Triple-voltage supervisor in a compact SOT-23-8
The Maxim Integrated MAX6728KALTD3-T is a triple-voltage power supply monitor that asserts an active-low reset signal when any monitored rail drops below its threshold. It tracks three voltages simultaneously with thresholds of 3.075 V, 4.625 V, and one adjustable input, making it a fit for multi-rail systems like industrial controllers, telecom line cards, and embedded computing modules where a single supervisor must watch the core, I/O, and auxiliary supplies. The open-drain output stays low for a minimum of 140 ms after all rails return above threshold, providing a clean power-good handshake to the processor or FPGA. The industrial temperature range (-40°C to 85°C) suits it for outdoor enclosures, factory-floor PLCs, and engine-bay electronics where ambient conditions swing widely.
Threshold selection and reset timing
The fixed thresholds at 3.075 V and 4.625 V cover common logic rails, while the adjustable input lets you set a third trip point with an external resistor divider. The 140 ms minimum reset timeout ensures the monitored devices complete their startup sequence before the reset is released, avoiding brown-out glitches during power-up.
Package and mounting
Housed in an 8-pin SOT-23 package, the MAX6728KALTD3-T is a surface-mount device that fits dense PCB layouts. The SOT-23-8 footprint is common among multi-voltage supervisors, so board layout reuse across similar parts is straightforward.
Lifecycle and sourcing
It is RoHS non-compliant, which matters for designs targeting EU RoHS exemptions or legacy BOMs that allow tin-lead finishes.