TLC5510, TLC5510A
8-BIT HIGH-SPEED ANALOG-TO-DIGITAL CONVERTERS
SLAS095K – SEPTEMBER 1994 – REVISED MAY 1999
PRINCIPLES OF OPERATION
functional operation
The output code change with input voltage is shown in Table 1.
Table 1. Functional Operation
INPUT SIGNAL
VOLTAGE
Vref(B)
•
•
•
•
•
•
STEP
255
•
•
DIGITAL OUTPUT CODE
MSB
0
•
•
LSB
0
•
•
0
•
•
0
•
•
0
•
•
0
•
•
0
•
•
0
•
•
128
127
•
•
0
1
•
•
1
0
•
•
1
0
•
•
1
0
•
•
1
0
•
•
1
0
•
•
1
0
•
•
1
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
D
D
D
D
D
External analog and digital circuitry should be physically separated and shielded as much as possible to
reduce system noise.
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.
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.
V
DDA
to AGND and V
DDD
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.
V
DDA
, 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.
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.
8
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•
DALLAS, TEXAS 75265
TI [ TEXAS INSTRUMENTS ]
