Double heterostructure InP HBT technology for high resolution A/D converters

Abstract

For high resolution analog circuits we have developed a double heterostructure bipolar transistor (DHBT) technology using InP as the collector material. Our baseline DHBTs have demonstrated current gain /spl beta/, early voltage V/sub A/, f/sub T/, and f/sub max/ of 55, 100 V, 70 GHz, and 60 GHz, respectively. We have implemented an analog cell library to build high resolution /spl Delta//spl Sigma/ modulator circuits in this technology. We have used the cell library to demonstrate a first order modulator and to verify the design of these analog cells. At a sample rate of 4 GSPS and an OSR equal to 32 (i.e., input bandwidth of 62.5 MHz) the first order modulator demonstrated an SNR of 40.3 dB. This first order modulator operates using /spl plusmn/5 V power supplies and dissipates 572 mW.