Datasheet

12
LTC1657/LTC1657L
A Wide Swing, Bipolar Output 16-Bit DAC
This circuit shows how to make a bipolar output 16-bit
DAC with a wide output swing using an LTC1657 and an
LT1077. R1 and R2 resistively divide down the LTC1657
output and an offset is summed in using the LTC1657
onboard 2.048V reference and R3 and R4. R5 ensures that
the onboard reference is always sourcing current and
never has to sink any current even when V
OUT
is at full
scale. The LT1077 output will have a wide bipolar output
swing of –4.096V to 4.096V as shown in the figure below.
With this output swing, 1LSB = 125µV.
DATA (0:15)
CSLSB
CSMSB
WR
LDAC
CLR
0.1µF
24
25
7
6
4
26 21 20 22 23
3
5:19
2
3
1
28
27
2
V
CC
V
OUT
GND REFHI REFOUTREFLOX1/X2
R1
100k
1%
5V
LTC1657
1657 TA05
–
+
LT1077
5V
–5V
R2
200k
1%
R3
100k
1%
R5
100k
1%
R4
200k
1%
(2)(D
IN
)(4.096)
65536
V
OUT
: – 4.096V
D
IN
V
OUT
4.096
–4.096
32768
0
65535
TRANSFER CURVE
µP
TYPICAL APPLICATIO S
U