LTC1329-10/
LTC1329-50/LTC1329A-50
Micropower 8-Bit Current
Output D/A Converter
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FEATURES
DESCRIPTION
The LTC®1329-10/LTC1329-50/LTC1329A-50 are
micropower 8-bit current output D/A converters (DACs)
with an output range of 0µA to 10µA for the LTC1329-10
and 0µA to 50µA for the LTC1329-50/LTC1329A-50. The
DAC current output can be biased from –15V to 2V or
–15Vto2.5Vin3.3Vand5Vsystems,respectively.Supply
current is only 95µA for the LTC1329-50/LTC1329A-50
and 75µA for LTC1329-10. A shutdown mode drops the
supply current to 0.2µA.
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Guaranteed Precision Full-Scale DAC Output
Current at 25°C:
LTC1329A-50
LTC1329-10
LTC1329-50
50µA ±1%
10µA ±3%
50µA ±3%
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Wide Output Voltage DC Compliance: –15V to 2.5V
Wide Supply Range: 2.7V ≤ VCC ≤ 6.5V
Supply Current in Shutdown: 0.2µA
Low Supply Current: 75µA for LTC1329-10,
95µA for LTC1329-50/LTC1329A-50
Available in 8-Pin SO
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.
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Triple ModeTM 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
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In3-wiremode, thesystemMPUcanseriallytransfer8-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 DIN.
DAC Contents Are Retained in Shutdown
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APPLICATIONS
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LCD Contrast Control
Backlight Brightness Control
Battery Charger Current/Voltage Adjustment
Power Supply Voltage Adjustment
LTC1329 is available in 8-pin SO packages.
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, LTC and LT are registered trademarks of Linear Technology Corporation.
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Triple Mode is a trademark of Linear Technology Corporation.
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Trimmer Pot Elimination
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TYPICAL APPLICATION
Digitally Controlled LCD Bias Generator
V
IN
5V
L1*
100µH
1N4148
200k
0.1µF
47Ω
1
2
8
7
I
D
OUT
OUT
I
V
SW1
LIM
IN
V
D
IN
+
CC
LT®1173
GND
47µF
MPU
(e.g., 8051)
LTC1329-50
FB
+
6
3
4
SW2
SHDN
CLK
GND
CS
4.7µF
10.1k
5
P1.2
1N5818
1N5818
P1.1
P1.0
+
220k
22µF
V
*GOWANDA GA10-103K OR
COILTRONICS CTX100-4
OUT
–22V at 40mA
1329 TA01
1