The MAX138, MAX139 and MAX140 are 3½‑digit analog‑to‑digital converters with an on‑board LCD/LED display driver, bandgap reference and charge‑pump voltage inverter. They operate from a single supply voltage of +2.5 V to +7 V and can measure both positive and negative input voltages.
The document provides electrical characteristics, ordering information, typical application circuits, and detailed guidance on component selection, noise reduction, and troubleshooting for accurate conversion performance.
| Supply Voltage Range | +2.5 V to +7.0 V |
|---|
They operate from a single supply voltage of +2.5 V to +7.0 V.
The internal oscillator is trimmed to 40 kHz, giving roughly 2.6 conversions per second.