AD9480BSUZ-250 Analog Devices Inc, AD9480BSUZ-250 Datasheet - Page 17

• Manufacturer Part Number: AD9480BSUZ-250
• Description: IC,A/D CONVERTER,SINGLE,8-BIT,BICMOS,TQFP,44PIN
• Manufacturer: Analog Devices Inc

Specifications of AD9480BSUZ-250

• Number Of Bits: 8
• Sampling Rate (per Second): 250M
• Data Interface: Parallel
• Number Of Converters: 1
• Power Dissipation (max): 590mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-TQFP, 44-VQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The AD9480 can be easily configured for different full-scale
ranges. See the Voltage Reference section for more information.
Optimal performance is achieved with a 1 V p-p analog input.
500mV
VOLTAGE REFERENCE
A stable and accurate 1.0 V reference is built into the AD9480.
Users can choose this internal reference or provide an external
reference for greater accuracy and flexibility. Figure 35 shows
the typical reference variation with temperature. Table 9
summarizes the available reference configurations.
Table 9. Reference Configurations
SENSE Voltage
AVDD
0.5 V (Self-Biased)
AGND to 0.2 V
10µF
+
2.0V
0.1µF
SENSE
SENSE = GND
VIN+
VIN–
Figure 34. Internal Reference Equivalent Circuit
VREF
VIN+
VIN–
DIGITALOUT = ALL 1s
Figure 33. Analog Input Full Scale
7kΩ
7kΩ
Resulting VREF
N/A (External Reference Input)
0.5 × (1 + R1/R2) V
1.0 V
SELECT
LOGIC
DIGITALOUT = ALL 0s
0.5V
CORE
ADC
Rev. A | Page 17 of 28
2.0V
Reference
External
Programmable
Internal Fixed
Fixed Reference
The internal reference can be configured for a differential span
of 1 V p-p (see Figure 37). It is recommended to place a 0.1 µF
capacitor as close as possible to the VREF pin; a 10 µF capacitor
is also required (see the PCB layout for guidance). If the
internal reference of the AD9480 is used to drive multiple
converters to improve gain matching, the loading of the
reference by the other converters must be considered. Figure 37
depicts how the internal reference voltage is affected by loading.
1.0085
1.0080
1.0075
1.0070
1.0065
1.0060
1.0055
1.0050
1.0045
1.0040
1.0035
–0.1
–0.2
–0.3
–0.4
–0.5
0
–40
Figure 35. Typical Reference Variation with Temperature
0
10µF
Figure 36. Internal Fixed Reference (1 V p-p)
Figure 37. Internal VREF vs. Load Current
–20
0.5
0.1µF
0
1.0
TEMPERATURE (°C)
Differential Span
1 × External Reference Voltage
1 × VREF (0.75 V p-p to 1.5 V p-p)
1 V p-p
IREF (mA)
20
1.5
VREF
SENSE
40
2.0
60
2.5
AD9480
80
3.0