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MAX4397SCTM+中文资料

General Description

The MAX4397 dual SCART switch matrix routes audio and video signals between an MPEG encoder and two external SCART connectors under I 2C control, and meets the requirements of EN50049-1, IEC 933-1,Canal+, and BSkyB standards.

The video and audio channels feature input source selection multiplexers, input buffers, and output buffers for routing all inputs to selected outputs. The MAX4397D audio encoder input is differential DC-coupled, while the MAX4397S audio encoder input is single-ended AC-coupled. Except for the MAX4397D’s audio encoder input, all other inputs and outputs are AC-coupled with internal DC-biasing set to predefined levels.

The MAX4397 provides programmable gain control from +5dB to +7dB in 1dB steps for Red, Green, and Blue component video signals. All other video outputs have a fixed +6dB gain. Additional features include an internal Luma and Chroma (Y/C) mixer that generates a Composite video signal (CVBS) to supply an RF modulator output, and internal video reconstruction low-pass filters with passband ripple between -1dB and +1dB from 100kHz to 5.5MHz. The MAX4397 TV audio channel features clickless switching and programmable volume control from -56dB to +6dB in 2dB steps. The VCR audio output also has programmable gain for -6dB, 0dB, or +6dB. The device also generates monaural audio from left and right stereo inputs.All audio drivers deliver a 3.0V RMS minimum output.

The MAX4397 operates with standard 5V and 12V power supplies and supports slow-switching and fast-switching signals. The I 2C interface programs the gain and volume control, and selects the input source for routing.

The MAX4397 is available in a compact 48-pin thin QFN package and is specified over the 0°C to +70°C com-mercial temperature range.

Applications

Satellite Set-Top Boxes Cable Set-Top Boxes TVs VCRs DVDs

Features

?Video Outputs Drive 2V P-P into 150??Audio Outputs Drive 3V RMS into 10k ??Clickless, Popless Audio Gain Control and Switching ?AC-Coupled Video Inputs with Internal Clamp and Bias ?DC-Coupled Video Outputs

?Composite Video Signal Created Internally from Y/C Inputs ?Internal Video Reconstruction Filters Provide -40dB at 27MHz ?Differential (MAX4397D) or Single-Ended (MAX4397S) Audio Encoder Input ?Red/Chroma Switch for Bidirectional I/O ?I 2C-Programmable RGB Gain from +5dB to +7dB ?I 2C-Programmable Audio Gain Control from +6dB to -56dB ?Meets EN50049-1, IEC 933-1, Canal+, and BSkyB Requirements

MAX4397

________________________________________________________________Maxim Integrated Products 1

For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/ed2644505.html,.

Pin Configuration and Typical Application Circuits appear at end of data sheet.

System Block Diagram appears at end of data sheet.

M A X 4397

Audio/Video Switch for Dual SCART Connectors

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V 12= 12V, V VID = V AUD = 5V, 0.1μF X5R capacitor in parallel with a 10μF aluminum electrolytic capacitor from V AUD to GNDAUD,V 12to GNDAUD, and V VID to GNDVID ,SET = 100k ?nominal, R LOAD = 150?, T A = 0°C to +70°C, unless otherwise noted. Typical values are at T A = +25°C.) (Note 1)

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.

V VID to GNDVID........................................................-0.3V to +6V V 12to GNDAUD.....................................................-0.3V to +14V V AUD to GNDAUD....................................................-0.3V to +6V GNDAUD to GNDVID............................................-0.1V to +0.1V All Video Inputs, ENCIN_FS, VCRIN_FS,

SET to GNDVID......................................-0.3V to (V VID + 0.3V)All Audio Inputs,

AUDBIAS to GNDAUD.........................-0.3V to (V AUD + 0.3V)SDA, SCL, DEV_ADDR to GNDVID..........................-0.3V to +6V All Audio Outputs, TV_SS,

VCR_SS to GNDAUD...............................-0.3V to (V 12+ 0.3V)

All Video Outputs, TVOUT_FS to V VID , V AUD ,

GNDAUD, GNDVID................................................Continuous All Audio Outputs to V VID , V AUD , V 12,

GNDVID, GNDAUD................................................Continuous Continuous Power Dissipation (T A = +70°C)

48-Pin Thin QFN (derate 27mW/°C above +70°C)......2105.3mW Operating Temperature Range...............................0°C to +70°C Junction Temperature......................................................+150°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°C

MAX4397

Audio/Video Switch for Dual SCART Connectors

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ELECTRICAL CHARACTERISTICS (continued)

M A X 4397

Audio/Video Switch for Dual SCART Connectors 4_______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

MAX4397

Audio/Video Switch for Dual SCART Connectors

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ELECTRICAL CHARACTERISTICS (continued)

R/G/B VIDEO LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

-5-4-3-2-101234-6

0.110

GROUP DELAY vs. FREQUENCY

M A X 4397 t o c 02

FREQUENCY (MHz)

G R O U P D E L A Y (n S )

204060801001200

0.1

Y VIDEO LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

-5

-4-3-2-101234

-6

0.1

Typical Operating Characteristics

(V 12= 12V, V VID = V AUD = 5V, 0.1μF X5R capacitor in parallel with a 10μF aluminum electrolytic capacitor from V AUD to GNDAUD,V 12to GNDAUD, V VID to GNDVID no load, T A = 0°C to +70°C, unless otherwise noted. Typical values are at T A = +25°C.)

M A X 4397

Audio/Video Switch for Dual SCART Connectors 6_______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

Note 2:The settling time is measured from the 50% of the input swing to the 0.1% of the final value of the output.

Note 3:Maximum load capacitance is 200pF. All the listed parameters are measured at application’s inputs, unless otherwise

noted. See the Typical Application Circuits .

Note 4:Difference in propagation delays of fast-blanking signal and RGB signals. Measured from 50% input transition to 50%

output transition. Signal levels to be determined.

Note 5:Guaranteed by design.

MAX4397

Audio/Video Switch for Dual SCART Connectors

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AUDIO CROSSTALK vs. FREQUENCY

FREQUENCY (kHz)

C R O S S T A L K (d B )

0.1

-100-80

-60-40

-200

-120

0.01

100

AUDIO LARGE-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (kHz)

G A I N (d B )

100

1000

3210-1-2-3-4-5-6

AUDIO TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

FREQUENCY (kHz)

T H D +N (%)

0.001

0.01

0.1

0.0001

0.01

100

0.1

R/G/B VIDEO SMALL-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

-5-4-3-2-101234-60.1

Y VIDEO SMALL-SIGNAL BANDWIDTH

vs. FREQUENCY

FREQUENCY (MHz)

G A I N (d B )

-5-4-3-2-101234-6

0.110

VIDEO CROSSTALK vs. FREQUENCY

FREQUENCY (MHz)

C R O S S T A L K (d B )

-90-80-70-60-50-40-30-20-10

-100

0.110

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

FREQUENCY (kHz)

P S R R (d B )

0.1

0.01

100-90-80-70-60-50-40-30-20-10-100

V VID QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

TEMPERATURE (°C)

V V I D Q U I E S C E N T S U P P L Y C U R R E N T (m A )

502555606570758050

075

Typical Operating Characteristics (continued)

M A X 4397

Audio/Video Switch for Dual SCART Connectors 8_______________________________________________________________________________________

Typical Operating Characteristics (continued)

V VID STANDBY QUIESCENT SUPPLY CURRENT vs. TEMPERATURE

TEMPERATURE (°C)

V V I D S T A N D B Y Q U I E S C E N T S U P P L Y C U R R E N T (m A )

V 12 QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

M A X 4397 t o c 13

TEMPERATURE (°C)V 12 Q U I E S C E N T S U P P L Y C U R R E N T (m A )

1.5

2.02.5

3.03.5

4.04.5

5.01.0

V AUD QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

M A X 4397 t o c 14

TEMPERATURE (°C)

V A U D Q U I E S C E N T S U P P L Y C U R R E N T (m A )

0.51.01.52.02.53.03.54.0

INPUT CLAMP AND BIAS LEVEL

vs. TEMPERATURE

TEMPERATURE (°C)

I N P U T C L A M P A N D B I A S L E V E L (V )

0.70.91.11.31.71.51.92.12.32.5

0.5

INPUT CLAMP CURRENT vs. TEMPERATURE

M A X 4397 t o c 16

TEMPERATURE (°C)

I N P U T C L A M P C U R R E N T (μA )

2.5

3.03.5

4.04.5

5.05.5

6.0

2.0

V IN = 1.75V

INPUT CLAMP CURRENT vs. INPUT VOLTAGE

M A X 4397 t o c 17

INPUT VOLTAGE (V)

I N P U T C L A M P C U R R E N T (m A )

-0.4-0.3-0.2-0.1

00.10.20.30.40.5-0.5

OUTPUT BIAS VOLTAGE vs. TEMPERATURE

TEMPERATURE (°C)

O U T P U T B I A S V O L T A G E (V )

50250.51.01.52.02.53.0

075

MAX4397

Audio/Video Switch for Dual SCART Connectors

M A X 4397

Audio/Video Switch for Dual SCART Connectors 10

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Detailed Description

The MAX4397 is a switch matrix that routes audio and video signals between different ports using the I 2C interface. The ports consist of the MPEG decoder out-put, and two SCART connectors for the TV and VCR.Per EN50049 and IEC 933, the encoder can only input a signal to the SCART connector, while TV and VCR SCART connectors are bidirectional.

The MAX4397 circuitry consists of four major sections:the video section, the audio section, the slow- and fast-switching section, and the digital interface.

The video section consists of clamp and bias circuitry,input buffers, reconstruction filters, a switch matrix, a Y/C mixer, and output buffers. All video inputs are AC-coupled through a 0.1μF capacitor to set an acceptable

al Red/Chroma outputs can be connected to ground using I 2C control to make them terminations when Red/Chroma is an input (see the Video Inputs section).The audio section features an input buffer, a switching matrix, volume- or gain-control circuitry, and output dri-vers. The audio inputs are AC-coupled through a 0.1μF capacitor. Only the audio encoder inputs of the MAX4397D are different from the MAX4397S. The MAX4397S has a single-ended audio encoder input while the audio encoder input for the MAX4397D is dif-ferential. The TV output audio path has volume control from -56dB to +6dB in 2dB steps, while the VCR output audio path has volume control from -6dB to +6dB in 6dB steps. The MAX4397 can be configured to switch inputs during a zero-crossing function to reduce clicks.

MAX4397

Audio/Video Switch for Dual SCART Connectors

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The slow-switching feature allows for bidirectional, tri-level, slow-switching input and output signals at pin VCR_SS and TV_SS, respectively. The slow-switching signals from the VCR set the aspect ratio or video source of the TV screen. See the Slow Switching section.

Fast switching consists of two inputs from the encoder and VCR, and one output to the TV to insert an on-screen display (OSD). F ast switching is used to route video signals from the VCR or from the encoder to the TV. In addition, the fast-switching output can be config-ured to a high or low voltage. F ast switching is con-trolled through the I 2C interface.

The digital block contains the 2-wire interface circuitry,control, and status registers. The MAX4397 can be configured through an I 2C-compatible interface.DEV_ADDR sets the I 2C-compatible address.

SCART Video Switching

The MAX4397 switches video signals between an MPEG decoder, TV SCART, and VCR SCART. The video switch includes reconstruction filters, multiplexed video ampli-fiers, and a Y/C mixer driver for an RF modulator. See Figure 1 for the functional diagram of the video section.While the SCART connector supports RGB, S-video, and Composite video formats, RGB, and S-video typically share a bidirectional set of SCART connector pins.

M A X 4397

Video Inputs

All video inputs are AC-coupled with an external 0.1μF capacitor. Either a clamp or bias circuit sets the DC input level of the video signals. The clamp circuit posi-tions the sync tip of the Composite (CVBS), the Component RGB, or the S-Video Luma signal. If the sig-nal does not have a sync tip, then the clamp positions the minimum of the signal at the clamp voltage. The bias circuitry is used to position the S-video Chroma signal at midlevel of the Luma (Y) signal. On the video inputs that can receive either a Chroma or a Red video signal, the bias or clamp circuit is selected through I 2C. See Tables 3–12 for loading register details.

The MPEG decoder and VCR uses the RGB format and fast switching to insert an on-screen display (OSD), usu-ally text, onto the TV. The MAX4397 supports RGB as an input from either the VCR or the MPEG decoder and as an output only to the TV. The Red video signal of the RGB format and the Chroma video signal of the S-VHS format share the same SCART connector pin. Therefore,RGB and S-video signals cannot be present at the same time. Loop-through is possible with a Composite video signal but not with RGB signals because the RGB SCART pins are used for both input and output.

In SCART, there is the possibility of a bidirectional use of the Red/Chroma pin. When using the Red/Chroma pin as an input port, terminate the Red/Chroma output

with a 75?resistor to ground. Thus, a ground state is provided by an active pulldown to GNDVID on the Red/Chroma output to support the bidirectional Chroma or Red I/O, turning the output source resistors into ter-minations (see Figure 2). The active pulldown also pro-vides the “Mute Output” function, and disables the deselected video outputs. The “Mute Output” state is the default power-on state for video.

For high-quality home video, the MPEG decoder, VCR,and TV use the S-video format. The MAX4397 supports S-video signals as an input from the VCR, the MPEG decoder, and the TV, and also as a separately switch-able output to the TV and VCR. Because S-video sup-port was not included in the original specifications of the SCART connector, the Luma (Y) signal of S-video and the CVBS signal share the same SCART connector pins. If S-video is present, then a Composite signal must be created from the Y and C signals to drive the RF _CVBS_OUT pin. F or S-video, loop-through is not possible since the Chroma SCART port is used for both input and output.

The MAX4397 supports Composite video (CVBS) for-mat, with inputs from the VCR, MPEG decoder, and TV.F ull loop-through is possible to the TV and VCR only,since the MPEG decoder SCART connector has sepa-rate input and output pins for the CVBS format.

Audio/Video Switch for Dual SCART Connectors 12______________________________________________________________________________________

Figure 2. Bidirectional SCART Pins

Video Outputs

The DC level at the video outputs is controlled so that coupling capacitors are not required, and all of the video outputs are capable of driving a DC-coupled, 150?,back-terminated coax load with respect to ground.

In a typical television input circuit (see F igure 3) the video output driver on the SCART chip only needs to source current. Users should note that, while the SCART specification states 75?impedance, in prac-tice, typical SCART chip implementations assume 75?input resistance to ground (and source current from the video output stage).

Since some televisions and VCRs use the horizontal sync height for automatic gain control, the MAX4397accurately reproduces the sync height to within ±2%.

Slow Switching

The MAX4397 supports the IEC 933-1, Amendment 1,tri-level slow switching that selects the aspect ratio for the display (TV). Under I 2C-compatible control, the MAX4397 sets the slow-switching output voltage level.Table 1 shows the valid input levels of the slow-switch-ing signal and the corresponding operating modes of the display device.

Two bidirectional ports are available for slow-switching signals for the TV and VCR. The slow-switching input status is continuously read and stored in the register 0Eh. The slow-switching outputs can be set to a logic level or high impedance by writing to registers 07h and 09h. See Tables 8 and 10 for details.

Fast Switching

The VCR or MPEG decoder outputs a fast-switching signal to the display device or TV to insert on-screen display (OSD). The fast-switching signal can also be

set to a constant high or low output signal through the I 2C interface. The fast-switching output can be set through writing to register 07h.

Y/C Mixer

The MAX4397 includes an on-chip mixer to produce Composite video (CVBS) when S-video (Y and C) is present. The Composite video drives the RF _CVBS_OUT output pin. The circuit sums Y and C signals to obtain the CVBS component. A +6dB output buffer drives RF_CVBS_OUT.

Video Reconstruction Filter

The encoder DAC outputs need to be lowpass-filtered to reject the out-of-band noise. The MAX4397 inte-grates the reconstruction filter. The filter is fourth order,which is composed of two Sallen-Key biquad in cas-cade, implementing a Butterworth-type transfer func-tion. The internal reconstruction filters feature a 6MHz cutoff frequency, and -35dB minimum attenuation at 27MHz. Note that the SET pin is used to set the accura-cy of the filter cutoff frequency. Connect a 100k ?resis-tor from SET to ground.

SCART Audio Switching

Audio Inputs

All audio inputs for the MAX4397S are single-ended and are AC-coupled. The MAX4397D audio inputs are singled-ended and AC-coupled except for the audio encoder input, which is differential DC-coupled. The audio block has three stereo audio inputs from the TV, the VCR, and the MPEG decoder SCART. Each input has a 100k ?resistor connected to an internally generated voltage equal to 0.23 x V 12, except for the encoder input of the MAX4397D, where the DC bias is fixed externally.

MAX4397

Audio/Video Switch for Dual SCART Connectors

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Table 1. Slow-Switching Modes

Figure 3. Typical TV Input Circuit

M A X 4397

Audio Outputs

Both right and left channels have a stereo output for the TV and VCR SCART. The monaural output, which is a mix of the TV right and left channels, drives the RF modulator, RF _MONO_OUT. The monaural mixer, a resistor summer, attenuates the amplitude of each of the two signals by 6dB. A 12.54dB gain block follows the monaural mixer. If the left and right audio channels

were completely uncorrelated, then a 9.54dB gain block is used. See F igures 4 and 5 for the functional diagram of the audio section.

Clickless Switching

The TV channel incorporates a zero-crossing detect (ZCD) circuit that minimizes click noise due to abrupt signal level changes that occur when switching between audio signals at an arbitrary moment.

Audio/Video Switch for Dual SCART Connectors 14______________________________________________________________________________________

Figure 4. MAX4397D Audio Section Functional Diagram

To implement the zero-crossing function when switch-ing audio signals, set the ZCD bit by loading register 00h through the I 2C-compatible interface (if the ZCD bit is not already set). Then set the mute bit low by loading register 00h. Next, wait for a sufficient period of time for the audio signal to cross zero. This period is a function of the audio signal path’s low-frequency 3dB corner (f L3dB ). Thus, if f L3dB = 1kHz, the time period to wait for a zero-crossing detect is 1/2kHz or 0.5ms.

Next, set the appropriate TV switches using register 01h. F inally, clear the mute bit (while leaving the ZCD bit high) using register 00h. The MAX4397 switches the signal out of mute at the next zero crossing.

To implement the zero-cross function for TV volume changes, or for TV and phono volume bypass switch-ing, simply ensure the ZCD bit in register 00h is set.

MAX4397

Audio/Video Switch for Dual SCART Connectors

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Figure 5. MAX4397S Audio Section Features Singled-Ended Encoder Input

M A X 4397

Volume Control

The TV channel volume control ranges from -56dB to +6dB in 2dB steps. The VCR volume control settings are programmable for -6dB, 0dB, and +6dB. These gain levels are referenced to the application inputs,where some dividers are present. With the ZCD bit set,the TV volume control switches only at zero-crossings,thus minimizing click noise. The TV outputs can bypass the volume control. Likewise, the monaural output sig-nal can be processed by the TV volume control or it can bypass the volume control.

Digital Section

Serial Interface

The MAX4397 uses a simple 2-wire serial interface requiring only two standard microprocessor port I/O lines. The fast-mode I 2C-compatible serial interface allows communication at data rates up to 400kbps or 400kHz. Figure 6 shows the timing diagram of the sig-nals on the 2-wire interface.

The two bus lines (SDA and SCL) must be at logic-high when the bus is not in use. The MAX4397 is a slave device and must be controlled by a master device.Pullup resistors from the bus lines to the supply are required when push-pull circuitry is not driving the lines.

The logic level on the SDA line can only change when the SCL line is low. The start and stop conditions occur when SDA toggles low/high while the SCL line is high (see F igure 6). Data on SDA must be stable for the duration of the setup time (t SU,DAT ) before SCL goes high. Data on SDA is sampled when SCL toggles high with data on SDA stable for the duration of the hold time (t HD,DAT ). Note that data is transmitted in an 8-bit byte.A total of nine clock cycles are required to transfer a byte to the MAX4397. The device acknowledges the successful receipt of the byte by pulling the SDA line low during the 9th clock cycle.

Audio/Video Switch for Dual SCART Connectors

16______________________________________________________________________________________

Figure 6. SDA and SCL Signal Timing Diagram

Data Format of the I2C Interface

The MAX4397 is compatible with existing I2C systems.

SCL and SDA are high-impedance inputs. SDA has an

open drain that pulls the bus line to a logic-low during

the 9th clock pulse. Figure7 shows a typical I2C inter-

face application. The communication protocol supports

the standard I2C 8-bit communications. The MAX4397

address is compatible with the 7-bit I2C addressing

protocol only; 10-bit format is not supported.

Digital Inputs and Interface Logic

The I2C-compatible, 2-wire interface has logic levels

defined as V IL= 0.8V and V IH= 2.0V. All of the inputs

include Schmitt-trigger buffers to accept low-transition

interfaces. The digital inputs are compatible with 3V

CMOS logic levels.

Programming

Connect DEV_ADDR to ground to set the MAX4397

write and read address as shown in Table2.

Data Register Writing and Reading

Program the SCART video and audio switches by writ-

ing to registers 00h through 0Dh. Registers 00h through

0Eh can also be read, allowing read-back of data after

programming and facilitating system debugging. The

status register is read-only and can be read from

address 0Eh. See Tables 3–12 for register program-

ming information.

Applications Information

Hot-Plug of SCART Connectors

The MAX4397 features high-ESD protection on all

SCART inputs and outputs, and requires no external

transient-voltage suppressor (TVS) devices to protect

against floating chassis discharge. Some set-top boxes

have a floating chassis problem in which the chassis is

not connected to earth ground. As a result, the chassis

can charge up to 500V. When a SCART cable is con-

nected to the SCART connector, the charged chassis

can discharge through a signal pin. The equivalent cir-

cuit is a 2200pF capacitor charged to 311V connected

through less than 0.1?to a signal pin. The MAX4397 is

soldered on the PC board when it experiences such a

discharge. Therefore, the current spike flows through

the ESD protection diodes and is absorbed by the sup-

ply bypass capacitors, which have high capacitance

and low ESR.

To better protect the MAX4397 against excess voltages

during the cable discharge condition, place an addi-

tional 75?resistor in series with all inputs and outputs

to the SCART connector. For harsh environments where

±15kV protection is needed, the MAX4385E and

MAX4386E single and quad high-speed op amps fea-

ture the industry’s first integrated ±15kV ESD protection

on video inputs and outputs.

MAX4397 Audio/Video Switch for Dual SCART Connectors ______________________________________________________________________________________17

Figure7. Typical I2C Interface Application

Write Mode

M A X 4397

Power Supplies and Bypassing

The MAX4397 features single 5V and 12V supply opera-tion and requires no negative supply. The +12V supply V 12is for the SCART switching function. F or pin V 12,place all bypass capacitors as close as possible with a 10μF capacitor in parallel with a 0.1μF ceramic capacitor.Connect all V AUD pins together to +5V and bypass with a 10μF electrolytic capacitor in parallel with a 0.47μF low-ESR ceramic capacitor to audio ground. Bypass V AUD pins with a 0.1μF capacitor to audio ground. Bypass AUD_BIAS to audio ground with a 10μF electrolytic in parallel with a 0.1μF ceramic capacitor.

Bypass V DIG with a 0.1μF ceramic capacitor to digital ground. Bypass each V VID to video ground with a 0.1μF ceramic capacitor. Connect V VID in series with a 200nH ferrite bead to the +5V supply.

Layout and Grounding

F or optimal performance, use controlled-impedance traces for video signal paths and place input termina-tion resistors and output back-termination resistors close to the MAX4397. Avoid routing video traces par-allel to high-speed data lines.

The MAX4397 provides separate ground connections for video, audio, and digital supplies. F or best perfor-mance, use separate ground planes for each of the ground returns and connect all three ground planes together at a single point. Refer to the MAX4397 evalu-ation kit for a proven circuit board layout example.

Audio/Video Switch for Dual SCART Connectors 18______________________________________________________________________________________

MAX4397

Audio/Video Switch for Dual SCART Connectors

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Table 5. Register 00h: TV Audio control

Table 4. Data Format for Read Mode

M A X 4397

Audio/Video Switch for Dual SCART Connectors 20______________________________________________________________________________________

Table 7. Register 06h: TV Video Input Control