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POWER-DOWN TOPOWER-UP RESPONSE

Power-DownDuration(ms)

300

250

200

150

100

50

0

0.1

1

10

100

T

V

S

PWRD

BUSY

CS

CONV

EXT/INT

DATA

DATACLK

R1

IN

GND

R2

IN

R3

IN

BUF

CAP

REF

GND

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

1

2

3

4

8

7

6

5

0.01µF

1µF

1RF7604

+

Power-DownSignal

LAYOUT

POWER FOR TSSOP-20 PACKAGE

GROUNDING

ADS8513

SLAS486 – JUNE 2007

POWER DOWN (continued)

Figure 13. Power-Down to Power-Up Response

Figure 14. Improved Power-Up Response Circuit

For optimum performance, tie the analog and digital power pins to the same +5-V power supply and tie the

analog and digital grounds together. As noted in the electrical characteristics, the ADS8507 uses 90% of its

power for the analog circuitry. The ADS8507 should be considered as an analog component.

The +5-V power for the A/D converter should be separate from the +5 V used for the system's digital logic.

digital logic. For best performance, the +5-V supply can be produced from whatever analog supply is used for the

rest of the analog signal conditioning. If +12-V or +15-V supplies are present, a simple +5-V regulator can be

used. Although it is not suggested, if the digital supply must be used to power the converter, be sure to properly

tied to the same +5-V source.

Two types of ground pins are present on the TSSOP package ADS8507. DGND is the digital supply ground.

AGND is the analog supply ground.

16

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Product Folder Link(s): ADS8513