MAX8740 Datasheet, PDF (1/12 Pages) Maxim Integrated Products – TFT-LCD Step-Up DC-DC Converter

19-3698; Rev 0; 5/05
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TFT-LCD Step-Up DC-DC Converter
General Description
The MAX8740 is a high-performance, step-up DC-DC
converter that provides a regulated supply voltage for
active-matrix, thin-film transistor (TFT), liquid-crystal
displays (LCDs). The MAX8740 incorporates current-
mode, fixed-frequency, pulse-width modulation (PWM)
circuitry with a built-in n-channel power MOSFET to
achieve high efficiency and fast transient response.
Users can select 640kHz or 1.2MHz operation using a
logic input pin (FREQ). The high switching frequencies
allow the use of ultra-small inductors and low-ESR
ceramic capacitors. The current-mode architecture pro-
vides fast transient response to pulsed loads. A com-
pensation pin (COMP) gives users flexibility in adjusting
loop dynamics. The 30V internal MOSFET can generate
output voltages up to 28V from a 2.6V and 5.5V input
voltage range. Soft-start slowly ramps the input current
and is programmed with an external capacitor.
The MAX8740 is available in a 10-pin thin DFN package.
Features
♦ 90% Efficiency
♦ Adjustable Output from V_IN to 28V
♦ 2.6V to 5.5V Input Supply Range
♦ Input Supply Undervoltage Lockout
♦ Pin-Programmable 640kHz/1.2MHz Switching
Frequency
♦ Programmable Soft-Start
♦ 0.1µA Shutdown Current
♦ Small, 10-Pin Thin DFN Package
Applications
Notebook Computer Displays
LCD Monitor Panels
PART
MAX8740ETB
Ordering Information
TEMP RANGE PIN-PACKAGE
-40°C to +85°C 10 TDFN 3mm x 3mm
Pin Configuration
TOP VIEW
10 9 8 7 6
MAX8740
12345
THIN DFN
3mm x 3mm
Minimal Operating Circuit
V_IN
2.6V TO 5.5V
V_OUT
6
LX
8
IN
7
LX
FB ²
9
FREQ
3 _SHDN
MAX8740
GND ⁵
GND ⁴
10
SS
COMP ¹
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.