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Power Darlington Amplifier with Integrated Clamp Diode

IP.com Disclosure Number: IPCOM000080166D
Original Publication Date: 1973-Nov-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 78K

Publishing Venue

IBM

Related People

Jones, FD: AUTHOR [+2]

Abstract

Planar technology may be utilized to fabricate hammer drivers with high gain (Hft approx. 500) and relatively long-fall times (T(F) approx. 3-30 mu sec.).

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Power Darlington Amplifier with Integrated Clamp Diode

Planar technology may be utilized to fabricate hammer drivers with high gain (Hft approx. 500) and relatively long-fall times (T(F) approx. 3-30 mu sec.).

Fig. 1 shows a hammer driver including TX1 and TX2 which form a Darlington pair. TX3 and TX4 form a diode for the driver. Fig. 2 shows one of the Darlington transistors TX1 or TX2. The slow-fall time is achieved by using a homogenous base layer of P- epi 10 isolated by N+ regions 12. A N+ emitter region 14 is formed in the region 10. A P diffusion 16 is formed about the emitter region to lower resistance to the base contact 18, and the sheet resistance for forming a base resistor, not shown. The region 16 also prevents inversion of the region 10. A collector 20 completes the Darlington amplifier. The collector 20 comprises an antimony-doped N+ substrate 22, and a N- epi layer 24. Both the base contact 18 and an emitter contact 26 are adhered to the respective regions, through openings in an overlying silicon dioxide coating 28.

Fig. 3 shows the diode structure for TX3 and TX4 in Fig. 1. Corresponding elements in Figs. 2 and 3 have the same reference characters. P regions 30 are added to Fig. 3 to connect the base region 10 to the collector through the isolation diffusions 12.

The Darlington pair in Fig. 2 and the diodes in Fig. 3 are suitably connected together to form the configuration of Fig. 1.

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