ADM1281 Datasheet | Analog Devices

FEATURES - Drop-in replacement to ADM1278 - ±0.3% accurate, 12-bit ADC for IOUT, VIN, VOUT, and temperature - 290 ns response time to short-circuit - Shutdown on detection of FET health fault - Constant power foldback for tighter FET SOA protection - Remote temperature sensing with programmable warning and shutdown thresholds - Resistor-programmable 5 m V to 25 m V VSENSE current limit - Programmable start-up current limit - 1% accurate UV, OV, and PWRGD thresholds - Split hot-swap and power monitor inputs to allow additional external ADC filtering - Reports power and energy consumption over time - Peak detect registers for current, voltage, and power - PROCHOT power throttling capability - PMBus fast mode pliant interface - Available in 5 mm × 5 mm, 32-lead LFCSP package APPLICATIONS - Servers - Power monitoring and control/power budgeting - Telemunication and data munication equipment GENERAL DESCRIPTION The ADM1281 is a hot-swap controller that allows a circuit board to be removed from or inserted into a live backplane. It also features current, voltage, power, and temperature readback through an integrated 12-bit analog-to-digital converter (ADC), accessed using a PMBus™ interface. The load current is measured using an internal current sense amplifier that measures the voltage across a sense resistor in the power path through the HS+ and HS- pins. A default current limit of 20 m V is set, but this limit can be adjusted, if required. The ADM1281 limits the current through the sense resistor by controlling the gate voltage of an external N-channel FET in the power path, through the GATE pin. The sense voltage, and therefore the load current, is maintained below the preset maximum. The ADM1281 protects the external FET by limiting the time that the FET remains on while the current is at its maximum value. This current-limit time is set by the choice of capacitor connected to the TIMER pin. In addition, a constant power foldback scheme is used to control the power...