Datasheet

1
LTC1329-10/
LTC1329-50/LTC1329A-50
Micropower 8-Bit Current
Output D/A Converter
Guaranteed Precision Full-Scale DAC Output
Current at 25
°
C:
LTC1329A-50 50µA ±1%
LTC1329-10 10µA ±3%
LTC1329-50 50µA ±3%
Wide Output Voltage DC Compliance: –15V to 2.5V
Wide Supply Range: 2.7V V
CC
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
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
FEATURES
DESCRIPTION
U
APPLICATIONS
U
LCD Contrast Control
Backlight Brightness Control
Battery Charger Current/Voltage Adjustment
Power Supply Voltage Adjustment
Trimmer Pot Elimination
TYPICAL APPLICATION
U
Digitally Controlled LCD Bias Generator
1
2
8
7
D
OUT
D
IN
I
OUT
V
CC
SHDN
CLK
LTC1329-50
GND
CS
47µF
1329 TA01
V
OUT
22V at 40mA
V
IN
5V
200k
3
4
6
5
4.7µF
22µF
0.1µF
LT
®
1173
1N4148
1N5818
1N5818
L1*
100µH
*GOWANDA GA10-103K OR
COILTRONICS CTX100-4
I
LIM
V
IN
FB
SW2
GND
SW1
220k
47
10.1k
MPU
(e.g., 8051)
P1.2
P1.1
P1.0
+
+
+
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
– 15V to 2.5V in 3.3V and 5V systems, 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.
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.

Summary of content (8 pages)