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NCV8871SEPGEVB
NCV8871 Automotive Grade
High-Frequency SEPIC
Controller Evaluation Board
User's Manual
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EVAL BOARD USER’S MANUAL
Description
Key Features
This NCV8871 evaluation board provides a convenient
way to evaluate a high-frequency current-mode control
SEPIC converter design. The topology uses two inductors.
No additional components are required, other than dc
supplies for the input and enable voltages. An external clock
can be used to synchronize the switching frequency. The
output is rated 12 V / 2 A with a 170 KHz switching
frequency over the typical 6 V to 18 V automotive input
voltage range.
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•
•
•
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•
•
12 V / 2 A Output
170 KHz Switching Frequency (NCV887100)
Input Undervoltage Lockout
Internal Soft-Start
Wide Input Voltage of 6 V to 40 V
Regulates through 45 V Load Dump Conditions
External Clock Synchronization up to 1.1 MHz
Automotive Grade
Figure 1. NCV887100 SEPIC Evaluation Board
© Semiconductor Components Industries, LLC, 2012
July, 2012 − Rev. 4
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Publication Order Number:
EVBUM2080/D
NCV8871SEPGEVB
Table 1. EVALUATION BOARD TERMINALS
Terminal
Function
VIN
Positive DC input voltage.
GND
Common DC return.
VOUT
Regulated DC output voltage.
EN/SYNC
Enable and synchronization input.
Table 2. ABSOLUTE MAXIMUM RATINGS (Voltages are with respect to GND)
Rating
Value
Unit
DC Supply Voltage (VIN)
−0.3 to 40
V
DC Supply Voltage (EN/SYNC)
−0.3 to 6
V
Peak Transient Voltage (Load Dump on VIN)
45
V
Junction Temperature
−40 to 150
°C
Ambient Temperature (evaluation board)
−40 to 105
°C
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
Table 3. ELECTRICAL CHARACTERISTICS
(TA = 25°C, 4.5 V ≤ VIN ≤ 40 V, VEN = 2 V, VOUT = 3.3 V, 0 ≤ IOUT ≤ 1.2 A, unless otherwise specified)
Characteristic
Conditions
Typical Value
Unit
170
KHz
Switching
Switching Frequency
Soft−start Time
SYNC Frequency Range
7.4
ms
170 − 1025
KHz
10
A
< 6*
V
Current Limit
Cycle-by-cycle Current Limit (FET)
Protections
Input Undervoltage Lockout (UVLO)
VIN decreasing
Input Undervoltage Lockout (UVLO)
VIN increasing
6.7
V
Thermal Shutdown
TA increasing
170
°C
*See Note 3 from Operational Guidelines (on next page)
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NCV8871SEPGEVB
OPERATIONAL GUIDELINES
1. Connect a DC input voltage, within the 6 V to
40 V range, between VIN and GND.
2. Connect a DC enable voltage, within the 2.0 V to
5.0 V range, between EN/SYNC and GND.
3. The evaluation board feedback components were
selected to for continuous operation at rated
12 V / 2 A output power at a minimum input
voltage of 6 V. The NCV887100 VIN has its
operational voltage diode-ored between the
converter output (12 V) and input voltages. The
converter turns-on typically at 6.7 V. Once
energized, the output voltage supplies power to the
IC when the battery voltage is below
(approximately) 11.5 V. The decreasing VIN
UVLO voltage depends on load current as well as
VIN, and will be less than 6 V when operating
below rated output current.
4. Optionally for external clock synchronization,
connect a pulse source between EN/SYNC and
GND. The high state level should be within the 2
to 5 V range, and the low state level within the
−0.3 V to 0.8 V range, with a minimum pulse
width of 40 ns and a frequency within the 170 and
1100 KHz range.
NOTE: The converter was designed for 170 KHz
12 V / 2 A continuous mode operation.
Operation beyond 170 KHz and/or at a different
output voltage may require modifications of
feedback loop component and inductor values.
Vin
Venable
Figure 2. Evaluation Board Connections
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NCV8871SEPGEVB
TYPICAL PERFORMANCE
VOUT
EN
Figure 3. Typical Start−up with VIN = 12 V, ROUT = 6 W
IL1
IL2
VDS
Figure 4. Operational Waveforms, VIN = 12 V, ROUT = 6 W
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NCV8871SEPGEVB
SCHEMATIC
Figure 5. NCV887100 SEPIC Evaluation Board Schematic
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NCV8871SEPGEVB
Table 4. BILL OF MATERIALS
Component
Description
C1
DO NOT POPULATE
Manufacturer P/N
Vendor P/N
C2
DO NOT POPULATE
C3
DO NOT POPULATE
C4
DO NOT POPULATE
C5
CAP CER 4.7UF 50V 10% X7R 1210
GRM32ER71H475KA88L
490−1864−1−ND
C6
DO NOT POPULATE
C7
DO NOT POPULATE
C8
CAP POLY ALUM 47UF 16V SMD
PCG1C470MCL1GS
493−3095−1−ND
C9
CAP POLY ALUM 47UF 16V SMD
PCG1C470MCL1GS
493−3095−1−ND
C10
CAP POLY ALUM 47UF 16V SMD
PCG1C470MCL1GS
493−3095−1−ND
C11
CAP CER 1UF 50V X7R 1206
GCM31MR71H105KA55L
490−4795−1−ND
C12
CAP CER .082UF 10% 16V X7R 0603
0603YC823KAT2A
478−1238−1−ND
C13
CAP CER 680PF 50V 5% C0G 0603
GRM1885C1H681JA01D
490−1447−1−ND
C14
CAP CER .1UF 50V X7R 0603
GCM188R71H104KA57D
490−4779−1−ND
C15
CAP 100UF 50V ELECT FC RADIAL
EEU−FC1H101
P10323−ND
C16
CAP CER 1UF 16V X7R 10% 0603
GCM188R71C105KA64D
490−5241−1−ND
C17
CAP CER .1UF 50V X7R 0603
GCM188R71H104KA57D
490−4779−1−ND
D1
60 V, 3.0 A Schottky Rectifier DPAK
MBRD360G
MBRD360G
D2
DIODE SCHOTTKY 40V 1A SOD123FL
MBR140SFT1G
MBR140SFT1G
D3
DIODE SCHOTTKY 40V 1A SOD123FL
MBR140SFT1G
MBR140SFT1G
L1
High Temp SMT Power Inductor 2.3A
MSS1260T−223ML
MSS1260T−223ML
L2
High Temp SMT Power Inductor 1.9A
MSS1038T−223ML
MSS1038T−223ML
Q1
N−CHANNEL MOSFET, LOGIC LEVEL,
60V 16mOHMS
NVD5865NL
NVD5865NL
R1
RES 5.10 OHM 1/8W 1% 0805 SMD
CRCW08055R10FKEA
541−5.10CCCT−ND
R2
RES .04 OHM 3W 1% 2512 SMD
CRA2512−FZ−R040ELF
CRA2512−FZ−R040ELFCT−ND
R3
DO NOT POPULATE
R4
RES 90.9K OHM 1/10W 1% 0603 SMD
RC0603FR−0790K9L
311−90.9KHRCT−ND
R5
RES 10.0K OHM 1/10W 1% 0603 SMD
MCR03EZPFX1002
RHM10.0KHCT−ND
R6
RES 10.0 OHM 1/10W 1% 0603 SMD
RC0603FR−0710RL
311−10.0HRCT−ND
R7
RES 715 OHM 1/10W 1% 0603 SMD
CRCW0603715RFKEA
541−715HCT−ND
U1
ON SEMI Non−Sync Boost Controller
NCV887100
NCV887100D1R2G
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NCV8871SEPGEVB
PCB LAYOUT
Figure 6. Top View
Figure 7. Bottom View
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NCV8871SEPGEVB
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EVBUM2080/D