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19-4238; Rev 2; 11/08
KIT ATION EVALU BLE AVAILA
Low-Power Video Switches for Dual SCART Connectors
General Description Features
Dual SCART Support for Video Signals Supports CVBS Input from TV SCART (MAX9656) Reconstruction Filters with 9.5MHz Passband and 47dB Attenuation at 27MHz Fixed Gain of 2V/V Input Sync-Tip Clamps 2.7V to 3.6V Single-Supply Operation
MAX9655/MAX9656
The MAX9655/MAX9656 dual SCART switches route video signals between a set-top box decoder chip and two external SCART connectors. Under the control of the TV_SEL logic input, the MAX9655 selects whether the CVBS and RGB signals from the encoder or the VCR SCART are routed to the TV SCART. The CVBS signal from the encoder is always routed to the VCR SCART. The MAX9656 is similar to the MAX9655 except that under the control of the VCR_SEL logic input, the MAX9656 selects whether the CVBS signal from the encoder or the TV SCART is routed to the VCR SCART. The MAX9656 also features a low-power shutdown mode, in which quiescent current falls to 35A. The incoming video signals must be AC-coupled to the inputs, which have sync-tip clamps to set the internal DC level. After the input stages, multiplexers select which video signals are routed to the reconstruction filters and output amplifiers. The reconstruction filters are optimized for standard-definition signals and typically have 1dB passband flatness out to 9.5MHz and 47dB attenuation at 27MHz. The amplifiers have 2V/V gain, and the outputs can be DC-coupled to a 75 load, which is the equivalent of two video loads, or AC-coupled to a 150 load.
Ordering Information
PART MAX9655AEE+ MAX9656AEP+ PIN-PACKAGE 16 QSOP 20 QSOP TV SCART CVBS RETURN SUPPORT No Yes
Note: All devices are specified over the -40C to +125C operating temperature range.
+Denotes a lead-free/RoHS-compliant package.
Applications
SCART Set-Top Boxes
Pin Configurations and Typical Application Circuits appear at end of data sheet.
Functional Diagram
VDD TV_SEL 0 ENC_B_IN 1 ENC_G_IN UNKNOWN BIAS ENC_R_IN 1 ENC_CVBS_IN CLAMPREF 0 VCR_B_IN 1 VCR_G_IN CLAMPREF 0 VCR_R_IN 1 VCR_CVBS_IN CLAMPREF BUFFER 0 LPF 2V/V VCR_CVBS_OUT BUFFER LPF 2V/V TV_CVBS_OUT BUFFER LPF 2V/V TV_R_OUT CLAMPREF 0 BUFFER LPF 2V/V 300mV TV_G_OUT BUFFER LPF 2V/V
MAX9655
TV_B_OUT
TV_SEL
CLAMPREF
GND
________________________________________________________________ Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
ABSOLUTE MAXIMUM RATINGS
Supply Voltage VDD to GND ...........................................................-0.3V to +4V All Video and Logic Input Pins..................(GND - 0.3V) to +4V Duration of Output Short Circuit to VDD or GND ........Continuous Continuous Input Current All Video and Logic Input Pins .....................................20mA Continuous Power Dissipation (TA = +70C) 16-Pin QSOP (derate 8.3mW/C above +70C)............667mW 20-Pin QSOP (derate 9.1mW/C above +70C)............727mW Operating Temperature Range .........................-40C to +125C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VDD = 3.3V, VGND = 0, V SHDN = VDD, VCR_SEL = VDD, TV_SEL = VDD, RL = 150 to GND, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Supply Voltage Range Quiescent Supply Current Shutdown Supply Current Input Voltage Input Resistance Sync-Tip Clamp Level Input Voltage Range VCLP Guaranteed by outputvoltage swing 2.7V VDD 3.6V 3.0V VDD 3.6V Sync-tip clamp; percentage reduction in sync pulse (0.3VP-P); guaranteed by input clamping current measurement 1 300 VDD = 2.7V, 0V VIN 1.05V VDD = 3.0V, 0V VIN 1.2V 1.96 1.96 -2 0.218 0.3 2.1 2.1 2.4 2.4 2.1 VP-P 2 2 2.04 V/V 2.04 +2 0.39 % V SYMBOL VDD IDD ISHDN No load VSHDN = TV_SEL = VCR_SEL = GND (MAX9656 only) Unselected input Unselected input 0.23 CONDITIONS Guaranteed by power-supply rejection test MIN 2.7 TYP 3.3 21 35 VDD/3 222 0.3 0.39 1.05 1.2 2 2 MAX 3.6 45 70 UNITS V mA A V k V VP-P
Sync Crush Input Clamping Current Maximum Input Source Resistance
% A
DC Voltage Gain
AV
RL = 150 to GND (Note 2)
DC Gain Mismatch Output Level
Guaranteed by output-voltage swing Measured at output, CIN_ = 0.1F to GND Measured at output, VDD = 2.7V, VIN = VCLP to (VCLP +1.05V), RL = 150 to -0.2V Measured at output, VDD = 2.7V, VIN = VCLP to (VCLP +1.05V), RL = 150 to VDD/2
Output-Voltage Swing
Measured at output, VDD = 3.0V, VIN = VCLP to (VCLP +1.2V), RL = 150 to -0.2V Measured at output, VDD = 3.0V, VIN = VCLP to (VCLP +1.2V), RL = 150 to VDD/2 Measured at output, VDD = 3.135V, VIN = VCLP to (VCLP +1.05V), RL = 75 to -0.2V
2
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Low-Power Video Switches for Dual SCART Connectors
ELECTRICAL CHARACTERISTICS (continued)
(VDD = 3.3V, VGND = 0, V SHDN = VDD, VCR_SEL = VDD, TV_SEL = VDD, RL = 150 to GND, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) (Note 1)
PARAMETER Output Short-Circuit Current Output Resistance Power-Supply Rejection Ratio ROUT SYMBOL CONDITIONS Short to GND (sourcing) Short to VDD (sinking) VOUT = 1.5V, -10mA ILOAD +10mA 2.7V VDD 3.6V f = 1MHz, 100mVP-P VOUT = 2VP-P, reference frequency is 100kHz, 1dB passband flatness Standard-Definition Reconstruction Filter f = 5.5MHz VOUT = 2VP-P, reference frequency is 100kHz f = 9.5MHz f = 10MHz f = 27MHz Differential Gain DG 5-step modulated staircase of 129mV step size and 286mV peak-to-peak subcarrier amplitude, f = 4.43MHz 5-step modulated staircase of 129mV step size and 286mV peak-to-peak subcarrier amplitude, f = 4.43MHz 100kHz f 5MHz, outputs are 2VP-P 100kHz f 5MHz 2T = 200ns 2T = 200ns; bar time is 18s; the beginning 2.5% and the ending 2.5% of the bar time are ignored 2T = 200ns; bar time is 18s; the beginning 2.5% and the ending 2.5% of the bar time are ignored 5-step staircase f = 5.5MHz f = 15kHz f = 4.43MHz f = 30MHz 48 MIN TYP 140 70 0.2 64 20 9.5 0.1 -1 -3 -47 0.4 % dB MAX UNITS mA dB MHz
MAX9655/MAX9656
Differential Phase Group-Delay Distortion Peak Signal to RMS Noise 2T Pulse Response 2T Bar Response
DP
0.45 9 71 0.2 0.2
deg ns dB K% K%
2T Pulse-to-Bar K Rating Nonlinearity Output Impedance All-Hostile Crosstalk Output-to-Input Crosstalk
0.3 0.1 8.07 -82 -78 -68 0.3 x VDD 0.7 x VDD 10
K% % dB dB
LOGIC SIGNALS (MAX9655: TV_SEL, MAX9656: TV_SEL, VCR_SEL, SHDN) Logic-Low Threshold Logic-High Threshold Logic Input Current VIL VIH IIN TA = +25C TA = +25C TA = +25C V V A
Note 1: All devices are 100% production tested at TA = +25C. Specifications over temperature limits are guaranteed by design. Note 2: Voltage gain (AV) is a two-point measurement in which the output-voltage swing is divided by the input-voltage swing. _______________________________________________________________________________________ 3
Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
Typical Operating Characteristics
(VDD = 3.3V, VGND = 0, V SHDN = VDD, RL = 150 to GND, TA = +25C.)
SMALL-SIGNAL GAIN vs. FREQUENCY
VIN = 50mVP-P NOTE: GAIN IS NORMALIZED TO 0dB
MAX9655 toc01
SMALL-SIGNAL GAIN FLATNESS vs. FREQUENCY
2 1 0 GAIN (dB) -1 -2 -3 -4 -5 -6 -7 VIN = 50mVP-P NOTE: GAIN IS NORMALIZED TO 0dB
MAX9655 toc02
10 5 0 -5 GAIN (dB) -10 -15 -20 -25 -30 -35 -40 -45 -50
3
100k
1M
10M
100M
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
LARGE-SIGNAL GAIN vs. FREQUENCY
VIN = 1VP-P NOTE: GAIN IS NORMALIZED TO 0dB
MAX9655 toc03
LARGE-SIGNAL GAIN FLATNESS vs. FREQUENCY
2 1 0 GAIN (dB) -1 -2 -3 -4 -5 -6 -7 VIN = 1VP-P NOTE: GAIN IS NORMALIZED TO 0dB
MAX9655 toc04
10 5 0 -5 -10 -15 -20 -25 -30 -35 -40 -45 -50 GAIN (dB)
3
100k
1M
10M
100M
100k
1M
10M
100M
FREQUENCY (Hz)
FREQUENCY (Hz)
VIDEO CROSSTALK vs. FREQUENCY
MAX9655 toc05
VIDEO GROUP DELAY DISTORTION vs. FREQUENCY
120 110 100 90 GROUP DELAY (ns) 80 70 60 50 40 30 20 10 0 VIN = 1VP-P NOTE: GAIN IS NORMALIZED TO 0dB
MAX9655 toc06
0 -20 -40 GAIN (dB) -60
VIN = 1VP-P NOTE: GAIN IS NORMALIZED TO 0dB
ALL-HOSTILE -80 -100 -120 100k 1M 10M 100M FREQUENCY (Hz) 2 ADJACENT CHANNELS 1 ADJACENT CHANNEL
100k
1M
10M
100M
FREQUENCY (Hz)
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Low-Power Video Switches for Dual SCART Connectors
Typical Operating Characteristics (continued)
(VDD = 3.3V, VGND = 0, V SHDN = VDD, RL = 150 to GND, TA = +25C.)
VIDEO PSRR vs. FREQUENCY
VDD = 3.3V + 100mVP-P
MAX9655 toc07
MAX9655/MAX9656
VOLTAGE GAIN vs. TEMPERATURE
2.08 2.06 VOLTAGE GAIN (V/V) 2.04 2.02 2.00 1.98 1.96 1.94 1.92 1.90
MAX9655 toc08
0 -10 -20 PSRR (dB) -30 -40 -50 -60 -70 -80
2.10
100k
1M
10M
100M
-50
-25
0
25
50
75
100
125
FREQUENCY (Hz)
TEMPERATURE (C)
DIFFERENTIAL GAIN
DIFFERENTIAL GAIN (%) DIFFERENTIAL GAIN (%) 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 0 0.8 0.6 0.4 0.2 0 -0.2 -0.4 0 1 2 3 1 2 3 f = 3.58MHz 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 0 0.8 0.6 0.4 0.2 0 -0.2 -0.4 0
MAX9655 toc09
DIFFERENTIAL GAIN
f = 4.43MHz
MAX9655 toc10
4
5
1
2
3
4
5
DIFFERENTIAL PHASE (deg)
DIFFERENTIAL PHASE (deg)
DIFFERENTIAL PHASE
f = 3.58MHz
DIFFERENTIAL PHASE
f = 4.43MHz
4
5
1
2
3
4
5
2T RESPONSE
MAX9655 toc11
12.5T RESPONSE
MAX9655 toc12
IN 200mV/div
IN 200mV/div
OUT 400mV/div
OUT 400mV/div
100ns/div
400ns/div
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Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
Typical Operating Characteristics (continued)
(VDD = 3.3V, VGND = 0, V SHDN = VDD, RL = 150 to GND, TA = +25C.)
NTC-7 VIDEO TEST SIGNAL FIELD SQUARE WAVE
MAX9655 toc13
MAX9655 toc14
IN 500mV/div
IN 500mV/div
OUT 1V/div
OUT 1V/div
10s/div
2ms/div
VIDEO SYNC-TIP CLAMP VOLTAGE vs. TEMPERATURE
MAX4617 toc15
VIDEO SYNC-TIP CLAMP CURRENT vs. TEMPERATURE
MAX4617 toc16
0.40 SYNC-TIP CLAMP VOLTAGE (V) 0.38 0.36 0.34 0.32 0.30 0.28 0.26 -50 -25 0 25 50 75 100
1.04 SYNC-TIP CLAMP CURRENT (A) 1.02 1.00 0.98 0.96 0.94 0.92 0.90
125
-50
-25
0
25
50
75
100
125
TEMPERATURE (C)
TEMPERATURE (C)
SYNC-TIP CLAMP CURRENT vs. INPUT VOLTAGE
MAX9655 toc17
QUIESCENT SUPPLY CURRENT vs. TEMPERATURE
MAX4617 toc18
500 SYNC-TIP CLAMP CURRENT (A) 400 300 200 100 0 -100 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4
23.0 QUIESCENT SUPPLY CURRENT (mA) 22.5 22.0 21.5 21.0 20.5 20.0
1.6
-50
-25
0
25
50
75
100
125
INPUT VOLTAGE (V)
TEMPERATURE (C)
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Low-Power Video Switches for Dual SCART Connectors
Pin Description
PIN MAX9655 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 -- -- -- MAX9656 2 3 4 5 6 7 8 9 11 13 14 15 16 17 18 19 1 10 12 NAME ENC_B_IN ENC_G_IN ENC_R_IN ENC_CVBS_IN VCR_B_IN VCR_G_IN VCR_R_IN VCR_CVBS_IN GND VCR_CVBS_OUT TV_CVBS_OUT TV_R_OUT TV_G_OUT TV_B_OUT TV_SEL VDD TV_CVBS_IN N.C. SHDN FUNCTION Encoder Blue Video Input. AC-couple the signal through a 0.1F capacitor. Encoder Green Video Input. AC-couple the signal through a 0.1F capacitor. Encoder Red Video Input. AC-couple the signal through a 0.1F capacitor. Encoder Composite Video Input. AC-couple the signal through a 0.1F capacitor. VCR SCART Blue Video Input. AC-couple the signal through a 0.1F capacitor. VCR SCART Green Video Input. AC-couple the signal through a 0.1F capacitor. VCR SCART Red Video Input. AC-couple the signal through a 0.1F capacitor. VCR SCART Composite Video Input. AC-couple the signal through a 0.1F capacitor. Ground VCR SCART Composite Video Output. The sync tip is biased at 0.3V. TV SCART Composite Video Output. The sync tip is biased at 0.3V. TV SCART Red Video Output. The sync tip is biased at 0.3V. TV SCART Green Video Output. The sync tip is biased at 0.3V. TV SCART Blue Video Output. The sync tip is biased at 0.3V. TV SCART Output Selection. Connect to GND to route the encoder video signals to the TV SCART outputs. Connect to VDD to route the VCR SCART video signals to the TV SCART outputs. Positive Power Supply. Bypass with 0.1F ceramic capacitors to GND. Television SCART Composite Video Input. AC-couple the signal through a 0.1F capacitor. No Connection. Not internally connected. Active-Low Shutdown Logic Input. Connect to GND to place device in shutdown. Connect to VDD for normal operation. VCR SCART Output Selection. Connect to GND to route ENC_CVBS_IN to the VCR SCART CVBS output. Connect to VDD to route TV_CVBS_IN to the VCR SCART CVBS output.
MAX9655/MAX9656
--
20
VCR_SEL
Detailed Description
A MAX9655 or a MAX9656 can comprise the video portion of a low-cost, dual SCART solution in set-top boxes with a subset of the full SCART functions. The MAX9655/MAX9656 select whether the CVBS, red, green, and blue video signals from the encoder or the VCR SCART are routed to the TV SCART. The MAX9655/MAX9656 support the output of one CVBS signal to the VCR SCART. In the MAX9655, the CVBS signal from the encoder is routed to the VCR SCART. In the MAX9656, the CVBS signal routed to the VCR SCART can come from the encoder or TV SCART. In the typical usage case, the VCR (or DVD recorder) records a television program from the set-top box. In such a case, the encoder would be the source of the
CVBS signal. Support for the TV SCART CVBS return path is useful when a person wants to record on his VCR (or more likely DVD recorder) a television program received through the television's antenna. The television program is transmitted from the television to the set-top box and then to the VCR. Both the MAX9655 and MAX9656 have integrated reconstruction filters so that when the encoder video signals are routed to the TV SCART or the VCR SCART, the steps and spikes left by the video digital-to-analog converter (DAC) are smoothed away. Although the incoming video signals from the VCR SCART are assumed to be filtered already, the reconstruction filter has wide enough bandwidth so that the video signals from the VCR SCART are not degraded.
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Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
The incoming video signals can have any DC bias because the input sync-tip clamps restore the DC level. The output amplifiers have a gain of 2V/V. The MAX9655/MAX9656 operate from a single 3.3V supply and consume low quiescent power and low average power. In addition, the MAX9656 also has shutdown mode.
Table 1. TV_SEL Logic (Applicable to Both the MAX9655 and the MAX9656)
LOGIC STATE Low High MODE Encoder video signals are routed to the TV SCART. VCR SCART video signals are routed to the TV SCART.
Operating Modes
TV_SEL controls whether the encoder or VCR video signals are sent to the TV SCART. See Table 1. On the MAX9656, VCR_SEL controls whether the CVBS signal from the TV SCART or the encoder is sent to the VCR SCART. SHDN controls whether the device is on or off. See Tables 2 and 3. In shutdown, the outputs of the MAX9656 are high impedance.
Table 2. VCR_SEL Logic (Only Applicable to the MAX9656)
LOGIC STATE Low High MODE CVBS signal from encoder is routed to the VCR SCART. CVBS signal from the TV SCART is routed to the VCR SCART.
Input
Every video signal must be AC-coupled to the MAX9655/MAX9656 through 0.1F capacitors. The MAX9655/MAX9656 have sync-tip clamps and bias circuits to restore the DC level of the video signal after the input coupling capacitor. When a video input is selected, the input has a sync-tip clamp, which accepts video signals that have sync pulses or that reach their minimum level during sync. Composite video with blanking and sync (CVBS) is an example of a video signal with sync pulses. The red, green, and blue signals in an RGBS signal set are examples of signals that return to their blank level during sync. The sync-tip voltage is internally set to 300mV. When a video input is not selected, the inputs to the MAX9655 and the MAX9656 do not distort the video signal in case the video source is driving video signals to another video circuit such as a video multiplexer. The inputs are biased at VDD/3, which is sufficiently above ground so that the ESD diodes never forward bias as the video signal changes. The input resistance
Table 3. SHDN Logic (Only Applicable to the MAX9656)
LOGIC STATE Low High MODE Off On
is 220k, which presents negligible loading on the video current DAC. The sole exception to this condition is ENC_CVBS_IN (MAX9655), in which the input circuit is always a sync-tip clamp. Table 4 summarizes which input circuit is active on the inputs of the MAX9655 depending on TV_SEL. Table 5 summarizes which input circuit is active on the inputs of the MAX9656 depending on TV_SEL and VCR_SEL.
Table 4. MAX9655 Input Circuit of Input as Determined by State of TV_SEL
INPUT ENC_B_IN ENC_G_IN ENC_R_IN ENC_CVBS_IN VCR_B_IN VCR_G_IN VCR_R_IN VCR_CVBS_IN INPUT CIRCUIT (TV_SEL = LOW) Sync-tip clamp Sync-tip clamp Sync-tip clamp Sync-tip clamp Bias Bias Bias Bias INPUT CIRCUIT (TV_SEL = HIGH) Bias Bias Bias Sync-tip clamp Sync-tip clamp Sync-tip clamp Sync-tip clamp Sync-tip clamp
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Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
Table 5. MAX9656 Input Circuit of Input as Determined by State of TV_SEL
INPUT ENC_B_IN ENC_G_IN ENC_R_IN ENC_CVBS_IN TV_CVBS_IN VCR_B_IN VCR_G_IN VCR_R_IN VCR_CVBS_IN Sync-tip clamp (VCR_SEL = 0) Bias (VCR_SEL = 0) Bias Bias Bias Bias INPUT CIRCUIT (TV_SEL = LOW) Sync-tip clamp Sync-tip clamp Sync-tip clamp Sync-tip clamp (VCR_SEL = 1) Sync-tip clamp (VCR_SEL = 1) INPUT CIRCUIT (TV_SEL = HIGH) Bias Bias Bias Sync-tip clamp (VCR_SEL = 0) Bias (VCR_SEL = 0) Sync-tip clamp Sync-tip clamp Sync-tip clamp Sync-tip clamp Bias (VCR_SEL = 1) Sync-tip clamp (VCR_SEL = 1)
Note: VCR_SEL = X (don't care), except where noted.
When the MAX9656 is in shutdown, its inputs are biased at the same voltage and present the same input resistance as unselected inputs.
Applications Information
Audio Switch for Dual SCART Connectors
In addition to video signals, SCART connectors also support left and right audio signals that are full duplex. Figure 1 shows a matching audio switch for the MAX9655. Notice that it can be made from low-cost, discrete components. It is assumed that the set-top box chip generates the left and right audio signals directly, or the set-top box chip sends an I2S stream to a stereo audio DAC that generates the left and right audio signals. In both cases, the audio signals are filtered and amplified by a dual audio op amp before they are presented to the audio switch. Figure 2 shows a matching audio switch for the MAX9656. Similar to how the MAX9656 handles video signals, the audio signals from the set-top box chip or the audio signals from the TV SCART are routed to the VCR SCART.
Video Filter
The MAX9655/MAX9656 video filter features 1dB passband out to 9.5MHz and 47dB attenuation at 27MHz, making the filter suitable for standard-definition video signals from all sources (e.g., broadcast and DVD). Broadcast video signals are channel limited: NTSC signals have 4.2MHz bandwidth, and PAL signals have 5MHz bandwidth. Video signals from a DVD player, however, are not channel limited; so the bandwidth of DVD video signals can approach the Nyquist limit of 6.75MHz. Recommendation: ITU-R BT.601-5 specifies 13.5MHz as the sampling rate for standarddefinition video. Therefore, the maximum bandwidth of the signal is 6.75MHz. To ease the filtering requirements, most modern video systems oversample by two times, clocking the video current DAC at 27MHz.
Outputs
The video output amplifiers can both source and sink load current, allowing output loads to be DC- or ACcoupled. The amplifier output stage needs approximately 300mV of headroom from either supply rail. The devices have an internal level-shift circuit that positions the sync tip at approximately 300mV at the output. If the supply voltage is greater than 3.135V (5% below a 3.3V supply), each amplifier can drive two DC-coupled video loads to ground. If the supply is less than 3.135V, each amplifier can drive only one DC-coupled or AC-coupled video load.
AC-Coupling the Outputs
The outputs can be AC-coupled since the output stage can source and sink current as shown in Figure 3. Coupling capacitors should be 220F or greater to keep the highpass filter, formed by the 150 equivalent resistance of the video transmission line, to a corner frequency of 4.8Hz or below. The frame rate of PAL systems is 25Hz. The corner frequency should be well below the frame rate.
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9
Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
12V 12V 12V 0.1F 7 180pF 12V 1M 10F DAC 8 + 2.7nF 300k 2.7nF 3 4 4.7k 4.7k 1.2k 0.1F 2 8 1 U1 1/2 LM833 TV_SEL 12V 9, 10, 11 8 7 100k 10F SDATA DEMSCLK LRCK MCLK 1 2 3 4 1M U0 CS4334 + 10F 5.1k 9.5k 12V 180pF 10F DAC 5 + 2.7nF 300k 6 12V 10k 3.3V TV_SEL JU0 10k 2N3904 TV_SEL 3.3V VCR_SEL JU1 10k 1M 2N3904 12V 10k 10F VCR_SEL + 21 100k 12V 100k 10F + 1 2.7nF 5 7 1/2 LM833 1M 4.7k 4.7k 1.2k 100k 6 10F 10F + 100k 4 VCR SCART + 2 6 3 5.1k 100k 5 12V + 3 U2 HEF4053 21 10F 15 + 1 6 2 21 4 TV SCART 9.5k 10F 2 + 100k 15 1 0.1F 100k 16 10F 3
Figure 1. Audio Switch for the MAX9655
10
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Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
12V 12V 0.1F 12V 0.1F 7 180pF 12V 0.1F 2 8 1 3 4 U1 1/2 LM833 TV_SEL 12V 100k 10F + SDATA DEMSCLK LRCK MCLK 1 2 3 4 U0 CS4334 + 10F 5.1k 9.5k 180pF 5 + 2.7nF 300k 6 12V 10k 3.3V TV_SEL JU0 10k 2N3904 TV_SEL 3.3V VCR_SEL JU1 10k 2N3904 10F 5 + 1M 100k U2 HEF4053 21 12V 10k VCR_SEL VCR_SEL 12V 100k 3 10F 15 + 1 9, 10, 11 8 7 4 1M 2.7nF 5 7 1/2 LM833 1 10F 2 + 100k VCR SCART 4.7k 4.7k 1.2k 6 12V 12V 16 0.1F 2 6 10F 3 15 + 5.1k 5 12V 1M 100k U2 HEF4053 21 3 10F 15 + 1 6 2 21 10F 9.5k 1M + 100k 16 10F 15+ 3
10F DAC 8 +
4.7k
4.7k
1.2k
9, 10, 11 8 7 4 TV SCART
2.7nF 300k
2.7nF
DAC
21
Figure 2. Audio Switch for the MAX9656
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11
Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
Table 6. Quiescent and Average Power Consumption for MAX9655/MAX9656
MEASUREMENTS Quiescent Power Consumption Average Power Consumption POWER CONSUMPTION (mW) 69 175 (MAX9655) 200 (MAX9656)
MAX9655 MAX9656
CONDITIONS
TV_B_OUT 220F
No load. 150 to ground on each output. 50% flat field signal on each input.
LPF
AV = 2V/V 75
TV_G_OUT LPF AV = 2V/V 75
220F TV SCART 220F
Power Consumption
The quiescent power consumption and average power consumption of the MAX9655/MAX9656 are very low because of the 3.3V operation and low-power circuit design. Quiescent power consumption is defined when the MAX9655/MAX9656 are operating without loads and without any video signals. Average power consumption represents the normal power consumption when the devices drive real video signals into real video loads. It is measured when the MAX9655/MAX9656 drive a 150 load to ground with a 50% flat field, which serves as a proxy for a real video signal. Table 6 shows the quiescent and average power consumption of the MAX9655/MAX9656.
LPF AV = 2V/V
TV_R_OUT 75
TV_CVBS_OUT LPF AV = 2V/V 75
220F
VCR_CVBS_OUT LPF AV = 2V/V 75
220F
TO VCR SCART
Figure 3. AC-Coupled Outputs
Power-Supply Bypassing and Ground
The MAX9655/MAX9656 operate from a single-supply voltage down to 2.7V, allowing for low-power operation. Bypass V DD to GND with a 0.1F capacitor. Place all external components as close as possible to the device.
Chip Information
PROCESS: BiCMOS
12
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Low-Power Video Switches for Dual SCART Connectors
Typical Application Circuits
+3.3V 0.1F MPEG DECODER TV_SEL GPIO DAC B 0.1F DAC G 75 ENC_G_IN DAC R 75 DAC CVBS 0.1F 1 ENC_CVBS_IN 0.1F 75 BUFFER VCR_B_IN 0.1F VCR SCART 75 VCR_G_IN 0.1F 75 VCR_R_IN 0.1F 75 VCR_CVBS_IN 0.1F 75 BUFFER 0 TVSEL CLAMPREF LPF 2V/V 75 VCR_CVBS_OUT 1 CLAMPREF 0 BUFFER LPF 2V/V 75 TV_CVBS_OUT 1 CLAMPREF LPF 2V/V 75 TV_R_OUT 0 CLAMPREF 1 0.1F 0 ENC_R_IN 75 BUFFER LPF 2V/V 75 TV SCART TV_G_OUT CLAMPREF ENC_B_IN 0 BUFFER LPF 2V/V 75 MAX9655 TV_B_OUT
MAX9655/MAX9656
VDD
GND
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13
Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
Typical Application Circuits (continued)
+3.3V 0.1F MPEG DECODER GPIO GPIO 0.1F 75 B 0.1F DAC G 75 ENC_G_IN DAC R 75 DAC CVBS 0.1F 1 ENC_CVBS_IN 0.1F 75 BUFFER VCR_B_IN 0.1F VCR SCART 75 VCR_G_IN 0.1F 75 BUFFER VCR_R_IN 0.1F 75 VCR_CVBS_IN 0.1F 75 1 BUFFER 0 TVSEL VCRSEL 0 CLAMPREF LPF 2V/V 75 VCR_CVBS_OUT 1 CLAMPREF VCR_SEL LPF 2V/V 75 TV_CVBS_OUT 0 1 CLAMPREF LPF 2V/V 75 TV_R_OUT 0 CLAMPREF 1 0.1F 0 ENC_R_IN 75 BUFFER LPF 2V/V 75 TV SCART TV_G_OUT CLAMPREF ENC_B_IN 0 BUFFER LPF 2V/V 75 TV_B_OUT MAX9656
SHDN TV_SEL TV_CVBS_IN
VDD
DAC
GND
14
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Low-Power Video Switches for Dual SCART Connectors
Pin Configurations
TOP VIEW
ENC_B_IN 1 ENC_G_IN 2 ENC_R_IN 3 ENC_CVBS_IN 4 VCR_B_IN 5 VCR_G_IN 6 VCR_R_IN 7 VCR_CVBS_IN 8 + 16 VDD 15 TV_SEL 14 TV_B_OUT TV_CVBS_IN 1 ENC_B_IN 2 ENC_G_IN 3 ENC_R_IN 4 ENC_CVBS_IN 5 VCR_B_IN 6 VCR_G_IN 7 VCR_R_IN 8 VCR_CVBS_IN 9 N.C. 10 + 20 VCR_SEL 19 VDD 18 TV_SEL 17 TV_B_OUT
MAX9655/MAX9656
MAX9655
13 TV_G_OUT 12 TV_R_OUT 11 TV_CVBS_OUT 10 VCR_CVBS_OUT 9 GND
MAX9656
16 TV_G_OUT 15 TV_R_OUT 14 TV_CVBS_OUT 13 VCR_CVBS_OUT 12 SHDN 11 GND
QSOP
QSOP
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15
Low-Power Video Switches for Dual SCART Connectors MAX9655/MAX9656
Package Information
For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE 16 QSOP 20 QSOP PACKAGE CODE E16-4 E20-1 DOCUMENT NO. 21-0055 21-0055
QSOP.EPS
16
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Low-Power Video Switches for Dual SCART Connectors
Revision History
REVISION NUMBER 0 1 2 REVISION DATE 3/08 10/08 11/08 Initial release Removed future product reference from MAX9656, updated Shutdown Supply Current parameter, updated Table 6 Updated Shutdown Supply Current maximum value in EC table. DESCRIPTION PAGES CHANGED -- 1, 2, 12 2
MAX9655/MAX9656
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17
(c) 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

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