Efficient models for non-quasi-static effects and correlated noise in SiGe HBTs

Abstract

The capability of a single CR sub-circuit to model a wide range of non-quasi-static (NQS) delays in silicon germanium heterojunction bipolar transistors is explored. A comparative study is carried out to show that the suitable use of a single CR sub-circuit following the partitioned-charge-based approach can replace the popularly used CR-LCR combination to model both the input and output NQS effects. Based on this NQS model, a correlated noise model is developed, which requires only three additional nodes for implementation in Verilog-A. Results show excellent agreement with numerically simulated data.

Graded Applications of NQS Theory for Modeling Correlated Noise in SiGe HBTs

“…The model parameter k c is termed the charge partitioning factor and A Q1 is used as an additional model parameter to increase the model flexibility [12]. In [13], negative of this charge partitioning factor is termed k (=−k c ).…”

“…It is already reported in [12] that (3) and (4) can be implemented using a single-node CR subcircuit and they model the reference device simulation data as accurately as the CR-LCR NQS model of HICUM. In order to ensure that the differences in modeling results, if any, are caused only by the respective noise models, we have used our single-node CR-subcircuit NQS model in all the simulations presented in the following section.…”