ADV7188BSTZ Analog Devices Inc, ADV7188BSTZ Datasheet - Page 36

• Manufacturer Part Number: ADV7188BSTZ
• Description: IC DECODER VID MULTIFORM 80LQFP
• Manufacturer: Analog Devices Inc
• Type: Video Decoderr

Specifications of ADV7188BSTZ

• Applications: Set-Top Boxes, Video Players, Recorders
• Voltage - Supply, Analog: 3.15 V ~ 3.45 V
• Voltage - Supply, Digital: 1.65 V ~ 2 V
• Mounting Type: Surface Mount
• Package / Case: 80-LQFP
• Resolution (bits): 12bit
• Input Format: Analog
• Output Format: Digital
• Adc Sample Rate: 54MSPS
• No. Of Input Channels: 12
• Supply Voltage Range: 3V To 3.6V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant

ADV7188
Luma Gain
LAGC [2:0], Luma Automatic Gain Control,
Address 0x2C [6:4]
The luma automatic gain control mode bits select the mode of
operation for the gain control in the luma path.
Analog Devices internal parameters can be used to customize the
peak white gain control. Contact an Analog Devices representative
for more information.
Table 40. LAGC [2:0] 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 bits allow the user to influence
the tracking speed of the luminance automatic gain control.
Note that these bits only have an effect if the LAGC [2:0] bits are
set to 010 or 100 (automatic gain control modes).
If peak white AGC is enabled and active (see the Status Register 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.
The update speed for the peak white algorithm can be customized
by using internal parameters. Contact an Analog Devices
representative for more information.
Table 41. LAGT [1:0] Function
LAGT [1:0]
00
01
10
11 (default)
Description
Manual fixed gain (use LMG [11:0])
Reserved
AGC peak white algorithm enabled
(blank level to sync tip)
Reserved
AGC peak white algorithm disabled
(blank level to sync tip)
Reserved
Reserved
Freeze gain
Description
Slow (TC = 2 sec)
Medium (TC = 1 sec)
Fast (TC = 0.2 sec)
Adaptive
Rev. A | Page 36 of 112
LMG [11:0]/LG [11:0], Luma Manual Gain/Luma Gain,
Address 0x2F [3:0], Address 0x30 [7:0]
Luma manual gain [11:0] are dual-function bits. If these bits are
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 2 and Equation 3 show how to
calculate a desired gain for NTSC and PAL standards,
respectively.
If read back, this register returns the current gain value.
Depending on the settings of the LAGC [2:0] bits, this value is
one of the following:
•
•
Table 42. LG [11:0]/LMG [11:0] Function
LG [11:0]/LMG [11:0]
LMG [11:0] = X
LG [11:0]
For example, to program the ADV7188 into manual fixed gain
mode with a desired gain of 0.89 for the NTSC standard:
1.
2.
3.
4.
5.
NTSC Luma_Gain =
PAL Luma_Gain =
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)
Use Equation 2 to convert the gain:
0.95 × 1128 = 1071.6
Truncate to integer value:
1071.6 = 1071
Convert to hexadecimal:
1071d = 0x42F
Split into two registers and program:
Luma Gain Control 1 [3:0] = 0x4
Luma Gain Control 2 [7:0] = 0x2F
Enable manual fixed gain mode:
Set LAGC [2:0] to 000
1024
1024
<
<
LMG
LMG
1222
1128
[
[
11
11
Read/Write
Write
Read
:
:
] 0
] 0
≤
≤
4095
4095
=
=
Description
Manual gain for luma path
Actual gain used
. 0
. 0
838
9078
K
K
. 3
. 3
351
63
(2)
(3)