Datasheet

9
LTC1454/LTC1454L
Figure 2
APPLICATIONS INFORMATION
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A Single Supply, 4-Quadrant Multiplying DAC
The LTC1454 can also be used for 4-quadrant multiplying
with an offset signal ground of 1.22V. This application is
shown in Figure 2. The inputs are connected to REFHI B or
REFHI A and have a 1.22V amplitude around a signal
ground of 1.22V. The outputs will swing from 0V to 2.44V,
as shown by the equation with the figure. Since the signal
ground is around 1.22V, REFLO is offset above ground by
using an LT1034CS8-1.2 as shown.
V
OUT B
V
CC
REFHI B
GND
REFLO
REFHI A
REFOUT
V
CC
V
OUT B
V
OUT A
V
INB
1.22V ± 1.22V
V
INA
1.22V ± 1.22V
LT1034CS8-1.2
CLK
D
IN
CS/LD
LTC1454
1454 F02
X1/X2 B
CLR
CLK
D
IN
CS/LD
D
OUT
X1/X2 A
V
OUT A
5V
0.1µF
10k
V
OA/B
= V
IN
– V
REFLO
GAIN – 1 +1 + V
REFLO
= V
IN
– 1.22 2.0 – 1.0 + 1.22V
()
()
()
()
D
IN
4096
D
IN
4096