Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 10
Copyright
2000
Rev. 1.1, 2002-11-21
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M
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LX1741
High Efficiency High Voltage Boost Controller
P
RODUCTION
D
ATA
S
HEET
I N T E G R A T E D P R O D U C T S
E V A L U A T I O N B O A R D ( C O N T I N U E D )
Table 2: Jumper Pin Position Assignments
Jumper / Position
Function
VCC/ VBAT
Use this position when powering VBAT and VCC from the same supply. Do not connect power to the
VCC input when using this jumper position.
VCC/ SEP
Use this position when using a separate VCC supply (different from VBAT).
REF/ EXT
Use this position when using an external source to adjust the output voltage.
REF/ INT
Use this position when using the fixed output voltage mode. In this mode the output voltage can be
varied by changing the value of R1 as described in the data sheet.
Use this position when adjusting the output with an external PWM that has a repetition rate in excess of
100KHz.
Use this position when adjusting the output with an external PWM that has a repetition rate less than
100KHz. Or when using a DC adjustment voltage.
Use this position when adjusting the output voltage to prevent the output voltage from accidentally
exceeding 25V.
This position disables the output voltage adjustment clamp. This position may be desired if maximizing
efficiency when operating near 25V output level.
Note: Always put jumpers in one of the two possible positions
ADJ/ HF
ADJ/ LF
VLIM/ IN
VLIM/ OUT
Table 3: Factory Installed Component List for the LX1741Evaluation Board
Description
Supplier
Part Number
C1
CAPACITOR, COG, 1000pF, 0402, 50V
MURATA
GRM36X7R102M050
C2
CAPACITOR, X7R, 0.1uF, 0805, 50V
MURATA
GRM40X7R104M050
C3
CAPACITOR, Y5V, 2.2uF, 0805, 16V
AVX
0805YG225ZAT
C4,5
CAPACITOR, X5R, 4.7uF, 1210, 25V
RECTIFIER, SCHOTTKY, 1A, 40V,
POWERMITE
INDUCTOR, 47UH, 480mA, SMT
TAIYO YUDEN
CETMK325BJ475MN
CR1
MICROSEMI
UPS5819
L1
TOKO
A920CY-470M
JP1-7
3 TERM HEADER, 0.1 IN CTR
3M
929647-09-36-I
SB1-4
JUMPER
3M
929955-06
Q1
MOSFET, N-CHAN, 25V, SOT-23
FAIRCHILD
FDV303N
Q2
TRANSISTOR, NPN, 40V, SOT-23
ON
MMBT3904LT1
R1
RESISTOR, 698K, 1/16W, 0603
PANASONIC
ERJ3EKF6983
R2
RESISTOR, 49.9K, 1/16W, 0603
PANASONIC
ERJ3EKF4992
R3
RESISTOR, 619K, 1/16W, 0603
PANASONIC
ERJ3EKF6193
R4
RESISTOR, 100K, 1/16W, 0603
PANASONIC
ERJ3EKF1003
R5,R6
RESISTOR, 1.00K, 1/16W, 0603
PANASONIC
ERJ3EKF1001
R7
RESISTOR, 10.0K, 1/16W, 0603
PANASONIC
ERJ3EKF1002
R8
RESISTOR, 4.02K, 1/16W, 0603
PANASONIC
ERJ3EKF4021
U1
IC, BOOST CONTROLLER
MICROSEMI
LX1741
VR1
ZENER, 24V,225mW, SOT-23
ON
BZX84C24LT1
Note: The minimum part set for a working power supply consists of: C1, C2, C5, CR1, L1, Q1, R1, R2, R8, U1
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B
O
A
R
D