65V, Low-Quiescent-Current, High-Voltage Linear Regulators with µP Reset and Watchdog Timer

The MAX5023/MAX5024 high-voltage linear regulators operate from a +6.5V to +65V input voltage and deliver up to 150mA of output current. These devices consume only 60µA of quiescent current with no load and withstand a -60V reverse-battery voltage at the input. The MAX5023/MAX5024 include an active-low internal microprocessor (µP) reset circuit that asserts when the regulator output drops below the preset output voltage threshold by 7.5% or 12.5%, depending on the device selected. Both devices are available with a fixed +3.3V or +5V output. These devices are short-circuit protected and include thermal shutdown.

In addition to an enable input to turn on or off the regulator, the MAX5023/MAX5024 include an active-low HOLD input that allows for the implementation of a self-holding circuit without requiring external components. Setting active-low HOLD low after enabling the regulator, forces the regulator to remain on even if EN is subsequently set low. Releasing active-low HOLD shuts down the regulator.

The MAX5023 includes a watchdog input that monitors a pulse train from the µP and generates reset pulses if the watchdog input remains high or low for a duration longer than the 1.6s watchdog timeout period. The MAX5024 includes a SET input which, when connected to ground, selects a preset output voltage of +3.3V (MAX5024S/MAX5024T) or +5V (MAX5024L/MAX5024M). Set the adjustable output voltage by connecting SET to the regulator's output through a resistive-divider network.

The MAX5023/MAX5024 operate over the automotive temperature range (-40°C to +125°C) and are available in a thermally enhanced, surface-mount 8-pin SO-EP package.

Applications

* Automotive * Fire/Smoke Alarms * Home Security * Industrial * Telecom/Networking

* Wide Operating Input Voltage Range +6.5V to +65V

* Thermally Enhanced 8-Pin SO Package with Exposed Pad Dissipates 1.5W

* Guaranteed 150mA Output Current

* 60µA No-Load Supply Current

* -60V Reverse-Battery Protection

* Preset +3.3V or +5.0V Output Voltage

* Thermal and Short-Circuit Protection

* Operate Over -40°C to +125°C Temperature Range

* Integrated µP Reset Circuit

* Watchdog Timer with 1.6s Timeout Period (MAX5023)

* Regulator Enable and Hold Inputs Implement Self-Holding Circuit

* SET Input for Adjustable Output Voltage (MAX5024)