The ADM1021A is a temperature monitor chip from Analog Devices. It has the characteristics of low cost, high precision, and programmability.
The ADM1021A is a two-channel digital thermometer and under/over temperature alarm designed for use in personal computers and other systems requiring thermal monitoring. It measures the temperature of a microprocessor using a diode-connected PNP transistor or a discrete NPN/PNP device, as well as an on-chip temperature sensor to monitor the device and its environment. A novel measurement technique cancels out the absolute value of the transistor's base emitter voltage, eliminating the need for calibration.
The device communicates over a two-wire serial interface compatible with SMBus standards. Users can program under and over temperature limits via the serial bus, and an ALERT output signals when the on-chip or remote temperature is out of range. This output can function as an interrupt or an SMBus alert. The ADM1021A operates with a supply voltage range of 3 V to 5.5 V and features a small 16-lead QSOP package.
| Temperature Resolution | 1 °C |
|---|---|
| Temperature Error, Local Sensor | +1 °C / -3 °C |
| Temperature Error, Remote Sensor | 3 °C / -5 °C |
| Supply Voltage Range | 3 V to 5.5 V |
| Standby Supply Current | 1 pA |
| Average Operating Supply Current | 130 pA |
| Conversion Time | 65 ms |
| SMBus Clock Frequency | 100 kHz |
| Operating Temperature Range | -55°C to +125°C |
| Package Type | 16-Lead QSOP |
No, a novel measurement technique cancels out the absolute value of the transistor's base emitter voltage, so that no calibration is required.
The accuracy for the on-chip sensor is 1°C.
The accuracy for the remote sensor is 3°C.
It uses a 2-Wire SMBus Serial Interface that supports System Management Bus (SMBus) Alert.