The APL6536 is a four channel supervisory IC designed to monitor voltage supplies in µP and digital system. This IC can supervise any positive voltage using an external resistor divider to translate to a lower voltage for comparison to the internal 0.633V reference. Once any VMON input falls below 0.633V the PGOOD output is pulled low, the hysteresis of the internal reference is 15mV. The PGOOD pin has an internal 20kΩ pull-up to VCC making an external pull-up resistor unnecessary. Each rail’s VMON point is independently adjustable with a resistor divider. The PGOOD output is guaranteed to be valid with IC bias lower than 1V. This IC is designed to reject fast line transient glitches 30µs on VMON input. The PGOOD output is an open-drain to allow ORing of multiple signals. If less than four voltages are being monitored, connect the unused VMON pins to VCC. The ENABLE input pin provides for a reset of the PGOOD output when it is pulled down below 0.5V. With an internal 10µA pull-up to VCC, it can be signaled with common logic or pulled to ground with a push button switch. APL6536 come in a miniature SOP-8 package.