MAX8728 Datasheet, PDF (1/29 Pages) Maxim Integrated Products – Low-Cost, Multiple-Output Power Supply for LCD Monitors/TVs

19-3910; Rev 0; 1/06
Low-Cost, Multiple-Output
Power Supply for LCD Monitors/TVs
General Description
The MAX8728 generates all the supply rails for thin-film
transistor (TFT) liquid-crystal display (LCD) panels in TVs
and monitors. It includes step-down and step-up regula-
tors, positive and negative charge pumps, and a dual-
mode, logic-controlled high-voltage switch control block.
The MAX8728 can operate from input voltages from 7V to
13.2V and is optimized for LCD TV panel and LCD moni-
tor applications running directly from 12V supplies.
The step-up and step-down regulators feature internal
power MOSFETs and high-frequency operation allow-
ing the use of small inductors and capacitors, resulting
in a compact solution. Both switching regulators use
fixed-frequency, current-mode control architectures,
providing fast load-transient response and easy com-
pensation. The positive and negative charge-pump reg-
ulators provide TFT gate-driver supply voltages. Both
output voltages can be adjusted with external resistive
voltage-dividers.
The MAX8728 is available in a small (5mm x 5mm), low-
profile (0.8mm), 32-pin TQFN package and operates
over the -40°C to +85°C temperature range.
LCD Monitors
Applications
LCD TVs
Ordering Information
PART
TEMP RANGE
PIN-
PACKAGE
PACKAGE
CODE
MAX8728ETJ+
-40°C to +85°C
32 TQFN-EP*
5mm x 5mm
T3255-4
+Denotes lead-free package.
*EP = Exposed pad.
Pin Configuration
TOP VIEW
24 23 22 21 20 19 18 17
GND2 25
16 DRVP
LX2 26
15 GNDP
GATE 27
14 FBP
EN 28
MODE 29
MAX8728
13 REF
12 GND
DEL 30
11 SHDN
COMP 31
FB1 32
10 V_CC
9 VL
1 2345678
Features
♦ Optimized for 10.8V to 13.2V Input Supply
♦ 7V to 13.2V Input Supply Range
♦ Selectable Frequency (500kHz/1MHz/1.5MHz)
♦ Current-Mode Step-Down Regulator
14V Internal n-Channel MOSFET
1.5% Accurate Output
♦ Current-Mode Step-Up Regulator
19V Internal n-Channel MOSFET
1% Accurate Output
True Shutdown™ (Output Goes to Zero)
♦ 180° Out-of-Phase Switching
♦ Adjustable Positive/Negative Charge Pumps
♦ Soft-Start and Timer Delay Fault Latch for All
Outputs
♦ Logic-Controlled, High-Voltage Switches
♦ Power-Up and Power-Down Sequences
♦ Thermal-Overload Protection
Simplified Operating Circuit
VIN
AVDD
OUT1
VGOFF
VL
VL ^{INL GATE}
LX2
GND2
FB2
BST
COMP
IN
LX1
GND1
SHDN
EN
DEL
ON/OFF
LCD ENABLE
OUT1 MAX8728 _CTL
THR
FROM TCON
FBI
MODE
FSEL
DRN
VL
VCC
GON
VGON
REF
SRC
GND
FBN
DRVN
SUPP
FBP
DRVP
VIN
TQFN
True Shutdown is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
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.