19-0671; Rev 0; 11/06 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices Features The MAX7481/MAX7482 bidirectional video filters/ buffers provide the reconstruction filter and line drive buffer for both composite (CVBS) and S-Video (Y/C) video signals in playback mode, and anti-aliasing in record mode for portable media devices. Each channel consists of a lowpass filter and an output buffer capable of driving a full 2VP-P video signal into one standard 150Ω load (DC-coupled to ground). In record mode, the MAX7481/MAX7482 output buffers have a gain of +6dB. In playback mode, the MAX7481 output buffers have a gain of +6dB and the MAX7482 output buffers have a gain of +7dB. The MAX7481/MAX7482 feature DirectDrive™ by utilizing an internal negative charge pump and regulator to maintain the output blanking level at ground, eliminating the need for a negative supply voltage, a large output coupling capacitor, or a sag correction configuration. The MAX7481/MAX7482 operate from a single +2.7V to +3.6V power supply. These devices are available in a space-saving 28-pin TQFN package and operate over the -40°C to +85°C extended temperature range. ♦ Composite and S-Video, Video-Playback and VideoRecord Interface for Portable Video Devices ♦ Saves Space by Sharing Connectors in Portable Devices ♦ DirectDrive Eliminates Expensive AC-Coupling Capacitors Blanking Level at Ground with Single Supply ♦ Composite and Y/C Signals ♦ Advanced Power-Down Modes for Extended Battery Life ♦ Low Supply Current in Shutdown Mode, < 1µA (typ) ♦ Filter Response Ideal for NTSC and PAL ♦ +6dB (MAX7481) or +7dB (MAX7482) Gain ♦ +2.7V to +3.6V Single-Supply Operation ♦ Small, 28-Pin, TQFN Package (5mm x 5mm) Ordering Information PART TEMP RANGE PINPACKAGE MAX7481ETI+ -40°C to +85°C 28 TQFN-EP* T2855-6 MAX7482ETI+ -40°C to +85°C 28 TQFN-EP* T2855-6 Applications Portable Media Devices Digital Camcorders PKG CODE +Denotes lead-free package. *EP = Exposed pad. Digital Cameras Pin Configuration appears at end of data sheet. Simplified Block Diagram VIDEO DAC PLAYBACK SIGNAL FLOW OUT4 VIDEO ADC MAX7481 MAX7482 0V IN1 LPF OUT1 IN3 0V IN5 P/R VIDEO PROCESSOR CVBSON YCON OUT3 CONTROL LOGIC OUT2 IN2 VIDEO DAC LPF 0V IN4 VIDEO ADC 0V OUT5 RECORD SIGNAL FLOW ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 MAX7481/MAX7482 General Description MAX7481/MAX7482 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices ABSOLUTE MAXIMUM RATINGS VCC to GND ............................................................. -0.3V to +4V IN1–IN5 to GND..........................................-0.3V to (VCC + 0.3V) OUT1–OUT5 to GND ....................................-1.8V to (VCC + 0.3V) OUT1–OUT5 to GND (Shutdown) .................-0.3V to (VCC + 0.3V) BIAS, SHDN, P/R, YCON, CVBSON to GND....................................................-0.3V to (VCC + 0.3V) CPVCC to CPGND ....................................................-0.3V to +4V C1P to GND............................................... -0.3V to (VCC + 0.3V) C1N to GND ............................................... (VSS - 0.3V) to +0.3V CPGND to GND.....................................................-0.1V to +0.1V CPVSS to VSS .........................................................-0.1V to +0.1V VSS to GND........................................................... -3.6V to +0.3V Continuous Current IN1–IN5, BIAS, CVBSON, YCON, C1P, C1N................±50mA Output Short-Circuit Current.............................................±90mA Continuous Power Dissipation (TA = +70°C) 28-Pin TQFN (derate 21.3mW/°C above +70°C) .......1702mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C 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 (VCC = CPVCC = +3.0V, TA = +25°C, C1 = C2 = 1µF, C3 = C4 = C5 = 0.1µF, load at OUT1–OUT5 = 150Ω to GND, RBIAS = 100kΩ to GND, unless otherwise noted. See the Functional Diagram/Typical Application Circuit.) PARAMETER SYMBOL Passband Flatness Stopband Attenuation CONDITIONS MIN f = 100kHz to 4.2MHz -1 f = 27MHz 35 TYP MAX UNITS +1 dB dB Differential Gain Error dG 5-step modulated staircase 0.2 % Differential Phase Error dP 5-step modulated staircase 0.3 Degrees Peak signal (2VP-P) to RMS noise, f = 100kHz to 4.2MHz 72 dB Signal-to-Noise Ratio SNR IN1, VIN = -0.10V to 0.92V 1.15 IN2, VIN = -0.09V to 0.92V Input Dynamic Swing VRANGE AC-coupled Input Leakage Current IN4 0.90 IN5 1.15 10 MAX7481: All outputs MAX7482: OUT4, OUT5 5.5 6 6.5 MAX7482: OUT1, OUT2, OUT3 6.5 7 7.5 f = 100kHz Output Black Level Variation Group-Delay Deviation 1.15 IIN Low Frequency Gain Clamp Settling Time 0.83 IN3 TCLAMP TG VP-P µA dB OUT1, OUT2, OUT4 ±150 OUT3, OUT5 ±200 To 5% with a 100 IRE step Deviation from 100kHz to 4.2MHz mV 300 Lines 4 ns Line-Time Distortion HDIST Deviation in a line with an 18µs, 100 IRE bar; 1 line = 63.5µs 0.3 % Field-Time Distortion VDIST Deviation in 130 lines with an 18µs, 100 IRE bar 0.5 % Channel-to-Channel Crosstalk XTALK f = 100kHz to 4.2MHz 2 -60 _______________________________________________________________________________________ dB Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices (VCC = CPVCC = +3.0V, TA = +25°C, C1 = C2 = 1µF, C3 = C4 = C5 = 0.1µF, load at OUT1–OUT5 = 150Ω to GND, RBIAS = 100kΩ to GND, unless otherwise noted. See the Functional Diagram/Typical Application Circuit.) PARAMETER Power-Supply Rejection Ratio SYMBOL PSRR CONDITIONS VCC = +2.7V to +3.6V MIN TYP MAX 50 UNITS dB CHARGE PUMP Switching Frequency 250 kHz LOGIC SIGNALS (CVBSON, P/R, YCON) Logic-Low Threshold VIL VCC = +2.7V to +3.6V Logic-High Threshold VIH VCC = +2.7V to +3.6V Logic Input Current IIL 0.5 V 10 µA 3.6 V 1.5 V SUPPLY Supply Voltage Range Quiescent Supply Current VCC, CPVCC ICC Shutdown Supply Current ISHDN Bias Voltage VBIAS 2.7 ICC = IVCC + ICPVCC, no load, P/R = GND, playback mode CVBSON = YCON = GND 9 18 CVBSON = VCC, YCON = GND 19 33 CVBSON = GND, YCON = VCC 28 42 CVBSON = YCON = VCC 40 52 1 10 mA ISHDN = IVCC + ICPVCC; SHDN = VCC, P/R = GND, CVBSON = YCON = VCC 1 µA V _______________________________________________________________________________________ 3 MAX7481/MAX7482 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VCC = CPVCC = +3.0V, TA = +25°C, unless otherwise noted.) INPUT = 1VP-P -40 INPUT = 1VP-P 2 -20 -40 -60 -60 1 1 10 FREQUENCY (MHz) FREQUENCY (MHz) MAX7482 PASSBAND FLATNESS MAX7481 GROUP-DELAY RESPONSE INPUT = 1VP-P 110 GROUP DELAY (ns) 3 120 2 1 0 -1 100 90 80 1 10 120 INPUT = 1VP-P 110 100 90 80 70 60 60 0.1 0.1 1 FREQUENCY (MHz) 10 0.1 2T RESPONSE 12.5T RESPONSE MAX7481 toc07 4 1 FREQUENCY (MHz) FREQUENCY (MHz) 200ns/div 10 MAX7482 GROUP-DELAY RESPONSE 70 -2 1 FREQUENCY (MHz) GROUP DELAY (ns) INPUT = 1VP-P 0.1 100 MAX7481 toc05 4 -1 -3 0.1 100 10 MAX7481 toc04 0.1 0 -2 -80 -80 1 MAX7481 toc06 -20 0 3 OUTPUT AMPLITUDE (dB) OUTPUT AMPLITUDE (dB) 0 20 MAX7481 toc02 INPUT = 1VP-P MAX7481 toc01 20 OUTPUT AMPLITUDE (dB) MAX7481 PASSBAND FLATNESS MAX7482 FREQUENCY RESPONSE MAX7481 toc03 MAX7481 FREQUENCY RESPONSE OUTPUT AMPLITUDE (dB) MAX7481/MAX7482 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices MAX7481 toc08 IN1 200mV/div IN1 200mV/div OUT1 200mV/div OUT1 200mV/div 400ns/div _______________________________________________________________________________________ 10 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 0 -0.01 -0.05 -0.02 -0.05 FIELD SQUARE-WAVE RESPONSE FIELD SQUARE-WAVE RESPONSE -0.13 MAX7481 toc11 MAX7481 toc10 MAX7481 toc09 DIFFERENTIAL GAIN (%) 0.05 0 -0.05 -0.10 -0.15 -0.20 -0.25 DIFFERENTIAL PHASE (deg) DIFFERENTIAL GAIN vs. DIFFERENTIAL PHASE 0 1st -0.07 2nd -0.12 -0.15 3rd 4th -0.24 5th IN1 500mV/div IN3 500mV/div OUT1 500mV/div OUT4 500mV/div -0.37 6th STEP 2ms/div 2ms/div Pin Description PIN NAME FUNCTION 1 CPVCC 2, 14, 17, 20 GND Charge-Pump Positive Power Supply. Bypass with a 1µF capacitor to CPGND. 3 IN2 Video Input 2 4 IN1 Video Input 1 5 OUT5 Video Output 5 6 OUT4 Video Output 4 Ground 7, 13, 23 VCC Positive Power Supply. Bypass with a 1µF capacitor to GND. 8 BIAS Bias Current Setting Control. Connect a 100kΩ ±1% resistor from BIAS to GND. 9 SHDN Shutdown Input. Drive high to put device in shutdown mode. 10 P/R 11 CVBSON 12 YCON 15 IN3 16 OUT1 Video Output 1 18 OUT3 Video Output 3 19 IN5 21 OUT2 Playback/Record Logic Input. Drive high for record mode and pull low for playback mode. CVBS Select Logic Input. Drive high for composite video on output OUT3 in playback mode and output OUT4 in record mode. See Table 1. Y/C Select Logic Input. Drive high to enable Y/C video on outputs OUT1 and OUT2 in playback mode and on outputs OUT4 and OUT5 in record mode. See Table 1. Video Input 3 Video Input 5 Video Output 2 _______________________________________________________________________________________ 5 MAX7481/MAX7482 Typical Operating Characteristics (continued) (VCC = CPVCC = +3.0V, TA = +25°C, unless otherwise noted.) MAX7481/MAX7482 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices Pin Description (continued) PIN NAME FUNCTION 22 IN4 Video Input 4 24 VSS Negative Power Supply. Connect to CPVSS. 25 CPVSS 26 C1N 27 CPGND 28 C1P Charge-Pump Flying Capacitor Positive Terminal. Connect a low-ESR 1µF capacitor from C1P to C1N. EP Exposed Pad. Internally connected to GND. Do not route any PCB traces directly under the package. Connect EP to GND for improved heat dissipation. — Charge-Pump Negative Power Supply. Bypass with a low-ESR 1µF capacitor to CPGND. Charge-Pump Flying Capacitor Negative Terminal. Connect a low-ESR 1µF capacitor from C1P to C1N. Charge-Pump Power Ground Detailed Description The MAX7481/MAX7482 bidirectional video filters and buffers are ideal for portable video applications where low-voltage, low-power operation is critical and applications that require both analog video inputs and outputs. The MAX7481/MAX7482 provide the reconstruction filter and line drivers for both composite video (CVBS) and Y/C (S-Video) for playback, while providing antialiasing filters and drivers for recording. In playback mode, the IN1 and IN2 inputs are enabled while the IN3, IN4, and IN5 inputs are disabled. The MAX7481/MAX7482 provide the filtered Y/C outputs at OUT1 and OUT2, and the composite output at OUT3. In record mode, IN1 and IN2 are disabled while IN3, IN4, and IN5 are enabled. Switches connecting OUT1 to GND, OUT2 to GND, and OUT3 to GND are turned on. These switches provide low-impedance paths to ground so that the same 75Ω external resistors that connect the playback outputs (OUT1, OUT2, and OUT3) and the external device can be used as terminating resistors for the recording signal source. Inputs IN3, IN4, and IN5 require AC-coupling capacitors because the signal from the external video source can be DC level-shifted and an internal clamp uses these capacitors to restore the blanking level to GND. The internal clamp operates only on signals coming from the external source due to the uncertainty in the DC offset. The gain in either direction is fixed at +6dB for the MAX7481. The MAX7482 output buffers have a gain of +7dB in playback mode and +6dB in record mode. The MAX7481/MAX7482 feature DirectDrive technology that allows the blanking level to stay at GND in a single supply system. The MAX7481/MAX7482 internally generate a negative supply voltage from an inverting charge pump and internal linear regulator. The regulated negative supply allows output buffers to drive 2VP-P video signals without exceeding operating voltage limits. 6 Comparison Between DirectDrive Output and AC-Coupled Output DirectDrive refers to the connection of the video signal from the MAX7481/MAX7482 to an external device without requiring large series AC-coupling capacitors in a single supply system. The actual level of the video signal varies less with a DirectDrive output than an ACcoupled output. The video-signal average can change greatly depending upon the picture content. With an AC-coupled output, the average changes according to the time constant formed by the series capacitor and series resistance (usually 150Ω). For example, Figure 1 shows an AC-coupled video signal alternating between a completely black screen and a completely white screen. Notice the excursion of the video signal as the screen changes. With a DirectDrive amplifier, the black level is held at ground. The video signal is constrained between -0.3V to +0.7V. Figure 2 shows the video signal from a DirectDrive amplifier with the same input signal as the AC-coupled system. The large series AC-coupling capacitors create a highpass filter. Since the lowest frequency in video is the frame rate, which can be between 24Hz and 30Hz, the pole of the highpass filter should ideally be an order of magnitude lower in frequency than the frame rate. Therefore, the AC-coupling capacitor must be very large, typically from 220µF to 3000µF. For space-constrained equipment, the series capacitor is unacceptable. Changing from a single series capacitor to a SAG network that requires two smaller capacitors can reduce space, but increases cost. Playback Mode Playback mode takes the video signal from the video processor and provides the reconstruction filter and line drive for both composite and Y/C video outputs. Figure 3 shows a signal flow diagram and Figure 4 shows the signal flow from the video processor to an external media _______________________________________________________________________________________ Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices OUTPUT 500mV/div INPUT 500mV/div 0V 0V OUTPUT 1V/div 2ms/div 2ms/div Figure 1. AC-Coupled Output Figure 2. DirectDrive Output device, such as a display in playback mode. In playback mode, internal switches S1, S2, S4, and S5 close the path from the video processor to the filter upon driving CVBSON and/or YCON high. Driving either YCON or CVBSON high enables the signal path from the video processor through the filter. Switches S6, S7, and S8 are open and not in the signal path in playback mode. Driving YCON high drives the Y signal to OUT1 and C signal to OUT2 while enabling CVBSON combines the Y and C signals to form composite video and output on OUT3. Both composite and Y/C video can be active in this mode. Pull P/R low for playback mode. Connection Sharing for Inputs and Outputs Outputs OUT1, OUT2, and OUT3 and inputs IN3, IN4, and IN5 can share one connector to save space. Figure 6 shows a possible interface at OUT1/OUT2/ OUT3 and IN3/IN4/IN5. In record mode, the switch closes, OUT1/OUT2/OUT3 go to GND, and the external 75Ω resistor looks like a load-termination resistor. Figure 4 shows that in playback mode, IN3/IN4/IN5 are not used and the switches to GND are open. The external 75Ω resistor serves as a back-termination resistor in playback mode and provides the cable termination in record mode. Record Mode Bidirectional Video Filter and Buffer Record mode takes the video signal from an external video source and provides anti-aliasing for both composite and Y/C signals. Figure 5 shows the signal flow from the external video source to the video processor. Upon driving P/R high, switches S1, S2, S4, and S5 change states so that the signals utilize the same filters and now route to the video processor. Switches S6, S7, and S8 all close to ground so that the incoming signal sees a 75Ω load termination to ground. The inputs IN3, IN4, and IN5 are AC-coupled with a 0.1µF capacitor that works with an internal clamping circuit. Enabling CVBSON drives the video signal from IN5 through the upper filter and outputs at OUT4. In this mode, OUT5 is disabled and pulled to GND. Enabling YCON drives the Y signal from IN3 through the upper filter to output at OUT4 and the C signal from IN4 through the lower filter to output at OUT5. Switch S3 connects OUT4 to either the Y channel if YCON is high, or the composite video channel if CVBSON is high. Driving both CVBSON and YCON high results in an invalid state, resulting in all output buffers shutting down and pulling to GND. The MAX7481/MAX7482 output buffers are designed to drive both Y/C channels as well as composite video. The output buffers use the internally generated negative supply to shift the blanking level of video outputs (composite and Y only) to ground so that the active video signal is above ground and the negative sync pulse is below ground. The C signal is shifted so that it is centered at GND. The output buffers are capable of driving a full 2VP-P video signal into a standard 150Ω load DC-coupled to GND. The output buffers can drive an AC-coupled load provided that the load impedance is greater than 5kΩ. The MAX7481/MAX7482 utilize the same filter in both playback and record modes by using switches that route the signals through different paths in the two modes (see Figure 3). Switches S1–S8 change states depending on the mode of operation and control input settings. The use of these internal switches enables utilizing a single filter in both modes for a unique solution in space constrained and cost-sensitive applications. _______________________________________________________________________________________ 7 MAX7481/MAX7482 INPUT 500mV/div MAX7481/MAX7482 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices VIDEO ADC MAX7481 MAX7482 S1 VIDEO DAC 75Ω LPF S2 S6 0.1μF S3 VIDEO PROCESSOR 0.1μF P/R CVBSON YCON CONTROL LOGIC S7 VIDEO DAC 75Ω S5 S4 LPF 75Ω S8 0.1μF VIDEO ADC Figure 3. Signal Flow Diagram Clamp In record mode, signals are AC-coupled into IN3, IN4, and IN5 through small 0.1µF capacitors. The clamp circuit internally DC-restores the signal for optimal performance of the circuit so that the OUT4 blanking level sits at GND and the OUT5 signal is centered at GND. Do not connect any resistors in series or parallel with clamp capacitors. Analog Inputs/Outputs Figures 4 and 5 show the signal flow diagrams for playback and record modes. P/R controls the mode of operation, while CVBSON and YCON select which outputs are enabled. Table 1 shows the various combinations of inputs and outputs that can be selected. In playback mode, inputs IN1 and IN2 are active and the outputs are selected by driving CVBSON and YCON. IN1 receives the composite or luma (Y) signal and level-shifts the signal by approximately 350mV at the output such that the sync tip is below GND and the active video is above GND. IN2 receives the chroma (C) signal and level-shifts by approximately 500mV at the output such that the signal is centered at GND. Drive 8 YCON high for outputs OUT1 and OUT2 to be active and/or drive CVBSON high to combine IN1 and IN2 into composite video and output on OUT3. Pull both control inputs low to disable outputs and power down the output buffers. OUT4 and OUT5 are always disabled in playback mode. In record mode, drive YCON high and CVBSON low to output Y/C format video on OUT4 and OUT5 or drive CVBSON high and YCON low to output composite video on OUT4. Pull both control inputs low to disable OUT4 and OUT5 and power down the output buffers. Driving both CVBSON and YCON high in record mode results in an invalid state and all output buffers power down. The Y signal inputs on IN3, C signal inputs on IN4, and composite signal inputs on IN5. OUT4 is shared between the composite signal and Y signal. The composite or Y signal that outputs on OUT4 has the blanking level set to GND with the sync tip below GND and active video above GND. The C signal that outputs on OUT5 is centered at GND. The outputs get levelshifted by the bias of the video processor input after the AC-coupling capacitors. _______________________________________________________________________________________ Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices MAX7481/MAX7482 Table 1. Input/Output Truth Table P/R High High High High PLAYBACK Low Low RECORD Low Low CVBSON YCON OUT3 (CVBS) OUT1 (Y) AND OUT2 (C) OUT4 (Y, CVBS) OUT5 (C) IN3 AND IN4 (Y, C) IN5 (CVBS) IN1 (Y) IN2 (C) Low Low Not Active Not Active GND GND Not Used Not Used Active Active Low High Not Active Active GND GND Not Used Not Used Active Active Active High Low Active Not Active GND GND Not Used Not Used Active High High Active Active GND GND Not Used Not Used Active Active Low Low GND GND GND GND Not Used Not Used Not Used Not Used Not Used Low High GND GND Active Active Active Not Used Not Used High Low GND GND Active GND Not Used Active Not Used Not Used High High GND GND GND GND Not Used Not Used Not Used Not Used VIDEO ADC OUT4 VIDEO DAC IN1 MAX7481 MAX7482 S1 OUT1 75Ω LPF S6 S2 S3 IN3 0.1μF IN5 0.1μF P/R = LOW CVBSON YCON VIDEO DAC IN2 OUT3 CONTROL LOGIC 75Ω S7 S5 S4 OUT2 75Ω LPF S8 VIDEO ADC OUT5 IN4 0.1μF Figure 4. Signal Flow Diagram for Playback Mode Short-Circuit Protection The MAX7481/MAX7482 typical application circuit includes a 75Ω back-termination resistor that limits shortcircuit current if an external short is applied to the video output. The MAX7481/MAX7482 provide additional output short-circuit protection to prevent damage in applications where amplifier output can be directly shorted. Charge Pump and Linear Regulator Portable video applications have space constraints that limit the use of AC-coupling capacitors and power constraints that limit the use of batteries to generate the negative supply rail. The MAX7481/MAX7482 simplify and reduce space and power constraints by integrating a charge pump and linear regulator to create a lownoise negative supply from a single positive supply. The charge pump inverts the positive supply to create _______________________________________________________________________________________ 9 MAX7481/MAX7482 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices VIDEO ADC OUT4 VIDEO DAC IN1 MAX7481 MAX7482 75Ω S2 S1 LPF S6 IN3 0.1μF S3 IN5 P/R = HIGH CVBSON YCON 75Ω S7 VIDEO DAC IN2 S4 75Ω S5 LPF S8 YCON = HIGH VIDEO ADC 0.1μF CONTROL LOGIC IN4 0.1μF OUT5 Figure 5. Signal Flow Diagram for Record Mode a raw negative voltage that is fed into a linear regulator. The linear regulator filters out the charge-pump noise for a clean negative supply rail. The use of an integrated charge pump facilitates a direct connection without the use of large series AC-coupling capacitors in a single supply system. BIAS Connect a 100kΩ resistor with 1% accuracy or better from BIAS to GND to create the bias current used throughout the MAX7481/MAX7482. Power-Down Modes The MAX7481/MAX7482 feature a shutdown mode that significantly reduces power consumption. Drive SHDN high to put the MAX7481/MAX7482 in shutdown mode. In shutdown mode, the video filters, output buffers, charge pump, and linear regulator are turned off, and all video output drivers are pulled to GND. The MAX7481/MAX7482 consume less than 10µA in shutdown mode. The MAX7481/MAX7482 also feature advanced powerdown modes that turn off the output buffers not in use 10 OUTPUT BUFFER OUT1, OUT2, OUT3 75Ω SINGLE CONNECTION 75Ω CABLE IN3, IN4, IN5 0.1μF Figure 6. Single Connector for Input and Output during normal operation. In playback mode, the record output buffers are turned off and in record mode, the playback output buffers are turned off. CVBSON and YCON further reduce power dissipation by turning off output buffers not in use. The MAX7481/MAX7482 are designed to extend battery life in portable video applications. ______________________________________________________________________________________ Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices MAX7481 MAX7482 IN1 DAC +6dB OR +7dB OUT1 150Ω LOWPASS FILTER CLAMP 75Ω Y IN3 C3 = 0.1μF OUT4 ADC +6dB +6dB OR +7dB 0.1μF OUT3 75Ω P/R CVBS CVBSON IN5 YCON C5 = 0.1μF +6dB OR +7dB IN2 DAC OUT2 LOWPASS FILTER 75Ω 150Ω C CLAMP IN4 C4 = 0.1μF ADC OUT5 REGULATOR +6dB 0.1μF CHARGE PUMP GND VCC BIAS SHDN CPVCC CPGND C1P 100kΩ 1μF VCC C1 = 1μF VSS C1N CPVSS C2 = 1μF 1μF VCC Applications Information Power-Supply Considerations The MAX7481/MAX7482 operate from a +2.7V to +3.6V single supply and require proper layout and bypassing. For best performance, place components as close as possible to the device. Proper grounding improves performance, minimizes crosstalk, and prevents any switching noise from coupling into the video signal. Connect GND (pin 2) and CPGND together at a single point on the PCB. Route CPGND and all traces carrying switching transients away from GND traces and components in the video signal path. Bypass each analog supply (VCC) with a 1µF capacitor to GND, placed as close as possible to the device. Bypass the charge-pump supply (CPVCC) with a 1µF capacitor to CPGND, placed as close as possible to the device. Connect CPV SS to V SS and bypass with a low-ESR 1µF capacitor to CPGND as close as possible to the device. ______________________________________________________________________________________ 11 MAX7481/MAX7482 Functional Diagram/Typical Application Circuit Pin Configuration Chip Information PROCESS: BiCMOS GND OUT3 GND OUT1 IN3 21 IN5 TOP VIEW OUT2 Exposed Pad and Heat Dissipation The MAX7481/MAX7482 are available in TQFN packages that have an exposed pad on the bottom. This pad is electrically connected to GND and can be soldered to the ground plane for improved thermal conductivity. Do not route signals directly under the package. 20 19 18 17 16 15 IN4 22 14 GND VCC 23 13 VCC VSS 24 MAX7481 MAX7482 CPVSS 25 C1N 26 CPGND 27 4 5 6 7 OUT4 VCC 3 OUT5 2 IN1 1 IN2 + GND C1P 28 CPVCC MAX7481/MAX7482 Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices TQFN 12 ______________________________________________________________________________________ 12 YCON 11 CVBSON 10 P/R 9 SHDN 8 BIAS Bidirectional Video Filters/Buffers for Composite and S-Video Portable Media Devices QFN THIN.EPS 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 ____________________ 13 © 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc. MAX7481/MAX7482 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information go to www.maxim-ic.com/packages.)