sm5309a Nippon Precision Circuits Inc, (NPC), sm5309a Datasheet - Page 16

• Manufacturer Part Number: sm5309a
• Description: 3-channel Video Buffer With Built-in Wideband Lpf
• Manufacturer: Nippon Precision Circuits Inc, (NPC)

R
R
1.8kΩ. In power-down mode and filter bypass mode, no current flows into R
Note. A value other than 1.8kΩ will change the current consumption of SM5309A. In the determination of
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 component signals.
Group Delay Characteristics
The group delay varies with the cutoff frequency setting. Note also that in half fc mode, the group delay
between CH-1 and CH-2/CH-3 varies.
Filter Bypass Mode
In filter bypass mode, the internal lowpass filter in SM5309A is bypassed and the signal is input to the output
buffer stage directly. In filter bypass mode, the input type and multiplexer function are set just as for filter
mode. But the cutoff frequency setting and fc mode setting have no effect on the outputs. In this mode, the
passband frequency is 80MHz (typ), which can support SXGA-class signals.
Input Multiplexer Switching (MUXSEL)
The input multiplexer setting can also be set using the MUXSEL input. When set using the I
amount of communication time is required, but the setting can be made using the MUXSEL input with arbi-
trary timing for high-speed switching. The input circuit of MUXSEL pin is placed in analog supply (VCC,
GND) area.
*1. n = 1, 2, 3
ISET
ISET
MUXSEL pin
resistance value, caution should be taken to ensure the power dissipation does not exceed the absolute
maximum rating for the package.
controls the internal current source, and its connection is essential. The recommended value (R
L: GND
L: GND
H: VCC
H: VCC
50
45
40
35
30
25
20
15
10
Figure 1. Cutoff frequency vs. FCDATA (R
5
0
MUX flag
0
H
H
L
L
32
64
Multiplexer selection
96
SM5309A
INnA
INnB
INnB
INnB
FCDATA
128
*1
160
ISET
192
= 1.8kΩ)
ISET
224
SEIKO NPC CORPORATION —16
.
256
2
C-BUS, a certain
ISET
) is