MAX686EEE Datasheet Download

Part No.:
MAX686EEE
Download:
Download Datasheet
Description:
[DAC-Controlled Boost/Inverter LCD Bias Supply with Internal Switch]
File Size:
200 K
Page:
16 Pages
Logo:
Manufacturer:
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
PCB Prototype
 MAX686EEE Datasheet Page:2MAX686EEE Datasheet Page:3MAX686EEE Datasheet Page:4MAX686EEE Datasheet Page:5MAX686EEE Datasheet Page:6MAX686EEE Datasheet Page:7MAX686EEE Datasheet Page:8MAX686EEE Datasheet Page:9 
19-1327; Rev 1; 2/98
KIT
ATION
EVALU
BLE
AVAILA
DAC-Controlled Boost/Inverter
LCD Bias Supply with Internal Switch
General Description
____________________________Features
o
Internal 500mA, 28V N-Channel Switch
(no external FET required)
o
Adjustable Output Voltage to +27.5V or -27.5V
o
6-Bit DAC-Controlled Output Voltage
o
Up to 90% Efficiency
o
Small 16-Pin QSOP Package
(Same size as 8-pin SO)
o
Power-OK Indicator
o
65µA Quiescent Current
o
1.5µA Shutdown Current
o
Up to 300kHz Switching Frequency
MAX686
The MAX686 DAC-controlled boost/inverter IC converts
a positive input voltage to a positive or negative LCD
bias voltage up to +27.5V or -27.5V. The device features
an internal N-channel MOSFET switch, programmable
current limiting, and an internal 6-bit digital-to-
analog converter (DAC) for digital adjustment of the
output voltage. It comes in a small 16-pin QSOP pack-
age (same size as an 8-pin SO).
The MAX686 uses a current-limited, pulse-frequency-
modulation (PFM) control scheme to provide high effi-
ciency over a wide range of load conditions. Its high
switching frequency (up to 300kHz) allows the use of
small external components.
An
LCDON
output allows the LCD bias voltage to be
automatically disabled when the display logic voltage is
removed, protecting the display. The MAX686 has a
+2.7V to +5.5V input voltage range for the IC, and a
+0.8V to +27.5V input voltage range for the inductor.
Typical quiescent supply current is 65µA. Shutdown
current is 1.5µA.
The MAX686 offers high-level integration to save space,
reduce power consumption, and increase battery life,
making it an excellent choice for battery-powered
portable equipment. The MAX629 is similar to the
MAX686, except that it does not contain a built-in DAC.
Both devices have evaluation kits to facilitate designs.
Ordering Information
PART
MAX686C/D
MAX686EEE
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
Dice*
16 QSOP
*Dice
are specified at T
A
= +25°C, DC parameters only.
Functional Diagram appears at end of data sheet.
Applications
Positive or Negative LCD Bias
Personal Digital Assistants
Notebook Computers
Portable Data-Collection Terminals
Palmtop Computers
Varactor Tuning Diode Bias
V
IN
= 0.8V TO 27.5V
Typical Operating Circuit
22µH
MBR0530L
V
OUT
V
CC
= 2.7V TO 5.5V
0.1µF
R2
V
CC
V
DD
LX
DACOUT
LCDON
R3
Pin Configuration
TOP VIEW
PGND 1
UP 2
DN 3
POL 4
V
DD
5
ISET 6
SHDN 7
DACOUT 8
16 LX
15 N.C.
14 LCDON
FB
UP
DAC CONTROL
DN
ON/OFF
SHDN
POL
GND
POK
REF
ISET
PGND
0.1µF
MAX686
R1
MAX686
13 GND
12 V
CC
11 POK
10 FB
9
REF
QSOP
________________________________________________________________
Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.