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MIC1700
Micrel
MIC1700
HDTV/SDTV 6th Order Video Filter for Component Video plus Composite Video
General Description
The MIC1700 is a complete reconstruction filter solution for high definition set-top boxes. The device has two independent component inputs (YPRPB or RGB) selectable via a 2-to-1 multiplexer, and a separate Svideo input (Y/C). Component channel filters have a selectable cutoff frequency (8MHz or 36MHz) to support both standard (SD) and high definition (HD) applications. S-video filters have fixed cutoff (8MHz) to support legacy composite applications. In addition, S-video channels are summed to provide a filtered CV output for an RF modulator or VCR. All inputs are DC-coupled with a 0V to 1V peak-to-peak range. All outputs are designed to drive 2V peak-to-peak into AC-coupled 150 loads. This supports 1V peak-to-peak into a 75 load with a 75 series source terminator. Filters have 6th order near Butterworth characteristics with cutoffs of 8MHz (SD and CV) and 36MHz (HD). These characteristics are chosen to provide good passband flatness with sufficient stop band attenuation and minimal group delay distortion. The device operates from a 5VDC supply. Data sheets and support documentation are available at Micrel's web site, www.micrel.com.
Features
* * * * * * * * * * * S-video (Y/C) input, S-video and summed (CV) output 2 YPRPB or RGB inputs, YPRPB or RGB output YPRPB/RGB 2-1 input multiplexer DC coupled inputs - AC-coupled output drive 6db output gain for 75 source termination Component filters selectable for SD or HD cutoffs 6th order Butterworth characteristic Flat passband (HD 0.5dB @ 30MHz typ) Low group delay distortion (HD: 12ns @ 30MHz typ) Single 5V supply 28-pin wide body SOIC package (with exposed pad for improved thermal performance) HDTV HDTV set-top boxes Video games HDTV systems DVD players Digital satellite set-top boxes HDTV monitors
Applications
* * * * * * *
Ordering Information
Part Number MIC1700BWME Junction Temp. Range 0C to +70C Package SOIC-28
Typical Application
MIC1700x-x HSEL Y1A Y1B PR1 PR2
1 2 3 4 5 6
HSEL Y1A Y1B PR1
VCC VCC Y1OUT PROUT
28 27 26
VCC 4.7F 220F 220F 220F 0.1F 75 75 75 75 75 75 220F 220F 220F 75 YOUT 75 75 COUT 75 75 75 VCC CVOUT Y1OUT PROUT PBOUT
25
PR2 GND PB1 PB2 YIN CIN GND MUX CVOUT GND VCC GND
20 19 18 17
PBOUT GND YOUT COUT
24 23 22
PB1 PB2 Composite Inputs YIN CIN
7 8 9 10 11
21
MUX
12
Micrel, Inc. * 1849 Fortune Drive * San Jose, CA 95131 * USA * tel + 1 (408) 944-0800 * fax + 1 (408) 944-0970 * http://www.micrel.com
October 2003
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MIC1700
MIC1700
Micrel
Pin Configuration
HSEL 1 Y1A 2 Y1B 3 PR1 4 PR2 5 GND 6 PB1 7 PB2 8 YIN 9 CIN 10 GND 11 MUX 12 NC 13 NC 14 28 VCC 27 VCC 26 Y1OUT 25 PROUT 24 PBOUT 23 GND 22 YOUT 21 COUT 20 CVOUT 19 GND 18 VCC 17 GND 16 NC 15 NC
28-Pin Wide Body SOIC (WM)
Pin Description
Pin Number 1 2 3 4 5 6, 11, 17, 19, 23 7 8 9 10 12 13, 14, 15, 16 18, 27, 28 20 21 22 24 25 26 Pin Name HSEL Y1A Y1B PR1 PR2 GND PB1 PB2 YIN CIN MUX NC VCC CVOUT COUT YOUT PBOUT PROUT Y1OUT Pin Function Digital (Input): selects for the HD or SD filtering. A high selects HD filters. Y (Input): component channel 1, selected when the MUX is high. 0V to 1V range. Y (Input): component channel 2, selected when the MUX is low. 0V to 1V range. PR (Input): component channel 1, selected when the MUX is high. 0V to 1V range. PR (Input): component channel 2, selected when the MUX is low. 0V to 1V range. Ground. PB (Input): component channel 1, selected when the MUX is high. 0V to 1V range. PB (Input): component channel 2, selected when the MUX is low. 0V to 1V range. Legacy (S-video): luminance input, 0V to 1V. Legacy (S-video): chroma input, 0V to 1V. Digital MUX control to select input 1 or 2 of the component channel. A high selects input 1. No connect. Do not connect these pins. Positive side of the 5V power supply. Legacy composite video output, typically 1V to 3V. Legacy chroma output, typically 1V to 3V. Legacy luminance video output, typically 1V to 3V. PB color component output, either SD or HD, typically 1V to 3V. PR color component output, either SD or HD, typically 1V to 3V. Luminance component output, either SD or HD, typically 1V to 3V.
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Truth Table
MUX Select Pin H H HSEL L HDTV Mode Y1A, PB1, PR1 Inputs SD Mode Y1A, PB1, PR1 Inputs L HDTV Mode Y1B, PB2, PR2 Inputs SD Mode Y1B, PB2, PR2 Inputs
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Absolute Maximum Ratings (Note 1)
Maximum Input Voltage ................................................ VCC Supply Voltage ................................................................ 6V Lead Temperature (soldering, 5 sec) ........................ 260C ESD Rating, ............................................................. Note 3
Operating Ratings (Note 2)
Analog Input Voltage Range .............................. 0V to 1.1V Digital Input Voltage Range ................................... 0 to VCC Supply Voltage (VCC) ...............................................5V5% Ambient Temperature Range ....................... -0C to +70C Package Thermal Resistance SOIC (JA), Note 4, 6 .......................................... 35C/W
Electrical Characteristics (Note 5)
VCC = 4.75V to 5.25V, TA = 25C. Values in bold apply over entire operating temperature range. TA from 0C to +70C. Values apply to all channels unless noted. Symbol PD VO ZIN IIN Parameter Power Dissipation Linear Output Range Input Impedance, Note 7 Input Bias Current, Note 7 Crosstalk, Note 7 Crosstalk, Note 7 Crosstalk, Note 7 PSSR Power Supply Rejection Ratio Conditions No load RL = 150, AC-Coupled VIN = 0V to 1V VIN = 0V to 1V channel-to-channel, f = 3MHz, NTSC Mode channel-to-channel, f = 20MHz, HDTV Mode between MUX inputs, f = 3MHz at 400kHz Min Typ 725 2.0 1 40 -70 -64 -60 40 Max 900 2.2 Units mW V M A dB dB dB dB
Filter Specifications, HD Operating Mode f-3dB f-1dB A74MHz Av Av PK TD TGD SNR DG DP -3dB Bandwidth -1dB Bandwidth 74MHz Attenuation Low Frequency Gain Gain Matching Peaking, Note 7 Baseband Delay Group Delay distortion Signal to Noise, Note 7 Differential Gain, Note 7 Differential Phase, Note 7 f = 100kHz f = 3.6MHz f = 6.0MHz Note 2 40IRE modulated ramp @ both 3.58MHz and 4.43MHz VAC = 0.5Vp-p, VDC = 0.5V VAC = 0.5Vpk-pk, VDC = 0.5V VAC = 0.5Vpk-pk, VDC = 0.5V VAC = 0.5Vpk-pk, VDC = 0.5V at 400kHz VAC = 0.5Vpk-pk, VDC = 0.5V channel-to-channel 25 5.5 33 30 36 30 30 6 1 1 65 5 20 77 2 2 6.3 MHz MHz dB dB % dB ns ns ns dB %
Filter Specifications, NTSC/PAL Operating Mode f-1dB f-3dB A27MHz Av Av GD SNR Digital I/O VIH VIL Input High Input Low HSTL and MUX pin HSTL and MUX pin 2.0 0.5 V V -1dB Bandwidth -3dB Bandwidth 27MHz Attenuation Low Frequency Gain Gain Matching Group Delay, Note 7 Signal to Noise, Note 7 VAC = 0.5Vpk-pk, VDC = 0.5V VAC = 0.5Vpk-pk, VDC = 0.5V VAC = 0.5Vpk-pk, VDC = 0.5V VAC = 0.5Vpk-pk, VDC = 0.5V at 400kHz channel-to-channel f = 3.6MHz Note 8 7.6 36 5.5 7.9 8.7 44 6 1 70 68 6.3 MHz MHz dB dB % ns dB
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MIC1700
Note 1. Note 2. Note 3. Note 4. Note 5. Note 6. Note 7. Note 8. Exceeding the absolute maximum rating may damage the device. The device is not guaranteed to function outside its operating rating. Devices are ESD sensitive. Handling precautions recommended. With SOIC attached by leads only. Specification for packaged product only. When thermally enhanced SOIC heatsink pad is soldered to a copper pad on a single layer PCB. Guaranteed by design and characterization. Low pass filter enabled. VIN = 1Vpk-pk. Wideband noise floor over 20MHz.
Micrel
October 2003
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MIC1700
MIC1700
Micrel
Typical Characteristics
8 7 6
GAIN (dB)
NTSC Gain
Input Signal = 50mVp-p VDC = 0.5V
GAIN (dB)
20 10 0 -10 -20 -30 -40 -50 -60
NTSC Gain
NTSC Group Delay
110 100 90 80 70 60 50 40 30 20 10 0 0
5 4 3 2 1 0 -1 -2 1M
10M FREQUENCY (Hz)
100M
-70 -80 100k
Input Signal = 50mVp-p VDC = 0.5V 1M 10M 100M
GROUP DELAY (ns)
2
4
6
8
10 12 14 16
FREQUENCY (Hz)
FREQUENCY (MHz)
8 7 6
GAIN (dB)
HDTV Gain
20 10 0
GAIN (dB)
HDTV Gain
HDTV Group Delay
35 30
GROUP DELAY (ns)
5 4 3 2 1 0 -1 -2 1M
-10 -20 -30 -40 -50 -60 -70 -80 1M Input Signal = 50mVp-p VDC = 0.5V 10M FREQUENCY (Hz) 100M
25 20 15 10 5 0 0 10 20 30 40 50 60
10M FREQUENCY (Hz)
100M
FREQUENCY (MHz)
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MIC1700
Micrel
Functional Diagram
HSEL MUX Select (HDTV or NTSC/PAL Select)
Y1A Y1B PR1 PR2 PB1 PB2
2:1 MUX
Selectable Filter
Y1OUT
2:1 MUX
Selectable Filter
PROUT
Component Video
2:1 MUX
Selectable Filter
PBOUT
YOUT YIN 8MHz Filter CVOUT CIN 8MHz Filter COUT Composite Video
MIC1700 Block Diagram
Functional Description
The MIC1700 is a multi-channel active filtering device with channels for both component and composite video signals. Component channel filters have selectable SD or HD bandwidths while composite filters have fixed bandwidth. One of two component inputs may be selected via a 2-to-1 mux. Output drivers are sufficient to drive 1V signals into 75 loads via a 75 source terminator. Input Inputs are all high impedance with low input bias current. Signal excursions at the inputs are limited to a specified range of 0V to 1V to meet distortion and other performance specifications. Two groups of three pins each comprise the two selectable component inputs, intended for YPRPB or RGB applications. One group of two pins comprises the composite S-video input, intended for legacy applications. Component Multiplexer Either of two component inputs may be selected using the component input multiplexer. The output of this high isolation multiplexer feeds the internal component filters. Input characteristics are not altered by the action of the multiplexer. Component Filters The component filters are 6th order with near Butterworth response characteristics. Cutoff frequencies are selectable
between 8MHz SD (Standard Definition) and 36MHz HD (High Definition). The 6th order Butterworth characteristic provides a maximally flat passband with 39dB of attenuation an octave above cutoff, and low group delay distortion minimizes overshoots in the time domain. Composite Filters The composite filters have the same characteristics as the SD mode of the component filters. These filters are additionally specified for DG (differential gain, variation of subcarrier amplitude with luma level) and DP (differential phase, variation of subcarrier phase with luma level). These distortions (which are intermodulation distortions) cannot occur with true S-video inputs applied, since luma and chroma are in separate channels. However, the composite filters can also be used with full legacy composite signals. In these cases, the DG and DP specifications are applicable. Output Drivers The output drivers are configured to provide low distortion 2V peak-to-peak swing into a 150 load from a single +5V supply. To achieve this, the operating range is approximately from 1V to 3V for normal inputs. AC-coupling at the outputs helps keep power dissipation within specification while preventing excessive DC components from coupling to downstream equipment.
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MIC1700
MIC1700
Micrel
+5V R1 1.5k C1* 10F Q4 Q2N3904 +5V
Applications Information
Achieving Additional Stop Band Attenuation For customers requiring greater stop band attenuation, a simple passive filter can be added to the input of MIC1700. The following circuit increases stop band attenuation above 60MHz by at least 15dB. Attenuation at the critical clocking frequency of 74MHz is increased by at least 20dB even allowing for typical value variations (we recommend 5% inductor, 2% capacitors).
Comparison of Response
10 0
+5V
RGB Video Source
R3 20k
MIC1700
C2* 10F
Q5 Q2N3904
+5V C3* 10F Q6 Q2N3904
R4 20k
GROUP DELAY (ns)
-10
MIC1700
-20 -30 -40 -50 -60 1
Stopband Improvement MIC1700 with Passive Filter
R5 20k Q7 Q2N3904
10
100
300
C4 10F
FREQUENCY (MHz)
*Polarity dependant on DC operating point of source
Figure 1. Comparison of Response
22pF
Figure 4. Triple Clamp for RGB Applications Clamps for AC-Coupled Inputs For RGB or Composite inputs that do not meet the DC input requirements MIC1700 can be driven via sync tip clamps (RGB sources work best with sync on all channels). These clamps work with signals that are unipolar, in which the sync tip is the most negative excursion of the signal. Current is bled from the input capacitor during active video causing a slow droop in average level. This rate of droop is a critical video parameter and should be well under 1% for all operating conditions. The droop is controlled by the load resistance (plus additional load currents) and the coupling cap. Charge removed from the coupling cap during active video is replaced during sync tip by the emitter current of the clamping transistor. The VBE drop during sync will be a function of the replacement current which is a function of sync tip duty cycle. Sync tip duty cycle for SD is 4.7s/63.5s = 0.074 or 7.4%. For HD trilevel sync the duty cycle is about half of this or 0.037. Assuming a droop current of about 100A, this gives a maximum replacement current (for HD signals) of 2.7mA. To keep this sync tip at or above GND, the biasing transistor should be operated at the same current, giving a biasing resistor of 1.5k. This will bias HD sources with the sync tip at GND, with SD sources slightly above GND. The luma channel of S-video sources can be clamped the same as component RGB channels, but the chroma channel should simply be AC-coupled with a bias of 0.5V. Realization of these schemes is shown in Figure 4 and 5.
75 Encoder Output
220nH MIC1700 Input 62pF
Figure 2. Passive Filter Circuit for 75 source
47pF
37.5 Encoder Output
100nH MIC1700 Input 130pF
Figure 3. Passive Filter Circuit for 37.5 source
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MIC1700
+5V R1 1.5k C1* 10F Q4 Q2N3904 +5V
Micrel
RGB Video Source
R2 20k
+5V C2* 10F R4 1.8k
*Polarity dependant on DC operating point of source
Figure 5. Clamp and AC Biasing for S-Video Applications
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MIC1700
C4 10F
Q7 Q2N3904
MIC1700
MIC1700
Micrel
Package Information
28-Pin Wide Body SOIC (WM)
MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL
+ 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com
The information furnished by Micrel in this datasheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser's use or sale of Micrel Products for use in life support appliances, devices or systems is at Purchaser's own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. (c) 2003 Micrel, Incorporated.
MIC1700
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October 2003

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