The ADT7421 is a dual -channel digital thermometer and under/overtemperature alarm, intended for use in PCs and thermal management systems. It is pin- and register-compatible with the ADM1032, ADT7461 and ADT7461A. The ADT7421 includes Beta Cancellation Technology. This enables accurate measurement of temperature from very small geometry (45 nm) processes. Significant variations in the Beta factor can be observed when different currents are applied to transistors embedded in small geometry CPU's. This leads to large temperature errors. The ADT7421 automatically cancels the effects of error induced by beta variations.