MAX7438 Datasheet, PDF (8/10 Pages) Maxim Integrated Products – Triple-Channel Video Reconstruction Filters with Back-Porch Clamp to GND

Triple-Channel Video Reconstruction Filters with
Back-Porch Clamp to GND
Typical Operating Circuit
ENCODER
DAC3
R_T
V_CC
R_HFB2-1
DAC2
R_T
10kΩ
R_HFB2-2
V_CC
DAC1
EXT IN2
HFB2 IN3
R_HFB3-1
R_T
IN1
V_CC
R_HFB1-1
HFB3
R_HFB3-2
R_HFB1-2
HFB1
MAX7438
MAX7439
Z₀ = 75Ω
OUT1
75Ω
75Ω
V_CC
Z₀ = 75Ω
75Ω
75Ω
1µF
0.1µF
OUT2
OUT3
8
GND
V_SS
Z₀ = 75Ω
75Ω
75Ω
Z₀ = 75Ω
75Ω
75Ω
0.1µF
1µF
V_CC = +5V
V_SS = -5V
Z₀ = 75Ω
75Ω
75Ω
Z₀ = 75Ω
75Ω
75Ω
Microprocessor Control of High-Frequency
Boost and Bypass
Use a DAC output to control the bypass and high-fre-
quency boost levels on each channel (see Figure 2).
Set the DAC output voltage to the corresponding
bypass or boost levels desired (see Table 1).
MAX7438
MAX7439
DAC
HFB_
Figure 2. DAC Control of High-Frequency Boost and Bypass
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