FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
February 2007
FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
Features
■ Six 4th-order 8MHz (SD) filters ■ Drives single, AC- or DC-coupled, video loads (2Vpp, 150Ω) ■ Drives dual, AC- or DC-coupled, video loads (2Vpp, 75Ω) ■ Transparent input clamping ■ AC- or DC-coupled inputs ■ AC- or DC-coupled outputs ■ DC-coupled outputs eliminate AC-coupling capacitors ■ 5V only ■ Robust 8kV ESD protection ■ Lead-free TSSOP-14 package
Description
The FMS6146 Low-Cost Video Filter (LCVF) is intended to replace passive LC filters and drivers with a low-cost integrated device. Six 4th-order filters provide improved image quality compared to typical 2nd or 3rd-order passive solutions. The FMS6146 may be directly driven by a DC-coupled DAC output or an AC-coupled signal. Internal diode clamps and bias circuitry may be used if AC-coupled inputs are required (see Applications section for details). The outputs can drive AC- or DC-coupled single (150Ω) or dual (75Ω) loads. DC coupling the outputs removes the need for output coupling capacitors. The input DC levels are offset approximately +280mV at the output (see Applications section for details).
Applications
■ Cable set-top boxes ■ Satellite set-top boxes ■ DVD players ■ HDTV ■ Personal Video Recorders (PVR) ■ Video On Demand (VOD)
Functional Block Diagram
IN1
Transparent Clamp
6dB
OUT1
IN2
Transparent Clamp
6dB
OUT2
IN3
Transparent Clamp
6dB
OUT3
IN4
Transparent Clamp
6dB
OUT4
IN5
Transparent Clamp
6dB
OUT5
IN6
Transparent Clamp
6dB
OUT6
8MHz, 4th order
Ordering Information
Part Number
FMS6146MTC14 FMS6146MTC14X
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
Package
TSSOP-14 TSSOP-14
Pb-Free
Yes Yes
Operating Temperture Range
-40°C to +85°C -40°C to +85°C
Packaging Method
Tube Tape and Reel
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
Pin Configuration
IN1 IN2 IN3
1 2 3 4 5 6 7
14
OUT1 OUT2
FMS6146 14-pin TSSOP
13 12 11 10 9 8
OUT3 GND
VCC IN4 IN5 IN6
OUT4 OUT5 OUT6
Pin Assignments
Pin#
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Pin Name
IN1 IN2 IN3 VCC IN4 IN5 IN6 OUT6 OUT5 OUT4 GND OUT3 OUT2 OUT1
Type
Input Input Input Input Input Input Input Output Output Output Output Output Output Output Video input, Channel 1 Video input, Channel 2 Video input, Channel 3 +5V supply, do not float Video input, Channel 4 Video input, Channel 5 Video input, Channel 6 Filtered video output, Channel 6 Filtered video output, Channel 5 Filtered video output, Channel 4
Description
Must be tied to ground, do not float Filtered video output, Channel 3 Filtered video output, Channel 2 Filtered video output, Channel 1
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings are stress ratings only.
Parameter
DC Supply Voltage Analog and Digital I/O Output Channel - Any One Channel (Do Not Exceed)
Min.
-0.3 -0.3
Max.
6 VCC + 0.3 50
Unit
V V mA
Reliability Information
Symbol
TJ TSTG TL ΘJA
Parameter
Junction Temperature Storage Temperature Range Lead Temperature (Soldering, 10 seconds) Thermal Resistance, JEDEC Standard Multi-layer Test Boards, Still Air
Min.
-65
Typ.
Max.
150 +150 300
Unit
°C °C °C °C/W
90
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to absolute maximum ratings.
Parameter
Operating Temperature Range VCC Range
Min.
-40 +4.75
Typ.
+5.0
Max.
+85 +5.25
Unit
°C V
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
DC Electrical Characteristics
TA = 25°C, VCC = 5V, RSOURCE = 37.5Ω; all inputs are AC coupled with 0.1μF; all outputs are AC coupled with 220μF into 150Ω loads; unless otherwise noted.
Symbol
ICC VIN PSRR
Parameter
Supply Current(1) Video Input Voltage Range Power Supply Rejection
Conditions
FMS6146 (No Load) Referenced to GND if DC coupled DC (All Channels)
Min. Typ. Max. Units
35 1.4 -50 55 mA Vpp dB
Notes: 1. 100% tested at 25°C.
AC Electrical Characteristics
TA = 25°C, VIN = 1Vpp, VCC = 5V, RSOURCE = 37.5Ω; all inputs are AC coupled with 0.1μF; all outputs are AC coupled with 220μF into 150Ω loads; unless otherwise noted.
Symbol
AV f1dB fc fSB dG dφ THD XTALK SNR tpd
Parameter
Channel Gain(1) -1dB Bandwidth -3dB Bandwidth
(1)
Conditions
All Channels All Channels All Channels All Channels at f = 27MHz All Channels All Channels
Min. Typ. Max. Units
5.6 4.5 6.0 6.8 7.8 48 0.3 0.6 0.4 -60 75 59 6.6 dB MHz MHz dB % ° % dB dB ns
Attenuation (Stopband Reject) Differential Gain Differential Phase
Output Distortion (All Channels) VOUT = 1.8Vpp, 1MHz Crosstalk (Channel-to-Channel) at 1MHz Signal-to-Noise Ratio Propagation Delay All Channels NTC-7 Weighting: 100kHz to 4.2MHz Delay from Input-to-Output, 4.5MHz
Notes: 1. 100% tested at 25°C.
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
Typical Performance Characteristics
TA = 25°C, VCC = 5V, RSOURCE = 37.5Ω; all inputs AC coupled with 0.1μF; all outputs are AC coupled with 220μF into 150Ω loads; unless otherwise noted.
5 0 -5 -10 -15 -20 -25 -30 Mkr -35 Ref -40 1 -45 2 -50 3 -55 400kHz
2 1
40 30 20
1
Normalized Gain (dB)
Delay (ns)
10 0 -10 -20 -30 -40
Frequency 400kHz 6.83MHz 7.84MHz 27MHz
Gain 6dB -1dB BW -3dB BW -47.57dB 3
1 = 8.2MHz (16.02ns)
5
10
15
20
25
30
-50 400kHz
5
10
15
20
25
30
Frequency (MHz)
Frequency (MHz)
Figure 1. Frequency Response
-60 -70
Figure 2. Group Delay vs. Frequency
0.2 0.1
NTSC
Differential Gain (%)
-80
0 -0.1 -0.2 -0.3 -0.4 -0.5
Min = -0.24 Max = 0.02 ppMax = 0.26
Noise (dB)
-90 -100 -110 -120 -130 400kHz 1 2 3 4 5 6
1st
2nd
3rd
4th
5th
6th
Frequency (MHz)
Figure 3. Noise vs. Frequency
1.0
Figure 4. Differential Gain
NTSC
Differential Phase (deg)
0.8 0.6 0.4 0.2 0 -0.2 -0.4 1st 2nd 3rd 4th 5th 6th
Min = 0.00 Max = 0.64 ppMax = 0.64
Figure 5. Differential Phase
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
Typical Application Diagrams
The following circuit may be used for direct DC-coupled drive by DACs with an output voltage range of 0V to 1.4V. AC-coupled or DC-coupled outputs may be used with AC-coupled outputs, offering slightly lower power dissipation.
DVD Player or STB
0.1 uF 1.0 uF
+5V
1 ROUT 2 IN1 OUT1
14
75Ω
220uF
75Ω Video Cables 75Ω
R
13 GOUT IN2 OUT2
75Ω
220uF 75Ω
G
3 BOUT IN3
FMS6146 14L TSSOP
OUT3
12
75Ω
220uF 75Ω
B
Video SoC
YOUT
4 VCC GND
11
5 IN4 OUT4
10
75Ω
220uF
75Ω Video Cables 75Ω
Y
6 COUT IN5 OUT5
9
75Ω
220uF 75Ω
C
7 CVOUT IN6 OUT6
8
75Ω
220uF 75Ω
CV
DAC Load Resistors per SoC specs. AC-Coupling Caps are Optional.
Figure 6. Typical Application Diagram
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
Application Information
Application Circuits
The FMS6146 Low Cost Video Filter (LCVF) provides 6dB gain from input to output. In addition, the input is slightly offset to optimize the output driver performance. The offset is held to the minimum required value to decrease the standing DC current into the load. Typical voltage levels are shown in the diagram below:
1.0 -> 1.02V 0.65 -> 0.67V 0.3 -> 0.32V 0.0 -> 0.02V
0.65V
75Ω
Video Cables
LOAD2 (optional)
75Ω
YIN
Driver
YOUT
LOAD1
75Ω
Video Cables
75Ω
Figure 8. Input Clamp Circuit
I/O Configurations
VIN
For a DC-coupled DAC drive with DC-coupled outputs, use the configuration shown in Figure 9.
Driven by: DC-Coupled DAC Outputs AC-Coupled and Clamped Y, CV, R, G, B
0V - 1.4V
2.28V 1.58V 0.88V 0.28V VOUT
DVD or STB SoC DAC Output
LCVF Clamp Inactive
75Ω
There is a 280mV offset from the DC input level to the DC output level. VOUT = 2 * VIN + 280mV.
0.85V 0.5V 0.15V VIN Driven by: AC-Coupled and Biased U, V, Pb, Pr, C VOUT
Figure 9. DC-Coupled Inputs and Outputs Alternatively, if the DAC’s average DC output level causes the signal to exceed the range of 0V to 1.4V, it can be AC coupled as shown in Figure 10.
0V - 1.4V
1.98V 1.28V 0.58V
DVD or STB SoC DAC Output
0.1μ
LCVF Clamp Active
75Ω
Figure 7. Typical Voltage Levels The FMS6146 provides an internal diode clamp to support AC-coupled input signals. If the input signal does not go below ground, the input clamp does not operate. This allows DAC outputs to directly drive the FMS6146 without an AC coupling capacitor. When the input is AC coupled, the diode clamp sets the sync tip (or lowest voltage) just below ground. The worst-case sync tip compression due to the clamp cannot exceed 7mV. The input level set by the clamp, combined with the internal DC offset, keeps the output within its acceptable range. For symmetric signals like Chroma, U, V, Pb, and Pr, the average DC bias is fairly constant and the inputs can be AC coupled with the addition of a pull-up resistor to set the DC input voltage. DAC outputs can also drive these same signals without the AC coupling capacitor. A conceptual illustration of the input clamp circuit is shown in Figure 8. Figure 10. AC-Coupled Inputs, DC-Coupled Outputs When the FMS6146 is driven by an unknown external source or a SCART switch with its own clamping circuitry, the inputs should be AC coupled as shown in Figure 11.
0V - 1.4V
External video source must be AC-coupled
0.1μ
LCVF Clamp Active
75Ω
75Ω
Figure 11. SCART with DC-Coupled Outputs
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8 www.fairchildsemi.com 7
FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
The same method can be used for biased signals, with the addition of a pull-up resistor to make sure the clamp never operates. The internal pull-down resistance is 800kΩ ±20%, so the external resistance should be 7.5MΩ to set the DC level to 500mV as shown in Figure 12.
External video source must be AC-coupled
External video source must be AC-Coupled
0V - 1.4V 0.1μ
LCVF Clamp Active
75Ω
220μ
75Ω
0.1μ
7.5MΩ
LCVF Bias Input
75Ω
Figure 15. Biased SCART with AC-Coupled Outputs NOTE: The video tilt or line time distortion is dominated by the AC-coupling capacitor. The value may need to be increased beyond 220μF to obtain satisfactory operation in some applications.
75Ω
500mV +/-350mV
Figure 12. Biased SCART with DC-Coupled Outputs The same circuits can be used with AC-coupled outputs if desired.
0V - 1.4V
Power Dissipation
The FMS6146 output drive configuration must be considered when calculating overall power dissipation. Care must be taken not to exceed the maximum die junction temperature. The following example can be used to calculate the FMS6146’s power dissipation and internal temperature rise. Tj = TA + Pd • θJA where: Pd = PCH1 + PCH2 + PCH3 and PCHx = VCC • ICH - (VO /RL)
2
DVD or STB SoC DAC Output
0.1μ
LCVF Clamp Active
75Ω
220μ
EQ. 1 EQ. 2 EQ. 3 EQ. 4 EQ. 5
where: VO = 2VIN + 0.280V ICH = (ICC/3) + (VO/RL) Figure 13. DC-Coupled Inputs, AC-Coupled Outputs
0V - 1.4V
VIN = RMS value of input signal ICC = 35mA VCC = 5V RL = channel load resistance Board layout can also affect thermal characteristics. Refer to Layout Considerations for more information. The FMS6146 is specified to operate with output currents typically less than 50mA, more than sufficient for a dual (75Ω) video load. Internal amplifiers are current limited to a maximum of 100mA and should withstand brief-duration short-circuit conditions; this capability is not guaranteed.
DVD or STB SoC DAC Output
0.1μ
LCVF Clamp Active
75Ω
220μ
Figure 14. AC-Coupled Inputs and Outputs
Layout Considerations
General layout and supply bypassing play major roles in high-frequency performance and thermal characteristics. Fairchild offers a demonstration board, FMS6146DEMO, to guide layout and aid device testing and characterization. The FMS6146DEMO is a four-layer board with full power and ground planes. Following this layout configuration provides the optimum performance and thermal characteristics. For optimum results, follow the guidelines below as a basis for high-frequency layout:
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
■ Include 1μF and 0.1μF ceramic bypass capacitors. ■ Place the 1μF capacitor within 0.75 inches of the
power pin.
■ Place the 0.1μF capacitor within 0.1 inches of the
power pin.
■ For multi-layer boards, use a large ground plane to help
dissipate heat.
■ For two-layer boards, use a ground plane that extends
beyond the device by at least 0.5 inches.
■ Minimize all trace lengths to reduce series inductances.
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
Mechanical Dimensions
Dimensions are in millimeters unless otherwise noted.
Figure 16. TSSOP-14 Package
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
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FMS6146 Low-Cost Six-Channel 4th-Order Standard Definition Video Filter Driver
© 2006 Fairchild Semiconductor Corporation FMS6146 Rev. 1.0.8
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