Datasheet

Data Sheet AD5547/AD5557
Rev. D | Page 15 of 20
2-Quadrant Multiplying Mode, V
OUT
= 0 V to +V
REF
The AD5547/AD5557 are designed to operate with either
positive or negative reference voltages. As a result, a positive
output can be achieved with an additional op amp, (see
Figure 22); the output becomes
V
OUT
= +V
REF
× D/65,536 (AD5547) (3)
V
OUT
= +V
REF
× D/16,384 (AD5557) (4)
Table 8 shows the positive output vs. code for the AD5547.
Table 8. AD5547 Unipolar Mode Positive Output vs. Code
D in Binary V
OUT
(V)
1111 1111 1111 1111 +V
REF
(65,535/65,536)
1000 0000 0000 0000 +V
REF
/2
0000 0000 0000 0001 +V
REF
(1/65,536)
0000 0000 0000 0000
0
C9
1µF
C8
0.1µF
–5V
WR
WR
RS
RS
2
LDAC
–2.5V
+2.5V
0V TO +2.5V
+5V
04452-005
AD8628
AD8628
AD5547/AD5557
C7
R
1A
16/14 DATA
VDD
R
COMA
R2R1
R
OFSA
R
FBA
C6
RFBROFS
MSB A0, A1
I
OUTA
AGNDA
U2B
C4
1µF
0.1µF
C1
1µF
C2
1µF
C3
0.1µF
C5
V
OUTA
V
REFA
MSB
A0, A1
LDAC
+V
–V
GND
ADR034
V
OUT
TRIM
5
6
V
IN
U3
U2
2
+5V
16-/14-BIT
Figure 22. Unipolar 2-Quadrant Multiplying Mode, V
OUT
= 0 to +V
REF