BJT Process Spread Compensation Utilizing Base Recombination Current in Standard CMOS

This letter presents a compensation topology which minimizes the inter-/intra-die spread and proportional-to-absolute-temperature (PTAT) drift of the base-emitter voltage (Vbe) of a bipolar junction transistor (BJT). Without using special devices, the base recombination current from a deep-saturated BJT is utilized in this scheme. Before compensation, the Vbe standard deviation (STD) of 15 standalone BJTs measures 3.24 mV at 25 °C with constant external bias currents. After compensation, V
_be
STD of 30 dies from two batches reduces to 1.8 mV with on-chip bias current. The PTAT drift of V
_be
as that in typical BJT-based designs are also alleviated.