LTC1392 Micropower Temperature, Power Supply and Differential Voltage Monitor UFEATUSREDESCRIPTIO ■ Complete Ambient Temperature Sensor Onboard The LTC®1392 is a micropower data acquisition system ■ System Power Supply Monitor designed to measure temperature, on-chip supply voltage ■ 10-Bit Resolution Rail-to-Rail Common-Mode and a differential voltage. The differential inputs feature Differential Voltage Input rail-to-rail common mode input voltage range. The LTC1392 ■ Available in 8-Pin SO and PDIP contains a temperature sensor, a 10-bit A/D converter with ■ 0.2µA Supply Current When Idle sample-and-hold, a high accuracy bandgap reference and ■ 700µA Supply Current When Sampling at a 3-wire half-duplex serial interface. Maximum Rate The LTC1392 can be programmed to measure ambient ■ Single Supply Voltage: 4.5V to 6V temperature, power supply voltage and an external volt- ■ 3-Wire Half-Duplex Serial I/O age at the differential input pins, that can also be used for ■ Communicates with Most MPU Serial Ports and All current measurement using an external sense resistor. MPU Parallel I/O Ports When measuring temperature, the output code of the A/D OU converter is linearly proportional to the temperature in °C. APPLICATIS Production trimming achieves ±2°C initial accuracy at ■ room temperature and Temperature Measurement ±4°C over the full –40°C to 85°C ■ temperature range. Power Supply Measurement ■ Current Measurement The on-chip serial port allows efficient data transfer to a ■ Remote Data Acquisition wide range of MPUs over three or four wires. This, ■ Environment Monitoring coupled with low power consumption, makes remote location sensing possible and facilitates transmitting , LTC and LT are registered trademarks of Linear Technology Corporation. data through isolation barriers. OUTYPICAL APPLICATIOutput Temperature ErrorComplete Temperature, Supply Voltage andSupply Current Monitor 5 LTC1392C 4 GUARANTEED 1µF LIMIT 5V + 3 °C) LTC1392I 2 GUARANTEED LIMIT LTC1392 1 TYPICAL 1 8 P1.4 D V 0 IN CC RSENSE MPU 2 7 D –V –1 OUT IN (e.g., 68HC11) 3 6 P1.3 CLK +V –2 IN ILOAD 4 5 TEMPERATURE ERROR ( P1.2 CS GND –3 –4 LTC1392 • TA01 –5 –40 –20 0 20 40 60 80 100 TEMPERATURE (°C) LTC1392 • TA02 1