LX1742 データシートの表示（PDF） - Microsemi Corporation

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LX1742

High Efficiency High Voltage Boost Controller

Microsemi Corporation 

INTEGRATED PRODUCTS

LX1742

High Efficiency High Voltage Boost Controller

PRODUCTION DATA SHEET

EVALUATION BOARD (CONTINUED)

Jumper / Position

VIN

n/a

VOUT

n/a

Table 2: Jumper Pin Position Assignments

Function

Attach the primary input power form to this contact. Input power may also be applied to the pin marked

Vin on J4.

Use this contact to measure the circuit’s output voltage at pin 8.

SWITCH

n/a

Use this contact to observe the switching waveform at the Schottky anode (i.e., LX1742 pin 1).

FDBK

n/a

Use this contact to measure the circuit’s feedback voltage at pin 3.

GND /

GND2

/SHDN

JU3

JU1

JU4

n/a

1/0

1

1/0/0

0/1/0

Use these contact to connect to circuit ground.

Inserting a jumper (1) enables the LX1742 by connecting pin 4 directly to VIN. Removing this jumper (0)

disables the LX1742

Remove the factory installed jumper and insert a 4 ~6cm wire loop (optional) to observe the inductor

current waveform using a current probe.

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 with an external PWM that has a repetition rate in excess of

100KHz.

JU5

0 / 0 / 1 Use this position to ground the ADJ (pin 5) when using the LX1742 in a fixed output voltage mode

Note: (1) = jumper installed; (0) = jumper not installed.

Table 3: Factory Installed Component List for the LX1742 Evaluation Board

Ref

Part Description

C1

CAPACITOR, 4.7µF, 1210, 35V

C2

CAPACITOR, 4.7µF, 1210, 35V

C3

CAPACITOR, 1000pF, 0805, 35V

C4

CAPACITOR, 2.2µF, 0603, 35V

C5 & C6

CAPACITOR, (SPARE); see note 1.

CR1

Microsemi UPS5819, SCHOTTKY, 1A, 40V, POWERMITE

L1

INDUCTOR, 47µH, 480mA, SMT

Q1

MMBT3904 TRANSISTOR, NPN, 40V, SOT-23

D1

BZX84C24, ZENER DIODE, TBD

R1

RESISTOR, 625K, 1/16W, 0805

R2, R5, R6

RESISTOR, 1.0K, 1/16W, 0805

R3

RESISTOR, 1.0M, 1/16W, 0805

R4

RESISTOR, 72K, 1/16W, 0805

R7

RESISTOR, 100K, 1/16W, 0805

U1

Microsemi LX1742CDU BOOST CONTROLLER; see note 2.

Notes

1.

2.

Use these locations to insert additional input (C6) and/or output (C5) capacitance.

The minimum part set for a working power supply consists of: C1, C2, CR1, L1, R2, R3, R4, U1.

Copyright © 2000

Rev. 1.0b, 2005-03-03

Microsemi

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

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