LTC1329-10/
LTC1329-50/LTC1329A-50
Micropower 8-Bit Current
Output D/A Converter
FEATURES
s
DESCRIPTION
The LTC
廬
1329-10/LTC1329-50/LTC1329A-50 are
micropower 8-bit current output D/A converters (DACs)
with an output range of 0碌A(chǔ) to 10碌A(chǔ) for the LTC1329-10
and 0碌A(chǔ) to 50碌A(chǔ) for the LTC1329-50/LTC1329A-50. The
DAC current output can be biased from 鈥?15V to 2V or
鈥?15V to 2.5V in 3.3V and 5V systems, respectively. Supply
current is only 95碌A(chǔ) for the LTC1329-50/LTC1329A-50
and 75碌A(chǔ) for LTC1329-10. A shutdown mode drops the
supply current to 0.2碌A(chǔ).
The LTC1329 can communicate with external circuitry by
using one of three interface modes: standard 3-wire serial
mode and two pulse modes. Upon power-up, the internal
counter resets to 1000 0000B, the DAC output assumes
midrange and the chip is configured in 3-wire or pulse
mode depending on the signal level at CS.
In 3-wire mode, the system MPU can serially transfer 8-bit
data to and from the LTC1329. In pulse mode, the upper
six bits of the DAC output can be programmed for incre-
ment-only (1-wire interface) or increment/decrement
(2-wire interface) operation depending on the signal level
at D
IN
.
LTC1329 is available in 8-pin SO packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Triple Mode is a trademark of Linear Technology Corporation.
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Guaranteed Precision Full-Scale DAC Output
Current at 25
擄
C:
LTC1329A-50
50碌A(chǔ)
鹵1%
LTC1329-10
10碌A(chǔ)
鹵3%
LTC1329-50
50碌A(chǔ)
鹵3%
Wide Output Voltage DC Compliance: 鈥?15V to 2.5V
Wide Supply Range: 2.7V
鈮?/div>
V
CC
鈮?/div>
6.5V
Supply Current in Shutdown: 0.2碌A(chǔ)
Low Supply Current: 75碌A(chǔ) for LTC1329-10,
95碌A(chǔ) for LTC1329-50/LTC1329A-50
Available in 8-Pin SO
Triple Mode
TM
Interface Modes
1. Standard 3-Wire Mode
2. Pulse Mode 1-Wire Interface: Increment-Only
3. Pulse Mode 2-Wire Interface: Increment/Decrement
Can Read Back the 8-Bit DAC Value in 3-Wire Mode
DAC Powers Up at Midrange
DAC Contents Are Retained in Shutdown
APPLICATIONS
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LCD Contrast Control
Backlight Brightness Control
Battery Charger Current/Voltage Adjustment
Power Supply Voltage Adjustment
Trimmer Pot Elimination
TYPICAL APPLICATION
Digitally Controlled LCD Bias Generator
V
IN
5V
47鈩?/div>
V
IN
SW1
廬
LT 1173
FB
GND
SW2
1N5818
I
LIM
L1*
100碌H
1N4148
200k
0.1碌F
1
2
I
OUT
V
CC
D
OUT
D
IN
8
7
MPU
(e.g., 8051)
+
47碌F
+
4.7碌F
10.1k
1N5818
LTC1329-50
3
4
SHDN
CLK
GND
CS
6
5
+
22碌F
*GOWANDA GA10-103K OR
COILTRONICS CTX100-4
220k
V
OUT
鈥?2V at 40mA
1329 TA01
U
U
U
P1.2
P1.1
P1.0
1
1
2
3
4
5
6
7
8
