Ultracompact, 1.5 A Thermoelectric Cooler
(TEC) Controller
Data Sheet
ADN8834
FEATURES
FUNCTIONAL BLOCK DIAGRAM
VLIM/
Patented high efficiency single inductor architecture
Integrated low RDSON MOSFETs for the TEC controller
TEC voltage and current operation monitoring
No external sense resistor required
Independent TEC heating and cooling current limit settings
Programmable maximum TEC voltage
2.0 MHz PWM driver switching frequency
External synchronization
Two integrated, zero drift, rail-to-rail chopper amplifiers
Capable of NTC or RTD thermal sensors
2.50 V reference output with 1% accuracy
Temperature lock indicator
VDD
SD ILIM VTEC ITEC
PVIN
ERROR
AMP
TEC DRIVER
IN1P
IN1N
TEC CURRENT
AND VOLTAGE
SENSE AND LIMIT
LDR
LINEAR
POWER
STAGE
OUT1
COMP
AMP
IN2P
IN2N
CONTROLLER
SW
PWM
POWER
STAGE
SFB
OUT2
Available in a 25-ball, 2.5 mm × 2.5 mm WLCSP or in a
24-lead, 4 mm × 4 mm LFCSP
VOLTAGE
REFERENCE
OSCILLATOR
APPLICATIONS
TEC temperature control
AGND
VREF
EN/SY
PGNDx
Optical modules
Optical fiber amplifiers
Figure 1.
Optical networking systems
Instruments requiring TEC temperature control
GENERAL DESCRIPTION
The ADN8834 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 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.
Table 1. TEC Family Models
Device No. MOSFET
Thermal Loop
Package
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.
ADN8831
ADN8833
Discrete
Integrated Digital
Digital/analog
LFCSP (CP-32-7)
WLCSP (CB-25-7),
LFCSP (CP-24-15)
ADN8834
Integrated Digital/analog
WLCSP (CB-25-7),
LFCSP (CP-24-15)
Rev. A
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