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.
Noise performance: 3 µVp-p from 0.1 Hz to 10 Hz, 2.5 µVrms from 10 Hz to 10 kHz
Low-frequency flicker noise is specified at 3 µVp-p over the 0.1 Hz to 10 Hz band, which is the band that matters for precision ADC references and weigh-scale or strain-gauge front ends. 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
For a BOM line that needs a stable reference through a multi-year production run, this part does not force an early redesign.
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 operating temperature range of -40°C to +125°C covers automotive under-hood environments, industrial motor drives, and outdoor telecom cabinets. 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.