MAX1968 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – Power Drivers for Peltier TEC Modules

19-2447; Rev 0; 4/02
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Power Drivers for Peltier TEC Modules
General Description
The MAX1968/MAX1969 are highly integrated and cost-
effective, high-efficiency, switch-mode drivers for Peltier
thermoelectric cooler (TEC) modules. Both devices uti-
lize direct current control to eliminate current surges in
the TEC. On-chip FETs minimize external components
while providing high efficiency. A 500kHz/1MHz switch-
ing frequency and a unique ripple cancellation scheme
reduce component size and noise.
The MAX1968 operates from a single supply and pro-
vides bipolar ±3A output by biasing the TEC between
the outputs of two synchronous buck regulators. Bipolar
operation allows for temperature control without “dead
zones” or other nonlinearities at low load currents. This
arrangement ensures that the control system does not
hunt when the set point is very close to the natural
operating point, requiring a small amount of heating or
cooling. An analog control signal precisely sets the TEC
current. The MAX1969 provides unipolar output up to
6A. Reliability is optimized with settable limits for both
TEC voltage and current, with independently set limits
for heating and cooling current. An analog output also
monitors TEC current.
The MAX1968/MAX1969 are available in a low-profile
28-pin TSSOP-EP package and is specified over the
-40°C to +85°C temperature range. The thermally-
enhanced TSSOP-EP package with exposed metal pad
minimizes operating junction temperature. An evalua-
tion kit is available to speed designs.
Applications
Fiber Optic Laser Modules
WDM, DWDM Laser Diode Temperature Control
Fiber Optic Network Equipment
EDFA Optical Amplifiers
Telecom Fiber Interfaces
ATE
Biotech Lab Equipment
Features
o Direct Current Control Prevents TEC Current
Surges
o On-Chip Power MOSFETs
o High-Efficiency Switch-Mode Design
o Ripple Cancellation for Low Noise
o No Dead-Zone or Hunting at Low-Output Current
o Adjustable TEC Voltage Limit
o Separately Adjustable Heating and Cooling
Current Limits
o ITEC Output Monitors TEC Current
o 1% Accurate Voltage Reference
o 500kHz/1MHz Switching Frequency
o ±3A Output Current (MAX1968)
o 6A Output Current (MAX1969)
o Thermally Enhanced TSSOP-EP Package
Ordering Information
PART
TEMP RANGE
MAX1968EUI
-40°C to +85°C
MAX1969EUI
-40°C to +85°C
*EP = exposed paddle
PIN-PACKAGE
28 TSSOP-EP*
28 TSSOP-EP*
Typical Operating Circuit
TEC
3V TO
CURRENT- 5.5V
CONTROL
SIGNAL
CTLI
V_DD
COMP
LX2
GND OS2
PV_DD1 PV_DD2
MAX1968
OS2
CS
PGND1
PGND2
LX1
TEC
Pin Configuration and Functional Diagram appear at end
of datasheet.
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