MAX1978ETM+

The MAX1978ETM+ by Analog Devices is a compact and accurate single-chip temperature controller specifically designed for Peltier thermoelectric cooler (TEC) modules. It integrates on-chip power FETs and thermal control-loop circuitry, minimizing the need for external components and reducing the overall circuit footprint and height.

This controller features selectable 500kHz/1MHz switching frequencies and a unique ripple-cancellation scheme to optimize component size, efficiency, and noise reduction. The internal MOSFETs' switching speeds are optimized to minimize EMI. A key feature is its ultra-low-drift chopper amplifier, which maintains a temperature stability of ±0.001°C. The device directly controls output current, not voltage, to prevent current surges and provides individual heating and cooling current and voltage limits for enhanced TEC protection.

The MAX1978 operates from a single 3V to 5.5V supply and provides bipolar ±3A output. It utilizes two synchronous buck regulators to bias the TEC, enabling true bipolar operation without dead zones or nonlinearities at low load currents. The control system is designed to avoid hunting when the setpoint is near the natural operating point.

It includes integrated amplifiers for PI or PID control and can interface with external sensors like NTC/PTC thermistors, thermocouples, or semiconductor temperature sensors. Analog outputs are available to monitor TEC temperature and current, with separate over/undertemperature outputs. The MAX1978ETM+ is supplied in a low-profile 48-lead TQFN (7x7) package, specified for operation from -40°C to +85°C. The thermally enhanced package with an exposed metal pad helps minimize operating junction temperature.