The MCP9902/3/4 is a high-accuracy， low-cost， System Management Bus （SMBus） temperature sensor. The MCP9902/3/4 monitors up to four temperature channels. Advanced features such as Resistance Error Correction （REC）， Beta Compensation and automatic diode-type detection combine to provide a robust solution for complex environmental monitoring applications. Resistance Error Correction automatically eliminates the temperature error caused by series resistance allowing greater flexibility in routing thermal diodes. Beta Compensation eliminates temperature errors caused by low， variable beta transistors common in today‘s fine geometry processors. The automatic beta detection feature monitors the external diode/transistor and determines the optimum sensor settings for accurate temperature measurements regardless of processor technology. This frees the user from providing unique sensor configurations for each temperature monitoring application. These advanced features plus ±1°C measurement accuracy for both external and internal diode temperatures provide a low-cost， highly flexible and accurate solution for critical temperature monitoring applications.