ABSTRACT
The worldwide interest in SiGe heterojunction bipolar transistors (HBTs) as a commercial IC technology
is growing rapidly [1]. The corresponding circuit design activities essentially depend on accurate
compact models of SiGe HBTs in all relevant modes of the transistor operation. This chapter gives an
overview of the vertical bipolar transistor compact model Mextram (the acronym of the ‘‘most exquisite
transistor model’’) and its capabilities to meet SiGe HBT circuit design challenges. The Mextram has
been introduced by De Graaff and Kloosterman at Royal Philips Electronics in 1985 [2]. Appearing to be
the fifth existing bipolar transistor model (after the previous four described in Ref. [3]), the first
Mextram release was introduced as Level 501. Following the requirements of the continuous technology
development, Mextram has appeared later in several update releases: Level 502 in 1987 [4], Level 503 in
1994, and Level 504 in 2000 [5].
