A bipolar junction transistor (BJT)-based CMOS temperature sensor exploiting the piecewise BJT process spread compensation property of the base recombination current is proposed to reduce the process variations of the base-emitter voltage (V-be). The weighted combinations of different on-chip resistors are explored to minimise their associated process spread. Fabricated in standard 0.18-m CMOS, the chip prototype occupies an active area of 0.036 mm(2) and draws 3 A from a 1.2 V supply, with a measured maximum inter-/intra-die variation in V-be of <1.5 mV from -40 to 125 degrees C from two batches. Using the measured V-be, V-be and the first-batch-only calibration parameters, the chip prototype demonstrates an untrimmed batch-to-batch inaccuracy of +/- 1.5 degrees C (3 sigma) within the same temperature range (24 samples from 2 batches).