DC568A - Demo Manual

QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568
DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR
LTC3407
DESCRIPTION
Demonstration circuit 568 is a Dual Synchronous,
600mA, 1.5MHz Step-Down DC/DC Regulator featuring the LTC®3407. The DC568 has an input voltage
range of 2.5V to 5.5V, and either output is capable of
delivering up to 600mA of output current. In Burst
Mode operation, the LTC3407 requires only 40 uA
of quiescent current, and the DC568 provides higher
efficiency at light load currents. In Pulse Skip mode,
the DC568 provides lower output ripple voltage at
light load currents. In either mode, the DC568 can
provide up to 96% efficiency on either channel and
consumes less than 1uA in shutdown. The LTC3407
comes in a small 10-Pin MS10E package, which has
an exposed pad on the bottom-side of the IC for better thermal performance. These features, plus the
nominal operating frequency of 1.5MHz (allowing the
exclusive use of low profile surface mount components), make the DC568 demo board an ideal circuit
for use in battery-powered, hand-held applications.
Design files for this circuit board are available.
Call the LTC factory.
LTC and Burst Mode is registered trademark of Linear Technology Corporation.
Table 1. Performance Summary (T A = 25°C)
PARAMETER
Minimum Input Voltage
CONDITION
VALUE
2.5V
Maximum Input Voltage
5.5V
1.2V ±2%
Output Voltage VOUT1
VIN = 2.5V to 5.5V, IOUT1 = 0A to 600 mA
1.5V ±2%
1.8V ±2%
Typical Output Ripple VOUT1
VIN = 5V, IOUT1 = 600 mA (20 MHz BW)
20mVP–P
Line
±1%
Load
±1%
Output Voltage VOUT2
VIN = 2.5V to 5.5V, IOUT2 = 0A to 600 mA
2.5V ±2%
Typical Output Ripple VOUT2
VIN = 5V, IOUT2 = 600 mA (20 MHz BW)
20mVP–P
Line
±1%
Load
±1%
Output Regulation
Output Regulation
Nominal Switching Frequency
1.5 MHz
QUICK START PROCEDURE
Demonstration circuit 568 is easy to set up to
evaluate the performance of the LTC3407. Refer to
Figure 1 for proper measurement equipment setup
and follow the procedure below:
NOTE: When measuring the input or output voltage
ripple, care must be taken to avoid a long ground lead
on the oscilloscope probe. Measure the input or
output voltage ripple by touching the probe tip
1
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568
DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR
directly across the VIN or VOUT and GND terminals.
See Figure 2 for proper scope probe technique.
1. Connect the input power supply to the VIN and
GND terminals on the left-side of the board. Do
not hot-plug VIN or increase VIN over the rated
maximum supply voltage of 5.5V, or the part may
be damaged. Connect the loads between the VOUT
and GND terminals on the right-side of the board.
Refer to figure 1 for the proper measurement
equipment setup.
2. Before proceeding to operation, insert jumpers JP1
and JP2 into the OFF positions, jumper JP3 into
the VOUT1 voltage position of choice (1.2V, 1.5V,
and 1.8V), and jumper JP4 into the desired mode
of operation: Pulse Skip or Burst Mode.
3. Apply 3.3V at VIN.
Measure both VOUTs; they
should read 0V. If desired, one can measure the
shutdown supply current at this point. The supply
current will be approximately 33 uA in shutdown,
with roughly 32 uA due to the optional 100k• pullup resistor of the Power-On Reset (POR) feature.
This resistor can be removed, and the actual
shutdown supply current can be measured, if the
POR feature is not required.
4. Turn on VOUT1 and VOUT2 by changing jumpers
JP1 and JP2 from the OFF position(s) to the ON
position(s). Vary the input voltage from 2.5V to
5.5V and adjust each load current from 0 to
600mA.
Both output voltages should be
regulating.
5. Set the load current of both outputs between 200
mA and 600 mA, and measure both output ripple
voltages; they should measure less than 20 mVAC
each. Also, observe the voltage waveform at the
switch node (pin 3) of each regulator. The
switching frequencies should be between 1.2 MHz
and 1.8 MHz (T = 0.833 us and 0.555 us), and each
switch node waveform should be rectangular in
shape.
6. To change the mode of operation, change jumpers
JP1 and JP2 from the ON position(s) to the OFF
position(s). Then change jumper JP4 to the
alternative position. Re-insert jumpers JP1 and
JP2 into the ON position(s). Observe the voltage
waveform at both switch nodes.
When finished, insert jumpers JP1 and JP2 to the
OFF position(s) and disconnect the power.
2
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568
DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR
Figure 1. Proper Measurement Equipment Setup
Figure 2. Measuring Input or Output Ripple
3
QUICK START GUIDE FOR DEMONSTRATION CIRCUIT 568
DUAL SYNCHRONOUS, 600MA, 1.5MHZ STEP-DOWN DC/DC REGULATOR
4
5
4
3
2
1
REVISION HISTORY
ECO
REV
DESCRIPTION
3
D
ON
OFF
R1
4.7M
5%
C1
604K
10pF
1 FBK1
GND
R8
R9
604K
402K
301K
LTC3407EMS
VIN
1.8V
1.5V
R5
1.2V
E4
1
C
L2
SW2 7
VOUT2
E3
2.2uH
FBK2 10
C2
R6
10pF
887K
2.5V @ 600mA
COUT2
C4
10uF
OPTIONAL
6.3V
GND
R7
BURST
MODE
E6
280K
2
3
JP3
5%
R10 4.7M
5%
B
4.7M
POR 8
MODE/SYNC
R4
OFF
6
COUT1
10uF
6.3V
GND
C3
CH.2
RUN2 9
4 SW1
5
2.2uH
OPTIONAL
2 RUN1
ON
R3
100K
L1
VOUT1
E2
R2
U1
3
JP2
2
JP1
2
1
CH.1
E5
1.2V/1.5V/1.8V
@ 600mA
D
VIN 3
CIN
10uF
6.3V
1
+
3
E1
C
JP4
1
B
POR
PULSE SKIP
E7
CONTRACT NO.
APPROVALS
DRAWN
MEI
DATE
02/19/03
CHECKED
A
APPROVED
ENGINEER
DESIGNER
Wednesday, June 11, 2003
5
APPROVED
02/19/03
VIN
VIN
2.5V-5.5V
C5
47uF
10V
GND
DATE
PROTO
4
3
TECHNOLOGY
1630 McCarthy Blvd.
Milpitas, CA 95035
Phone: (408)432-1900
Fax: (408)434-0507
TITLE
A
SCH, LTC3407EMS DUAL DC/DC CONVERTER
SIZE CAGE CODE
DWG NO
FILENAME: 568A-3.DSN
SCALE:
2
REV
DC568A
3
SHEET
1
1
OF
1
Linear Technology Corporation
LTC3407EMS
Item
1
2
3
4
5
6
7
8
10
11
12
13
14
15
16
17
Qty
3
2
0
1
7
3
1
2
3
1
2
1
1
1
1
1
Ref
COUT1,COUT2,CIN
C2,C1
C3,C4
C5
E1,E2,E3,E4,E5,E6,E7
JP1,JP2,JP4
JP3
L1,L2
R1,R3,R10
R2
R4,R5
R6
R7
R8
R9
U1
DC568A Rev 3
6/17/2005
Parts List
Desc
CAP, X5R 10uF 6.3V 20% 0805
CAP, NPO 10pF 50V 10% 0402
CAP, 0805
CAP, TANT 47uF 10V 20% 6032
TURRETS
HEADER, 3P 2mm
HEADER, 3X2 2mm
IND, 2.2uH
RES, 4.7M OHMS 5% 1/16W 0402
RES, 100K OHMS 1% 1/16W 0402
RES, 604K OHMS 1% 1/16W 0402
RES, 887K OHMS 1% 1/16W 0402
RES, 280K OHMS 1% 1/16W 0402
RES, 402K OHMS 1% 1/16W 0402
RES, 301K OHMS 1% 1/16W 0402
IC, LTC3407EMS
1 of 1
Part Number
TAIYO YUDEN JMK212BJ106MG
AVX 04025A100KAT
TBD
AVX TAJW476M010R
MILL-MAX 2501-2
COMM CON 2802S-03-G1
COMM CON 2202S-06G1
TAIYO YUDEN LQLBC25182R2M
AAC CR05-475JM
AAC CR05-1003FM
AAC CR05-6043FM
AAC CR05-8873FM
AAC CR05-2803FM
AAC CR05-4023FM
AAC CR05-3013FM
LINEAR TECH. LTC3407EMS
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