Integrated TEC controller for precision thermal management
The Maxim Integrated MAX1978ETM+T is a single-chip controller and driver for Peltier thermoelectric cooler (TEC) modules, integrating the power stage, control loop, and temperature-monitoring interface in a 48-TQFN (7x7 mm) package with an exposed pad for heat sinking. It accepts a supply from 3V to 5.5V, covering common 3.3V and 5V rails found in optical transceivers, laser diode modules, and industrial temperature chambers. The operating temperature range of -40°C to 85°C suits outdoor telecom cabinets and factory-floor instrumentation where the ambient can swing well beyond commercial limits.
Supply range and what it means for your power rail
With a supply range of 3V to 5.5V, the MAX1978ETM+T can run directly off a 3.3V or 5V rail without a separate regulator. At the low end, 3V leaves about 0.3V headroom above the minimum for a 3.3V rail with typical tolerance, so a well-regulated supply is needed. The upper end at 5.5V gives margin for a 5V rail that might rise during light load. This flexibility simplifies BOM consolidation when the same TEC controller is used across multiple board variants with different system voltages.
Package and thermal: the exposed pad is the heat path
The 48-WFQFN exposed pad (7x7 mm) is the primary thermal path for the TEC drive current. The pad must be soldered to a copper plane on the PCB with thermal vias to inner ground layers. Without adequate via stitching, the junction temperature can exceed the 85°C operating limit even at moderate output currents. The 48-TQFN footprint is standard for this package family, so layout guides from Maxim's application notes for the MAX1978 family apply directly.
Active lifecycle — no LTB risk for new designs
The MAX1978ETM+T carries an Active product status with ROHS3 compliance. For a BOM line that requires a dedicated TEC controller, this part can be specified into new production without near-term obsolescence concern.