Datasheet

AD1580
Rev. F | Page 10 of 12
The AD1580 is ideal for creating the reference level to use with 12-bit
multiplying DACs, such as the AD7943, AD7945, and AD7948.
In the single-supply bias mode (see Figure 26), the impedance
seen looking into the I
OUT2
terminal changes with DAC code. If
the AD1580 drives I
OUT2
and AGND directly, less than 0.2 LSBs
of additional linearity error results. The buffer amp eliminates
any linearity degradation that could result from variations in
the reference level.
DAC
RBF
AGND
DGND
A1
C1
3.3V
41.2kΩ
3.3V
AD1580
SIGNAL GROUND
A1: OP295
AD822
OP2283
A1
V
REF
V
IN
V
DD
I
OUT1
I
OUT2
V
OUT
AD7943/
AD7945/
AD7948
00700-026
Figure 26. Single-Supply System