Rainbow Electronics MAX8727 - Manual

General Description
The MAX8727 is a high-performance step-up DC-DC
converter that provides a regulated supply voltage for
active-matrix thin-film transistor (TFT) liquid-crystal dis-
plays (LCDs). The MAX8727 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 24V from an input voltage
between 2.6V and 5.5V. Soft-start slowly ramps the input
current and is programmed with an external capacitor.
The MAX8727 is available in a 10-pin thin DFN package.
Applications
Notebook Computer Displays
LCD Monitor Panels
Features
♦ 90% Efficiency
♦ Adjustable Output from V
IN to 24V
♦ 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
MAX8727
TFT-LCD Step-Up DC-DC Converter
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3480; Rev 0; 10/04
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.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
MAX8727ETB -40 °C to +85°C 10 Thin DFN 3mm x 3mm
COMP 1
FB 2
3
GND 4
GND 5
10
9
8
7
6
SHDN
SS
FREQ
LX
LX
IN MAX8727
TOP VIEW
THIN DFN
3mm x 3mm
Pin Configuration
LX LX
FB
GND
GND
FREQ
IN
COMP SS
1
4
5
2
3
9
8
6 7
10
V OUT
V IN
2.6V TO 5.5V
SHDN
MAX8727
Minimal Operating Circuit