1
dc2253af
DEMO MANUAL DC2253A
Description
LTC3789EGN
300W 2-Phase Interleaved
Synchronous Buck-Boost Converter
Demonstration circuit 2253A is a high power, high ef-
ficiency, 2-phase interleaved synchronous buck-boost
converter with a 6V to 36V input range. It can supply a
25A maximum load current with a 12V output. This demo
board features 2x LTC3789EGN controllers.
The LT C
®
3789 is a high performance current-mode
buck-boost switching regulator controller that operates
from input voltages above, below or equal to the output
voltage, while an output current feedback loop provides
support for output current limit and battery charging. With
a wide 4V to 38V (40V maximum) input and output range
and seamless, low noise transitions between operating
regions, the LTC3789 is ideal for automotive, telecom and
battery-powered systems. 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 light load operating mode of the controller is de-
termined through the MODE/PLLIN pin. By default, the
forced continuous mode (CCM) operation is pre-selected
on this demo board. Switching frequency is preset at
about 200kHz. Tw o paralleling schemes are available for
this demo board and by default the method of shared ITH
pins is adopted. Please refer to the Quick Start Procedure
section for the optional Master-Slave paralleling scheme.
To shut down the converter, force the RUN pin below 1.2V
(JP1: OFF) Please refer to LTC3789 data sheet for more
detailed information.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2253A
Specifications are at TA = 25°C
PARAMETER CONDITION VALUE
Input Voltage Range 6V to 36V
Output Voltage, VOUT VIN = 6V to 36V, IOUT = 0A to 25A 12V ±2%
Maximum Output Current, IOUT VIN = 6V to 36V, VOUT = 12V 25A
Typical Output Ripple VIN = 36V, IOUT = 25A (20MHz BW)
VIN = 12V, IOUT = 25A (20MHz BW)
VIN = 6V, IOUT = 25A (20MHz BW)
36mVP-P
200mVP-P
380mVP-P
Typical Efficiency VIN = 12V, VOUT = 12V, IOUT = 25A, see Figure 3 97.8%
Typical Switching Frequency 200kHz
2
dc2253af
DEMO MANUAL DC2253A
Quick start proceDure
Demonstration circuit 2253A is easy to set up to evaluate
the performance of the LTC3789EGN. Refer to Figure 1
for the proper measurement equipment setup and follow
the procedure below:
1. With power off, connect the input power supply to VIN
(6V to 36V) and GND (input return).
2. Connect the 12V output load between VOUT and GND
(Initial load: no load).
3. Connect the DVMs to the input and output. Set the
default jumper position, JP1: ON.
4. Turn on the input power supply and check for the proper
output voltages. VOUT should be 12V ±2%.
5. Once the proper output voltages are established, ad-
just the loads within the operating range and observe
the output voltage regulation, ripple voltage and other
parameters.
Note: When measuring the output or input voltage ripple,
do not use the long ground lead on the oscilloscope probe.
See Figure 2 for the proper scope probe technique. Short,
stiff leads need to be soldered to the (+) and (–) terminals
of an output capacitor. The probe’s ground ring needs to
touch the (–) lead and the probe tip needs to touch the
(+) lead.
Optional Master-Slave Paralleling Scheme
Besides the default paralleling scheme by tying the ITH pins
together, another optional Master-Slave scheme can be
achieved on the demo board to obtain a better sharing of
the inductor currents and output currents between phases.
Please refer to the schematic in Page 8. To implement it,
1. Remove R67, R69 and R70.
2. Populate R68, R71 with 0Ω.
3. Set RFB3 5~10% higher than RFB1 and set RFB4 = RFB2.
4. Choose the current reference divider R65 and R66 so
that when the Vout is regulated, the voltage drop on
R65 is equal to VILIM, where VILIM is the output current
limit threshold voltage. For example, when ILIM pin is
grounded, VILIM = 50mV. For VOUT = 12V, select R65
= 100Ω and R66 = 24kΩ and then the voltage drop on
R65 will be 50mV.
3
dc2253af
DEMO MANUAL DC2253A
Figure 2. Measuring Output Voltage Ripple
Quick start proceDure
Figure 1. Proper Measurement Equipment Setup
+ –
VOUT GND
COUT
4
dc2253af
DEMO MANUAL DC2253A
Quick start proceDure
Figure 3. Efficiency vs Load Current (VOUT = 12V, CCM) Figure 4. Output Current Sharing (VIN = 6V, VOUT = 12V)
LOAD CURRENT (A)
0
80
EFFICIENCY (%)
82
84
86
88
90
96
100
98
92
94
5 10 15 20 25 30
DC2253A F03
36VIN
12VIN
6VIN
TOTAL OUTPUT CURRENT (A)
0
0
PHASE OUTPUT CURRENT (A)
2
4
10
14
12
6
8
5 10 15 20 25
DC2253A F04
±2%
Figure 5. Output Current Sharing (VIN = 12V, VOUT = 12V) Figure 6. Output Current Sharing (VIN = 36V, VOUT = 12V)
TOTAL OUTPUT CURRENT (A)
0
0
PHASE OUTPUT CURRENT (A)
2
4
10
14
12
6
8
5 10 15 20 25
DC2253A F05
±1.4%
TOTAL OUTPUT CURRENT (A)
0
0
PHASE OUTPUT CURRENT (A)
2
4
10
14
12
6
8
5 10 15 20 25
DC2253A F06
±3.7%
5
dc2253af
DEMO MANUAL DC2253A
Quick start proceDure
Figure 7. Thermal Performance (VIN = 12V, VOUT = 12V, 25A Load, No Air Flow)
Figure 8. Thermal Performance (VIN = 6V, VOUT = 12V, 25A Load, 200LFM)
6
dc2253af
DEMO MANUAL DC2253A
Quick start proceDure
Figure 9. Thermal Performance (VIN = 36V, VOUT = 12V, 25A Load, 200LFM)
7
dc2253af
DEMO MANUAL DC2253A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
1 2 CC1, CC4 CAP., C0G, 100pF, 50V, 10% 0603 AVX, 06035A101KAT2A
2 2 CC2, CC3 CAP., X7R, 0.01µF, 50V, 10% 0603 AVX, 06035C103KAT2A
3 5 CSS1, C15, C39, C61, CSS CAP., X7R, 0.1µF, 50V, 10% 0603 AVX, 06035C104KAT2A
4 0 CF1, CF2, CF3, C7, C8, CF, C23 CAP., 0603 OPTIONAL
5 C29, C30, C31-C34
6 C12, C13, C59, C60 CAP., 1206 OPTIONAL
7 C14, C35, C36, C41, C46-C50 CAP., 1210 OPTIONAL
8 4 C62, C63, C66, C67 CAP., X7R, 2.2µF, 50V, 10% 1206 KEMET C1206C225K5RACTU
9 4 C64, C65, C68, C69 CAP., X7R, 2.2µF, 25V, 10% 1206 AVX 12063C225KAT2A
10 2 C11, C51 CAP., NPO, 68pF, 50V, 10% 0603 AVX, 06035A680KAT2A
11 2 C10, C38 CAP., X5R, 4.7µF, 10V, 10% 0603 AVX, 0603ZD475KAT2A
12 2 C24, C55 CAP., X7R, 1µF, 16V, 20% 0603 AVX, 0603YC105MAT2A
13 4 CIN1, CIN2, CIN3, CIN4 CAP., ALUM, 270µF, 50V, 20% SUN ELECTRONICS, 50ME270WX+T
14 4 COUT1, COUT2, COUT3, COUT4 CAP., OS-CON, 330µF, 25V, 20% SANYO, 25SEPF330M
15 12 C16, C17, C19, C20, C21, C28 CAP., X7R, 22µF, 16V, 20% 1210 AVX, 1210YC226MAT2A
16 C40, C42, C43, C44, C53, C58
17 4 C4, C5, C22, C52 CAP., X7R, 0.22µF, 16V, 20% 0603 AVX, 0603YC224MAT2A
18 8 C9, C25, C26, C27 CAP., X7R, 3.3µF, 50V, 20% 1210 AVX, 12105C335MAT2A
19 C37, C45, C54, C56
20 2 C18, C57 CAP., X5R, 10µF, 6.3V, 20% 1206 AVX, 12066D106MAT2A
21 4 D4, D7, D12, D13 DIODE, SCHOTTKY 1A 60V POWERDI123 DIODE INC., DFLS160-7
22 4 D5, D6, D10, D11 DIODE, SCHOTTKY 3A 40V SMA DIODE INC., B340A-13-F
23 1 D8 DIODE, ZENER 5.1V 350MW SOT23-3 DIODE INC., BZX84C5V1-7-F
24 1 JP1 HEADER, 3 PIN 0.079 SINGLE ROW SAMTEC, TMM-103-02-L-S
25 1 XJP1 SHUNT, .079" CENTER SAMTEC, 2SN-BK-G
26 4 J2, J4, J5, J6 STUD, TESTPIN PEM KFH-032-10
27 8 J1, J2, J3, J4 (x2) NUT, BRASS 10-32 ANY #10-32
28 4 J1, J2, J3, J4 RING, LUG #10 KEYSTONE, 8205, #10
29 4 J1, J2, J3, J4 WASHER, TIN PLATED BRASS ANY #10, #10EXT BZ TN
30 2 L1, L2 INDUCTOR, 3µH COILCRAFT LNC. XAL1580-302ME
31 6 Q2, Q4, Q6, Q16, Q17, Q12 MOSFET N-CHANNEL INFINEON, BSC027N04LS
32 6 Q3, Q5, Q10, Q15, Q9, Q14 MOSFET N-CHANNEL INFINEON, BSC010NE2LS
33 0 Q7, Q8, Q11, Q13 OPT
34 1 RFB1 RES., CHIP., 113k, 0.1W, 1% 0603 YAGEO, RC0603FR-07113KL
35 1 RFB2 RES., CHIP., 8.06k, 0.1W, 1% 0603 YAGEO, RC0603FR-078K06L
36 4 R18, R32, R35, R64 RES., CHIP., 0.006Ω, 2W, 1% 2512 SUSUMU., KRL3264E-C-R006
37 2 R2, R59 Sense RES 0.003Ω 1W 1% 2512 SMD YAGEO, PR2512FKF070R003L
38 12 R3, R4, R9, R10, R13, R14, R36 RES., CHIP., 100Ω, 0.1W, 1% 0603 YAGEO, RC0603FR-07100RL
39 R37, R40, R41, R53, R54
40 2 R5, R58 RES., CHIP, 5.1Ω, 0.1W, 5% 0805 YAGEO, RC0805JR-075R1L
41 0 R6, R12, R15, R22, R28, R29, R38, R39 RES., 0603, OPTIONAL
42 R63, R68, R71, R74, R75, R65, R66, R73
8
dc2253af
DEMO MANUAL DC2253A
parts List
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
43 RFB3, RFB4
44 R28, R29, R60, R61 RES., 1206, OPTIONAL
45 2 R7, R50 RES., CHIP., 100k, 0.1W, 1% 0603 YAGEO, RC0603FR-07100KL
46 1 R8 RES., CHIP., 10Ω, 0.1W, 5% 0603 YAGEO, RC0603JR-0710RL
47 2 R26, R55 RES., CHIP., 10Ω, 0.1W, 5% 0805 YAGEO, RC0805JR-0710RL
48 17 R1, R11, R17, R23, R25 RES., CHIP., 0Ω 1% 0603 YAGEO, RC0603FR-070RL
49 R27, R43, R46, R48, R51, R76
50 R57, R62, R67, R69, R70, R72
51 1 R20, R33 RES., CHIP., 0Ω 2512 TEPRO, RN5326
52 2 R16, R45 RES., CHIP., 1k, 0.1W, 1% 0603 YAGEO, RC0603FR-071KL
53 6 RC1, R21, R24, R34, R44, RC RES., CHIP., 10k, 0.1W, 1% 0603 YAGEO, RC0603FR-0710KL
54 1 R30 RES., CHIP., 41.2k, 0.1W, 1% 0603 YAGEO, RC0603FR-0741K2L
55 1 R31 RES., CHIP., 12.1k, 0.1W, 1% 0603 YAGEO, RC0603FR-0712K1L
56 1 R56 RES., CHIP., 499k, 0.1W, 1% 0603 YAGEO, RC0603FR-07499KL
57 5 TP1, TP2, TP3, TP7, TP20 TESTPOINT, TURRET, .061" PBF MILL-MAX, 2308-2-00-80-00-00-07-0
58 6 TP4, TP5, TP6, TP10-TP12 TESTPOINT, TURRET, .094" PBF MILL-MAX, 2501-2-00-80-00-00-07-0
59 2 U1, U2 I.C.,LTC3789EGN SSOP N LINEAR TECH., LTC3789EGN#PBF
60 1 U3 I.C.,LTC6908CDCB-1 2mm × 3mm LINEAR TECH., LTC6908CDCB-1
61 4 MTGS AT 4 CORNERS STAND-OFF, NYLON 0.5" KEYSTONE, 8833 (SNAP ON)
62 1 FAB, PRINTED CIRCUIT BOARD DEMO CIRCUIT FT228A
63 2 STENCILS STENCIL BOTH SIDES STENCIL FT228A
9
dc2253af
DEMO MANUAL DC2253A
schematic Diagram
5
5
4
4
3
3
2
2
1
1
D
D
C
C
B
B
A
A
2. INSTALL SHUNTS AS SHOWN.
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
NOTE: UNLESS OTHERWISE SPECIFIED
XAL1580-302ME
16V
6.3V
(OPT) (OPT)
(OPT)
2512
0805
(OPT)
(OPT)
0805
VOS+
VOS+
VOUT
VIN1+
VOUT
INTVCC1
VOUT
VIN1+
VOUT1
VIN1+
INTVCC1
VIN
INTVCC1
INTVCC1
PLLIN1
VFB1
ITH1
SS
IREF1
RUN
EXTVCC
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Wednesday, September 03, 2014
13
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Wednesday, September 03, 2014
13
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Wednesday, September 03, 2014
13
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
CHARLIE Z.PRODUCTION2 6-9-11
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
CHARLIE Z.PRODUCTION2 6-9-11
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
CHARLIE Z.PRODUCTION2 6-9-11
__
R11 0R11 0
TP7 GND
TP7 GND
R17 0R17 0
C4
0.22uF
16V
C4
0.22uF
16V
R75
OPT
R75
OPT
C10
4.7uF
C10
4.7uF
R27 0R27 0
R29
(OPT)
R29
(OPT)
R26 10R26 10
C22
0.22uF
16V
C22
0.22uF
16V
TP12
EXTVCC1 TP12
EXTVCC1
C29C29
C17
22uF
16V
C17
22uF
16V
CF1 OPTCF1 OPT
CC2
0.01uF
CC2
0.01uF
R15 OPT
R15 OPT
R5
5.1
R5
5.1
R7
100K
R7
100K
R9 100
R9 100
R25
0
R25
0
R14
100
R14
100
R10 100
R10 100
R32
0.006
2W
R32
0.006
2W
R8
10
R8
10
Q2
BSC027N04LS
Q2
BSC027N04LS
G
DS
C23
1210
C23
1210
R65
(OPT)
R65
(OPT)
C13
(OPT)
C13
(OPT)
JP1
ON
OFF
RUN
JP1
ON
OFF
RUN
1
3
2
RC
10K
RC
10K
R6 OPT
R6 OPT
R28
(OPT)
1206
R28
(OPT)
1206
R1 0R1 0
C18 10uFC18 10uF
J1 VIN
6V - 36V
J1 VIN
6V - 36V
CSS
0.1uF
CSS
0.1uF
TP6
ITH1 TP6
ITH1
R16 1KR16 1K
Q6Q6
G
DS
D7
DFLS160
D7
DFLS160
D6
B340A
D6
B340A
C7 OPTC7 OPT
C31C31
+
COUT1
330uF
25V
+
COUT1
330uF
25V
C35
3.3uF
50V
1210
C35
3.3uF
50V
1210
C11
68pF
C11
68pF
+
CIN1
270uF
50V
+
CIN1
270uF
50V
C19
22uF
16V
C19
22uF
16V
D5
B340A
D5
B340A
D8
BZX84C5V1
D8
BZX84C5V1
RFB2 8.06KRFB2 8.06K
Q9
BSC010NE2LS
Q9
BSC010NE2LS
G
DS
C65
2.2uF
50V
1206
C65
2.2uF
50V
1206
C27C27
R2 0.003
1W
R2 0.003
1W
TP3 VIN1+
TP3 VIN1+
Q8
BSC010NE2LS
Q8
BSC010NE2LS
G
DS
R24
10K
R24
10K
R18
0.006
2W
R18
0.006
2W
+
CIN2
270uF
50V
+
CIN2
270uF
50V
L1 3uH
L1 3uH
R12 OPTR12 OPT
J2 GND
J2 GND
C16
22uF
16V
C16
22uF
16V
Q3Q3
G
DS
C26C26
C32C32
TP5
SS TP5
SS
C20
22uF
16V
C20
22uF
16V
R23 0R23 0
R21
10K
R21
10K
R30
41.2K
R30
41.2K
J3 VOUT
12V @ 25A MAX
J3 VOUT
12V @ 25A MAX
C12
(OPT)
1206
C12
(OPT)
1206
C14
3.3uF
50V
1210
C14
3.3uF
50V
1210
Q5Q5
G
DS
TP11
SGND
TP11
SGND
R3 100R3 100
C63
2.2uF
50V
1206
C63
2.2uF
50V
1206
TP2 VOS+
TP2 VOS+
C28
22uF
16V
1210
C28
22uF
16V
1210
C9
3.3uF
C9
3.3uF
C8 OPTC8 OPT
CC1 100pF
CC1 100pF
R66
(OPT)
R66
(OPT)
R22
OPT
R22
OPT
C15
0.1uF
50V
C15
0.1uF
50V
TP4
PGOOD1 TP4
PGOOD1
C21
22uF
16V
C21
22uF
16V
C25
50V
1210
C25
50V
1210
CF
OPT
CF
OPT
R20 0R20 0
C62
2.2uF
50V
1206
C62
2.2uF
50V
1206
C64C64
Q4Q4
G
DS
Q7
BSC027N04LS
Q7
BSC027N04LS
R13
100
R13
100
C30C30
U1
LTC3789EGN
U1
LTC3789EGN
VFB
1
SS
2
SENSE1+
3
SENSE1-
4
ITH
5
SGND
6
MODE/PLLIN
7
FREQ
8
RUN
9
VINSNS
10
VOUTSNS
11
ILIM
12
IOSENSE+
13
IOSENSE-
14
TRIM
15
SW2
16
TG2
17
BOOST2
18
BG2
19
EXTVCC
20
INTVCC
21
VIN
22
PGND
24
BOOST1
25
SW1
27
PGOOD
28
TG1
26
BG1
23
+
COUT2
330uF
25V
+
COUT2
330uF
25V
RFB1
113K
RFB1
113K
C24 1uF
C24 1uF
J4 GND
J4 GND
R4 100R4 100
TP1 VOS-
TP1 VOS-
R31
12.1K
R31
12.1K
TP10
PLLIN1 TP10
PLLIN1
D4
DFLS160
D4
DFLS160
10
dc2253af
DEMO MANUAL DC2253A
schematic Diagram
5
5
4
4
3
3
2
2
1
1
D D
C C
B B
A A
XAL1580-302ME
(OPT)
16V
2512
6.3V
2. INSTALL SHUNTS AS SHOWN.
NOTE: UNLESS OTHERWISE SPECIFIED
1. ALL RESISTORS ARE IN OHMS, 0603.
ALL CAPACITORS ARE IN MICROFARADS, 0603.
(OPT)
0805
(OPT)
(OPT)
(OPT)
0805
VOUT2
VIN2+
VOUT
INTVCC2
INTVCC2
VOUT
VOUT
INTVCC2
INTVCC2
VIN2+VOS+
VIN
SS
ITH1
VFB1
PLLIN2
IREF1
Run
EXTVCC
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
CHARLIE Z.PRODUCTION2 6-9-11
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
CHARLIE Z.PRODUCTION2 6-9-11
__
REVISION HISTORY
DESCRIPTION DATEAPPROVEDECO REV
CHARLIE Z.PRODUCTION2 6-9-11
__
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Wednesday, September 03, 2014
23
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Wednesday, September 03, 2014
23
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY
Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Wednesday, September 03, 2014
23
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
C66
2.2uF
50V
1206
C66
2.2uF
50V
1206
C59
(OPT)
C59
(OPT)
R69
0
R69
0
R58
5.1
R58
5.1
CF2
OPT
CF2
OPT
R74
OPT
R74
OPT
C41
3.3uF
50V
1210
C41
3.3uF
50V
1210
+
COUT3
330uF
16V
+
COUT3
330uF
16V
R54 100
R54 100
C5
0.22uF
16V
C5
0.22uF
16V
C43
22uF
16V
C43
22uF
16V
R51 0R51 0
R62
0
R62
0
R71
OPT
R71
OPT
R43 0R43 0
C51
68pF
C51
68pF
Q16
BSC027N04LS
Q16
BSC027N04LS
G
DS
R39 OPTR39 OPT
C55 1uF
C55 1uF
Q10Q10
G
DS
R70
0
R70
0
CC3
0.01uF
CC3
0.01uF
C42
22uF
16V
C42
22uF
16V
Q13
BSC027N04LS
Q13
BSC027N04LS
C34 OPTC34 OPT
R44
10K
R44
10K
R53 100
R53 100
RFB3
(OPT)
RFB3
(OPT)
C36
3.3uF
50V
1210
C36
3.3uF
50V
1210
R460R460
U2
LTC3789EGN
U2
LTC3789EGN
VFB
1
SS
2
SENSE1+
3
SENSE1-
4
ITH
5
SGND
6
MODE/PLLIN
7
FREQ
8
RUN
9
VINSNS
10
VOUTSNS
11
ILIM
12
IOSENSE+
13
IOSENSE-
14
TRIM
15
SW2
16
TG2
17
BOOST2
18
BG2
19
EXTVCC
20
INTVCC
21
VIN
22
PGND
24
BOOST1
25
SW1
27
PGOOD
28
TG1
26
BG1
23
R41
100
R41
100
Q12Q12
G
DS
R50
100K
R50
100K
R35
0.006
2W
R35
0.006
2W
R60
(OPT)
R60
(OPT)
C60
(OPT)
1206
C60
(OPT)
1206
R45 1KR45 1K
CC4 100pF
CC4 100pF
R59 0.003
1W
R59 0.003
1W
R48 0R48 0
R57 0R57 0
R38 OPT
R38 OPT
C67
2.2uF
50V
1206
C67
2.2uF
50V
1206
CSS1
0.1uF
CSS1
0.1uF
C50C50
R55 10R55 10
C57 10uFC57 10uF
R34
10K
R34
10K
R36 100R36 100
C37
3.3uF
C37
3.3uF
RC1
10K
RC1
10K
C40
22uF
16V
C40
22uF
16V
R68 OPTR68 OPT
+
CIN4
270uF
50V
+
CIN4
270uF
50V
CF3 OPTCF3 OPT
R76 0R76 0
C54C54
TP20 VIN2+
TP20 VIN2+
D13
DFLS160
D13
DFLS160
D11
B340A
D11
B340A
Q15Q15
G
DS
C69C69
C45C45
R67
0
R67
0
+
CIN3
270uF
50V
+
CIN3
270uF
50V
C38
4.7uF
C38
4.7uF
R63
OPT
R63
OPT
C47C47
C53
22uF
16V
1210
C53
22uF
16V
1210
R61
(OPT)
1206
R61
(OPT)
1206
D12
DFLS160
D12
DFLS160
D10
B340A
D10
B340A
R33 0R33 0
C33 OPTC33 OPT
C49C49
C56
50V
1210
C56
50V
1210
Q14
BSC010NE2LS
Q14
BSC010NE2LS
G
DS
C52
0.22uF
16V
C52
0.22uF
16V
C58
22uF
16V
C58
22uF
16V
RFB4 (OPT)RFB4 (OPT)
R40
100
R40
100
C39
0.1uF
50V
C39
0.1uF
50V C48C48
R64
0.006
2W
R64
0.006
2W
R73 (OPT)R73 (OPT)
C46
1210
C46
1210
R72
0
R72
0
C44
22uF
16V
C44
22uF
16V
C68
2.2uF
50V
1206
C68
2.2uF
50V
1206
Q17Q17
G
DS
Q11
BSC010NE2LS
Q11
BSC010NE2LS
G
DS
L2 3uHL2 3uH
+
COUT4
330uF
16V
+
COUT4
330uF
16V
R37 100R37 100
11
dc2253af
DEMO MANUAL DC2253A
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
C C
B B
A A
INTVCC1
PLLIN2
PLLIN1
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Tuesday, May 06, 2014
33
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Tuesday, May 06, 2014
33
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
SIZE
DATE:
IC NO. REV.
SHEET OF
TITLE:
APPROVALS
PCB DES.
APP ENG.
TECHNOLOGY Fax: (408)434-0507
Milpitas, CA 95035
Phone: (408)432-1900
1630 McCarthy Blvd.
LTC Confidential-For Customer Use Only
CUSTOMER NOTICE
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.
THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND
SCHEMATIC
SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS.
SCALE = NONE
www.linear.com
1
Tuesday, May 06, 2014
33
HIGH EFFICIENCY 2-PHASE BUCK-BOOST CONVERTER
HZ
Jeoffrey W.
N/A
LTC3789EGN
DEMO CIRCUIT 2253A
R56
499K
R56
499K
C61
0.1uF
C61
0.1uF
U3
LTC6908CDCB-1
U3
LTC6908CDCB-1
SET
1
V+
2
GND
3
OUT2
5
OUT1
4
MOD
6
GND
7
12
dc2253af
DEMO MANUAL DC2253A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
LINEAR TECHNOLOGY CORPORATION 2014
LT 1014 • PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
Linear Technology Corporation (LT C ) 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 LT C 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 LT C 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. LT C assumes no liability for applications assistance,
customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind.
LT C 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 LT C applica-
tion engineer.
Mailing Address:
Linear Technology
1630 McCarthy Blvd.
Milpitas, CA 95035
Copyright © 2004, Linear Technology Corporation
