Datasheet

Data Sheet AD5547/AD5557
Rev. D | Page 17 of 20
AC Reference Signal Attenuator
Besides handling the digital waveform decoded from the
parallel input data, the AD5547/AD5557 can also handle low
frequency ac reference signals for signal attenuation, channel
equalization, and waveform generation applications. The
maximum signal range can be up to ±18 V (see Figure 24).
System Calibration
The initial accuracy of the system can be adjusted by trimming
the voltage reference ADR0x with a digital potentiometer (see
Figure 25). The AD5170 provides a one-time programmable
(OTP), 8-bit adjustment that is ideal and reliable for such
calibration. Analog Devices, Inc., OTP digital potentiometer
comes with programmable software that simplifies factory
calibration.
WR
WR
RS
RS
2
LDAC
04452-008
AD5547/AD5557
16/14 DATA
VDD
R
OFSA
R
FBA
C6
RFBROFS
MSB A0, A1
I
OUTA
AGNDA
C2
0.1µF
C1
1µF
V
OUTA
MSB
A0, A1
LDAC
+10V
–10V
+5V
OP2177
C7
R
1A
R
COMA
R2
R1
V
REFA
16-/14-BIT
C4
+15V
U2B
1µF
0.1µFC5
C8 1µF
0.1µFC9
OP2177
+V
–V
U2A
U1
–15V
Figure 24. Signal Attenuator with AC Reference
WR
WR
RS
RS
2
LDAC
04452-009
AD5547/AD5557
16/14 DATA
VDD
R
OFSA
R
FBA
C6
RFBROFS
MSB A0, A1
I
OUTA
U2B
+5V
AGNDA
C1
1µF
C2
0.1µF
C3
0.1µF
V
OUTA
MSB
A0, A1
LDAC
REF 01/AD
4
5
10kΩ
1kΩ
6
U3
AD5170
R7
R3
+2.5V
U4
U2
B
470kΩ
2
+5V
0V TO +2.5V
–2.5V
AD8628
C7
R
1A
R
COMA
R2
U1
R1
V
REFA
16-/14-BIT
GND
ADR03
V
OUT
TRIM
V
IN
C4
1µF
0.1µFC5
AD8628
+V
–V
Figure 25. Full-Span Calibration