ADS1610IPAPR.B datasheet(13/29 Pages) TI2

13 / 29 page

www.ti.com

10pF

AINP

ADS1610

8pF

VMID

10pF

AINN

8pF

VMID

AGND

ADS1610

THS4503

10 pF

100pF

AINP

AINN

100pF

12.5

Ω

787

Ω

787

Ω

12.5

Ω

374

Ω

374

Ω

56.2

Ω

10 pF

−V

5 .2

Ω

Off

SAMPLE = 1/fCLK

DRIVING THE INPUTS

392

Ω

O P A 2 8 22

A D S 1 6 10

A G N D

O P A 2 8 22

20 pF

VCM

(1)

V CM

(1)

100pF

AINP

AINN

100pF (3)

392

Ω

20 pF

100pF

(1) Recommended VCM = 2.5V.

(2) Optional ac−coupling circuit provides common−mode input voltage.

(3) Increase to 390pF when fIN ≤ 100kHz for improved SNR and THD.

(2)

−

VIN

392

Ω

392

Ω

392

Ω

0.01µF

392

Ω

1µF

392

Ω

1µF

392

Ω

12.5

Ω

12.5

Ω

ADS1610

SBAS344C – AUGUST 2005 – REVISED OCTOBER 2006

driver circuits low-thermal noise in the driver circuits

degrades the overall noise performance. When the

signal can be AC-coupled to the ADS1610 inputs, a

simple RC filter can set the input common mode

voltage. The ADS1610 is a high-speed, high-

performance ADC. Special care must be taken when

selecting the test equipment and setup used with this

device. Pay particular attention to the signal sources

to ensure they do not limit performance when

measuring the ADS1610.

Figure 25. Conceptual Diagram of Internal

Circuitry Connected to the Analog Inputs

Figure 27. Recommended Single-Ended to

Differential Conversion Circuit Using the

THS4503 Differential Amplifier

Figure 26. Timing for the Switches in Figure 25

The external circuits driving the ADS1610 inputs

must be able to handle the load presented by the

switching capacitors within the ADS1610. The input

switches S1 in Figure 25 are closed approximately

one half of the sampling period, tSAMPLE, allowing

only ~8 ns for the internal capacitors to be charged

by the inputs, when fCLK = 60MHz.

Figure 27 and Figure 28 show the recommended

circuits when using single-ended or differential op

amps, respectively. The analog inputs must be

driven differentially to achieve optimum performance.

If only a single-ended input signal is available, the

configuration in Figure 27 can be used by shorting

–VIN to ground.

This configuration would implement the single-ended

to differential conversion.

The external capacitors, between the inputs and from

each input to AGND, improve linearity and should be

placed as close to the pins as possible. Place the

drivers close to the inputs and use good capacitor

bypass techniques on their supplies; usually a

Figure 28. Recommended Driver Circuit Using

smaller high-quality ceramic capacitor in parallel with

the OPA2822

a larger capacitor. Keep the resistances used in the

Submit Documentation Feedback

ADS1610IPAPR.B Scheda tecnica(PDF) 13 Page - Texas Instruments

ADS1610IPAPR.B Scheda tecnica(HTML) 13 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

Scheda tecnica Scarica

Link URL