AD9653BCPZ-125 Analog Devices, AD9653BCPZ-125 Datasheet - Page 24

• Manufacturer Part Number: AD9653BCPZ-125
• Description: the ad9653 is a quad, 16-bit, 125 msps analog-to-digital converter (adc) with an...
• Manufacturer: Analog Devices

AD9653
If the internal reference of the
converters to improve gain matching, the loading of the reference
by the other converters must be considered. Figure 58 and
Figure 59 show how the internal reference voltage is affected by
loading.
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
–3.5
–4.0
–4.5
–5.0
0
0
Figure 58. V
0.5
REF
1.0
LOAD CURRENT (mA)
= 1.0 V Error vs. Load Current
2V p-p
AD9653
1.5
Figure 56. Differential Double Balun Input Configuration for Baseband Applications
0.1µF
2V p-p
INTERNAL V
is used to drive multiple
2.0
Figure 57. Differential Transformer-Coupled Configuration
ET1-1-I3
REF
49.9Ω
2.5
= 1.0V
1:1 Z RATIO
ADT1-1WT
3.0
0.1μF
for Baseband Applications
Rev. 0 | Page 24 of 40
0.1µF
0.1µF
C
C
*C1 IS OPTIONAL
33Ω
33Ω
R
R
33Ω
33Ω
0.1µF
*C1
C
5pF
*C1
External Reference Operation
The use of an external reference may be necessary to enhance
the gain accuracy of the ADC or improve thermal drift charac-
teristics. Figure 60 and Figure 61 show the typical drift characteris-
tics of the internal reference in 1.0 V mode and programmable
1.3 V mode, respectively.
33Ω
33Ω
R
R
*C1 IS OPTIONAL
C
200Ω
200Ω
–1
–2
–3
–4
–5
–6
–7
–8
–9
*C1
R
VIN+x
VIN–x
5pF
*C1
0
0
ADC
Figure 59. V
VCM
0.5
VIN+x
VIN–x
0.1µF
ADC
REF
1.0
LOAD CURRENT (mA)
C
VCM
=1.3 V Error vs. Load Current
0.1µF
1.5
INTERNAL V
2.0
Data Sheet
REF
2.5
= 1.3V
3.0