DEMO MANUAL DC1626A
LTC3838EFE
Wide Input Range, High Efficiency
Step-Down DC/DC Converter
DESCRIPTION
Demonstration circuit 1626A is a dual output 1.5V/15A
and 1.2V/15A synchronous buck converter operating with
a switching frequency of 300kHz over an input voltage
range of 4.5V to 26V. The demo board comes in two versions. The -A version uses inductor DCR current sensing
with an iron powder inductor for high efficiency. The -B
version uses a 2.5mΩ sense resistor for accurate current
sensing with a low DCR ferrite inductor. The fixed on-time
valley current mode architecture of the LTC3838 allows for
a fast load step response (see Figures 6 to 9). The load
step response can be tested with the on-board load step
circuit and a bench pulse generator.
The demo board uses a high density, two sided drop-in
layout. The entire converter, excluding the bulk output and
input capacitors, fits within a compact 1.5" × 1.0" area
on the board. The package style for the LTC3838EFE is a
38-lead TSSOP with an exposed ground pad.
PERFORMANCE SUMMARY
PARAMETER
The main features of the board are listed below:
• MODE jumper to program either DCM or FCM at light
or no load
• EXTVCC pin
• PLLIN pin to synchronize the converter to an external
clock
• Remote sensing for VOUT1
• Optional resistors to tie the two phases together
• Each rail has its own RUN pin, PGOOD pin and
TRACK/SS pin
Design files for this circuit board are available at
http://www.linear.com/demo
L, LT, LTC, LTM, μModule, Linear Technology and the Linear logo are registered trademarks of
Linear Technology Corporation. All other trademarks are the property of their respective owners.
(TA = 25°C)
CONDITION
Minimum Input Voltage
VALUE
4.5V
Maximum Input Voltage
26V
Output Voltage VOUT1
IOUT1 = 0A to 15A, VIN = 4.5V to 26V
Output Voltage VOUT2
IOUT2 = 0A to 15A, VIN = 4.5V to 26V
1.5V ±2%
VOUT1 Maximum Output Current, IOUT1
VIN = 4.5V to 26V, VOUT1 = 1.2V
15A
VOUT2 Maximum Output Current, IOUT2
VIN = 4.5V to 26V, VOUT2 = 1.5V
15A
Nominal Switching Frequency
-A Efficiency
See Figures 2 and 3
-B Efficiency
See Figures 4 and 5
1.2V ±2%
300kHz
VOUT1 = 1.2V, IOUT1 = 15A, VIN = 12V
89.1% Typical
VOUT2 = 1.5V, IOUT2 = 15A, VIN = 12V
90.2% Typical
VOUT1 = 1.2V, IOUT1 = 15A, VIN = 12V
85.9%
VOUT2 = 1.5V, IOUT2 = 15A, VIN = 12V
88.2%
dc1626afa
1
DEMO MANUAL DC1626A
QUICK START PROCEDURE
Demonstration circuit 1626A is easy to set up to evaluate the performance of the LTC3838EFE. Please refer to
Figure 1 for proper measurement equipment setup and
follow the procedure below.
1. With power off, connect the input supply, load and
meters as shown in Figure 1. Preset the load to 0A
and VIN supply to be 0V. Place jumpers in the following
positions:
JP4 RUN1 ON
JP1 RUN2 ON
JP3 MODE FCM
2. Adjust the input voltage to be between 4.5V to 26V.
VOUT1 should 1.2V ±2%.
VOUT2 should 1.5V ±2%.
3. Next, apply 15A load and recheck VOUT.
4. Once the DC regulation is confirmed, observe the output
voltage ripple, load step response, efficiency and other
parameters.
Load Step Transient Testing
Demonstration circuit 1626A provides a simple load step
circuit consisting of a MOSFET and sense resistor for each
rail. To apply a load step, follow the steps below.
1. Preset the amplitude of a pulse generator to 0.0V and
the duty cycle to 5% or less.
2. Connect the scope to the VOUT BNC connectors for
the rail under test with a coax cable. To monitor the
load step current, connect the scope probe across the
IOSTEP+/IOSTEP– turrets for that rail.
3. Connect the output of the pulse generator to the PULSE
GEN turret for the rail under test and connect the return
to one of the GND turrets.
4. With the converter running, slowly increase the amplitude of the pulse generator output to provide the desired
load step pulse height. The scaling for the LOAD STEP
signal is 10mV/A.
Note 1. Use the BNC connectors labeled VOUT1 or VOUT2
to measure the output voltage ripple.
Note 2. Do not apply the load from the VO1_SNS+ turret
to the VO1_SNS– turret or from the VO2+ turret to the
VO2– turret. These turrets are only intended to monitor
the voltage across COUT1 and COUT5 respectively. Heavy
load currents applied across these turrets may damage
the converter.
dc1626afa
2
DEMO MANUAL DC1626A
QUICK START PROCEDURE
Single Output/Dual Phase Operation
• Tie VFB2 to INTVCC by stuffing 0Ω at R1. This will
disable the error amp for phase 2 and internally tie the
two ITH signals together.
A single output/dual phase converter may be preferred for
high output current applications. The benefits of single
output/dual phase operation is lower ripple current through
the input and output capacitors, faster load step response
and simplified thermal design. To implement single output/
dual phase operation, make the following modifications:
• Remove the ITH compensation network, VFB divider
and TRACK/SS cap for phase 2.
• Tie VRNG1 to VRNG2 by stuffing 0Ω at R4.
• Tie RUN1 to RUN2 by stuffing 0Ω at R7.
• Tie VOUT1 to VOUT2 by tying together the exposed
copper pads on the VOUT shapes with pieces of heavy
copper foil.
• If the optional transient detect circuit is used, externally
tie the DTR1 pin to the DTR2 pin.
• Re-compensate if necessary.
Vout2 V
+
*
Iin
A
Iout2
+
Vin
supply
-
+
Vin V
-
Vout2
load
A
+
A
+
Vout1
load
Iout1
-
* Monitor the voltage across COUT3 and
COUT7 for accurate efficiency measurements.
+
V
Vout1
*
Figure 1. Proper Measurement Equipment Setup
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3
DEMO MANUAL DC1626A
QUICK START PROCEDURE
95
100
90
1.5V
90
1.2V
EFFICIENCY (%)
EFFICIENCY (%)
DCM
80
85
70
60
FCM
50
40
30
80
20
1.2V
1.5V
10
75
0
5
10
15
LOAD CURRENT (A)
BOTH RAILS:
QTOP = RJK0305DPB
QBOTTOM = RJK0330DPB
L = VISHAY IHLP4040DZ-01 0.56μH
DCR = 1.7mΩ TYP, 1.8mΩ MAX
0
0.01
20
dc1626a F03
100
90
EFFICIENCY (%)
1.2V
85
DCM
80
1.5V
90
70
60
FCM
50
40
30
80
20
1.2V
1.5V
10
75
100
Figure 3. Efficiency Curves for the DC1626A-A
(DCR Sense) in FCM and DCM.
95
EFFICIENCY (%)
1
10
LOAD CURRENT (A)
BOTH RAILS:
QTOP = RJK0305DPB
QBOTTOM = RJK0330DPB
L = VISHAY IHLP4040DZ-01 0.56μH
DCR = 1.7mΩ TYP, 1.8mΩ MAX
dc1626a F02
Figure 2. Efficiency Curves for the DC1626A-A
(DCR Sense) in FCM
0.1
0
5
10
15
LOAD CURRENT (A)
BOTH RAILS:
QTOP = RJK0305DPB
QBOTTOM = RJK0330DPB
L = WURTH 7443330068 0.68μH
DCR = 1.35mΩ ±10%
RSENSE = 2.5mΩ
20
dc1626a F04
Figure 4. Efficiency Curves for the DC1626A-B
(RSENSE) in FCM
0
0.01
0.1
1
10
LOAD CURRENT (A)
BOTH RAILS:
QTOP = RJK0305DPB
QBOTTOM = RJK0330DPB
L = WURTH 7443330068 0.68μH
DCR = 1.35mΩ ±10%
RSENSE = 2.5mΩ
100
dc1626a F05
Figure 5. Efficiency Curves for the DC1626A-B
(RSENSE) in FCM and DCM
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4
DEMO MANUAL DC1626A
QUICK START PROCEDURE
1.2VO(AC)
50mV/DIV
109mV
1.5VO(AC)
50mV/DIV
15A
LOAD STEP
5A/DIV
108mV
15A
LOAD STEP
5A/DIV
5A
5A
dc1626a F06
Figure 6. Load Step Response of the 1.2V Rail on the DC1626A-A
(DCR Sense) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 ||
2× 100μF X5R 6.3V 1206, L = 0.56μH, fSW = 300kHz
1.2VO(AC)
50mV/DIV
114mV
dc1626a F07
Figure 7. Load Step Response of the 1.5V Rail on the DC1626A-A
(DCR Sense) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 ||
2× 100μF X5R 6.3V 1206, L = 0.56μH, fSW = 300kHz
1.5VO(AC)
50mV/DIV
15A
LOAD STEP
5A/DIV
108mV
15A
LOAD STEP
5A/DIV
5A
dc1626a F08
Figure 8. Load Step Response of the 1.2V Rail on the DC1626A-B
(RSENSE) At VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF
X5R 6.3V 1206, L = 0.68μH, fSW = 300kHz
5A
dc1626a F09
Figure 9. Load Step Response of the 1.5V Rail on the DC1626A-B
(RSENSE) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF
X5R 6.3V 1206, L = 0.68μH, fSW = 300kHz
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5
DEMO MANUAL DC1626A
PARTS LIST
1626A-A (DCR Sense)
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
CAP, X7R 330pF 50V 0603
AVX 06035C331KAT2A
Required Circuit Components
1
1
C12
2
5
C3, C16, C4, C10, C13
CAP, X5R 0.1μF 50V 0603
AVX 06035D104KAT2A
3
2
C5, C14
CAP, X5R 0.01μF 25V 0603
AAC 0603D103KAT2A
4
2
C6, C11
CAP, NPO 47pF 16V 0603
AVX 0603YA470KAT4A
5
1
C7
CAP, NPO 220pF 25V 0603
AVX 06033A221KAT2A
6
1
C8
CAP, X5R 4.7μF 16V 0805
AVX 0805YD475KAT2A
7
2
C9, C18
CAP, X5R 1μF 16V 0603
AVX 0603YD105KAT2A
8
2
CIN1, CIN2
CAP, 100μF 35V SIZE-F
SUNCON 35HVH100M
9
3
CIN3, CIN4, CIN5
CAP, X5R 10μF 35V 1210
TAIYO YUDEN GMK325BJ106MN-T
10
4
COUT1, COUT2, COUT5, COUT6
CAP, 330μF 2.5V SIZE 7343
SANYO 2R5TPE330M9
11
4
COUT3, COUT4, COUT7, COUT8
CAP, X5R 100μF 6.3V 1206
MURATA GRM31CR60J107ME39L
12
2
D1, D2
DIODE, SCHOTTKY SOD-323
CENTRAL SEMI. CMDSH-4ETR
13
2
L1, L2
IND, 0.56μH
VISHAY IHLP4040DZERR56M01
14
2
Q1, Q3
MOSFET, N-CHANNEL LFPAK
RENESAS RJK0305DPB-00-J0
15
2
Q2, Q4
MOSFET, N-CHANNEL LFPAK
RENESAS RJK0330DPB-00-J0
16
2
R12, R38
RES, 100k 1% 0603
VISHAY CRCW0603100KFKEA
17
1
R13
RES, 15k 1% 0603
VISHAY CRCW060315K0FKEA
18
4
R17, R23, R40, R46
RES, 10k 1% 0603
VISHAY CRCW060310K0FKEA
19
2
R18, R32
RES, 4.02k 1% 0603
VISHAY CRCW06034K02FKEA
20
2
R19, R34
RES, 11k 1% 0603
VISHAY CRCW06011K0FKEA
21
1
R21
RES, 40.2k 1%, 0603
VISHAY CRCW060340K2FKEA
22
2
R27, R25
RES, 2.2Ω 1% 0603
VISHAY CRCW06032R20FKEA
23
1
R28
RES, 137k 1% 0603
VISHAY CRCW0603137KFKEA
24
1
R31
RES, 17.4k 1% 0603
VISHAY CRCW06017K4FKEA
25
2
R42, R43
RES, 10Ω 1% 0603
VISHAY CRCW060310R0FKEA
26
9
R8, R11, R16, R35, R39, R48, R55, R20, R36,
R30, R26
RES, 0Ω 0603
VISHAY CRCW06030000Z0EA
27
2
RS1, RS2
RES, 0.000Ω 1W 1% 2512
TEPRO RN5326
28
1
U1
LTC3838 38-LEAD TSSOP
LINEAR TECH. LTC3838EFE
Additional Circuit Components
1
0
C1, C2, C15, C17
CAP, 0603
OPTIONAL
2
0
CIN6-CIN8
CAP, 1210
OPTIONAL
3
0
COUT13-COUT16
CAP, 7343
OPTIONAL
4
0
Q5-Q8
MOSFET, N-CHANNEL LFPAK
OPTIONAL
5
0
R1, R4, R7, R9, R47, R14, R15, R24, R29, R41,
R45, R3, R6, R10, R37, R44, R49, R50
RES, 0603
OPTIONAL
6
2
Q9, Q10
MOSFET, N-CHANNEL DPAK
VISHAY SUD50N03-12P-E3
7
2
R51, R52
RES, 10k 1% 0603
VISHAY CRCW060310K0FKEA
8
2
R53, R54
RES, 0.01Ω 1/2W 1% 2010
VISHAY WSL2010R0100FEA
dc1626afa
6
DEMO MANUAL DC1626A
PARTS LIST
1626A-A (DCR Sense)
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
STAND-OFF, NYLON 0.25"
KEYSTONE 8831 (SNAP ON)
Hardware/Components (For Demo Board Only)
1
4
STAND-OFF
2
23
E1-E12, E14-E25
TESTPOINT, TURRET 0.095"
MILL-MAX 2501-2-00-80-00-00-07-0
3
6
J1-J6
JACK, BANANA
KEYSTONE 575-4
4
2
J7, J8
CONN, BNC 5PINS
CONNEX 112404
5
2
JP1, JP4
2MM SINGLE ROW HEADER, 3-PIN
SAMTEC TMM-103-02-L-S
6
4
JP1-JP4
SHUNT
SAMTEC 2SN-BK-G
7
2
JP2, JP3
2MM SINGLE ROW HEADER, 4-PIN
SAMTEC TMM-104-02-L-S
PART DESCRIPTION
MANUFACTURER/PART NUMBER
1626A-B (RSENSE)
ITEM
QTY
REFERENCE
Required Circuit Components
1
1
C12
CAP, X7R 330pF 50V 0603
AVX 06035C331KAT2A
2
2
C3, C16
CAP, X7R 1000pF 16V 0603
AVX 0603YC102KAT2A
3
3
C4, C10, C13
CAP, X5R 0.1μF 50V 0603
AVX 06035D104KAT2A
4
2
C5, C14
CAP, X5R 0.01μF 25V 0603
AAC 0603D103KAT2A
5
2
C6, C11
CAP, NPO 47pF 16V 0603
AVX 0603YA470KAT4A
6
1
C7
CAP, NPO 220pF 25V 0603
AVX 06033A221KAT2A
7
1
C8
CAP, X5R 4.7μF 16V 0805
AVX 0805YD475KAT2A
8
2
C9, C18
CAP, X5R 1μF 16V 0603
AVX 0603YD105KAT2A
9
2
CIN1, CIN2
CAP, 100μF 35V SIZE-F
SUNCON 35HVH100M
10
3
CIN3, CIN4, CIN5
CAP, X5R 10μF 35V 1210
TAIYO YUDEN GMK325BJ106MN-T
11
4
COUT1, COUT2, COUT5, COUT6
CAP, 330μF 2.5V SIZE 7343
SANYO 2R5TPE330M9
12
4
COUT3, COUT4, COUT7, COUT8
CAP, X5R 100μF 6.3V 1206
MURATA GRM31CR60J107ME39L
13
2
D1, D2
DIODE, SCHOTTKY SOD-323
CENTRAL SEMI. CMDSH-4ETR
14
2
L1, L2
IND, 0.68μH
WURTH 7443330068
15
2
Q1, Q3
MOSFET, N-CHANNEL LFPAK
RENESAS RJK0305DPB-00-J0
16
2
Q2, Q4
MOSFET, N-CHANNEL LFPAK
RENESAS RJK0330DPB-00-J0
17
2
R12, R38
RES, 100k 1% 0603
VISHAY CRCW0603100KFKEA
18
1
R13
RES, 15k 1% 0603
VISHAY CRCW060315K0FKEA
19
4
R14, R15, R41, R45
RES, 10Ω 1% 0603
VISHAY CRCW060310R0FKEA
20
4
R17, R23, R40, R46
RES, 10k 1% 0603
VISHAY CRCW060310K0FKEA
21
1
R21
RES, 45.3k 1% 0603
VISHAY CRCW060345K3FKEA
22
2
R27, R25
RES, 2.2Ω 1% 0603
VISHAY CRCW06032R20FKEA
23
1
R28
RES, 137k 1% 0603
VISHAY CRCW0603137KFKEA
24
1
R31
RES, 20k 1% 0603
VISHAY CRCW060320K0FKEA
25
2
R42, R43
RES, 10Ω 1% 0603
VISHAY CRCW060310R0FKEA
26
9
R8, R11, R16, R35, R39, R48, R55, R24, R29
RES, 0Ω 0603
VISHAY CRCW06030000Z0EA
27
2
RS1, RS2
RES, SENSE 0.0025 2512
VISHAY WSL25122L500FEA
28
1
U1
LTC3838 38-LEAD TSSOP
LINEAR TECH. LTC3838EFE
dc1626afa
7
DEMO MANUAL DC1626A
PARTS LIST
1626A-B (RSENSE)
ITEM
QTY
REFERENCE
PART DESCRIPTION
MANUFACTURER/PART NUMBER
CAP, 0603
OPTIONAL
Additional Circuit Components
1
0
C1, C2, C15, C17
2
0
CIN6-CIN8
CAP, 1210
OPTIONAL
3
0
COUT13-COUT16
CAP, 7343
OPTIONAL
4
0
Q5-Q8
MOSFET, N-CHANNEL LFPAK
OPTIONAL
5
2
Q9, Q10
SUD50N03-12P-E3
VISHAY SUD50N03-12P-E3
6
0
R1, R4, R7, R9, R47, R18, R19, R20, R32, R34,
R20, R36, R3, R6, R10, R37, R44, R49, R50,
R30, R26
RES, 0603
OPTIONAL
7
2
R51, R52
RES, 10k 1% 0603
VISHAY CRCW060310K0FKEA
8
2
R53, R54
RES, 0.01Ω 1/2W 1% 2010
VISHAY WSL2010R0100FEA
Hardware/Components (For Demo Board Only)
1
4
STAND-OFF
STAND-OFF, NYLON 0.25"
KEYSTONE, 8831 (SNAP ON)
2
23
E1-E12, E14-E25
TESTPOINT, TURRET 0.095"
MILL-MAX 2501-2-00-80-00-00-07-0
3
6
J1-J6
JACK, BANANA
KEYSTONE 575-4
4
2
J7, J8
CONN, BNC 5-PINS
CONNEX 112404
5
2
JP1, JP4
2MM SINGLE ROW HEADER, 3-PIN
SAMTEC TMM-103-02-L-S
6
4
JP1-JP4
SHUNT
SAMTEC 2SN-BK-G
7
2
JP2, JP3
2MM SINGLE ROW HEADER, 4PIN
SAMTEC TMM-104-02-L-S
dc1626afa
8
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
A
B
C
D
OFF
ON
JP1
RUN2
RUN2
1
FCM
OFF
ON
E19
E16
E15
R49
OPT
C18
1uF
EXTVCC
R50
OPT
VIN
RUN1
C17
OPT
R44
OPT
R37 TRK/SS1
OPT
-A (DCR SENSE)
-B (RSENSE)
ASSY
5
Vishay IHLP4040DZ-01 0.56uH
WURTH 7443330068(0.68uH)
L1,L2
2. INSTALL SHUNTS ON JUMPERS AS SHOWN.
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
NOTES: UNLESS OTHERWISE SPECIFIED
GND
EXTVCC
PGOOD1
RUN1
2
E10
E9
E8
3
2
R23
10K
E14
TRK/SS1
CLKOUT
PLLIN
JP4
RUN1
R39 0
INTVCC
C2
OPT
R55 0
*
*
R31
R46
10K
R40
10K
0.1uF
1000pF
C16, C3
C15
OPT
R24
*
*
C3
*
S1-
17
16
15
14
13
12
11
18
C16
* 19
S1+
9
8
7
10
VRNG2
6
5
4
3
2
1
INTVCC
4.02K
OPT
33
34
35
36
37
28
29
30
22
23
24
25
26
DTR1
20
RUN1 21
PGOOD1
BOOST1
TG1
SW1
BG1
DRVCC1 27
VIN
PGND
INTVCC
EXTVCC
31
11K
OPT
4
0
OPT
R36,R20
C13
0.1uF
R47
OPT
0.000 Ohm 2512
0.0025 Ohm 2512
E23
E22
VOUT1
4
4
RJK0305DPB
Q3
RJK0330DPB
Q4
J7
1
RJK0330DPB
Q2
OPT
0
3
0
OPT
17.4K
20K
4
SW1
4
40.2K
45.3K
R21
1
L2
*
R18
*
CIN5
10uF
35V
1210
CIN3
10uF
35V
1210
L1
R32
*
*
S1-
*
R36
*
R34
S1+
GND
IOSTEP2-
IOSTEP2+
CUSTOMER NOTICE
E20
PULSE1
E25
E24
2
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS;
HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO
VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL
APPLICATION. COMPONENT SUBSTITUTION AND PRINTED
CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT
PERFORMANCE OR RELIABILITY. CONTACT LINEAR
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE.
R51
10K
E17
LOAD STEP
10mV / A
5% DUTY CYCLE MAX
J8
COUT3
100uF
6.3V
1206
1
HZ
MIKE S.
SCALE = NONE
APP ENG.
PCB DES.
APPROVALS
VOUT2
330uF
2.5V
7343-D15T
E12
E11
R52
10K
J6
J5
E7
J4
J3
GND
DATE
5-11-11
OPT
7343-D15T
+ COUT16
OPT
7343-D15T
+ COUT14
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900 www.linear.com
Fax: (408)434-0507
LTC Confidential-For Customer Use Only
OPT
7343-D15T
+ COUT15
VOUT2
OPT
7343-D15T
+ COUT13
VOUT1
ONLY ADD FOOTPRINTS
ON SOLDERMASK, DO
NOT SHOW IN
SCHEMATIC.
OPTIONAL COUT
MIKE S.
APPROVED
DATE:
N/A
SIZE
LTC3838EFE
1
DEMO CIRCUIT 1626A
Thursday, October 13, 2011
IC NO.
SHEET 1
OF 1
2
REV.
WIDE INPUT RANGE, HIGH EFFICIENCY DUAL STEP-DOWN DC-DC CONVERTER
TECHNOLOGY
E21
PULSE2
GND
VOUT1
1.2V / 15A
VO2-
GND
VOUT2
1.5V / 15A
VO2+
VIN-
GND
VIN
4.5V - 26V
VIN+
E18
VO1_SNS-
TITLE: SCHEMATIC
1
E5
J2
J1
E3
E6
1
REVISION HISTORY
DESCRIPTION
PRODUCTION
VO1_SNS+
+ COUT1
Q10
SUD50N03-12P
R54
0.01
2010
VOUT2
R43
10
330uF
2.5V
7343-D15T
+ COUT2
VOUT1
330uF
2.5V
7343-D15T
100uF
35V
35HV100M
+ CIN1
2
REV
+ COUT5
100uF
35V
35HV100M
330uF
2.5V
7343-D15T
R42
10
__
ECO
VIN
+CIN2
+ COUT6
CIN6
OPT
1210
COUT7
100uF
6.3V
1206
CIN7
(OPT)
1210
VOUT2
COUT4
100uF
6.3V
1206
COUT8
100uF
6.3V
1206
CIN8
(OPT)
1210
LOAD STEP
CIRCUIT #2
*
2512
RS1
*
*
S2-
2512
RS2
2
R20
*
R19
S2+
DCR SENSE FILTER /
DIVIDER FOR PHASE 2
CIN4
10uF
35V
1210
DCR SENSE FILTER /
DIVIDER FOR PHASE 1
OPT
Q6
OPT
Q5
OPT
Q8
OPT
Q7
Q9
SUD50N03-12P
R53
0.01
2010
VOUT1
RJK0305DPB
Q1
4
SW2
4
NOTE:
EXTERNALLY TIE THE
DTR1 PIN TO THE DTR2 PIN
IF THE TRANSIENT DETECT
CIRCUIT IS USED
R29,R24 R30,R26 R31
IOSTEP1-
IOSTEP1+
LOAD STEP
10mV / A
5% DUTY CYCLE MAX
LOAD STEP
CIRCUIT #1
INTVCC
4
4
R27 2.2
RUN2
VRNG2
CMDSH-3
D1
C8
4.7uF
16V
0805
R48 0
R41,R45,
R14,R15, RS1, RS2
OPT
10
3
INTVCC
D2
CMDSH-3
R7 OPT
R4 OPT
R1 OPT
R38 100K INTVCC
R350
C10
0.1uF
C9 INTVCC
1uF
R25
2.2
C4
0.1uF
R12
100K
RUN1
VRNG1
VFB2
OPTIONAL COMPONENTS FOR SINGLE
OUTPUT, DUAL PHASE OPERATION
INTVCC
R160
DRVCC2 32
EXTVCC
BG2
SW2
TG2
BOOST2
PGOOD2
RUN2 38
NOTE:
TIE SGND PIN TO PGND PAD UNDERNEATH IC.
SENSE1-
SENSE1+
VOUTSENSE1-
U1
LTC3838EFE
VOUTSENSE1+
TRACK/SS1
ITH1
VRNG1
RT
SGND
CLKOUT
MODE/PLLIN
PHASEMD
VRNG2
ITH2
TRACK/SS2
VFB2
SENSE2+
SENSE2-
DTR2
R11 0
4
R32, R18 R34,R19
R45
S2+
S2-
VRNG1
R41 *
TRK/SS1
C12 330pF
*
*
OPT
TRK/SS2
C7 220pF
R15
R14
R9
R28 137K
C11 47pF
R29
C14 0.01uF
*
R30
*
C6 47pF
FSW = 300kHz
R26
*
C5 0.01uF
R13 VFB2
15K
R21
VOUT2
R10
OPT
TRK/SS2
C1
OPT
INTVCC
SYNC
DCM
0
R6
OPT
R3
OPT
R17
10K
2
R8
VIN
RUN2
3
90 DEG
60 DEG
JP3
MODE
E4
2
INTVCC
120 DEG
JP2
PHASMD
CLKOUT
TRK/SS2
3
1
4
1
4
1
3
PGND
39
5
1
2
3
5
1
2
3
5
1
2
3
5
1
2
3
5
4
3
2
5
1
2
3
5
1
2
3
5
1
2
3
5
1
2
3
5
2
3
E2
5
4
3
2
E1
2
3
PGOOD2
A
B
C
D
DEMO MANUAL DC1626A
SCHEMATIC DIAGRAM
dc1626afa
9
DEMO MANUAL DC1626A
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions:
This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT
OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete
in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety
measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union
directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations.
If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date
of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU
OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS
FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR
ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES.
The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims
arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all
appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or
agency certified (FCC, UL, CE, etc.).
No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive.
Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and
observe good laboratory practice standards. Common sense is encouraged.
This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
dc1626afa
10 Linear Technology Corporation
LT 1011 REV A • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
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