FEATURES
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LTC1923
High Efficiency Thermoelectric
Cooler Controller
DESCRIPTIO
The LTC
廬
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擄C is achievable with the LTC1923. Adding an
instrumentation amplifier front end allows setpoint stabil-
ity of 0.01擄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.
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High Efficiency, Low Noise Topology
Adjustable Output Slew Rate Reduces EMI
Full-Bridge Controller for Bidirectional
Current Control
Adjustable Pulse-by-Pulse Bidirectional TEC
Current Limit
Open/Shorted Thermistor Indication
Solution Footprint in Less Than 0.6"
脳
0.8"
(Double-Sided PCB)
Available in 5mm x 5mm QFN and
28-Pin SSOP Packages
TEC Voltage Clamping
TEC Current, Voltage and Heat/Cool Status Outputs
Adjustable/Synchronizable Oscillator Frequency
Reduces Filter Component Size and System Noise
2.5V Reference Voltage Output
2.7V Minimum Operating Voltage
APPLICATIO S
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Laser-Based Fiber Optic Links
Medical Instruments
CPU Temperature Regulators
TYPICAL APPLICATIO
10k
0.1%
Laser Temperature Control Loop Achieving Setpoint Stability of 0.01擄C
10k
PLLLPF
82k
REF
10k
NTC
TMP
CMD
LTC1658
V
OUT
R
T
C
T
V
REF
PDRVB
NDRVB
V
DD
LTC1923
1碌F
AGND
SS
I
LIM
V
SET
FAULT
V
THRM
C1, C2: TAIYO YUDEN JMK325BJ226MM-T (X7R)
L1, L2: SUMIDA CDRH6D2B-220NC
*MNA, MPA: SILICONIX Si9801
**MNB, MPB: SILICONIX Si9801
H/C
V
TEC
PGND
NDRVA
PDRVA
CS
+
CS
鈥?/div>
I
TEC
TEC
+
TEC
鈥?/div>
4
3
1
R
S
2
1碌F
MPA*
L1
10碌H
C1
MNB** 22碌F
COOLER
TEC
L2
10碌H
C2
22碌F
MNA*
V
REF
330pF
1碌F
+
鈥?/div>
R
SLEW
V
DD
SDSYNC
CNTRL
EAOUT
FB
REF
LTC2053
A = 10
4.7碌F
10M
100k
U
U
U
V
DD
10碌F
MPB**
1923 TA01
1923f
1
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