ADT14GS

a FEATURES Four Programmable Temperature Setpoints Programmable Thermal Hysteresis Accuracy ؎3 ؇ C Typ from –40؇ C to +125؇ C Temperature Output Scale Factor = 5 mV/K Resistor Programmable Temperature Setpoints 5 mA Open-Collector Setpoint Outputs Internal 2.5 V Reference 600 ␮A Max Quiescent Current at +5 V APPLICATIONS Power Supply Monitor and Control System Multiple Fan Controller System Workstation Thermal Management System Quad Setpoint, Programmable Temperature Monitor and Controller ADT14 FUNCTIONAL BLOCK DIAGRAM 2.5V VREF HYSTERESIS SETPOINT OUTPUT 1 SET 1 CURRENT MIRROR SET 2 SETPOINT OUTPUT 2 SET 3 WINDOW COMPARATORS SET 4 SETPOINT OUTPUT 3 SETPOINT OUTPUT 4 GENERAL DESCRIPTION The ADT14 is a temperature sensor and controller that generates an output voltage proportional to temperature and provides four temperature trip points. The four trip points, or temperature setpoints, and their hysteresis are determined by voltage levels set by the user. An on-chip voltage reference provides an easy method for setting the temperature trip points. The ADT14 consists of a bandgap voltage reference combined with four matched comparators. The reference provides both a temperature-stable 2.5 V output, and a voltage proportional to absolute temperature (VPTAT) which has a precise temperature coefficient of 5 mV/K = 5 mV/(°C +273.15). The VPTAT output is nominally 1.49 V at +25°C. The comparators determine whether the VPTAT output is above the voltages set up by external res...