The MAX6340/MAX6421-MAX6426 are low-power micro-processor supervisor circuits that monitor system voltages from 1.6V to 5V. These devices perform a single function: they assert a reset signal whenever the VCC supply voltage falls below its reset threshold. The reset output remains asserted for the reset timeout period after VCC rises above the reset threshold. The reset timeout is externally set by a capacitor to provide more flexibility. The MAX6421/MAX6424 have an active-low, push-pull reset output. The MAX6422 has an active-high, push-pull reset output and the MAX6340/MAX6423/MAX6425/MAX6426 have an active-low, open-drain reset output. The MAX6421/MAX6422/MAX6423 are offered in 4-pin SC70 or SOT143 packages. The MAX6340/MAX6424/MAX6425/MAX6426 are available in 5-pin SOT23-5 packages.
The MAX6340, MAX6421‑MAX6426 family are low‑power micro‑processor supervisor circuits that monitor system voltages from 1.6 V to 5 V. When VCC falls below a factory‑trimmed reset threshold the device asserts a reset signal, which remains active for a timeout period set by an external capacitor.
These devices are offered in 4‑pin SC70 or SOT‑143 packages (MAX6421‑MAX6424) and 5‑pin SOT‑23 packages (MAX6340, MAX6424‑MAX6426). They provide three reset‑output options—active‑low push‑pull, active‑high push‑pull, and open‑drain—allowing flexible interfacing to a variety of logic levels.
| Supply Voltage Range | 1.0 V to 5.5 V |
|---|---|
| Typical Supply Current (3.3 V) | 1.9 µA to 3.4 µA |
| Low Quiescent Current | 1.6 µA typ |
| Operating Temperature Range | -40 °C to +125 °C |
The capacitor value is derived from the formula Cert = (trp − 275 µs) / (2.73 × 10⁸), where trp is the desired timeout in seconds and Csprt is the capacitance in farads.
A low‑leakage capacitor (leakage < 10 nA) should be used; ceramic types are recommended.
The family offers active‑low push‑pull (MAX6421/6424), active‑high push‑pull (MAX6422), and active‑low open‑drain (MAX6340, MAX6423, MAX6425, MAX6426) reset outputs.