LTC1923 Datasheet, PDF (1/28 Pages) Linear Technology – High Efficiency Thermoelectric Cooler Controller

FEATURES
s _{High Efficiency, Low Noise Topology}
s _{Adjustable Output Slew Rate Reduces EMI}
s _{Full-Bridge Controller for Bidirectional}
Current Control
s _{Adjustable Pulse-by-Pulse Bidirectional TEC}
Current Limit
s _{Open/Shorted Thermistor Indication}
s _{Solution Footprint in Less Than 0.6" × 0.8"}
(Double-Sided PCB)
s _{Available in 5mm x 5mm QFN and}
28-Pin SSOP Packages
s _{TEC Voltage Clamping}
s _{TEC Current, Voltage and Heat/Cool Status Outputs}
s _{Adjustable/Synchronizable Oscillator Frequency}
Reduces Filter Component Size and System Noise
s _{2.5V Reference Voltage Output}
s _{2.7V Minimum OUperating Voltage}
APPLICATIO S
s _{Laser-Based Fiber Optic Links}
s _{Medical Instruments}
s _{CPU Temperature Regulators}
LTC1923
High Efficiency Thermoelectric
Cooler Controller
DESCRIPTIO
The LTC^®1923 is a pulse width modulator intended for
thermoelectric cooler (TEC) or heater applications requir-
ing either unidirectional or bidirectional drive circuits. All
of the necessary control circuitry and two sets of comple-
mentary output drivers are integrated into the LTC1923 to
drive a full bridge, providing an efficient means of bidirec-
tional current flow to the TEC. An accurate temperature
control loop to stabilize the temperature of a laser diode
system is easily achieved with the addition of just a few
external components. Typical temperature setpoint accu-
racy of 0.1°C is achievable with the LTC1923. Adding an
instrumentation amplifier front end allows setpoint stabil-
ity of 0.01°C.
The part features independent adjustable heating and
cooling pulse-by-pulse current limit, current soft-start for
controlled start-up, output slew rate control to reduce
system noise, differential current sense and voltage am-
plifiers and a host of auxiliary circuits to protect the laser
and provide redundant system monitoring.
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATIO
Laser Temperature Control Loop Achieving Setpoint Stability of 0.01°C
10k
0.1%
10k
NTC
82k
REF
+ _REF
LTC2053
V_DD
TMP
CMD
LTC1658 V_OUT
A = 10
–
4.7µF
10M
100k
1µF
C1, C2: TAIYO YUDEN JMK325BJ226MM-T (X7R)
L1, L2: SUMIDA CDRH6D2B-220NC
*MNA, MPA: SILICONIX Si9801
**MNB, MPB: SILICONIX Si9801
PLLLPF
R_T
R_SLEW
C_T
SDSYNC
V_REF
CNTRL PDRVB
EAOUT NDRVB
FB
V_DD
LTC1923
AGND
PGND
SS
NDRVA
I_LIM
V_SET
FAULT
PDRVA
CS⁺
CS^–
V_THRM
H/C
V_TEC
I_TEC
TEC⁺
TEC^–
10k
330pF
1µF
V_REF
V_DD
10µF
MPA*
L1
10µH
COOLER
L2
10µH
MPB**
1µF
TEC
C1
C2
MNB** 22µF
22µF
31
R_S
42
MNA*
1923 TA01
1923f
1