2-PHASE, DUAL-OUTPUT SWITCHING REGULATOR CONTROLLER
DEMO BOARD QUICK START GUIDE DC424
LTC3701
DESCRIPTION
Demonstration Circuit DC424 provides
2.5V/1.6A and 1.8V/1.6A using the
LTC3701 2-phase, dual-output switch-
ing regulator controller. The input
range is from 2.5V to 9.8V. Operating
the two controller channels 180° out
of phase significantly reduces peak
input ripple current; thereby reduc-
ing radiated and conducted EMI. Out-
put voltages can be externally set to
as low as 0.8V. The board is opti-
mized for small size and low cost.
Higher output current can be easily
achieved by changing external compo-
nents. For example, maximum output
current can be increased to 2A if Mu-
rata LQH55DN4R7M01 inductors are used
at the L1 and L2 locations.
Switching frequency is internally set
at 550kHz, allowing the use of small
inductors and capacitors. For noise
sensitive applications, an external
clock can be applied to synchronize
from 300kHZ to 750kHz. The frequency
can also be externally set by apply-
ing a voltage in the range from 0V to
2.4V to the PLLLPF pin.
Gerber files for this circuit board
are available. Call the LTC factory.
Table 1. Performance Summary
(Operating Temperature Range: –40°C to 85°C)
PARAMETER
Input Voltage
Range
Outputs
V
OUT1
= 2.5V; 0 to
1.6A
V
OUT2
= 1.8V; 0 to
1.6A
Typical Output
Ripple
Typical Oper-
ating Fre-
quency
Typical Shut-
down
Current
Typical
Standby
Current
10MHz BW; 1.6A Load;
V
IN
= 5V
PLLLPF Pin Floating
CONDITION
VALUE
2.5V to
9.8V
2.5V±
3%
1.8V±
3%
26mV
P–P
550kHz
V
IN
= 5V
V
IN
= 5V; RUN1 and
RUN2 are on; No Load
Current
15µA
310µA
QUICK START PROCEDURE
Refer to Figure 1 for equipment
requirements and proper setup.
1.
Apply a voltage source to the input
channel(s) by setting JP1 and JP2
to the run position.
3.
Connect
of the circuit between the Vin and
GND terminals. The circuit will
start up at input voltage higher
than 2.5V. Do not apply more than
9.8V to the input.
2.
Attach
the load at each
The board can supply up to
each output. Higher output
are possible by changing
components.
output.
1.6A for
currents
external
4.
Proper hook-up is essential for ac-
voltmeters or oscilloscope
probes between V
OUT1,
V
OUT2
and their
closest GND terminals to monitor
the outputs. Switch on the desired
curate and meaningful evaluation of
efficiency and regulation. Figure 1
shows the appropriate arrangement
of supply, loads, ammeters and
voltmeters.
1
2-PHASE, DUAL-OUTPUT SWITCHING REGULATOR CONTROLLER
DEMO BOARD QUICK START GUIDE DC424
+
–
+
+
LOAD
–
–
–
+
–
+
–
+
LOAD
–
Figure 1.
Proper Measurement Equipment Setup
+
+
BENCH
SUPPLY
+
–
–
2
5
4
3
2
1
E3
VIN
2.5V - 9.8V
D
M3
(Optional)
SI9803DY
8
R3
R7
169K
C9
1nF
U1
LTC3701EGN
R6
78.7K
R10
3
1
SENSE1-
SENSE1+
16
E8
GND
D
10
C8
0.68uF
3
2
1
7
6
5
4
R1
0.03
4
6
5
2
1
L1
4.7uH
E1
VOUT1 = 2.5V@1.6A
C14
1uF
C6
2
ITH/RUN1
VIN
15
M1
FDC638P
D1
MBRM120LT3
D3
MBRS320
(Optional)
3
RUN1
SD1
1
JP1
2
10K
220pF
3
VFB1
PGATE1
14
C2
10uF
10V
C1
47uF
E7
GND
4
SGND
PGND
13
3
C
RUN2
SD2
1
JP2
2
5
VFB2
PGATE2
12
C
R5
10K
R12
0
R8
80.6K
C4
220pF
C7
10nF
6
ITH/RUN2
PGOOD
11
R4
1M
R11
3
D2
MBRM120LT3
M2
FDC638P
D4
MBRS320
(Optional)
C5
47uF
7
PLLLPF
EXTCLKMODE
10
1M
R2
0.03
L2
4
4
1
2
5
6
8
SENSE2-
SENSE2+
9
E2
C15
1uF
VOUT2 = 1.8V @1.6A
4.7uH
C3
R9
100K
B
1
2
3
1nF
E6
PLLLPF
M4
(Optional)
SI9803DY
E4
5
6
7
8
PGOOD
E5
EXTCLK/MODE
B
E9
GND
L1
R10 C8
C6 C9
R7
D1
R6
U1
R8
R9
D2
C4
C3
R5
R3
L2
M1
C1
R1
C2
M2
R2
C5
CONTRACT NO.
APPROVALS
DRAWN
CHECKED
APPROVED
ENGINEER Dongyan Zhou
4/17/01
June Wu
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
A
DATE
4/17/01
A
TECHNOLOGY
TITLE
LTC3701EGN, 2-Phase Dual Step-Down Converter
SIZE CAGE CODE
DWG NO
REV
A
1
OF
1
PCB SILKSCREEN
DESIGNER
DC424A
SCALE:
FILENAME:
SHEET
1
Friday, November 16, 2001
5
4
3
2
Linear Technology Corporation
LTC3701EGN
Bill Of Material
Demo Bd. # 424A
6/17/2005
8:05 AM
Item Qty Reference
Part Description
Manufacture / Part #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
2
1
2
1
1
2
2
2
0
3
6
2
2
2
2
0
2
2
2
1
1
1
1
1
1
1
1
1
C1,C5
C2
C4,C6
C7
C8
C9,C3
C14,C15
D1,D2
D3,D4
(OPT)
E4-E6
E1-E3,E7-E9
JP1,JP2
JP1,JP2
L1,L2
M2,M1
M3,M4 (OPT)
R1,R2
R5,R10
R4,R11
R12
R6
R8
R7
R9
R3
U1
CAP., POSCAP, 47uF, 6.3V, C SIZE
CAP., X7R, 10uF, 10V, 20%, 1210
CAP., X7R, 220pF, 50V, 20% 0402
CAP., X7R, 10nF, 50V, 20% 0603
CAP., 0.68uF, 10V, 20% 0603
CAP., X7R, 1nF, 50V, 20% 0402
CAP., X5R, 1uF, 6.3V, 20%, 0603
DIODE, MBRM120LT3, POWERMITE
DIODE, MBRS320 SMC
TURRET, TEST PIN, .061
TURRET, TEST PIN, .095
JUMPER, 0.079, 3PIN
SHUNT
INDUCTOR, 4.7uH,
P-MOSFET, FDC638P, TSOP-6
P-MOSFET, SI9803DY, SO-8
RES., CHIP, 0.03, 1/4W, 1% 1206
RES., CHIP, 10K, 1/16W, 5% 0402
RES., CHIP, 1M, 1/16W, 5% 0603
RES., CHIP, 0, 1/16W, 0603
RES., CHIP, 78.7K, 1/16W, 1% 0402
RES., CHIP, 80.6K, 1/16W, 1%, 0402
RES., CHIP, 169K, 1/16W, 1% 0402
RES., CHIP, 100K, 1/16W, 1% 0402
RES., CHIP, 10, 1/16W, 5% 0402
I.C., LTC3701EGN, SSOP-16GN
PRINTED CIRCUIT BOARDS
STENCIL
SANYO, 6TPA47M
TAIYO TUDEN, LMK325BJ106MN
AVX, 04025C221MAT
AVX, 06035C103MAT
TAIYO TUDEN, LMK107BJ684MA
AVX, 04025C102MAT
TAIYO YUDEN, JMK107BJ105MA
ON SEMI., MBRM120LT3
OPTIONAL
MILL-MAX 2308-2-00-44
MILL-MAX 2501-2
COMM CON, 2802S-03G1
COMM CON, CCIJ2MM-138G
TOKO, A915AY-4R7M
FAIRCHILD, FDC638P
OPTIONAL
IRC, LR1206-01-R030-F
AAC, CR05-103JM
AAC, CR16-105JM
AAC, CJ06-000M
AAC, CR05-7872FM
AAC, CR05-8062FM
AAC, CR05-1693FM
AAC, CR05-1003FM
AAC, CR05-100JM
LINEAR, LTC3701EGN
DEMO BOARD DC424A
STENCIL DC424A
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