REF3033AIDBZR

The REF3033AIDBZR from Texas Instruments is a 3.3V precision series voltage reference in a tiny SOT-23-3 package, offering 0.2% initial accuracy and 75ppm/°C maximum temperature drift over the -40°C to +125°C range. With only 42μA typical quiescent current and 1mV dropout voltage, it is ideal for loop-powered and battery-powered applications. The 25mA output current capability and no-external-capacitor stability simplify PCB design. The 36μVpp low-frequency noise makes it suitable for high-resolution ADC/DAC reference applications.

The REF3033 uses a CMOS bandgap voltage reference architecture. The bandgap circuit generates a stable 1.25V reference by combining the negative temperature coefficient of a forward-biased diode (VBE) with the positive temperature coefficient of two diodes operating at different current densities (ΔVBE). These are scaled and summed to produce a near-zero temperature coefficient at the nominal bandgap voltage. An internal amplifier then scales this voltage to the 3.3V output level. The CMOS design minimizes quiescent current to 42μA while maintaining good noise performance. The series topology passes the supply current through the output, allowing very low dropout operation—only 1mV above the output voltage at zero load.

• 4-20mA pressure transmitter ADC reference with 42μA Iq budget
• 12-16 bit ADC/DAC precision voltage reference in portable instruments
• Battery-powered data logger with 1.8V minimum supply compatibility
• Intrinsically safe instrument reference without output capacitor
• Power supply voltage monitoring threshold reference