ADV7181BST Analog Devices Inc, ADV7181BST Datasheet - Page 30

• Manufacturer Part Number: ADV7181BST
• Description: IC VIDEO DECODER SDTV 64-LQFP
• Manufacturer: Analog Devices Inc
• Type: Video Decoderr

Specifications of ADV7181BST

• Rohs Status: RoHS non-compliant
• Applications: Recorders, Set-Top Boxes
• Voltage - Supply, Analog: 3.15 V ~ 3.45 V
• Voltage - Supply, Digital: 1.65 V ~ 2 V
• Mounting Type: Surface Mount
• Package / Case: 64-LQFP
• Adc/dac Resolution: 9b
• Screening Level: Industrial
• Package Type: LQFP
• Pin Count: 64
• For Use With: EVAL-ADV7181BEB - BOARD EVALUATION FOR ADV7181
• Lead Free Status / RoHS Status: Compliant

ADV7181B
Table 32. AGC Modes
Input Video Type
Any
CVBS
Y/C
YPrPb
Luma Gain
LAGC[2:0] Luma Automatic Gain Control,
Address 0x2C[7:0]
The luma automatic gain control mode bits select the mode of
operation for the gain control in the luma path.
There are ADI internal parameters to customize the peak white
gain control. Contact ADI sales for more information.
Table 33. LAGC Function
LAGC[2:0]
000
001
010 (default)
011
100
101
110
111
LAGT[1:0] Luma Automatic Gain Timing,
Address 0x2F[7:6]
The luma automatic gain timing register allows the user to
influence the tracking speed of the luminance automatic gain
control. This register only has an effect if the LAGC[2:0]
register is set to 001, 010, 011, or 100 (automatic gain control
modes).
If peak white AGC is enabled and active (see the
STATUS_1[7:0] Address 0x10[7:0] section), the actual gain
update speed is dictated by the peak white AGC loop and, as a
result, the LAGT settings have no effect. As soon as the part
leaves peak white AGC, LAGT becomes relevant again.
The update speed for the peak white algorithm can be
customized by the use of internal parameters. Contact ADI
sales for more information.
Description
Manual fixed gain (use LMG[11:0])
AGC (blank level to sync tip); peak white
algorithm off
AGC (blank level to sync tip); peak white
algorithm on
Reserved
Reserved
Reserved
Reserved
Freeze gain
Luma Gain
Manual gain luma
Dependent on horizontal sync depth
Peak white
Dependent on horizontal sync depth
Peak white
Dependent on horizontal sync depth
Rev. B | Page 30 of 100
Table 34. LAGT Function
LAGT[1:0]
00
01
10
11 (default)
LG[11:0] Luma Gain, Address 0x2F[3:0];
Address 0x30[7:0]; LMG[11:0] Luma Manual Gain,
Address 0x2F[3:0]; Address 0x30[7:0]
Luma gain[11:0] is a dual-function register. If written to, a
desired manual luma gain can be programmed. This gain
becomes active if the LAGC[2:0] mode is switched to manual
fixed gain. Equation 1 shows how to calculate a desired gain.
If read back, this register returns the current gain value.
Depending on the setting in the LAGC[2:0] bits, one of these
gain values is returned:
•
•
Table 35. LG/LMG Function
LG[11:0]/LMG[11:0]
LMG[11:0] = X
LG[11:0]
Luma manual gain value (LAGC[2:0] set to luma manual
gain mode)
Luma automatic gain value (LAGC[2:0] set to any of the
automatic modes)
Luma
Chroma Gain
Manual gain chroma
Dependent on color burst amplitude;
taken from luma path
Dependent on color burst amplitude;
taken from luma path
Dependent on color burst amplitude;
taken from luma path
Dependent on color burst amplitude;
taken from luma path
Taken from luma path
_
Gain
=
(
0
Read/Write
Write
Read
<
Slow (TC = 2 sec)
Medium (TC = 1 sec)
Fast (TC = 0.2 sec)
Adaptive
Description
LG
2048
≤
4095
)
=
Description
Manual gain for luma
path
Actually used gain
0
...
2
(1)