QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 491
TEC TEMPERATURE CONTROLLER
LTC1923EUH
DESCRIPTION
Demonstration circuit 491 features the LTC1923EUH
thermoelectric cooler (TEC) controller. The LTC1923EUH
comes in a small 32-lead QFN package (5mm by 5mm).
Since the switching frequency of the circuit is 1MHz,
small size inductors and capacitors are used as output
filters. The main components are within a small assem-
bly area about 0.75” by 0.5”. DC491 provides a complete
temperature control solution for TEC based temperature
control of fiber-optic lasers. Laser temperature may be
controlled at temperatures above or below ambient with
set point stability typically well within 0.05°C over widely
varying ambient temperature. Temperature set point is
established with a potentiometer. Considerably more
detail relating to TEC temperature control issues is avail-
able in LTC Application Note AN-89, A Thermoelectric
Cooler Temperature Controller for Fiber Optic Lasers.
This publication should be reviewed before demo board
results are evaluated.
Design files for this circuit board are available. Call
the LTC factory.
QUICK START PROCEDURE
Demonstration circuit 491 is easy to set up to evaluate
the performance of the LTC1923EUH. Refer to Figure 1
for proper measurement equipment setup and follow the
procedure below:
1.
Connect a turned-off power supply (2.7–5.5V) to the
VDD and GND terminals.
2.
Connect a thermistor to the NTC+ and NTC– termi-
nals. Although the thermistor is not a polarized de-
vice, one of its leads may be committed to the lasers
case ground. If this is so, this lead should be con-
nected to NTC–. Shielded cable should be used for the
thermistor leads, with the shield connected to ground.
3.
Adjust the temperature set point potentiometer (R15)
using a small screwdriver.
4.
Connect the TEC leads from the laser to the boards
TEC+ and TEC– terminals. Observe polarity.
5.
Turn on the power supply. The board will typically pull
hundreds of milliamps for several seconds. Once the
temperature set point is reached the current drops
and settles to some sustaining value.
6.
Performance optimization for any particular laser is
achievable by following the procedures and guidelines
given in LTC Application Note AN-89.
+
–
+
–
TEC
LASER
THERMISTOR
+–
+– +–
Figure 1.
Proper Measurement Equipment Setup
1
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
TEC
RT1
ITEC
GND
VTEC
NTC+
NTC-
TEC SUPPLY
FAULT
Heat
Cool
TEC+TEC-
2.7-5.5V
VDD
GND
CW
A
DC491A
Friday, April 05, 2002 11
LTC1923EUH, TEC Temperature Controller
June Wu 1/10/02
Wei Chen 1/10/02
SIZE
SCALE:
CAGE CODE DWG NOREV
SHEET OF
FILENAME:
TITLE
CONTRACT NO.
APPROVALS DATE
DRAWN
CHECKED
APPROVED
ENGINEER
DESIGNER
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
SHDN/SYNC
VSET
VDD
VDDF VDD
VDD
VDDF
VSET
VSET
VSET
VDDF
VSET
VDDF
VDDF
VDDF
VDDF
VDDF
VDDF
VDDF
VDD
VDDF
C19
0.1uF
SM Film
U1
LTC1923EUH
30
31
32 27
28
29
1
2
3
4
6
7
8
9
10
11
12
26
25
24
23
22
21
20
19
18
17
16
15
14
13
5
PLLPF
RSLEW
SDSYNCB VREF
CT
RT
CNTRL
EAOUT
FB
AGND
SS
ILIM
VSET
FAULTB
VTHRM
H/C
VTEC
N/C
N/C
PDRVB
NDRVB
VDD
VDD
PGND
NDRVA
PDRVA
CS+
CS-
ITEC
TEC+
TEC-
N/C
R5
10K 1%
C11
0.1uF
SM Film
C1
0.1uF
C15
10uF
6.3V
R13
47.5K
1%
C9
0.1uF
SM Film
C14
10uF
6.3V
R7
10M
1%
D3
LED(Grn)
C18
0.1uF
R9
100K
1%
R22
100K
C2
0.1uF R2
OPEN
R23
100K
C7
0.1uF
TP8
R21
200
Q6
2N7002 1
2 3
R18
100K
L1
4.2uH
TP10
R14
10K
0.1%
Q3
2N7002 1
2 3
C4
0.1uF
R16
10K
0.1%
R25
10K
C20
22uF
10V
R24
0
TP6
Q4
2N7002 1
2 3
R3
10K
0.1%
R15
20K
TEMP. ADJ.
1 3
2
+
C10
4.7uF
6.3V
TP4
R6
9.09K
1%
TP3
L2
4.2uH
-
+
U2
LTC2053CMS8
3
27
14
5 6
8TP1
TP5
R10
1K 1%
R1
2.2K
R4
2.2K
R20
200
R8
2.2
C6
0.1uF
C16
10uF
6.3V
TP7
C3
330pF
D2
LED(Orn)
C13
1uF
Q1-2
Si5915DC
4
5 3
6
D1
LED(Red)
R19
100K
Q1-1
Si5915DC
2
7 1
8
R12
10K
1%
Q2-1
Si5904DC
2
1 7
8
C12
1uF
C17
0.1uF
Q2-2
Si5904DC 4
3 5
6
C5
1uF
Q5
2N7002 1
2 3
C8
10uF
6.3V
R17
200
TP9
TP2
R11
0.02
0.25W 1%
Linear Technology Corporation
LTC1923EUH
Bill Of Material
Demo Bd. # 491A
6/17/2005
Item Qty Reference Part Description Manufacture / Part #
1 7 C1,C2,C4,C6,C7,C17,C18 CAP., X5R, 0.1uF, 10V, 20% 0402 TAIYO YUDEN, LMK105BJ104MV
2 1 C3 CAP., X7R, 330pF, 50V, 20% 0402 AVX, 04025C331MAT
3 3 C5,C12,C13 CAP., X5R, 1uF, 6.3V, 20% 0603 TAIYO YUDEN, JMK107BJ105MA
4 4 C8,C14,C15,C16 CAP., X5R, 10uF, 6.3V, 20% 1206 TAIYO YUDEN, JMK316BJ106ML
5 3 C9,C11,C19 CAP., SM Film, 0.1uF, 16V, 20% 0805 Panasonic, ECP-U1C104MA5
6 1 C10 CAP., Tant., 15uF, 10V, 20% 3216 AVX, TAJA156M010R
7 1 C20 CAP., Tant., 22uF, 10V, 20% 3528 AVX, TPSB226M010R
8 1 D1 LED(Red) Panasonic, LN1251-C-TR
9 1 D2 LED(Orn) Panasonic, LN1851-C-TR
10 1 D3 LED(Grn) Panasonic, LN1351-C-TR
11 2 L1,L2 INDUCTOR, 4.2uH CDRH5D28 SUMIDA, CDRH5D28-4R2
12 1 Q1 Dual P-MOSFET, Si5915DC 1206-8 VISHAY, SI5915DC
13 1 Q2 Dual N-MOSFET, Si5904DC 1206-8 VISHAY, SI5904DC
14 4 Q3,Q4,Q5,Q6 N-MOSFET, 2N7002 Diodes Inc., 2N7002-7
15 2 R1,R4 RES., CHIP, 2.2K, 1/16W, 5% 0402 AAC, CR05-222JM
16 1 R25 RES., CHIP, 10K, 1/16W, 5% 0402 AAC, CR05-103JM
17 0 R2(not install) RES., 0402
18 3 R3,R14,R16 RES., CHIP, 10K, 0.1W, 0.1% 0805 KOA, RN73T2A1002B
19 2 R5,R12 RES., CHIP, 10K, 1/16W, 1% 0402 AAC, CR05-1002FM
20 1 R6 RES., CHIP, 9.09K, 1/16W, 1% 0402
A
AC, CR05-9091FM
21 1 R7 RES., CHIP, 10M, 1/16W, 1% 0402
A
AC, CR05-1005FM
22 1 R8 RES., CHIP, 2.2, 1/16W, 5% 0402 AAC, CR05-2R2JM
23 5 R9,R18,R19,R22,R23 RES., CHIP, 100K, 1/16W, 1% 0402 AAC, CR05-1003FM
24 1 R10 RES., CHIP, 1K, 1/16W, 1% 0402 AAC, CR05-1001FM
25 1 R11 RES., CHIP, 0.02, 0.25W, 1% 1206 IRC, LRF1206-01-R020-F
26 1 R13 RES., CHIP, 47.5K, 1/16W, 1% 0402 AAC, CR05-4752FM
27 1 R15 Pot. 11 Turns 20K Bourns, 3224W-1-203E
28 3 R17,R20,R21 RES., CHIP, 200, 1/16W, 5% 0402 AAC, CR05-201JM
29 1 R24 RES., CHIP, 0, 1/16W, 5% 0402 AAC, CR05-000JM
30 10 TP1-TP10 TURRET, MILL-MAX, 2501-2
31 1 U1 I.C., LTC1923EUH, MLP-32 LINEAR., LTC1923EUH
32 1 U2 I.C., LTC2053, MS8 LINEAR., LTC2053CMS8
33 4 SCREW, #4-40, 1/4"
A
NY
34 4 STANDOFF, NYLON HEX #4-40 1/4" MICRO PLASTICS 14HTSP101
35 1 PRINTED CIRCUIT BOARD DEMO CIRCUIT 491A
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