HD49335F Renesas Electronics Corporation., HD49335F Datasheet - Page 21

• Manufacturer Part Number: HD49335F
• Description: Cds/pga And 10-bit A/d Tg Converter
• Manufacturer: Renesas Electronics Corporation.

HD49335F/HF
Ripple (pseudo outline made by quantized error) occurres on the point which swithing the ADC output multiple bit in
parallel. When switching the several of ADC output at the same time, ripple (pseudo outline caused by miss
quantization) occurs to the image.
Differential code and gray code are recommended for this countermeasure.
Figure 10 indicates circuit block. When luminance signal changes are smoothly, the number of bit of switching digital
output bit can be reduced and easily to reduce the ripple using this function.
This function is especially effective for longer the settings of sensor more than clk = 30 kHz, and ADC output.
Figure 11 indicates the timing specifications.
To use differential code, complex circuit is necessary at DSP side.
Rev.1.0, Feb.25.2004, page 21 of 29
1
1
ADCLK
OBP
Digital output
1
1
1
1
Standard data
control signal
(D12,D11,D10)
From ADC
(In case of select the positive polar)
ADC
Address
Address
1
1
Standard data
control signal
10
0
1
Differential SW(D9)
1
0
0
0
Differential data
Figure 11 Differential Code Timing Specifications
(1) Differential coded
Figure 10 Differential Code, Gray Code Circuit
Gray
Binary
2clk_DL
1
0
Figure 12 Complex Circuit Example
D7 D6 D5
P_RG
(In case of select the positive edge of ADCLK with D12)
Carry bit
round
D6 D5
Carry bit
round
(Beginning edge of OBP and standard edge of ADCLK should be exept ±5 ns)
+
P_SP2
1
P_ADCLK
STD1[7:0] (L)
STD1[7:0] (L)
2clk_DL
D4 D3 D2
2
D4
Standard
data
selector
Standard
Standard
data
selector
P_SP2
3
data
D2
4
P_SP1
D1 D0
D1 D0
P_SP1
5
Gray SW(D8)
(2) Gray
2,3 divided
select
6
D15 D14 D13
Differential data
D11
D10
D9
D0
Gray Binary
conversion
7
Binary conversion
P_RG
8
STD2[15:8] (H)
STD2[15:8] (H)
current
D12 D11 D10 D9 D8
D12
DLL
9
D11
D10
D9
D0
10-bit
output
10
D10
steps
P_ADCLK
DLL
11
D9 D8