REF5045 datasheet(45/62 Pages) TI2

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tCONV

tACQ

tCONV

tTHROUGHPUT

2 x tTHROUGHPUT

~50000X

IAVDD

Device Phase

~1200X

IREF

~2X

IAVG(AVDD+REF)

~50000X

~1200X

AVDD

AINP

AINN

GND

DIN

SCLK

DOUT

CONVST

REF

DVDD

1 µF

Digital

Supply

Analog

Supply

ADS8881

www.ti.com

SBAS547D – MAY 2013 – REVISED AUGUST 2015

Product Folder Links: ADS8881

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12 Power-Supply Recommendations

The device has two separate power supplies: AVDD and DVDD. The internal circuits of the device operate on

AVDD; DVDD is used for the digital interface. AVDD and DVDD can be independently set to any value within the

permissible range.

12.1 Power-Supply Decoupling

Decouple the AVDD and DVDD pins with GND, using individual 1-µF decoupling capacitors placed in close

proximity to the pin, as shown in Figure 74.

Figure 74. Supply Decoupling

12.2 Power Saving

The device has an auto power-down feature that powers down the internal circuitry at the end of every

conversion. Referring to Figure 75, the input signal is acquired on the sampling capacitors when the device is in

a power-down state (tacq); at the same time, the result for the previous conversion is available for reading. The

device powers up on the start of the next conversion. During conversion phase (tconv), the device also consumes

current from the reference source (connected to the REF pin).

Figure 75. Power Scaling With Throughput

REF5045 Datasheet(PDF) 45 Page - Texas Instruments

REF5045 Datasheet(HTML) 45 Page - Texas Instruments

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