AD9887AKS-140 Analog Devices Inc, AD9887AKS-140 Datasheet - Page 12

• Manufacturer Part Number: AD9887AKS-140
• Description: IC INTRFACE ANALOG/DVI 160-MQFP
• Manufacturer: Analog Devices Inc

Specifications of AD9887AKS-140

• Rohs Status: RoHS non-compliant
• Applications: Graphic Cards, VGA Interfaces
• Interface: Analog and Digital
• Voltage - Supply: 3.15 V ~ 3.45 V
• Package / Case: 160-MQFP, 160-PQFP
• Mounting Type: Surface Mount

AD9887
Power Management
The AD9887 is a dual interface device with shared outputs.
Only one interface can be used at a time. For this reason, the
chip automatically powers down the unused interface. When
the analog interface is being used, most of the digital interface
circuitry is powered down and vice-versa. This helps to minimize
the AD9887 total power dissipation. In addition, if neither inter-
face has activity on it, the chip powers down both interfaces.
The AD9887 uses the activity detect circuits, the active inter-
face bits in the serial registers, the active interface override bits,
AIO
1
0
Mode
Soft Power-Down (Seek Mode)
Digital Interface On
Analog Interface On
Serial Bus Arbitrated Interface
Serial Bus Arbitrated Interface
Override to Analog Interface
Override to Digital Interface
Absolute Power-Down
NOTES
1
2
3
Power-down is controlled via bit 0 in serial bus Register 12h.
Analog Interface Detect is determined by OR-ing Bits 7, 6, and 5 in serial bus Register 11h.
Digital Interface Detect is determined by Bit 4 in serial bus Register 11h.
Analog
Interface Detect
X
0
0
1
1
Digital
Interface Detect
X
0
1
0
0
Power-
Down
1
1
1
1
1
1
1
0
1
Analog
Interface Interface
Detect
0
0
1
1
1
X
X
X
Table IV. Power-Down Mode Descriptions
Table III. Interface Selection Controls
2
AIS
0
1
X
X
X
X
1
Digital
Detect
0
1
0
1
1
X
X
X
Inputs
Active
Interface
Analog
Digital
None
Digital
Analog
Analog
Digital
3
0
0
Active
Interface Interface
Override Select
0
0
0
1
1
X
and the power-down bit to determine the correct power state.
In a given power mode not all circuitry in the inactive interface
is powered down completely. When the digital interface is
active, the bandgap reference and HSYNC detect circuitry is not
powered down. When the analog interface is active, the digital
interface clock detect circuit is not powered down. Table IV
summarizes how the AD9887 determines which power mode to
be in and what circuitry is powered on/off in each of these
modes. The power-down command has priority, followed by the
active interface override, and then the automatic circuitry.
Description
Force the analog interface active.
Force the digital interface active.
Neither interface was detected. Both interfaces are
powered down and the SyncDT pin gets set to Logic 0.
The digital interface was detected. Power down the
analog interface.
The analog interface was detected. Power down the
digital interface.
Both interfaces were detected. The analog interface has
priority.
Both interfaces were detected. The digital interface has
priority.
Active
X
X
X
0
1
0
1
X
Powered On or Comments
Serial Bus, Digital Interface Clock Detect,
Analog Interface Activity Detect, SOG,
Bandgap Reference
Serial Bus, Digital Interface, Analog Interface
Activity Detect, SOG, Outputs, Bandgap
Reference
Serial Bus, Analog Interface, Digital Interface
Clock Detect, SOG, Outputs, Bandgap
Reference
Same as Analog Interface On Mode
Same as Digital Interface On Mode
Same as Analog Interface On Mode
Same as Digital Interface On Mode
Serial Bus