104N6 DMOS devices in parallel are used for pull-up because the current capability of a P-channel is about half of that of an N-channel VN0104N6 DMOS device. The 5 ohm resistors in series with the drains D damp ringing due to stray inductance and limit transient current spikes flowing from power supply to ground during switching. The DMOS devices are made by SUPERTEX, INC.

In the voltage amplifier and driver stages, very fast DMOS power transistors are used in place of the more conventional bipolar transistors. They have the advantages: 1. No s...