AD9212BCPZRL7-65 Analog Devices, Inc., AD9212BCPZRL7-65 Datasheet - Page 29

• Manufacturer Part Number: AD9212BCPZRL7-65
• Description: Octal, 10-bit, 40/65 Msps Serial Lvds 1.8 V A/d Converter
• Manufacturer: Analog Devices, Inc.

1µF
1
1µF
OPTIONAL.
REFERENCE
1
EXTERNAL
SENSE
0.1µF
SENSE
0.1µF
V
VIN+
VIN–
AVDD
VIN+
V
REF
VIN–
REF
1
Figure 67. Internal Reference Configuration
Figure 68. External Reference Operation
SELECT
LOGIC
SELECT
LOGIC
CORE
ADC
CORE
ADC
0.5V
0.5V
REFT
REFB
REFB
REFT
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
+
+
2.2µF
2.2µF
Rev. 0 | Page 29 of 56
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 70 shows the typical drift characteristics of the
internal reference in 1 V mode.
When the SENSE pin is tied to AVDD, the internal reference is
disabled, allowing the use of an external reference. The external
reference is loaded with an equivalent 6 kΩ load. An internal
reference buffer generates the positive and negative full-scale
references, REFT and REFB, for the ADC core. Therefore, the
external reference must be limited to a nominal of 1.0 V.
–0.02
–0.04
–0.06
–0.08
–0.10
–0.12
–0.14
–0.16
–0.18
0.02
–30
–10
–15
–20
–25
–5
0
5
0
–40
0
0.5
–20
Figure 69. V
Figure 70. Typical V
1.0
0
CURRENT LOAD (mA)
TEMPERATURE (°C)
REF
1.5
Accuracy vs. Load
20
2.0
REF
Drift
40
2.5
60
3.0
AD9212
80
3.5