sm5302a Nippon Precision Circuits Inc, (NPC), sm5302a Datasheet - Page 18

• Manufacturer Part Number: sm5302a
• Description: 3-channel Video Buffer With Built-in Wideband Lpf
• Manufacturer: Nippon Precision Circuits Inc, (NPC)

R
R
In disable mode and filter bypass mode, the ISET pin is high impedance, and no current flows into R
Note. A value other than 1.8kΩ will change the current consumption, so caution should be taken to ensure the
Half fc Mode
In half fc mode, the CH-2 and CH-3 cutoff frequency is 1/2 that of the CH-1 cutoff frequency setting. Half fc
mode is useful for systems where the sampling frequency varies due to luminance (Y) and color difference sig-
nal (Cr, Cb) requirements as in digital component signals. Note in figure 2 that the cutoff frequency ratio for a
given cutoff frequency setting (FCDATA) is not constant.
Group Delay Characteristics
The group delay varies with the cutoff frequency setting, as shown in figure 3. Note also that in half fc mode,
the group delay between CH-1 and CH-2/CH-3 varies.
ISET
ISET
* Ratio of CH-2 and CH-3 cutoff frequency at half fc mode based on
Figure 2. Cutoff frequency ratio (half fc mode)
CH-1 cutoff frequency.
power dissipation does not exceed the absolute maximum rating for the package.
60%
58%
56%
54%
52%
50%
48%
46%
44%
42%
40%
controls the internal current source, and its connection is essential. The recommended value is 1.8kΩ.
0
HALF = High
R
ISET
32
= 1.8kΩ
64
96 128
FCDATA
Figure 1. Cutoff frequency vs. FCDATA (R
160 192 224 256
50
45
40
35
30
25
20
15
10
5
0
0
32
64
SM5302A
96
FCDATA
128 160 192 224 256
Figure 3. Group delay characteristics
100
90
80
70
60
50
40
30
20
10
0
ISET
0
= 1.8kΩ)
10
FCDATA = 10
SEIKO NPC CORPORATION —18
20
Frequency [MHz]
30
FCDATA = 227
40
50
60
ISET
.