LTC1329-10 Datasheet, PDF (1/8 Pages) Linear Technology – Micropower 8-Bit Current Output D/A Converter

LTC1329-10/
LTC1329-50/LTC1329A-50
Micropower 8-Bit Current
Output D/A Converter
FEATURES
s _{Guaranteed Precision Full-Scale DAC Output}
Current at 25°C:
LTC1329A-50 50µA ±1%
LTC1329-10 10µA ±3%
LTC1329-50 50µA ±3%
s _{Wide Output Voltage DC Compliance: – 15V to 2.5V}
s _{Wide Supply Range: 2.7V ≤ VCC ≤ 6.5V}
s _{Supply Current in Shutdown: 0.2µA}
s _{Low Supply Current: 75µA for LTC1329-10,}
95µA for LTC1329-50/LTC1329A-50
s _{Available in 8-Pin SO}
s _{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
s _{Can Read Back the 8-Bit DAC Value in 3-Wire Mode}
s _{DAC Powers Up at Midrange}
s _{DAC Contents Are Retained in Shutdown}
U
APPLICATIONS
s _{LCD Contrast Control}
s _{Backlight Brightness Control}
s _{Battery Charger Current/Voltage Adjustment}
s _{Power Supply Voltage Adjustment}
s _{Trimmer Pot Elimination}
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
– 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.
TYPICAL APPLICATION
Digitally Controlled LCD Bias Generator
V_IN
5V
+
47µF
L1*
47Ω
100µH
I_LIM
V_IN
SW1
LT^®1173
FB
GND SW2
+
1N5818
*GOWANDA GA10-103K OR
COILTRONICS CTX100-4
1N4148
200k
4.7µF
10.1k
1N5818
+
22µF
0.1µF
1
I_OUT
2
V_CC
8
D_OUT
7
D_IN
LTC1329-50
3
SHDN
6
GND
4
CLK
5
CS
220k
V_OUT
–22V at 40mA
MPU
(e.g., 8051)
P1.2
P1.1
P1.0
1329 TA01
1