LTC1426I View Datasheet(PDF) - Analog Devices
Part Name
Description
Manufacturer
LTC1426I Datasheet PDF : 12 Pages
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LTC1426
Micropower
Dual 6-Bit PWM DAC
FEATURES
n Wide Supply Range: 2.7V ≤ VCC ≤ 5.5V
n Wide Reference Voltage Range: 0V to 5.5V
n Two Interface Modes:
Pulse Mode (Increment Only)
Pushbutton Mode (Increment/Decrement)
n Low Supply Current: 50µA
n 0.2µA Supply Current in Shutdown
n Available in 8-Pin MSOP and SO Packages
n DAC Contents Are Retained in Shutdown
n DACs Power-Up at Midrange
n Low Output Impedance: < 100Ω
n Output Frequency: 5kHz Typ
APPLICATIONS
n LCD Contrast and Backlight Brightness Control
n Power Supply Voltage Adjustment
n Battery Charger Voltage and Current Adjustment
n GaAs FET Bias Adjustment
n Trimmer Pot Elimination
DESCRIPTION
The LTC®1426 is a dual micropower 6-bit PWM DAC fea-
turing versatile PWM outputs and a flexible pushbutton
compatible digital interface. The DAC outputs provide a
PWM signal that swings from 0V to VREF, allowing the
full-scale output to be varied by adjusting the voltage at
VREF. The PWM output frequency is typically 5kHz, easing
output filtering requirements. VCC supply current is typi-
cally 50µA and drops to 0.2µA in shutdown.
The LTC1426 can be controlled using one of two inter-
face modes: pushbutton and pulse. The LTC1426 auto-
matically configures itself into the appropriate mode at
start-up by monitoring the state of the CLK pins. In push-
button mode, the CLK pins can be directly connected
to external pushbuttons to control the DAC output. In
pulse mode, the CLK pins can be connected to CMOS
compatible logic. The DAC outputs initially power up at
half scale and the contents of the internal DAC registers
are retained in shutdown.
The LTC1426 is available in 8-pin MSOP and SO packages.
All registered trademarks and trademarks are the property of their respective owners.
TYPICAL APPLICATION
RP1
47k
UP
DOWN
Pushbutton Adjustable CCFL/LCD Contrast Generator
UP TO 6mA
LAMP
RP2
47k
RSHDN
1M
SHDN
UP CONTRAST
LTC1426
UP/DOWN 1
CLK1
SHDN 8
CCFL UP/DOWN 2
CLK2
7
VCC
DOWN
3
GND
6
VREF
4
5
PWM1 PWM2
R3
R4
5.1k
4.99k
1%
1%
C3
10µF
R1
5V
44.2k
1%
C1
0.1µF
R5
20k
1%
C4
0.1µF
R6
40k
1%
R2
44.2k
1%
C2
1µF
ICCFL = 0µA TO 50µA
HIGH VOLTAGE
ROYER
1
16
CCFL PGND CCFL VSW
2
ICCFL
15
BULB
3
14
DIO LT1182 BAT
C7 1µF
4
CCFL VC
5
AGND
6 SHDN
13
ROYER
12
VIN
11
FBP
7
LCD VC
R7 8
C8 10k LCD PGND
0.68µF
10
FBN
9
LCD VSW
5V
C9
2.2µF
8V TO
28V
+ C10
2.2µF
35V
+ C11
2.2µF
35V
CONSULT THE LT1182 DATA SHEET FOR
DETAILS ON THE HIGH VOLTAGE ROYER
AND LCD CONTRAST CONVERTER SECTIONS
LCD
CONTRAST
CONVERTER
VOUT
NEGATIVE
1426 TA01
LCD CONTRAST
VOUT = –10V TO –30V
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For more information www.analog.com
Rev A
1
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