Rainbow Electronics MAX1748 - Manual

General Description
The MAX1748 triple-output DC-DC converter in a low-
profile TSSOP package provides the regulated voltages
required by active matrix, thin-film transistor (TFT) liquid
crystal displays (LCDs). One high-power DC-DC con-
verter and two low-power charge pumps convert the
+3.3V to +5V input supply voltage into three independent
output voltages.
The primary high-power DC-DC converter generates a
boosted output voltage (V
MAIN ) up to 13V that is regu-
lated within ±1%. The low-power BiCMOS control cir-
cuitry and the low on-resistance (0.35
Ω) of the
integrated power MOSFET allows efficiency up to 93%.
The 1MHz current-mode PWM architecture provides
fast transient response and allows the use of ultra-small
inductors and ceramic capacitors.
The dual charge pumps independently regulate one
positive output (V
POS ) and one negative output (V NEG ).
These low-power outputs use external diode and
capacitor stages (as many stages as required) to regu-
late output voltages up to +40V and down to -40V. A
proprietary regulation algorithm minimizes output rip-
ple, as well as capacitor sizes for both charge pumps.
The MAX1748 is available in the ultra-thin TSSOP pack-
age (1.1mm max height).
________________________Applications
TFT Active Matrix LCD Displays
Passive Matrix LCD Displays
PDAs
Digital Still Cameras
Camcorders
Features
♦ Three Integrated DC-DC Converters
♦ 1MHz Current-Mode PWM Boost Regulator
Up to +13V Main High-Power Output
±1% Accuracy
High Efficiency (93%)
♦ Dual Charge-Pump Outputs
Up to +40V Positive Charge-Pump Output
Down to -40V Negative Charge-Pump Output
♦ Internal Supply Sequencing
♦ Internal Power MOSFETs
♦ +2.7V to +5.5V Input Supply
♦ 0.1µA Shutdown Current
♦ 0.6mA Quiescent Current
♦ Internal Soft-Start
♦ Power-Ready Output
♦ Ultra-Small External Components
♦ Thin TSSOP Package (1.1mm max)
MAX1748
Triple-Output TFT LCD DC-DC Converter
________________________________________________________________ Maxim Integrated Products 1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
RDY TGND
LX
PGND
SUPP
DRVP
SUPN
DRVN
SHDN
TOP VIEW
MAX1748
TSSOP
FB
INTG
REF
IN
GND
FBP
FBN
Pin Configuration
19-1740; Rev 0; 6/00
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
Ordering Information
Typical Operating Circuit appears at end of data sheet.
16 TSSOP
PIN-PACKAGE TEMP. RANGE
-40°C to +85°C MAX1748EUE
PART