Integrated Temperature Controllers for Peltier Modules

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The MAX1978/MAX1979 are the smallest, safest, most accurate complete single-chip temperature controllers for Peltier thermoelectric cooler (TEC) modules. On-chip power FETs and thermal control-loop circuitry minimize external components while maintaining high efficiency. Selectable 500kHz/1MHz switching frequency and a unique ripple-cancellation scheme optimize component size and efficiency while reducing noise. Switching speeds of internal MOSFETs are optimized to reduce noise and EMI. An ultra-low-drift chopper amplifier maintains ±0.001°C temperature stability. Output current, rather than voltage, is directly controlled to eliminate current surges. Individual heating and cooling current and voltage limits provide the highest level of TEC protection.

The MAX1978 operates from a single supply and provides bipolar ±3A output by biasing the TEC between the outputs of two synchronous buck regulators. True bipolar operation controls temperature without "dead zones" or other nonlinearities at low load currents. The control system does not hunt when the set point is very close to the natural operating point, where only a small amount of heating or cooling is needed. An analog control signal precisely sets the TEC current. The MAX1979 provides unipolar output up to 6A.

A chopper-stabilized instrumentation amplifier and a high-precision integrator amplifier are supplied to create a proportional-integral (PI) or proportional-integral-derivative (PID) controller. The instrumentation amplifier can interface to an external NTC or PTC thermistor, thermocouple, or semiconductor temperature sensor. Analog outputs are provided to monitor TEC temperature and current. In addition, separate overtemperature and undertemperature outputs indicate when the TEC temperature is out of range. An on-chip voltage reference provides bias for a thermistor bridge.

The MAX1978/MAX1979 are available in a low-profile 48-lead thin QFN-EP package and is specified over the -40°C to +85°C temperature range. The thermally enhanced QFN-EP package with exposed metal pad minimizes operating junction temperature. An evaluation kit is available to speed designs.
MAX1978, MAX1979: Typical Operating Circuit MAX1978, MAX1979: Typical Operating Circuit Enlarge+

Key Features

  • Smallest, Safest, Most Accurate Complete Single-Chip Controller
  • On-Chip Power MOSFETS—No External FETs
  • Circuit Footprint < 0.93in²
  • Circuit Height < 3mm
  • Temperature Stability to 0.001°C
  • Integrated Precision Integrator and Chopper Stabilized Op Amps
  • Accurate, Independent Heating and Cooling Current Limits
  • Eliminates Surges By Directly Controlling TEC Current
  • Adjustable Differential TEC Voltage Limit
  • Low-Ripple and Low-Noise Design
  • TEC Current Monitor
  • Temperature Monitor
  • Over- and Undertemperature Alarm
  • Bipolar ±3A Output Current (MAX1978)
  • Unipolar +6A Output Current (MAX1979)


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See parametric specs for Multifunction PMICs (81)

Part NumberPrimary TopologyMonitor/Control FeaturesDC-DC/Power FeaturesVIN
Oper. Freq.
Inverting OutputsPackage/PinsBudgetary
minmaxminmaxSee Notes
MAX1978 H-Bridge
Volt. or PWM Controlled Output
Avg. Current Mode Control
Current Limit
Dual/ Multi-Phase
Fixed Freq./PWM
Internal Switch
Soft Start
Sync. Rectifier
TEC Driver
$16.19 @1k
Avg. Current Mode Control
Current Limit
Dual/ Multi-Phase
Fixed Freq./PWM
Internal Switch
Soft Start
TEC Driver
$16.16 @1k

Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

MAX1978EVKIT: Evaluation Kit for the MAX1978
Product Reliability Reports: MAX1978.pdf 
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C   Material Composition  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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