The effects of BJT self-heating on circuit behavior

Journal Article · Tue Jun 01 00:00:00 EDT 1993 · IEEE Journal of Solid-State Circuits (Institute of Electrical and Electronics Engineers); (United States)

DOI:https://doi.org/10.1109/4.217983· OSTI ID:6343076

Fox, R M; Lee, Sanggug; Zweidinger, D T ^[1]

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1. Univ. of Florida, Gainesville (United States)

This study demonstrates the circuit and device conditions under which self-heating can significantly affect bipolar junction transistor (BJT) circuit behavior. Simple quantitative measures are supplied that allow estimation of thermally induced errors in BJT small-signal parameters, based on knowledge of the transistor geometry and its Early voltage. It is shown that errors in output admittance and reverse transadmittance can be significant without much power dissipation, especially when the base and emitter driving impedances are small. Other smallsignal parameters are less affected unless the power dissipation becomes significant. Thermal effects in large-signal dc analysis can be significant in precision analog circuits that depend on close transistor matching; such circuits can also exhibit long settlingtime tails due to long thermal time constants. ECL delay is shown to be insensitive to self-heating. These effects are demonstrated through simulations of a variety of circuits using versions of SPICE modified to include physics-based models for thermal impedance.

• OSTI ID: 6343076
• Journal Information: IEEE Journal of Solid-State Circuits (Institute of Electrical and Electronics Engineers); (United States), Journal Name: IEEE Journal of Solid-State Circuits (Institute of Electrical and Electronics Engineers); (United States) Vol. 28:6; ISSN IJSCBC; ISSN 0018-9200
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
426000* -- Engineering-- Components
Electron Devices & Circuits-- (1990-)
COMPUTERIZED SIMULATION
ELECTRONIC EQUIPMENT
ENERGY LOSSES
EQUIPMENT
ERRORS
GEOMETRY
HEATING
IMPEDANCE
JUNCTION TRANSISTORS
LOSSES
MATHEMATICAL MODELS
MATHEMATICS
PERFORMANCE
POWER LOSSES
SEMICONDUCTOR DEVICES
SIMULATION
TRANSISTORS