AD9983A/PCBZ Analog Devices Inc, AD9983A/PCBZ Datasheet - Page 34

• Manufacturer Part Number: AD9983A/PCBZ
• Description: Pb-free EVALUATION Kit AD9983A
• Manufacturer: Analog Devices Inc
• Series: Advantiv®r

Specifications of AD9983A/PCBZ

• Main Purpose: Video, Video Processing
• Embedded: No
• Utilized Ic / Part: AD9983A
• Primary Attributes: 3 x 8-Bit 140 MSPS ADC's
• Secondary Attributes: Integrated PLL & VCO
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9983A
INPUT AND POWER CONTROL
0x1E—Bit[7] Channel Select Override
This bit provides an override to the automatic input channel
selection. Power-up default setting is 0.
Table 43. Channel Source Override
Override
0
1
0x1E—Bit[6] Channel Select
This bit selects the active input channel if Register 0x1E, Bit 7 = 1.
This selects between Channel 0 data and syncs or Channel 1
data and syncs. Power-up default setting is 0.
Table 44. Channel Select
Channel Select
0
1
0x1E—Bit[5] Programmable Bandwidth
This bit selects between a low or high input bandwidth. It is
useful in limiting noise for lower frequency inputs. The power-
up default setting is 1. Low analog input bandwidth is ~100 MHz;
high analog input bandwidth is ~200 MHz.
Table 45. Input Bandwidth Select.
Input Bandwidth
0
1
0x1E—Bit[4] Power-Down Control Select
This bit determines whether power-down is controlled
manually or automatically by the chip. If automatic control is
selected (Register 0x1E, Bit 4), the AD9983A decision is based
on the status of the sync detect bits (Register 0x24, Bit 2, Bit 3,
Bit 6, and Bit 7). If either an Hsync or a sync-on-green input is
detected on any input, the chip powers up or powers down. For
manual control, the AD9983A allows the flexibility of control
through both a dedicated pin and a register bit. The dedicated
pin allows a hardware watchdog circuit to control power-down,
while the register bit allows power-down to be controlled by
software. With manual power-down control, the polarity of the
power-down pin must be set (Register 0x1E, Bit 2) whether it is
used or not. If unused, it is recommended to set the polarity to
active high and hardwire the pin to ground with a 10 kΩ resistor.
Table 46. Auto Power-Down Select.
Power-Down Select
0
1
Result
Channel 0 data and syncs are selected
Channel 1 data and syncs are selected
Result
Channel input source determined by chip
Channel input source determined by user
Register 0x1E, Bit 6
Result
Low analog input bandwidth
High analog input bandwidth
Result
Manual power-down control
(user determines power-down)
Auto power-down control
(chip determines power-down)
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0x1E—Bit[3] Power-Down
This bit is used to manually place the chip in power-down
mode. It is only used if manual power-down control is selected
(see Bit 4 above). 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.)
Table 47. Power-Down Settings
Power-Down Select
0
1
0x1E—Bit[2] Power-Down Pin Polarity
This bit defines the polarity of the power-down pin (Pin 17). It
is only used if manual power-down control is selected (see
0x1E—Bit[4] Power-Down Control Select).
Table 48. Power-Down Pin Polarity
Select
0
1
0x1E—Bit[1] Power-Down Fast Switching Control
This bit controls a special fast switching mode. With this bit the
AD9983A 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.
Table 49. Power-Down Fast Switching Control
Fast Switching Control
0
1
0x1E—Bit[0] SOGOUT High Impedance Control
This bit controls whether the SOGOUT pin is in high
impedance or not, when in power-down mode. In most cases,
SOGOUT is not put in high impedance during normal oper-
ation. 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.
Table 50. SOGOUT High Impedance Control
SOGOUT Control
0
1
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
SOGOUT operates as normal during
power-down
SOGOUT is in high impedance
during power-down
Result
Normal operation
Power-down