Linear Technology LT8570 Quick setup guide

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dc2297afb
DEMO MANUAL DC2297A
DESCRIPTION
LT8570, LT8570-1
Boost/SEPIC/Inverting Regulator
Demonstration circuits 2297A-A and 2297A-B feature the
LT
®
8570 and LT8570-1 in a boost configuration. These
demo circuits demonstrate small size and low component
count. Both converters are designed to convert a 5V to
10V source to 12V. Refer to Figures 3 and 4 for maximum
load current at different input voltage levels.
Both converters use only one feedback resistor to set the
output voltage.
The LT8570 can operate with inputs as high as 40V but
in these demo circuits, the input is limited by the voltage
rating of the input capacitors, and the magnitude of the
output voltage.
PERFORMANCE SUMMARY
The LT8570 and LT8570-1 include many other features
suchassynchronizationtoexternalclock,userconfigurable
undervoltage lockout, soft-start, frequency foldback, and
other features that are easily configured as Boost, SEPIC
or Inverting Converters.
The data sheet gives a complete description of the device,
operationandapplicationinformation.Thedatasheetmust
bereadinconjunctionwiththisdemomanualforDC2297A.
Design files for this circuit board are available at
http://www.linear.com/demo/DC2297A
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.
Specifications are at TA= 25°C
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
DC2297A-A
VIN Input Supply Range 5 10 V
VOUT Output Voltage VIN = 5V, ILOAD = 125mA 11.64 12 12.36 V
RIPPLE VIN = 5V, ILOAD = 125mA 25 mV
EFFICIENCY VIN = 5V, ILOAD = 125mA 86 %
SWITCHING FREQUENCY 1.5 MHz
DC2297A-B
VIN Input Supply Range 5 10 V
VOUT Output Voltage VIN = 5V, ILOAD = 60mA 11.64 12 12.36 V
RIPPLE VIN = 5V, ILOAD = 60mA 5 mV
EFFICIENCY VIN = 5V, ILOAD = 60mA 86 %
SWITCHING FREQUENCY 1.5 MHz

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DEMO MANUAL DC2297A
QUICK START PROCEDURE
Demo circuit 2297A is easy to set up to evaluate the per-
formance of the LT8570 and LT8570-1. 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 directly across the VIN or
VOUT and GND terminals. See Figure 2 for proper scope
probe technique.
1. With power off, connect the input power supply to VIN
and GND.
2. Turn on the power at the input.
NOTE: Make sure that the input voltage does not
exceed 10V.
3. Check for the proper output voltage.
NOTE: If there is no output, temporarily disconnect the
load to make sure that the load is not set too high.
4. Oncethe proper output voltages are established, adjust
the load within the operating range and observe the
output voltage regulation, ripple voltage, efficiency and
other parameters.
Figure 1. Proper Measurement Equipment Setup
–
+
–
+
+–
+
–
LOAD
–
+
–
+
POWER
SUPPLY VIN VOUT
IOUT
IIN
GND VIN
Figure 2. Measuring Input or Output Ripple

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DEMO MANUAL DC2297A
QUICK START PROCEDURE
INPUT (V)
LOAD (mA)
450
50
400
300
200
100
350
250
150
075 9
DC2297A F03
1064 83
Figure 3. DC2297A-A Max Load Current vs Input Voltage
INPUT (V)
LOAD (mA)
240
80
60
40
20
220
180
140
100
200
160
120
075 9
DC2297A F04
1064 83
Figure 4. DC2297A-B Max Load Current vs Input Voltage
INPUT (V)
EFFICIENCY (%)
90
85
75
65
55
80
70
60
50 8040 120
DC2297A F05
1406020 1000
Figure 5. DC2297A-A Efficiency at 5VIN
INPUT (V)
EFFICIENCY (%)
90
85
75
65
55
80
70
60
50 3010 50
DC2297A F06
6020 400
Figure 6. DC2297A-B Efficiency at 5VIN

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DEMO MANUAL DC2297A
PARTS LIST
ITEM QTY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER
DC2297A-A
Required Circuit Components for Boost Regulator
1 1 C1 CAP., CER., 4.7µF, X7R, 16V, 10%, 0805 MURATA, GRM21BR71C475KA73L
2 1 C2 CAP., CER., 0.1µF, X7R, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D
3 1 C3 CAP., CER., 2.2nF, X7R, 16V, 10%, 0402 AVX, 0402YC222KAT2A
4 1 C4 CAP., CER., 47pF, C0G, 25V, 5%, 0402 AVX, 04023A470JAT2A
5 1 C6 CAP., CER., 4.7µF, X7R, 16V, 10%, 0805 MURATA, GRM21BR71C475KA73L
6 1 D1 DIODE, SCHOTTKY, 30V, 1A, DI123 DIODES INC., DFLS130-7
7 1 L1 IND., 33µH WÜRTH ELEKTRONIK, 744 042 330
8 1 R2 RES., 11.3k, 1/8W, 1%, 0805 VISHAY, CRCW080511K3FKEA
9 1 R3 RES., 10k, 1/8W, 1%, 0805 VISHAY, CRCW080510K0FKEA
10 1 R5 RES., 56.2k, 1/10W, 1%, 0603 VISHAY, CRCW060356K2FKEA
11 1 R6 RES., 6.04k, 1/10W, 1%, 0603 NIC, NRC06F6041TRF
12 1 R7 RES., 130k, 1/10W, 1%, 0603 VISHAY, CRCW0603130KFKEA
13 1 U1 I.C., LT8570EDD, 8DFN LINEAR TECH., LT8570EDD#PBF
Additional Demo Board Circuit Components
1 1 C5 CAP., CER., 0.1µF, X7R, 16V, 10%, 0603 TDK, C1608X7R1C104K
2 1 R4 RES., 100k, 1/8W, 1%, 0805 VISHAY, CRCW0805100KFKEA
Hardware: For Demo Board Only
1 6 E1–E6 TEST POINT, TURRET, 0.094" MTG HOLE MILL-MAX, 2501-2-00-80-00-00-07-0
DC2297A-B
Required Circuit Components for Boost Regulator
1 1 C1 CAP., CER., 4.7µF, X7R, 16V, 10%, 0805 MURATA, GRM21BR71C475KA73L
2 1 C2 CAP., CER., 0.1µF, X7R, 16V, 10%, 0402 MURATA, GRM155R71C104KA88D
3 1 C3 CAP., CER., 2.2nF, X7R, 16V, 10%, 0402 AVX, 0402YC222KAT2A
4 1 C4 CAP., CER., 47pF, C0G, 25V, 5%, 0402 AVX, 04023A470JAT2A
5 1 C6 CAP., CER., 2.2µF, X7R, 16V, 10%, 0805 MURATA, GRM21BR71C225KA12L
6 1 D1 DIODE, SCHOTTKY, 30V, 1A, DI123 DIODES INC., DFLS130-7
7 1 L1 IND., 68µH U ELEKTRONIK, 744 042 680
8 1 R2 RES., 11.3k, 1/8W, 1%, 0805 VISHAY, CRCW080511K3FKEA
9 1 R3 RES., 10k, 1/8W, 1%, 0805 VISHAY, CRCW080510K0FKEA
10 1 R5 RES., 56.2k, 1/10W, 1%, 0603 VISHAY, CRCW060356K2FKEA
11 1 R6 RES., 6.04k, 1/10W, 1%, 0603 NIC, NRC06F6041TRF
12 1 R7 RES., 130k, 1/10W, 1%, 0603 VISHAY, CRCW0603130KFKEA
13 1 U1 I.C., LT8570EDD-1, 8DFN LINEAR TECH., LT8570EDD-1#PBF
Additional Demo Board Circuit Components
1 1 C5 CAP., CER., 0.1µF, X7R, 16V, 10%, 0603 TDK, C1608X7R1C104K
2 1 R4 RES., 100k, 1/8W, 1%, 0805 VISHAY, CRCW0805100KFKEA
Hardware: For Demo Board Only
1 6 E–E6 TEST POINT, TURRET, 0.094" MTG HOLE MILL-MAX, 2501-2-00-80-00-00-07-0

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DEMO MANUAL DC2297A
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
C6*
16V
0805
C5
0.1µF
16V
0603
VOUT*
L1*
D1
DFLS130
VIN
5V TO 10V
VIN SW
3 4
R6
6.19k
0603
R3
10k
0805
R2
11.3k
0805
R7
130k
0603
R5
56.2k
0603
R4
100k
0805
SHDN SHDN
GND
GND
E1
E2
E3
E6
E4
E5 GND
FB
VC
15
2
SYNC
SYNC SYNC
RTSS
98 67
C3
2.2nF
C4
47pF
C2
0.1µF
C1
4.7µF
16V
0805
ASSEMBLY TYPE U1 C6 L1 VOUT
DC2297A-A LT8570EDD 4.7µF 33µF 12V/125mA
DC2297A-B LT8570-1EDD 2.2µF 66µH 12V/60mA
* VERSION TABLE
U1*
SHDN

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DEMO MANUAL DC2297A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] ●FAX: [phone] ●www.linear.com
 LINEAR TECHNOLOGY CORPORATION 2015
LT 0317 REV B • PRINTED IN USA
DEMONSTRATION BOARD IMPORTANT NOTICE
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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
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agency certified (FCC, UL, CE, etc.).
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