GC1012A Datasheet, PDF (26/30 Pages) Texas Instruments – DIGITAL TUNER CHIP

GC1012A DIGITAL TUNER
DATA SHEET REV 0.1
5.0 APPLICATION NOTES
5.1 POWER AND GROUND CONNECTIONS
The GC1012A chip is a very high performance chip which requires solid power and ground
connections to avoid noise on the V_CC and GND pins. If possible the GC1012A chip should be mounted on
a circuit board with dedicated power and ground planes and with at least two decoupling capacitors (0.01
and 0.1 mf) adjacent to each GC1012A chip. If dedicated power and ground planes are not possible, then
the user should place decoupling capacitors adjacent to each V_CC and GND pair.
IMPORTANT
The GC1012A chip may not operate properly if these power and ground guidelines are violated.
5.2 STATIC SENSITIVE DEVICE
The GC1012A chip is fabricated in a high performance CMOS process which is sensitive to the high
voltage transients caused by static electricity. These parts can be permanently damaged by static electricity
and should only be handled in static free environments.
5.3 80 MHZ OPERATION
Care must be taken in generating the clock when operating the GC1012A chip at its full 80 MHz
clock rate. The user must insure that the clock is above 2 volts for at least 5 nanoseconds and is below 1
volt for at least 5 nanoseconds. At 80 MHz the clock period is only 12.5 nanoseconds so that the clock must
have a duty cycle of exactly 50%, and the rise and fall times can only be 1.25 nanoseconds each. One must
also be careful to prevent clock undershoot below ground. An ideal clock at 80 MHz would be a square wave
with a low voltage of 0.5 volts and a high voltage of 2.5 volts.
5.4 REDUCED VOLTAGE OPERATION
The power consumed by the GC1012A chip can be greatly reduced by operating the chip at the
lowest V_CC voltage which will meet the applicationÕs timing requirements. When operating at a reduced
voltage, GRAYCHIP recommends driving the GC1012A chip inputs with 5 volt to 3 volt interface chips.
GRAYCHIP,INC.
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FEBRUARY 18, 1998
This document contains information which may be changed at any time without notice