Datasheet

MAX5156/MAX5157
Using an AC Reference
In applications where the reference has an AC signal
component, the MAX5156/MAX5157 have multiplying
capabilities within the reference input voltage range
specifications. Figure 12 shows a technique for apply-
ing a sinusoidal input REF_, where the AC signal is off-
set before being applied to the reference input.
Harmonic Distortion and Noise
The total harmonic distortion plus noise (THD+N) is typ-
ically less than -80dB at full scale with a 1Vp-p input
swing at 5kHz. The typical -3dB frequency is 600kHz
for both devices, as shown in the Typical Operating
Characteristics .
Low-Power, Dual, 12-Bit Voltage-Output DACs
with Configurable Outputs
14 ______________________________________________________________________________________
MAX5156
MAX5157
DAC
V
OUT
=
(
1
+ R1
) (
N
)(
V
REF_
)
R2 4096
REF_
V
OUT
FB_
OUT_
AGNDDGND
+5V/+3V
V
DD
R1
R2
Figure 10. Configurable Output Gain
AGNDDGND
MAX5156
MAX5157
DAC _
REF_
OUT_
FB_
10k 10k
V-
V+
V
DD
V
OUT
+5V/+3V
Figure 11. Bipolar Output Circuit
DAC_
OUT_
FB_
MAX5156
MAX5157
10k
26k
REF_
V
DD
DGND AGND
+5V/
+3V
AC
REFERENCE
INPUT
500mVp-p
MAX495
+5V/+3V
Figure 12. AC Reference Input Circuit
Table 3. Bipolar Code Table
0000 0000 0001(0)
0000 0000 0000(0)
0111 1111 1111(0)
0V1000 0000 0000(0)
DAC CONTENTS
MSB LSB
1000 0000 0001(0)
1111 1111 1111(0)
ANALOG OUTPUT
+V
2047
2048
REF






+V
1
2048
REF






-V
1
2048
REF






-V
2047
2048
REF






-V
2048
2098
- V
REF REF






=
Note: ( ) are for the sub bit.