Thermoelectric Cooler (TEC)

Controller

Preliminary Technical Data

ADN8831

FEATURES

True current sensing and over current protection

Separate heating and cooling current limits

High efficiency: >90%

Long-term temperature stability: 0.1°C

Temperature lock indication

Temperature monitoring output

Oscillator synchronization with an external signal

Clock phase adjustment for multiple controllers

Programmable switching frequency up to 1MHz

Programmable maximum TEC voltage

Low noise: <0.05% TEC current ripple

TEC current monitoring

Compact 5mm x 5mm LFCSP

APPLICATIONS

Thermoelectric Cooler (TEC) temperature control

Resistive heating element control

Temperature-Stabilization Substrate (TSS) control

FUNCTIONAL BLOCK DIAGRAM

MOSFET

Drivers

Heating

ILim

Limiter

Controls

PID

Compensation

Network

Error

Amplifier

Oscillator

2.5V

Reference

Cooling

ILim

VLim

Freq/Phase

Control

Temp

Set Input

Thermistor

Input

GENERAL DESCRIPTION

The ADN8831 is a monolithic controller that drives a

Thermoelectric Cooler (TEC) to stabilize the temperature of a

laser diode or a passive component used in

telecommunications equipment.

This device relies on a Negative Temperature Coefficient

(NTC) thermistor or a positive temperature coefficient RTD

device to sense the temperature of the object attached to the

TEC. The target temperature is set with an analog input

voltage either from a DAC or with an external resistor divider.

The loop is stabilized by a PID compensation amplifier with

high stability and low noise. The compensation network can

be adjusted by the user to optimize temperature settling time.

The component values for this network can be calculated

based on the thermal transfer function of the laser diode or

obtained from the look-up table given in the applications

notes.

Voltage outputs are provided to monitor both the temperature

of the object and the voltage across the TEC. A 2.5V voltage

reference is provided for the thermistor temperature sensing

bridge.

An external sense resistor provides true current sensing.

Current limits for both heating and cooling can be set

independently.

Rev. PrC

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However, no responsibility is assumed by Analog Devices for its use, nor for any

infringements of patents or other rights of third parties that may result from its use.

Specifications subject to change without notice. No license is granted by implication

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