Rainbow Electronics MAX1664 User Manual

Max1664, General description, Applications

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________________General Description

The MAX1664 integrates power-supply and backplane
drive circuitry for active-matrix thin-film-transistor (TFT) liq-
uid crystal displays. Included are a single-output, pulse-
width-modulation boost converter (0.25

Ω

switch), a

dual-output (positive and negative) gate-driver supply
using one inductor, an LCD backplane driver, and a sim-
ple phase-locked loop to synchronize all three outputs.

High switching frequency (1MHz nominal) and phase-
locked operation allow the use of small, minimum-
height external components while maintaining low
output noise. A +2.8V to +5.5V input voltage range
allows operation with any logic supply. Output voltages
are adjustable to +5.5V (DC-DC 1) and to +28V and
-10V (DC-DC 2). The negative output voltage can be
adjusted to -20V with additional components. Also
included are a logic-level shutdown and a “Ready” out-
put (RDY) that signals when all three outputs are in reg-
ulation.

The boost-converter operating frequency can be set at
16, 24, or 32 times the backplane clock. This flexibility
allows a high DC-DC converter frequency to be used
with LCD backplane clock rates ranging from 20kHz to
72kHz. The MAX1664 is supplied in a 1.1mm-high
TSSOP package.

________________________Applications

LCD Modules

LCD Panels

____________________________Features

♦

Integrates All Active Circuitry for Three DC-DC
Converters

♦

Ultra-Small External Components
(ceramic capacitors, 2µH to 5µH inductors)

♦

DC-DC Converters Phase-Locked to Backplane
Frequency for Lowest Noise

♦

Low Operating Voltage (down to +2.8V)

♦

Adjustable Output Voltage from V

to +5.5V

♦

Load Currents Up to 500mA

♦

Adjustable TFT Gate Driver Output:

Positive, V

to +28V

Negative, 0 to -10V (-20V with added
components)

♦

Includes 0.35

Ω

Backplane Driver

♦

1µA Shutdown Current

♦

Power-Ready Output Signal

MAX1664

________________________________________________________________

Maxim Integrated Products

REF

FB2-

INP

LX2P

LX2N

FB2+

PGND2

PLLC

GND
FPLL

RDY

REF

SHDN

OFF

5.5V

-10V

28V

BPV

BACKPLANE

DRIVER

SUPPLY

2.8V TO 5.5V

BPDRV

BPV

PGND1

FB1

LX1

BPCLK

MAX1664

Typical Operating Circuit

___________________Pin Configuration

19-1356; Rev 0; 4/98

PART

MAX1664CUP

0°C to +70°C

TEMP. RANGE

PIN-PACKAGE

20 TSSOP

_______________Ordering Information

FPLL

LX1