adc12d800rfrb National Semiconductor Corporation, adc12d800rfrb Datasheet - Page 50

• Manufacturer Part Number: adc12d800rfrb
• Description: 12-bit, 1.6/1.0 Gsps Rf Sampling Adc
• Manufacturer: National Semiconductor Corporation

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17.6.2 Power-on and Data Clock (DCLK)
Many applications use the DCLK output for a system clock.
For the ADC12D800/500RF, each I- and Q-channel has its
own DCLKI and DCLKQ, respectively. The DCLK output is
always active, unless that channel is powered-down or the
DCLK Reset feature is used while the device is in Demux
Mode. As the supply to the ADC12D800/500RF ramps, the
DCLK also comes up, see this example from the AD-
C12D800RFRB:
is no output at DCLK. As the supply continues to ramp, DCLK
functions intermittently with irregular frequency, but the am-
Figure
25. While the supply is too low, there
FIGURE 24. Power-on with Control Pins set by FPGA post Power-on Cal
FIGURE 23. Power-on with Control Pins set by FPGA pre Power-on Cal
FIGURE 22. Power-on with Control Pins set by Pull-up/down Resistors
50
plitude continues to track with the supply. Much below the low
end of operating supply range of the ADC12D800/500RF, the
DCLK is already fully operational.
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