AD9980KSTZ-80 Analog Devices Inc, AD9980KSTZ-80 Datasheet - Page 18

• Manufacturer Part Number: AD9980KSTZ-80
• Description: IC,Data Acquisition Signal Conditioner,3-CHANNEL,8-BIT,CMOS,QFP,80PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of AD9980KSTZ-80

• Applications: Video
• Interface: Analog
• Voltage - Supply: 3.13 V ~ 3.47 V
• Package / Case: 80-LQFP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: AD9980/PCBZ - KIT EVALUATION AD9980
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9980
Power Management
To meet display requirements for low standby power, the
AD9980 includes a power-down mode. The power-down state
can be controlled manually (with Pin 17 or Register 0x1E, Bit 3),
or completely automatically by the chip. If automatic control is
selected (0x1E, Bit 4), the AD9980’s decision is based on the
status of the sync detect bits (Register 0x24, Bits 2, 3, 6,
and 7). If either an Hsync or a sync-on-green input is detected
on any input, the chip powers up, otherwise it powers down. If
manual control is desired, the AD9980 includes the flexibility of
control with both a dedicated pin and a register bit. The dedi-
cated 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
Table 10.Power-Down Control and Mode Descriptions
Mode
Power-Up
Power-Down
Power-Up
Power-Down
1
2
3
QUADRANT
VSYNCOUT
Auto power-down control is set by Register 0x1E, Bit 4.
Power-down is controlled by OR’ing Pin 17 with Register 0x1E, Bit 3. The polarity of Pin 17 is set by Register 0x1E, Bit 2.
Sync detect is determined by OR’ing Register 0x24, Bits 2, 3, 6, and 7.
O/E FIELD
HSYNCIN
VSYNCIN
2
FIELD 1
SYNC SEPARATOR THRESHOLD
Figure 12. Vsync Filter—Odd/Even
3
Auto Power-Down
Control
1
1
0
0
4
FIELD 0
1
EVEN FIELD
1
2
FIELD 1
3
Power-Down
X
X
0
1
4
FIELD 0
Inputs
1
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2
the power-down pin must be set (0x1E, Bit 2) regardless of
whether the pin is used. If unused, it is recommended to set the
polarity to active high and hardwire the pin to ground with a
10 kΩ resistor.
In power-down mode, there are several circuits that continue to
operate normally. The serial register and sync detect circuits
maintain power so that the AD9980 can be woken up from
its power-down state. The bandgap circuit maintains power
because it is needed for sync detection. The sync-on-green and
SOGOUT functions continue to operate because the SOGOUT
output is needed when sync detection is performed by a
secondary chip. All of these circuits require minimal power to
operate. Typical standby power on the AD9980 is about 50 mW.
There are two options that can be selected when in power-
down. These are controlled by Bits 0 and 1 in Register 0x1E. The
first is to determine whether the SOGOUT pin is put in high
impedance or not. In most cases, SOGOUT is not put in high
impedance during normal operation. The option to put
SOGOUT in high impedance is included mainly to allow for
factory testing modes. The second option is to keep the AD9980
powered up 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.
Sync Detect
1
0
X
X
3
Powered-On or Comments
Everything
Only the serial bus, sync activity detect,
SOG, bandgap reference
Everything
Only the serial bus, sync activity detect,
SOG, bandgap reference
Preliminary Technical Data