Fixed 5V series reference with ±0.1% tolerance — no trim pot needed
The Maxim MAX6220ASA-5.0+ is a precision series voltage reference that delivers a fixed 5V output with ±0.1% initial accuracy and 20 ppm/°C temperature drift. Because the output is fixed, there are no external resistor dividers or trim pots to calibrate — the BOM stays simple and the drift risk from external components disappears. The series topology means the load current (up to 15 mA) comes through the reference itself, not through a separate bias resistor, so line regulation is inherently tighter than a shunt reference over the 8V to 40V input range.
Broadband noise at 2.5 µVrms (10 Hz to 10 kHz) keeps the reference clean for 16-bit SAR converters running at moderate sample rates. If your system integrates a delta-sigma ADC with a 20-bit noise floor, this reference does not become the dominant noise source.
Active lifecycle — no last-time-buy planning needed
Wide input range and extended temperature grade
The input voltage spans 8V to 40V, so the reference can run directly from a 24V industrial supply rail or an unregulated rectified line without a pre-regulator. The 8-SOIC package (0.154-inch body width, 3.90 mm) is a standard footprint that mates with common SOIC-8 land patterns.
Output capacitor — not required, but recommended for noise
The MAX6220ASA-5.0+ is a series reference that is stable without an output capacitor, but a 0.1 µF to 10 µF ceramic bypass capacitor on the output reduces broadband noise further and improves transient response. No minimum ESR requirement — any X5R or X7R capacitor works. The input should also be bypassed with 0.1 µF to 1 µF close to the VIN pin.