Influence of device parameters on the switching speed of BiCMOS buffers

Author

Rosseel, Geert P. ; Dutton, Robert W.

Author_Institution

Dept. of Electr. Eng., Stanford Univ., CA, USA

Volume

24

Issue

1

fYear

1989

Firstpage

90

Lastpage

99

Abstract

The influence of different MOS and bipolar device parameters on the switching speed of a BiCMOS buffer is described. This influence is studied by looking at the response of a BiCMOS inverter to a step input. Using suitable approximations for the high-level injection effects in the bipolar transistor, mathematical approximations for the response are derived. The approximate responses are compared to those determined by SPICE simulations and the agreement is satisfactory. High-current effects in the bipolar transistor strongly affect the performance. The effects of different bipolar transistor parasitic resistors are investigated, and it is found that only the collector resistance is important. The influence of different emitter sizes on the delay time is studied, and it is shown that for a given area, there is one optimal size ratio for the MOS and bipolar transistors for which the delay is minimum.<>

Keywords

BIMOS integrated circuits; buffer circuits; driver circuits; integrated circuit technology; semiconductor device models; switching circuits; BiCMOS; BiCMOS buffers; BiCMOS inverter; MOS device parameters; SPICE simulations; bipolar device parameters; bipolar transistor; bipolar transistor parasitic resistors; collector resistance; delay time; emitter sizes; high current effects; high-level injection effects; mathematical approximations; optimal size ratio; step input; switching speed; BiCMOS integrated circuits; Bipolar transistors; Delay effects; Inverters; Knee; Piecewise linear approximation; Resistors; SPICE; Transient response; Zero voltage switching;

fLanguage

English

Journal_Title

Solid-State Circuits, IEEE Journal of

Publisher

ieee

ISSN

0018-9200

Type

jour

DOI

10.1109/4.16306

Filename

16306