TLC5502-5M Datasheet, PDF (9/11 Pages) Texas Instruments – 8-BIT ANALOG-TO-DIGITAL CONVERTER

TLC5502Ć5M
8ĆBIT ANALOGĆTOĆDIGITAL CONVERTER
SGLS067 − MARCH 1992
APPLICATION INFORMATION
The following design recommendations will benefit the TLC5502-5M user:
1. External analog and digital circuitry should be physically separated and shielded as much as possible to
reduce system noise.
2. RF breadboarding or PCB techniques should be used throughout the evaluation and production process.
Breadboards should be copper clad for bench evaluation.
3. Since the ANLG GND, DGTL GND1, and DGTL GND2 are not connected internally, these pins need to be
connected externally. With breadboards, these ground lines should be connected through separate leads
with proper supply bypassing. A good method to use is a separate twisted-pair cable for the supply lines
to minimize noise pickup. An analog and digital ground plane should be used on PCB layouts.
4. Since the ANLG V_DD, DGTL V_DD1, and DGTL V_DD2 are not connected internally, these pins also need to
be connected externally. To connect ANLG V_DD, DGTL V_DD1, and DGTL V_DD2, a 50-Ω resistor should be
placed in series with DGTL V_DD1 and then a 0.1-µF capacitor to ground before being connected to
ANLG V_DD and DGTL V_DD2.
5. ANLG V_DD to ANLG GND, DGTL V_DD1 to DGTL GND1, and DGTL V_DD2 to DGTL GND2 should be
decoupled with 1-µF and 0.01-µF capacitors, respectively, as close as possible to the appropriate device
pins. A ceramic-chip capacitor is recommended for the 0.01-µF capacitor. Care should be exercised to
assure a solid noise free ground connection for the analog and digital grounds.
6. The no connection (NC) pins on the J package should be connected to ground.
7. ANLG V_DD, ANLG GND, and ANLG INPUT should be shielded from the higher-frequency pins, CLK and
D0−D7. If possible, ANLG GND traces should be placed on both sides of the ANLG INPUT traces on the
PCB.
8. 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.
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