TLC5510, TLC5510A

8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTERS

SLAS095L – SEPTEMBER 1994 – REVISED JUNE 2003

8

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

PRINCIPLES OF OPERATION

functional operation

The output code change with input voltage is shown in Table 1.

Table 1. Functional Operation

INPUT SIGNAL

STEP

DIGITAL OUTPUT CODE

INPUT SIGNAL

VOLTAGE

STEP

MSB

LSB

Vref(B)

255

0

0

0

0

0

0

0

0

•

•

•

••

••

••

•

•

•

•

••

••

••

•

•

128

0

11

11

11

1

•

127

1

00

00

00

0

•

•

•

••

••

••

•

•

•

•

••

••

••

•

Vref(T)

0

1

1

1

1

1

1

1

1

APPLICATION INFORMATION

The following notes are design recommendations that should be used with the device.

D External analog and digital circuitry should be physically separated and shielded as much as possible to

reduce system noise.

D RF breadboarding or printed-circuit-board (PCB) techniques should be used throughout the evaluation and

production process. Breadboards should be copper clad for bench evaluation.

D Since AGND and DGND are connected internally, the ground lead in must be kept as noise free as possible.

A good method to use is twisted-pair cables for the supply lines to minimize noise pickup. An analog and

digital ground plane should be used on PCB layouts when additional logic devices are used. The AGND

and DGND terminals of the device should be tied to the analog ground plane.

D VDDA to AGND and VDDD to DGND should be decoupled with 1-µF and 0.01-µF capacitors, respectively,

and placed as close as possible to the affected device terminals. A ceramic-chip capacitor is recommended

for the 0.01-

µF capacitor. Care should be exercised to ensure a solid noise-free ground connection for the

analog and digital ground terminals.

D VDDA, AGND, and ANALOG IN should be shielded from the higher frequency terminals, CLK and D0–D7.

When possible, AGND traces should be placed on both sides of the ANALOG IN traces on the PCB for

shielding.

D In testing or application of the device, the resistance of the driving source connected to the analog input

should be 10

Ω or less within the analog frequency range of interest.