Fan controller with ±3°C temperature tracking
The Microchip EMC2101-ACZL-TR combines fan speed control with a temperature monitor that reads both an internal sensor and an external diode-connected transistor, reporting temperature across a -64°C to 127°C range. Temperature accuracy is specified at ±3°C maximum — tight enough for thermal management in server PSUs, telecom line cards, or industrial controller enclosures where a fan failure or blocked intake drives the junction temperature past the trip point.
2-wire SMBus interface and alarm output
The device communicates over a 2-wire SMBus and includes a dedicated alarm output that asserts when the measured temperature exceeds the programmed limit — no polling required, the interrupt line pulls low and the host reads the fault register. Supply voltage range is 3V to 3.6V, which matches the 3.3V rail common in mixed-signal designs. Internal topology includes an ADC (Sigma Delta), comparator, fan control logic, multiplexer, and register bank — the sigma-delta ADC digitises the external diode voltage, the comparator checks it against the limit register, and the fan control block adjusts the PWM duty cycle or fan tachometer target.