BiMOS micropower ICs

Design techniques suitable for micropower integrated circuits are discussed. Some systems require subpicoampere input bias and amplifier, timing, and logic functions with a several hundred milliampere output capability-at a standby current level of a few microamperes. MOSFETs are characterized well into their subthreshold regions and, in concert with standard bipolar devices, are shown to extend the performance capabilities of linear circuit portions. Applications of subthreshold circuits are very broad, however, because the high transconductance-to-current ratios of MOSFET pairs also provide order-of-magnitude improvements in offset temperature-drift and life stability. In combination with bootstrapped input protective networks, subthreshold BiMOS devices can provide operational-amplifier performance normally attained by only die-trimming techniques or hybrid construction. It is shown that the MOSFET is useful not only for its high-impedance input, but also in intermediate and output functions of linear/digital ICs.