A Resistor-Less nW-Level Bandgap Reference With Fine-Grained Voltage and Temperature Coefficient Trims

A nW-level BJT-based bandgap reference with fine grained voltage and temperature coefficient trimming is presented. The bandgap reference utilizes switched capacitors (SC) as impedance elements instead of resistors in a current mode configuration. This configuration enabled low power (38nW) with a minimal area (0.0174 mm2). The voltage could be trimmed independently without affecting the temperature coefficient. The SC’s are stacked in order to achieve accurate trimming without using unrealistically small capacitors. The temperature coefficient can be trimmed between 50-200 ppm/°C in either direction, while the voltage can be trimmed between 580-800mV.