1
dc1801af
DEMO MANUAL DC1801A
DESCRIPTION
LTC3838EUHF
High Efficiency Dual Output
Step-Down DC/DC Converter
Demonstration circuit 1801A is a dual output 1.5V/20A and
1.2V/20A synchronous buck converter operating with a
switching frequency of 300kHz over an input voltage range
of 4.5V to 14V. The demo board comes in two versions.
The A version uses inductor DCR current sensing for high
efficiency. The B version uses 2mΩ sense resistor for ac-
curate current sensing with a low DCR ferrite inductor. The
fixed on-time valley current mode topology of the LTC3838
allows for a fast load step response (see Figures 6 to 9).
The load step response can be tested with the onboard
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 LTC3838EUHF is
a 38-pin QFN with an exposed ground pad.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
PERFORMANCE SUMMARY
The main features of the board are listed below:
• MODE jumper to program either discontinuous mode
(DCM) or forced continuous mode (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
(TA = 25°C)
PARAMETER CONDITIONS VALUE
Minimum Input Voltage 4.5V
Maximum Input Voltage 14V
Output Voltage VOUT1 I
OUT1 = 0A to 20A, VIN = 4.5V to 14V 1.2V ± 2%
Output Voltage VOUT2 I
OUT2 = 0A to 20A, VIN = 4.5V to 14V 1.5V ± 2%
VOUT1 Maximum Output Current, IOUT1 VIN = 4.5V to 14V, VOUT1 = 1.2V 20A
VOUT2 Maximum Output Current, IOUT2 VIN = 4.5V to 14V, VOUT2 = 1.5V 20A
Nominal Switching Frequency 300kHz
-A Efficiency (DCR Current Sense) VOUT1 = 1.2V, IOUT1 = 20A, VIN = 12V 91% Typical
See Figures 2 and 3 VOUT2 = 1.5V, IOUT2 = 20A, VIN = 12V 92% Typical
-B Efficiency (RSENSE Current Sense) VOUT1 = 1.2V, IOUT1 = 20A, VIN = 12V 89.5% Typical
See Figures 4 and 5 VOUT2 = 1.5V, IOUT2 = 20A, VIN = 12V 91% Typical
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dc1801af
DEMO MANUAL DC1801A
QUICK START PROCEDURE
Demonstration circuit 1801A is easy to set up to evalu-
ate the performance of the LTC3838EUHF. 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 14V.
VOUT1 should 1.2V ± 2%.
V
OUT2 should 1.5V ± 2%.
3) Next, apply 20A load and recheck VOUT.
4) Once the DC regulation is confirmed, observe the output
voltage ripple, load step response, efficiency and other
parameters.
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 moni-
tor the voltage across COUT1 and COUT5 respectively.
Heavy load currents applied across these turrets may
damage the converter.
LOAD STEP TRANSIENT TESTING
Demonstration circuit 1801A 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+/– 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 ampli-
tude of the pulse generator output to provide the desired
load step pulse height. The scaling for the LOAD STEP
signal is 10mV/Amp.
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DEMO MANUAL DC1801A
QUICK START PROCEDURE
Figure 1. Proper Measurement Equipment Setup
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:
• Tie VOUT1 to VOUT2 by tying together the exposed copper
pads on the VOUT shapes with pieces of heavy copper
foil.
• 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.
• Remove the ITH compensation network, VFB divider
and TRACK/SS capacitor for phase-2.
• Tie VRNG1 to VRNG2 by stuffing 0Ω at R4.
• Tie RUN1 to RUN2 by stuffing 0Ω at R7.
• If the optional transient detect circuit is used, externally
tie the DTR1 pin to the DTR2 pin.
• Recompensate if necessary.
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DEMO MANUAL DC1801A
QUICK START PROCEDURE
Figure 2. Efficiency Curves for the DC1801A-A
(DCRSENSE) in FCM
Figure 3. Efficiency Curves for the DC1801A-A
(DCRSENSE) in FCM and DCM.
Figure 4. Efficiency Curves for the DC1801A-B
(RSENSE) in FCM
Figure 5. Efficiency Curves for the DC1801A-B
(RSENSE) in FCM and DCM
LOAD CURRENT (A)
EFFICIENCY (%)
70
75
80
11 16
DC1801a F02
90
95
85
16 21
1.5V FCM
1.2V FCM
fSW = 300kHz
VIN = 12V
LOAD CURRENT (A)
0.01
0
EFFICIENCY (%)
10
20
30
40
90
80
70
60
50
100
0.1 1 10
DC1801a F03
1.5V FCM
1.2V FCM
1.5V DCM
1.2V DCM
fSW = 300kHz
VIN = 12V
LOAD CURRENT (A)
EFFICIENCY (%)
70
75
80
11 16
DC1801a F04
90
95
85
16 21
1.5V FCM
1.2V FCM
fSW = 300kHz
VIN = 12V
LOAD CURRENT (A)
0.01
0
EFFICIENCY (%)
10
20
30
40
90
80
70
60
50
100
0.1 1 10
DC1801a F05
1.5V FCM
1.2V FCM
1.5V DCM
1.2V DCM
fSW = 300kHz
VIN = 12V
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DEMO MANUAL DC1801A
5A
15A
DC1801a F06
LOAD STEP
1.2VO
50mV/DIV 106mV
20μs/DIV
5A
15A
DC1801a F07
LOAD STEP
1.5VO
50mV/DIV 127mV
20μs/DIV
QUICK START PROCEDURE
Figure 6. Load Step Response of the 1.2V Rail on the DC1801A-A
(DCRSENSE) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF
X5R 6.3V 1206, L = 0.47μH, fSW = 300kHz
Figure 7. Load Step Response of the 1.5V Rail on the DC1801A-A
(DCRSENSE) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF
X5R 6.3V 1206, L = 0.47μH, fSW = 300kHz
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dc1801af
DEMO MANUAL DC1801A
5A
15A
DC1801a F09
LOAD STEP
1.5VO
50mV/DIV 119mV
20μs/DIV
QUICK START PROCEDURE
Figure 8. Load Step Response of the 1.2V Rail on the DC1801A-B
(RSENSE) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF X5R
6.3V 1206, fSW = 300kHz, L = 0.44μH, fSW = 300kHz
Figure 9. Load Step Response of the 1.5V Rail on the DC1801A-B
(RSENSE) at VIN = 12V. COUT = 2× Sanyo 2R5TPE330M9 || 2× 100μF X5R
6.3V 1206, fSW = 300kHz, L = 0.44μH, fSW = 300kHz
5A
15A
DC1801a F08
LOAD STEP
1.2VO
50mV/DIV 112mV
20μs/DIV
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dc1801af
DEMO MANUAL DC1801A
PARTS LIST
Demo Board 1801A-A
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CIN1 CAP, 180μF, 16V, SVP-F8 SANYO, 16SVP180MX
2 2 CIN3, CIN5 CAP, X5R, 22μF, 16V, 1210 MURATA, GRM312ER61C226KE20L
3 4 COUT1, COUT2, COUT5, COUT6 CAP, 330μF, 2.5V, SIZE 7343 SANYO, 2R5TPE330M9
4 4 COUT3, COUT4, COUT7, COUT8 CAP, X5R, 100μF, 6.3V, 1206 MURATA, GRM31CR60J107ME39L
5 2 C3, C16 CAP, X6R, 0.22μF, 25V, 0603 MURATA, GRM188R60E224KA88D
6 5 C4, C5, C10, C13, C14 CAP, X5R, 0.1μF, 16V, 0603 AVX, 0603YD104KAT2A
7 2 C6, C11 CAP, NPO, 47pF, 16V, 0603 AVX, 0603YA470JAT2A
8 2 C7, C12 CAP, X7R, 470pF, 16V, 0603 AVX, 0603YC471JAT2A
9 1 C8 CAP, X5R, 4.7μF, 16V, 0805 AVX, 0805YD475KAT2A
10 2 C9, C18 CAP, X5R, 1μF, 16V, 0603 AVX, 0603YD105KAT2A
11 2 D1, D2 DIODE, SCHOTTKY, SOD-323 CENTRAL SEMI, CMDSH-4E TR
12 2 L1, L2 IND, 0.47μH WÜRTH, 744355047
13 2 Q1, Q3 MOSFET, OPTIMOS, PG-TDSON-8 INFINEON, BSC050NE2LS
14 2 Q2, Q4 MOSFET, OPTIMOS, PG-TDSON-8 INFINEON, BSC010NE2LS
15 2 Q9, Q10 MOSFET, N-CH, 30V, TO-252 VISHAY, SUD50N03-12P-E3
16 7 R8, R11, R16, R35, R39, R55, R57 RES, CHIP, 0, 0603 VISHAY, CRCW06030000Z0EA
17 2 R12, R38 RES, CHIP, 100k, 1%, 0603 VISHAY, CRCW0603100KFKEA
18 3 R13, R21, R31 RES, CHIP, 15k, 1%, 0603 VISHAY, CRCW060315K0FKEA
19 0 R14, R15, R24, R29, R41, R45 (OPT) RES, CHIP, 0603
20 4 R17, R23, R40, R46 RES, CHIP, 10k, 1%, 0603 VISHAY, CRCW060310K0FKEA
21 2 R18, R32 RES, CHIP, 2.15k 1%, 0603 VISHAY, CRCW06032K15FKEAEA
22 4 R20, R26, R30, R36 RES, CHIP, 0, 0603 VISHAY, CRCW06030000Z0EA
23 2 R25, R27 RES, CHIP, 2.2 1%, 0603 VISHAY, CRCW06032R20FKEA
24 1 R28 RES, CHIP, 133k, 1%, 0603 VISHAY, CRCW0603133KFKEA
25 2 R42, R43 RES, CHIP, 10, 1%, 0603 VISHAY, CRCW060310R0FKED
26 2 RS1, RS2 RES, CHIP, 0.000Ω, 2W, 2512 TEPRO, RN5326
27 1 U1 LTC3838EUHF, QFN, 38-LEAD LINEAR TECHNOLOGY LTC3838EUHF
Additional Demo Board Circuit Components
1 0 CIN2 (OPT) CAP, OPT, SVP-F8
2 0 CIN4, CIN6, CIN7, CIN8 (OPT) CAP, OPT, 1210
3 0 C1, C2, C15, C17 (OPT) CAP, OPT, 0603
4 0 COUT13 TO COUT16 (OPT) CAP, OPT, 7343
5 0 Q5 TO Q8 (OPT) MOSFET, OPTIMOS, PG-TDSON-8
6 0 R1, R3, R4, R6, R7, R9, R10, R19, R34,
R37, R44, R49, R50, R47, R48, R56 (OPT) RES, CHIP, 0603
7 2 R51, R52 RES, CHIP, 10k, 1%, 0603 VISHAY, CRCW060310K0FKEA
8 2 R53, R54 RES, CHIP, 0.01, 1/2W, 1%, 2010 VISHAY, WSL2010R0100FEA
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dc1801af
DEMO MANUAL DC1801A
PARTS LIST
Demo Board 1801A-A
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Hardware/Components (For Demo Board Only)
1 20 E1 TO E20 TESTPOINT, TURRET, 0.095" MILL-MAX, 2501-2-00-80-00-00-07-0
2 2 JP1, JP4 2mm SINGLE ROW HEADER, 3-PIN SAMTEC, TMM-103-02-L-S
3 2 JP2, JP3 2mm SINGLE ROW HEADER, 4-PIN SAMTEC, TMM-104-02-L-S
4 4 XJP1 TO XJP4 SHUNT SAMTEC, 2SN-BK-G
5 6 J1 TO J6 JACK, BANANA KEYSTONE, 575-4
6 2 J7, J8 CONN, BNC, 5 PINS CONNEX, 112404
7 2 J9, J10 2mm SINGLE ROW HEADER, 2-PIN SAMTEC, TMM-102-02-L-S
8 4 MH1 TO MH4 STAND-OFF, NYLON 0.25" KEYSTONE, 8831 (SNAP ON)
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DEMO MANUAL DC1801A
PARTS LIST
Demo Board 1801A-B
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Required Circuit Components
1 1 CIN1 CAP, 180μF, 16V, SVP-F8 SANYO, 16SVP180MX
2 2 CIN3, CIN5 CAP, X5R, 22μF, 16V, 1210 MURATA, GRM312ER61C226KE20L
3 4 COUT1, COUT2, COUT5, COUT6 CAP, 330μF, 2.5V, SIZE 7343 SANYO, 2R5TPE330M9
4 4 COUT3, COUT4, COUT7, COUT8 CAP, X5R, 100μF, 6.3V, 1206 MURATA, GRM31CR60J107ME39L
5 2 C3, C16 CAP, X7R, 1000pF, 16V, 0603 AVX, 0603YC102KAT2A
6 5 C4, C5, C10, C13, C14 CAP, X5R, 0.1μF, 16V, 0603 AVX, 0603YD104KAT2A
7 2 C6, C11 CAP, NPO, 47pF, 16V, 0603 AVX, 0603YA470JAT2A
8 2 C7, C12 CAP, X7R, 470pF, 16V, 0603 AVX, 0603YC471JAT2A
9 1 C8 CAP, X5R, 4.7μF, 16V, 0805 AVX, 0805YD475KAT2A
10 2 C9, C18 CAP, X5R, 1μF, 16V, 0603 AVX, 0603YD105KAT2A
11 2 D1, D2 DIODE, SCHOTTKY, SOD-323 CENTRAL SEMI, CMDSH-4E TR
12 2 L1, L2 IND, 0.44μH COOPER, FP1308R3-R44-R
13 2 Q1, Q3 MOSFET, OPTIMOS, PG-TDSON-8 INFINEON, BSC050NE2LS
14 2 Q2, Q4 MOSFET, OPTIMOS, PG-TDSON-8 INFINEON, BSC010NE2LS
15 2 Q9, Q10 MOSFET, N-CH, 30V, TO-252 VISHAY, SUD50N03-12P-E3
16 7 R8, R11, R16, R35, R39, R55, R57 RES, CHIP, 0, 0603 VISHAY, CRCW06030000Z0EA
17 2 R12, R38 RES, CHIP, 100k, 1%, 0603 VISHAY, CRCW0603100KFKEA
18 3 R13, R21, R31 RES, CHIP, 15k, 1%, 0603 VISHAY, CRCW060315K0FKEA
19 4 R14, R15, R41, R45 RES, CHIP, 10, 1%, 0603 VISHAY, CRCW060310R0FKED
20 4 R17, R23, R40, R46 RES, CHIP, 10k, 1%, 0603 VISHAY, CRCW060310K0FKEA
21 2 R24, R29 RES, CHIP, 0, 0603 VISHAY, CRCW06030000Z0EA
22 2 R25, R27 RES, CHIP, 2.2 1%, 0603 VISHAY, CRCW06032R20FKEA
23 1 R28 RES, CHIP, 133k, 1%, 0603 VISHAY, CRCW0603133KFKEA
24 2 R42, R43 RES, CHIP, 10, 1%, 0603 VISHAY, CRCW060310R0FKED
25 2 RS1, RS2 RES, CHIP, 2mΩ, 2W, 1%, 2512 VISHAY, WSL25122L000FEA
26 1 U1 LTC3838EUHF, QFN, 38-LEAD, LINEAR TECHNOLOGY LTC3838EUHF
Additional Demo Board Circuit Components
1 0 CIN2 (OPT) CAP, OPT, SVP-F8
2 0 CIN4, CIN6 TO CIN8 (OPT) CAP, OPT, 1210
3 0 C1, C2 ,C15, C17 (OPT) CAP, OPT, 0603
4 0 COUT13 TO COUT16 (OPT) CAP, OPT, 7343
5 0 Q5 TO Q8 (OPT) MOSFET, OPTIMOS, PG-TDSON-8
6 0 R1, R3, R4, R6, R7, R9, R10, R19, R34,
R37, R44, R49, R50, R47, R48, R56 (OPT) RES, CHIP, 0603
7 2 R51, R52 RES, CHIP, 10k, 1%, 0603 VISHAY, CRCW060310K0FKEA
8 2 R53, R54 RES, CHIP, 0.01, 1/2W, 1%, 2010 VISHAY, WSL2010R0100FEA
9 0 R18, R20, R26, R30, R32, R36 (OPT) RES, CHIP, 0603
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DEMO MANUAL DC1801A
PARTS LIST
Demo Board 1801A-B
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
Hardware/Components (For Demo Board Only)
1 20 E1 TO E20 TESTPOINT, TURRET, 0.095" MILL-MAX, 2501-2-00-80-00-00-07-0
2 2 JP1 TO JP4 2mm SINGLE ROW HEADER, 3-PIN SAMTEC, TMM-103-02-L-S
3 2 JP2, JP3 2mm SINGLE ROW HEADER, 4-PIN SAMTEC, TMM-104-02-L-S
4 4 XJP1 TO XJP4 SHUNT SAMTEC, 2SN-BK-G
5 6 J1 TO J6 JACK, BANANA KEYSTONE, 575-4
6 2 J7, J8 CONN, BNC, 5 PINS CONNEX, 112404
7 2 J9, J10 2mm SINGLE ROW HEADER, 2-PIN SAMTEC, TMM-102-02-L-S
8 4 MH1 TO MH4 STAND-OFF, NYLON 0.25" KEYSTONE, 8831 (SNAP ON)
11
dc1801af
DEMO MANUAL DC1801A
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
SCHEMATIC DIAGRAM
5
5
4
4
3
3
2
2
1
1
D D
CC
B B
A A
10mV / A
ON
CLKOUT
LOAD STEP
MODE
RUN1
120 DEG
VOUT1
PHASMD
1.5V / 20A
OFF
90 DEG
5% DUTY CYCLE MAX
1. ALL RESISTORS 0603.
ONLY ADD FOOTPRINTS
ON SOLDERMASK, DO
NOT SHOW IN
SCHEMATIC.
RUN2
60 DEG
NOTES: UNLESS OTHERWISE SPECIFI ED
LOAD STEP
ALL CAPACITORS ARE 0603.
OPTIONAL COUT
ON
SYNC
OFF
VOUT2
5% DUTY CYCLE MAX
4.5V - 14V
DCM
LOAD STEP CIRCUIT #1
FSW = 300kHz
FCM
10mV / A
NOTE:
TIE SGND PIN TO PGND PAD
UNDERNEATH IC.
1.2V / 20A
OPTIONAL COMPONENTS FOR SINGLE
OUTPUT, DUAL PHASE OPERATION
LOAD STEP CIRCUIT #2
DCR SENSE FILTER /
DIVIDER FOR PH A S E 2
DCR SENSE FILTE R /
DIVIDER FOR PH A S E 1
2. INSTALL SHUNTS ON JUMP E R S A S S H O W N .
0.000 Ohm 2512 TEPRO RN5326
ASSY
0.22uF OPTOPT AEF000L22152LSW YAHSIV 2152 mhO 200.0Fp0001
RS1, RS2
-B (RSENSE)
C3,
C16
0
R14,R15,
R41,R45
2.15K-A (DCR SENSE)
L1,L2
WURTH 744355047 (0.47uH) 10
R18,
R32
COILTRONICS FP1308R3-R44-R (0.44uH)
R20,
R36
OPT
2512
2512
R24,
R29 R26,
R30
OPT
0OPT
0
COUT1,2,5,6 = Sanyo 2R5TPE330M9
COUT3,4,7,8 = Murata GRM31CR60J107ME39L
CIN1 = Sanyo 16SVP180MX
CIN3,4 = Murata GRM32ER61C226KE20L
Q1,Q3 = Infineon BSC050NE2LS
Q2,Q4 = Infineon BSC010NE2LS
Note:
Make footprint for Q1-Q8 compatible with
LFPAK and PowerPAK MOSFETs.
1
Tuesday, March 08, 2011
11
HIGH EFFIVIENCY DUAL OUTPUT STEP-DOWN DC-DC CONVERTER
DING L.
N/A
LTC3838EUHF
DEMO CIRCUIT 1801A
JW
SIZE
DATE:
.VER.ON CI
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-05 07
Milpitas, CA 9503 5
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Custome r U s e On ly
CUSTOMER NOTICE
LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DE S IG N A
CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFIC A TIONS;
HOWEVER, IT REMAINS THE CUSTOM ER'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 LINEA R
TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSIST ANCE.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNO LOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
SW1
SW2 VOUT2
EXTVCC
TRK/SS2
VIN
VOUT1 VOUT2
VOUT2
S1-
INTVCC
VRNG2
EXTVCC
TRK/SS2
VOUT2
VFB2
VIN
INTVCC
VOUT1
S1+
S2-
VOUT1
VRNG1
RUN2
INTVCC
S2+
VIN
VRNG2
RUN1
VRNG1
INTVCC
INTVCC
INTVCC
INTVCC
S1+ S1-
S2+ S2-
TRK/SS1
TRK/SS1
VFB2
INTVCC
INTVCC
RUN2
RUN1
R21
15K
R15
*
R48
0
R14
*
R12
100K
J4 GND
CIN3
22uF
16V
1210
+
COUT5
330uF
7343-D15T
2.5V
R16
0
R20
*
R4 OPT
E22
IOSTEP1+
C8
4.7uF
16V
0805
+
COUT1
330uF
7343-D15T
2.5V
CIN4
22uF
16V
1210
R50
OPT
+
COUT16
OPT
7343-D15T
C16
*
E18 PULSE2
C14 0.1uF
R47
OPT
R6
OPT
RS1
*
E15
PGOOD1
E1
PGOOD2
C3
*
Q4 BSC010NE2LS
2
4
5
3
1
J3 VOUT2
R35
0R36
*
JP2
1
2
3
4
CIN5
OPT
1210
R30
*
R42
10
R45
*
L2
*
Q8
OPT
2
4
5
3
1
+
COUT14
OPT
7343-D15T
R27 2.2
J6 GND
U1
LTC3838EUHF
35
36
37
38
2
3
25
26
27
29
4
5
6
28
30
31
32
33
34
39
1
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
VOUT2
SENSE2-
SENSE2+
VFB2
ITH2
VRNG2
PGND
INTVCC
EXTVCC
BG2
PHASEMD
MODE/PLLIN
CLKOUT
DRVCC2
SW2
TG2
BOOST2
PGOOD2
RUN2
PGND
TRACK/SS2
SGND
RT
VRNG1
ITH1
TRACK/SS1
VOUTSENSE1+
VOUTSENSE1-
SENSE1+
SENSE1-
VOUT1
RUN1
PGOOD1
BOOST1
TG1
SW1
BG1
DRVCC1
VIN
JP1
JMP1X3
13
2
R17
10K
E9
CLKOUT
+
CIN1
180uF
16V
16SVP180MX
JP4
JMP1X3
13
2
Q6
OPT
2
4
5
3
1
J7
1
2
3
4
5
R7 OPT
C9 1uF
COUT7
100uF
6.3V
1206
R53
0.01
2010
COUT8
100uF
6.3V
1206
J5
VOUT1
E16
EXTVCC
R41
*
R29
*
R55 0
Q5
OPT
2
4
5
3
1
+
COUT6
330uF
7343-D15T
2.5V
C7 470pF
+
CIN2
OPT
E24
IOSTEP1-
D2
CMDSH-3
+
COUT13
OPT
7343-D15T
E10
TRK/SS1
E17 PULSE1
R1 OPT
C12
470pF
RS2
*
E19
GND
R24
*
+
COUT2
330uF
7343-D15T
2.5V
E6 VO2+
R26
*
J8
1
2
3
4
5
R34
OPT
C18
1uF
R23
10K
R19
OPT
Q3
BSC050NE2LS
2
4
5
3
1
E5 VIN-
C15
OPT
C10
0.1uF
C5 0.1uF
R57
OPT
CIN6
OPT
1210
R13
15K
D1
CMDSH-3
J1 VIN
E7 VO2-
R32
*
R44
OPT
E23
IOSTEP2+
Q10
SUD50N03-12P
3
1
2
R18
*
C2
OPT
C6 47pF
E21 GND
C11 47pF
R46
10K
E20GND
R37
OPT
R10
OPT
J2 GND
E11 VO1_SNS+
E25
IOSTEP2-
COUT3
100uF
6.3V
1206
CIN8
(OPT)
35V
1210
R51
10K
C4
0.1uF
C13
0.1uF
R8 0
JP3
1
2
3
4
R39
0
R11
OPT
Q1 BSC050NE2LS
2
4
5
3
1
R56 0
R40
10K
R49
OPT
C17
OPT
Q9
SUD50N03-12P
3
1
2
E2
RUN2
E3 VIN+
COUT4
100uF
6.3V
1206
R38
100K
L1
*
CIN7
(OPT)
35V
1210
Q7
OPT
2
4
5
3
1
E12 VO1_SNS-
E8
PLLIN
Q2 BSC010NE2LS
2
4
5
3
1
R31
15K
R25
2.2
E4
TRK/SS2
R54
0.01
2010
R28 133K
R52
10K
R9 OPT
R43
10
E14
RUN1
C1
OPT
R3
OPT
+
COUT15
OPT
7343-D15T
12
dc1801af
DEMO MANUAL DC1801A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2012
LT 0212 • PRINTED IN USA
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 applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
