ADN8834

The ADN8834¹ is a monolithic TEC controller with an integrated TEC controller. It has a linear power stage, a pulse-width modulation (PWM) power stage, and two zero-drift, rail-to-rail operational amplifiers. The linear controller works with the PWM driver to control the internal power MOSFETs in an H-bridge configuration. By measuring the thermal sensor feedback voltage and using the integrated operational amplifiers as a proportional integral differential (PID) compensator to condition the signal, the ADN8834 drives current through a TEC to settle the temperature of a laser diode or a passive component attached to the TEC module to the programmed target temperature.

The ADN8834 supports negative temperature coefficient (NTC) thermistors as well as positive temperature coefficient (PTC) resistive temperature detectors (RTD). The target temperature is set as an analog voltage input either from a digital-to-analog converter (DAC) or from an external resistor divider.

The temperature control loop of the ADN8834 is stabilized by PID compensation utilizing the built in, zero drift chopper amplifiers. The internal 2.50 V reference voltage provides a 1% accurate output that is used to bias a thermistor temperature sensing bridge as well as a voltage divider network to program the maximum TEC current and voltage limits for both the heating and cooling modes. With the zero drift chopper amplifiers, extremely good long-term temperature stability is maintained via an autonomous analog temperature control loop.

APPLICATIONS

• TEC temperature control
• Optical modules
• Optical fiber amplifiers
• Optical networking systems
• Instruments requiring TEC temperature control

¹ Product is covered by U.S. Patent No. 6,486,643.