AD9980/PCB Analog Devices Inc, AD9980/PCB Datasheet - Page 34

• Manufacturer Part Number: AD9980/PCB
• Description: BOARD EVAL 8BIT 95MSPS 80LQFP
• Manufacturer: Analog Devices Inc

Specifications of AD9980/PCB

• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD9980
Table 44. Auto Power-Down Select
Power-Down Select
0
1
0x1E
Table 45. Power-Down Settings
Power-Down Select
0
1
0x1E
This bit defines the polarity of the power-down pin (Pin 17). It
is only used if manual power-down control is selected (see Bit 4
above).
Table 46. Power-Down Pin Polarity
Select
0
1
0x1E
Table 47. Power-Down Fast Switching Control
Fast
Switching Control
0
1
0x1E
power-down to be controlled by software. With
manual power-down control, the polarity of the
power-down pin must be set (0x1E, Bit 2) whether it is
used or not. If unused, it is recommended to set the
polarity to active high and to hardwire the pin to
ground with a 10 kΩ resistor.
3
This bit is used to manually put the chip in power-
down mode. It is used only if manual power-down
control is selected (see Bit 4 of the power-down
register). Both the state of this register bit and the
power-down pin (Pin 17) are used to control manual
power-down (see the Power Management section for
more details on power-down.).
2
1
This bit controls a special fast switching mode. With
this bit, the AD9980 can stay active during power-
down and only put the outputs in high impedance.
This option is useful when the data outputs from two
chips are connected on a PCB and the user wants to
switch instantaneously between the two.
0
This bit controls whether the SOGOUT output pin is
in high impedance or not when in power-down mode.
Power-Down
Power-Down Polarity
Power-Down Fast Switching Control
SOGOUT High Impedance Control
Result
Manual power-down control
User determines power-down
Auto power-down control
Chip determines power-down
Pin 17
0
X
Result
Power-down pin is active low
Power-down pin is active high
Result
Normal power-down operation
The chip stays powered-up and the
outputs are put in high impedance
mode
Result
Normal operation
Power-down
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Table 48. SOGOUT High Impedance Control
SOGOUT
Control
0
1
OUTPUT CONTROL
0x1F
Table 49. Output Mode
Output Mode
00
01
10
0x1F
Table 50. Primary Output Enable
Select
0
1
0x1F
Table 51. Secondary Output Enable
Select
0
1
In most cases, SOGOUT is not put in high impedance
during normal operation. It is usually needed for sync
detection by the graphics controller. The option to put
SOGOUT in high impedance is included mainly to
allow for factory testing modes.
6:5
These bits choose between three options for the
output mode. In 4:4:4 mode RGB is standard, in 4:2:2
mode YCbCr is standard, which allows a reduction in
the number of output pins from 24 to 16. In 4:4:4
DDR output mode, the data is in RGB mode but
changes on every clock edge. The power-up default
setting is 00.
4
This bit places the primary output in active or high
impedance mode. The power-up default setting is 1.
3
This bit places the secondary output in active or high
impedance mode.
The secondary output is designated when using either
4:2:2 or 4:4:4 DDR. In these modes, the data on the
blue output channel is the secondary output while the
output data on the red and green channels are the
primary output. Secondary output is always a YCbCr
DDR data mode. See the Output Formatter section
and Table 11. The power-up default setting is 0.
Result
The SOGOUT output operates as normal
during power-down.
The SOGOUT output is in high impedance
during power-down.
Result
4:4:4 RGB mode
4:2:2 YCbCr mode
4:4:4 DDR mode
Result
Primary output is in high impedance mode
Primary output is enabled
Result
Secondary output is in high impedance mode
Secondary output is enabled
Output Mode
Primary Output Enable
Secondary Output Enable
Preliminary Technical Data