MAX1661 Datasheet, PDF (1/16 Pages) Maxim Integrated Products – Active-Matrix Liquid Crystal Display AMLCD Supply

19-1356; Rev 0; 4/98
Active-Matrix Liquid Crystal Display
(AMLCD) Supply
________________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 (0.25Ω 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
___________________Pin Configuration
TOP VIEW
SHDN 1
RDY 2
FB1 3
REF 4
GND 5
IN 6
FB2- 7
FB2+ 8
PLLC 9
BPV_SS 10
MAX1664
TSSOP
20 FPLL
19 LX1
18 PGND1
17 PGND2
16 LX2N
15 LX2P
14 INP
13 BPCLK
12 BPV_DD
11 BPDRV
____________________________Features
o Integrates All Active Circuitry for Three DC-DC
Converters
o Ultra-Small External Components
(ceramic capacitors, 2µH to 5µH inductors)
o DC-DC Converters Phase-Locked to Backplane
Frequency for Lowest Noise
o Low Operating Voltage (down to +2.8V)
o Adjustable Output Voltage from V_IN to +5.5V
o Load Currents Up to 500mA
o Adjustable TFT Gate Driver Output:
Positive, V_IN to +28V
Negative, 0 to -10V (-20V with added
components)
o Includes 0.35Ω Backplane Driver
o 1µA Shutdown Current
o Power-Ready Output Signal
_______________Ordering Information
PART
MAX1664CUP
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
20 TSSOP
Typical Operating Circuit
REF
IN
INP
FB2-
LX1
-10V
LX2P
FB1
MAX1664
PGND1
28V
LX2N
V_SUPPLY
2.8V TO 5.5V
5.5V
FB2+ BPV_DD
PGND2 BPDRV
BACKPLANE
DRIVER
PLLC
GND
FPLL
RDY
BPCLK
BPV_SS
SHDN
REF
ON
OFF
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