AD5439 Analog Devices, AD5439 Datasheet - Page 17

• Manufacturer Part Number: AD5439
• Description: (AD5424 - AD5547) High Bandwidth Multiplying DACs
• Manufacturer: Analog Devices

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 25).
+5V
1µF
C1
+10V
–10V
+5V
C2
0.1µF
1µF
C1
REF 01/AD
4
16/14 DATA
VIN
GND
A0, A1
2
LDAC
16/14 DATA
VOUT
ADR03
MSB
TRIM
0.1µF
WR
U3
RS
C2
A0, A1
LDAC
0.1µF
MSB
WR
5
6
RS
C3
470kΩ
R3
AD5170
VDD
WR
R7
LDAC
B
VDD
WR
AD5547/AD5557
10kΩ
1kΩ
U4
R
R1
1A
LDAC
Figure 25. Signal Attenuator with AC Reference
RS
AD5547/AD5557
+2.5V
R
R1
1A
U2A
U1
R
OP2177
RS
MSB A0, A1
COMA
Figure 26. Full-Span Calibration
R
U1
MSB A0, A1
C7
R2
COMA
AD8628
V
U2
Rev. 0 | Page 17 of 20
REFA
C7
R2
2
V
REFA
2
16-/14-BIT
R
ROFS
OFSA
–2.5V
System Calibration
The initial accuracy of the system can be adjusted by trimming
the voltage reference ADR0x with a digital potentiometer (see
Figure 26). The AD5170 provides a one-time programmable
(OTP), 8-bit adjustment that is ideal and reliable for such
calibration. ADI’s OTP digital potentiometer comes with
programmable software that simplifies factory calibration.
R
16-/14-BIT
ROFS
OFSA
R
RFB
FBA
R
RFB
AGNDA
FBA
I
OUTA
AGNDA
I
OUTA
C6
C6
U2B
OP2177
+15V
U2B
+V
–V
–15V
AD8628
C4
C5
C8
C9
+V
–V
+5V
0.1µF
0.1µF
C4
C5
1µF
1µF
AD5547/AD5557
0.1µF
1µF
0V TO +2.5V
V
OUTA
V
OUTA