MAX8574(2004) Ver la hoja de datos (PDF) - Maxim Integrated

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componentes Descripción

Fabricante

MAX8574
(Rev.:2004)

High-Efficiency LCD Boost with True Shutdown

Maxim Integrated 

High-Efficiency LCD Boost

with True Shutdown

Typical Operating Characteristics (continued)

(MAX8571, VCC = 3.6V, VOUT = 18V, Circuit of Figure 2, TA = +25°C, unless otherwise noted.)

LOAD TRANSIENT

MAX8570/71/73/74/75 toc15

STARTUP AND SHUTDOWN WAVEFORMS

MAX8570/71/73/74/75 toc16

VOUT

100mV/div

VSHDN

BOOST SOFT-START

5V/div

(AC-COUPLED)

SW TURN-ON

VOUT

10V/div

0

5mA/div

IOUT

0

100µs/div

ILX

1.8Ω LOAD

400µs/div

200mA/div

0

Pin Description

PIN

NAME

FUNCTION

FB

(MAX8570/ Feedback for setting the output voltage. Connect FB to the center of a resistor voltage-divider from the

MAX8571/ output to GND to set positive output voltages.

MAX8574)

1

OUT

(MAX8572/ Output. The output voltage is preset to 15V. Connect a 1µF ceramic capacitor from OUT to GND. In

MAX8573/ shutdown, OUT is pulled to GND by an internal 7.5MΩ resistor.

MAX8575)

2

GND Ground

3

SHDN

Shutdown Input. A logic low at SHDN places the part in low-power shutdown mode. Pull SHDN high or

connect to VCC for normal operation.

4

LX

Inductor Switching Connection

Isolation Switch Output. Internally connected to the drain of a p-channel MOSFET used to isolate the

5

SW

output from the input during shutdown. Connect a 4.7µF ceramic capacitor from SW to GND. If true

shutdown is not required, SW can be left open with the input supply connected directly to the inductor.

6

VCC

Input Voltage Supply. Connect a 2.7V to 5.5V input supply to VCC. Connect a 1µF ceramic capacitor from

VCC to GND.

_______________________________________________________________________________________ 5

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