AD9260AS Analog Devices Inc, AD9260AS Datasheet - Page 29

• Manufacturer Part Number: AD9260AS
• Description: IC ADC CMOS 16BIT OVRSAMP 44MQFP
• Manufacturer: Analog Devices Inc

Specifications of AD9260AS

• Rohs Status: RoHS non-compliant
• Number Of Bits: 16
• Sampling Rate (per Second): 20M
• Data Interface: Parallel
• Number Of Converters: 1
• Power Dissipation (max): 585mW
• Voltage Supply Source: Analog and Digital
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-MQFP, 44-PQFP

The actual reference voltages used by the internal circuitry of
the AD9260 appear on the CAPT and CAPB pins. If VREF is
configured for 2.5 V, thus providing a 4 V full-scale input span,
the voltages appear at CAPT and CAPB are 3.0 V and 1.0 V
respectively. For proper operation when using the internal or an
external reference, it is necessary to add a capacitor network to
decouple the CAPT and CAPB pins. Figure 67 shows the
recommended decoupling network. This capacitive network
performs the following three functions: (1) along with the
reference amplifier, A2, it provides a low source impedance over
a large frequency range to drive the A/D internal circuitry; (2) it
provides the necessary compensation for A2; and (3) it
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bandlimits the noise contribution from the reference. The turn-
on time of the reference voltage appearing between CAPT and
CAPB is approximately 15 ms and should be evaluated in any
power-down mode of operation.
0.1µF
Figure 67. Recommended Reference Decoupling Network
+
10µF
V
SENSE
REFCOM
REF
AD9260
CAPB
CAPT
0.1µF
+
10µF
0.1µF
0.1µF
AD9260