APPLICATIONS DESCRIPTION TYPICAL APPLICATION. LT1675/LT MHz, Triple and Single RGB Multiplexer with Current Feedback Amplifiers FEATURES

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MHz, Triple and Single RGB Multiplexer with Current Feedback Amplifiers FEATURES MHz Pixel Switching 3dB Bandwidth: MHz Small 6-Pin SSOP Package Channel Switching Time:.

1 MHz, Triple and Single RGB Multiplexer with Current Feedback Amplifiers FEATURES MHz Pixel Switching 3dB Bandwidth: MHz Small 6-Pin SSOP Package Channel Switching Time:.ns Expandable to Larger Arrays Drives Cables Directly High Slew Rate: /µs Low Switching Transient: mv Shutdown Supply Current: ma Output Short-Circuit Protected APPLICATIONS U RGB Switching Workstation Graphics Pixel Switching Coaxial Cable Drivers High Speed Signal Processing DESCRIPTION U The LT 67 is a high speed RGB multiplexer designed for pixel switching and fast workstation graphics. Included on chip are three SPDT switches and three current feedback amplifiers. The current feedback amplifiers drive double-terminated Ω or cables and are configured for a fixed gain of, eliminating six external gain setting resistors. The SPDT switches are designed to be break-before-make to minimize unwanted signals coupling to the input. The LT67- is a single version with two inputs, a single output and is ideal for a single channel application such as video sync. The key to the LT67 fast switching speed is Linear Technology s proprietary high speed bipolar process. This MUX can toggle between sources in excess of MHz, has a slew rate over /µs and has a 3dB bandwidth of MHz. The speed and ease of use of the LT67 make it ideal for high performance PCs, workstations and professional video monitors. The input-referred switching transient is only mv P-P and lasts just ns, making it virtually undetectable. Power supply requirements are ±V to ±6V and power dissipation is only 3mW on ±V, or mw for the LT67-. The expandable feature uses the disable pin to reduce the power dissipation to near mw in the off parts. Unlike competitive solutions that are in bulky high pin count packages, the LT67 is in a 6-lead narrow body SSOP. This small footprint, the size of an SO-8, results in a very clean high performance solution. The LT67- is available in the tiny MSOP and the SO-8., LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION U High Speed RGB MUX Select Pin Switches Inputs at MHz RED GREEN BLUE RED GREEN LT67 V OUT RED V OUT GREEN V OUT BLUE LOGIC PIN RED OUT 3V V V/DIV mv/div RED =, RED = V, R L = Ω MEASURED BETWEEN Ω BACK TERMINATION AND Ω LOAD 67 TA BLUE RGB/RGB 67 TA

2 ABSOLUTE MAXIMUM RATINGS W W W Supply Voltage... ±6.3V Inputs, and, Current... ±ma Output Short-Circuit Duration (Note )...Continuous Specified Temperature Range (Note 3)... C to 7 C U (Note ) Operating Temperature Range... C to 8 C Storage Temperature Range... 6 C to C Junction Temperature (Note )... C Lead Temperature (Soldering, sec)... 3 C PACKAGE/ORDER INFORMATION U W U V IN GND V IN 3 TOP VIEW MS8 PACKAGE 8-LEAD PLASTIC MSOP V OUT T JMAX = C, θ JA = C/ W V IN GND V IN 3 TOP VIEW S8 PACKAGE 8-LEAD PLASTIC SO T JMAX = C, θ JA = C/ W V OUT TOP VIEW RED GREEN BLUE GND GND RED GREEN BLUE V OUT RED V OUT GREEN V OUT BLUE GN PACKAGE 6-LEAD PLASTIC SSOP NARROW T JMAX = C, θ JA = C/ W ORDER PART NUMBER MS8 PART MARKING ORDER PART NUMBER S8 PART MARKING ORDER PART NUMBER GN PART MARKING LT67CMS8- LTGX LT67CS8-67 LT67CGN 67 Consult factory for Industrial and Military grade parts.

3 ELECTRICAL CHARACTERISTICS C T A 7 C, V S = ±V, R L =, V IN = LT67 (Pins,, 3, 6, 7, 8), LT67- (Pins, 3), =, unless otherwise specified. PARAMETER CONDITIONS MIN TYP MAX UNITS Output Offset Voltage Any Input Selected mv Output Offset Matching Between Outputs R to R, G to G, B to B mv Input Current Any Input Selected 3 µa Input Resistance V IN = ±V 7 kω PSRR V S =±.6V to ±6V, Measured at Output 38 db DC Gain Error to V V IN = V, R L = 3 6 % V IN = V, R L = Ω 8 % V IN = V, R L = % DC Gain Error to V V IN = V, R L = 3 6 % V IN = V, R L = Ω 8 % V IN = V, R L = 8 % Output Voltage V IN = V, R L = V V IN = V, R L = Ω.8 3. V V IN = V, R L =..8 V V IN = V, R L = V V IN = V, R L = Ω.7 3. V V IN = V, R L =..6 V Disabled Output Impedance Open... kω Maximum Output Current V IN = ±V, V O = 7 ma Supply Current LT67 = 33 ma =.7V µa LT67- = 8 ma =.7V.3 33 µa Pin Current LT67 = 6 µa LT67- = µa Pin Current LT67 = 9 8 µa LT67- = 3 6 µa Low (See Truth Table).8 V High (See Truth Table) V 3

4 AC CHARACTERISTICS C T A 7 C, V S = ±V, R L = Ω, V IN = LT67 (Pins,, 3, 6, 7, 8), LT67- (Pins, 3), =, unless otherwise specified. PARAMETER CONDITIONS MIN TYP MAX UNITS Slew Rate V OUT = V P-P V/µs Full Power Bandwidth (Note ) V OUT =6V P-P 8 MHz Small-Signal 3dB Bandwidth Less Than db Peaking MHz Gain Flatness Less Than.dB 7 MHz Gain Matching R to G to B. db R to R, G to G, B to B, LT67- V IN to V IN. db Channel-to-Channel Select Time R =, R = V Delay Time Measured from Time Pin Crosses Logic Threshold. ns Switching Time Time for V OUT to Go from to V. ns Enable Time ns Disable Time ns Input Pin Capacitance pf Pin Capacitance LT67. pf LT67-. pf Pin Capacitance LT67. pf LT67-. pf Output Pin Capacitance (Disabled) Open. pf Small-Signal Rise Time V IN = 3mV P-P, R L = Ω.8 ns Propagation Delay V IN = 3mV P-P, R L = Ω 3 ns Overshoot V IN = 3mV P-P, R L = Ω % On-Channel to Off-Channel Crosstalk Measured at MHz 6 db Chip Disable Crosstalk Measured at MHz, Open 9 db Channel Select Output Transient Measured Between Back Termination and Load mv P-P Differential Gain (Note 6).7 % Differential Phase (Note 6). DEG The denotes specifications that apply over the specified temperature range. Note : Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note : May require a heat sink. Note 3: The are guaranteed to meet specified performance from C to 7 C and are designed, characterized and expected to meet these extended temperature limits, but are not tested at C and 8 C. Guaranteed I grade parts are available; consult factory. Truth Table Note : T J is calculated from the ambient temperature T A and power dissipation P D according to the following formula: LT67CGN: T J = T A + (P D )( C/W) LT67CMS8-: T J = T A + (P D )( C/W) LT67CS8-: T J = T A + (P D )( C/W) Note : Full power bandwidth is calculated from the slew rate measurement: FPBW = SR/πV PEAK. Note 6: Differential Gain and Phase are measured using a Tektronix TSG YC/NTSC signal generator and a Tektronix 78R Video Measurement Set. The resolution of this equipment is.% and.. Nine identical MUXs were cascaded giving an effective resolution of.% and.. LT67 LT67- RED OUT GREEN OUT BLUE OUT VOUT RED GREEN BLUE VIN RED GREEN BLUE VIN X OFF OFF OFF OFF

5 TYPICAL PERFORMANCE CHARACTERISTICS U W GAIN (db) 3 3 Gain and Phase vs Frequency C L = pf R L = Ω GAIN PHASE k M M M G 67 G PHASE (DEG) GAIN (db) Frequency Response with Capacitive Loads 6 R L = Ω C L = pf 3 C L = pf C L = 3pF C L = pf 3 k M M M G 67 G GAIN (db) Gain vs Frequency 6. R L = Ω R G.8.7 B.6. k k M M M 67 G3 FREQUENCY (MHz) dB Bandwidth vs Supply Voltage R L = Ω 3 6 SUPPLY VOLTAGE (±V) 67 G CROSSTALK REJECTION (db) Crosstalk Rejection vs Frequency R S = R L = Ω R DRIVEN R ED 3 k M M M G 67 G CROSSTALK REJECTION (db) Crosstalk Rejection vs Frequency R S = R L = Ω G DRIVEN R ED 8 k M M M G 67 G3 CROSSTALK REJECTION (db) Crosstalk Rejection vs Frequency (Disabled) R S = R L = Ω POWER SUPPLY REJECTION RATIO (db) Power Supply Rejection Ratio vs Frequency PSRR +PSRR V S = ±V T A = C R L = Ω OUTPUT VOLTAGE (V P-P ) Undistorted Output Swing vs Frequency V S = ±V R L = Ω k M M M G 3 k M M M G M M M G 67 G6 67 G7 67 G8

6 TYPICAL PERFORMANCE CHARACTERISTICS U W OUTPUT IMPEDANCE (Ω) Output Impedance vs Frequency k DISABLED k D k M M M G 67 G9 DISTORTION (dbc) nd and 3rd Harmonic Distortion vs Frequency R L = Ω V O = V P-P ND 3RD FREQUENCY (MHz) LTXXXX 67 G INPUT BIAS CURRENT (µa) Input Bias Current vs Input Voltage V S = ±V C C C INPUT VOLTAGE (V) 67 G OUTPUT SHORT-CIRCUIT CURRENT (ma) Output Short-Circuit Current vs Temperature V S = ±V SOURCING V IN = V SINKING V IN = V 7 TEMPERATURE ( C) GAIN ERROR (%) 3 Positive DC Gain Error vs Temperature V S = ±V V IN = V R L = R L = Ω 7 TEMPERATURE ( C) GAIN ERROR (%) 8 6 Negative DC Gain Error vs Temperature V S = ±V V IN = V R L = R L = Ω 7 TEMPERATURE ( C) 67 G3 67 G 67 G 3 Output Voltage vs Input Voltage V S = ±V T A = C R L = R L = Supply Current vs Supply Voltage R L = 3 LT67- Supply Current vs Supply Voltage R L = OUTPUT VOLTAGE (V) R L = Ω SUPPLY CURRENT (ma) 3 C C C SUPPLY CURRENT (ma) 8 6 C C C 3 INPUT VOLTAGE (V) 3 6 SUPPLY VOLTAGE (±V) 3 6 SUPPLY VOLTAGE (±V) 67 G6 67 G 67 G 6

TYPICAL PERFORMANCE CHARACTERISTICS U W INPUT BIAS CURRENT (µa) Input Bias

Voltage vs Temperature V S = ±V 3 7 TEMPERATURE ( C) 67 G7 7 TEMPERATURE ( C)

RED OUT PIN V/DIV RED = RED = UNCORRELATED SINEWAVE R L = Ω, pf SCOPE PROBE 67

Enable and Disable V GEN mv/div PIN 9 V V/DIV V OUT mv/div RED OUT PIN V/DIV R

7 TYPICAL PERFORMANCE CHARACTERISTICS U W INPUT BIAS CURRENT (µa) Input Bias Current vs Temperature V S = ±V V IN = OUTPUT OFFSET VOLTAGE (mv) Output Offset Voltage vs Temperature V S = ±V 3 7 TEMPERATURE ( C) 67 G7 7 TEMPERATURE ( C) 67 G8 Toggling RED to RED Slew Rate 3V PIN V/DIV RED IN V/DIV RED OUT PIN V/DIV RED OUT PIN V/DIV RED = RED = UNCORRELATED SINEWAVE R L = Ω, pf SCOPE PROBE 67 G9 MEASURED AT PIN R L = Ω, pf SCOPE PROBE SR = /µs 67 G Small-Signal Rise Time Enable and Disable V GEN mv/div PIN 9 V V/DIV V OUT mv/div RED OUT PIN V/DIV R L = Ω MEASURED WITH FET PROBES 67 G AND DISABLE OF UNCORRELATED SINEWAVE R L = Ω 67 G 7

8 PIN FUNCTIONS 8 U U U LT67 RED (Pin ): Red Input. The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT RED will clip. The input must be terminated. GREEN (Pin ): Green Input. The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT GREEN will clip. The input must be terminated. BLUE (Pin 3): Blue Input. The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT BLUE will clip. The input must be terminated. GND (Pins, ): Signal Ground. Connect to ground plane. RED (Pin 6): Red Input. The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT RED will clip. The input must be terminated. GREEN (Pin 7): Green Input. The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT GREEN will clip. The input must be terminated. BLUE (Pin 8): Blue Input. The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT BLUE will clip. The input must be terminated. (Pin 9): Chip Enable. Ground this pin for normal operation. Take this pin to within 3mV of, or open to shut down the part. This pin is also used for router applications. When the part is disabled, the supply current is µa. LT67- V IN (Pin ): The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT will clip. The input must be terminated. GND (Pin ): Signal Ground. Connect to ground plane. V IN (Pin 3): The V video input signal to be switched is applied to this pin. If V are applied to this pin, V OUT will clip. The input must be terminated. (Pin ): Connect this pin to V and bypass with good tantalum capacitor (.7µF). The pin may also require a.µf or.µf depending on layout. (Pin ): Use this pin to select V IN or V IN. Use this pin for fast toggling. HIGH Selects V IN. (Pin ): Channel Select. Use this pin to select between RGB inputs and RGB inputs. Use this pin for fast toggling. HIGH Selects RGB. (Pins, ): Negative Power Supply. Connect these pins to V and bypass with good tantalum capacitor (.7µF). The pin may also require a.µf or.µf depending on layout. V OUT BLUE (Pin 3): Blue Output. It is twice BLUE or BLUE depending on which channel is selected by Pin. V OUT BLUE drives Ω or double-terminated cables. Do not add capacitance to this pin. V OUT GREEN (Pin ): Green Output. It is twice GREEN or GREEN depending on which channel is selected by Pin. V OUT GREEN drives Ω or double-terminated cables. Do not add capacitance to this pin. V OUT RED (Pin ): Red Output. It is twice RED or RED depending on which channel is selected by Pin. V OUT RED drives Ω or double-terminated cables. Do not add capacitance to this pin. (Pin 6): Positive Power Supply. Connect this pin to V and bypass with good tantalum capacitor (.7µF). The pin may also require a.µf or.µf depending on layout. V OUT (Pin 6): It is twice V IN or V IN depending on which channel is selected by Pin. V OUT drives Ω or double-terminated cables. Do not add capacitance to this pin. (Pin 7): Ground this pin for normal operation. Take this pin to within 3mV of, or open to shut down the part. This pin is also used for router applications. When the part is disabled, the supply current is.3µa. (Pin 8): Connect this pin to V and bypass with good tantalum capacitor (.7µF). The pin may also require a.µf or.µf depending on layout.

APPLICATIONS INFORMATION Power Supplies U W U U The LT67 will function with supply voltages below ±V (V total), however, to ensure a full V P-P video signal (V P-P at the output pins), the power

The power supplies should be bypassed with quality tantalum capacitors. It may be necessary to add.µf or.

9 APPLICATIONS INFORMATION Power Supplies U W U U The LT67 will function with supply voltages below ±V (V total), however, to ensure a full V P-P video signal (V P-P at the output pins), the power supply voltage should be between ±V to ±6V. The LT67 is designed to operate on ±V, and at no time should the supplies exceed ±6V. The power supplies should be bypassed with quality tantalum capacitors. It may be necessary to add.µf or.µf in parallel with the tantalum capacitors if there is excessive ringing on the output waveform. Even though the LT67 is well behaved, bypass capacitors should be placed as close to the LT67 as possible. Smallest Package and PC Board Space The LT67 has the internal gain set for V/V or 6dB, because it is designed to drive a double-terminated Ω or cable that has an inherent 6dB loss. There are several advantages to setting the gain internally. This topology eliminates six gain set resistors, reduces the pin count of the package and eliminates stray capacitance on the sensitivity feedback node. The LT67 fits into the small SSOP package, and these advantages lead to the smallest PC board footprint with enhanced performance. The LT67- eliminates two gain set resistors and is available in the tiny MSOP package and the cost-effective SO-8 package. Fast Switching The key to the LT67 fast switching speed is Linear Technology s proprietary high speed bipolar process. Internal switches can change state in less than ns, but the output of the MUX switches in about.ns, as shown in Figure. The additional delay is due to the finite bandwidth and the slew rate of the current feedback amplifier that drives the cable. For minimum ringing, it is important to minimize the load capacitance on the output of the part. This is normally not a problem in a controlled impedance environment, but stray PC board capacitance and scope probe capacitance can degrade the pulse fidelity. Figure shows the response of the output to various capacitive loads measured with a pf scope probe. PIN 3V V/DIV C L = pf C L = pf V/DIV RED OUT PIN mv/div C L = pf RED = V, RED = MEASURED BETWEEN BACK TERMINATION AND LOAD 67 F MEASURED AT PIN R L = Ω, pf SCOPE PROBE 67 F Figure. Toggling at MHz Figure. Response to Capacitive Loads 9

APPLICATIONS INFORMATION Switching Transients U W U U This MUX includes fast current steering break-beforemake SPDT switches that minimize switching glitches.

This transient is small and fast enough to not be visible on quality graphics terminals. Additionally, the break-before-make SPDT switch is open before the alternate channel is connected.

10 APPLICATIONS INFORMATION Switching Transients U W U U This MUX includes fast current steering break-beforemake SPDT switches that minimize switching glitches. The switching transients of Figure 3 are input-referred (measured between back termination and the load). The glitch is only mv P-P and the duration is just ns. This transient is small and fast enough to not be visible on quality graphics terminals. Additionally, the break-before-make SPDT switch is open before the alternate channel is connected. This means there is no input feedthrough during switching. Figure shows the amount of alternate channel that is coupled at the input. Expanding Inputs In video routing applications where the ultimate speed is not mandatory, as it is in pixel switching, it is possible to expand the number of MUX inputs by shorting the LT67 outputs together and switching with the pins. The internal gain set resistors have a nominal value of 7Ω and cause a Ω shunt across the cable termination. Figure shows schematically the effect of expanding the number of inputs. The effect of this loading is to cause a gain error that can be calculated by the following formula: 7 Ω Gain Error (db) = 6dB+ log n db 7+ 7 Ω n 7 Ω where n is total number of LT67s. For example, using ten LT67s ( Red, Green and Blue) the Gain Error is only.7db per channel. Figure 6 shows a -input RGB router. The response from RED Input to Red Output is shown in Figure 7 for a MHz square wave with Chip Select =. In this case the Gain Error is.3db. Toggling with Chip Select between IC # and IC # is shown in Figure 8. In this case RED Input is connected to and RED 3 Input is connected to an uncorrelated sinewave. 3V 3V PIN V/DIV PIN V/DIV RED OUT PIN mv/div RED IN PIN mv/div R L = Ω, pf SCOPE PROBE 67 F3 Figure 3. Input-Referred Switching Transient R S = 67 F Figure. Switching Transient at RED (Pin )

-Input Router Response 67 F7 mv/div mv/div Figure.

11 APPLICATIONS INFORMATION 7Ω 7Ω 7Ω OFF 7Ω OFF 7Ω ON 7Ω ṇ. U W U U R 7 n R n = NUMBER OF LT67s IN PARALLEL 67 F RED INPUT RED OUTPUT V V CHIP =, IC # DISABLED Figure 7. -Input Router Response 67 F7 mv/div mv/div Figure. Off Channels Load the Cable Termination with Each R A V = CHIP V V/DIV R RED OUTPUT V/DIV LT67 # R3 A V = RED OUT RED INPUT = RED 3 INPUT = UNCORRELATED SINEWAVE Figure 8. -Input Router Toggling 67 F8 R LT67 # CHIP 7HC 67 F6 Figure 6. Two LT67s Build a -Input RGB Router

12 TYPICAL APPLICATIO S U RGB Video Inverter RED LT67 VIDEO IN GREEN BLUE 97.6Ω 97.6Ω 97.6Ω 33Ω 33Ω V OUT RED V OUT GREEN V OUT BLUE + 33Ω 33Ω LT63 k V.V k.7v 33Ω + 33Ω + LT399 COMPOSITE BLANKING 67 TA3 This circuit is useful for viewing photographic negatives on video. A single channel can be used for composite or monochrome video. The inverting amplifier stages are only switched in during active video so the blanking, sync and color burst (if present) are not disturbed. To prevent video from swinging negative, a voltage offset equal to the peak video signal is added to the inverted signal.

13 TYPICAL APPLICATIO S U Logo or Bug Inserter RED LT67 VIDEO IN GREEN BLUE 3Ω 3Ω 3Ω V OUT RED V OUT GREEN V OUT BLUE A B OUTPUT NO VIDEO, % WHITE VIDEO PLUS 66% WHITE VIDEO PLUS 33% WHITE VIDEO, NO WHITE A A B B LT67 6Ω 6Ω 6Ω k V.V LT63 k.7v 67 TA This circuit highlights a section of the picture under control of a synchronous key signal. It can be used for adding the logo (also called a bug ) you see in the bottom corner of commercial television pictures or any sort of overlay signal, such as a crosshair or a reticule. The key signal has bits of control so there can be four levels of highlighting: unmodified video, video plus 33% white, video plus 66% white and % white. The two LT67s are configured as a -bit DAC. The resistors on the outputs set the relative bit weights. The output of the LT67 labeled B in the schematic is one half the weight of the A device. To properly match the video cable, the output resistors are selected so the parallel combination of the two is 7 ohms. The output will never exceed peak white, which is.7v for this NTSC-related RGB video. The reference white signal is adjustable to lower than peak white to make the effect less intrusive, if desired. 3

14 SI PLIFIED SCHE ATIC W W (LT67-, LT67 One Channel) OFF RED RED + RED V OUT 7Ω LOGIC 7Ω GND 67 SS

15 PACKAGE DESCRIPTION U Dimensions in inches (millimeters) unless otherwise noted. GN Package 6-Lead Plastic SSOP (Narrow.) (LTC DWG # -8-6).7.98 (.78.9). ±. (.38 ±.) 8 TYP.3.68 (.3.77)..98 (..9).89.96* (.8.978) (.9) REF.6. (.6.7) * DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED.6" (.mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED." (.mm) PER SIDE.8. (.3.3). (.63) BSC.9. ( ) ** ( ) GN6 (SSOP) 398 MS8 Package 8-Lead Plastic MSOP (LTC DWG # -8-66).8 ±.* (3. ±.).7 (.8). ±.6 (.3 ±.) 6 TYP SEATING PLANE. ±.6 (. ±.). (.3) REF.6 (.6) TYP.3 ±. (.86 ±.).6 ±. (. ±.) * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED.6" (.mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED.6" (.mm) PER SIDE.9 ±. (.88 ±.) ±.** (3. ±.) MSOP (MS8) 97 S8 Package 8-Lead Plastic Small Outline (Narrow.) (LTC DWG # -8-6).89.97* (.8.).8. (.3.).. (..8) 8 TYP.3.69 (.36.7).. (..) (.3.83) *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED.6" (.mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED." (.mm) PER SIDE. (.7) TYP.8. ( ) Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 3..7** ( ) SO8 996

16 TYPICAL APPLICATION V U NTSC-Related Color Bar Generator 7ACT CLOCK IS SUBCARRIER DIVIDED BY 9 OR 7.33kHz V COMPOSITE BLANKING A B C D CLR CLK LOAD ENP ENT QA 7LS63 QB QC 6.k B k 6.k R k 6.k G k LT67 V OUT BLUE V OUT RED V OUT GREEN.7V B WHITE YELLOW CYAN GREEN MAGENTA RED BLUE BLACK V k.8v 6Ω.7V R COMPOSITE SYNC 67 TA.7V G An RGB color bar test pattern is easily generated by dividing down a suitable clock. To form a stable pattern, the clock must be synchronous with the horizontal scan rate. Four times subcarrier, or.38mhz, is a readily available frequency, which when divided by 9, gives 7.33KHz. Dividing this signal by two, four and eight, gives the blue, read and green signals, respectively. This timing gives eight bars including white and black that fill the.6µs active video time. The digital signals are run through a 7ACT inverter because the CMOS output swings rail-to-rail. The inverter output is scaled to make video (.7V peak, for NTSC-related RGB). The LT67 drives the cable and adds sync to the RGB signals by switching in.86v. If no sync is required, this voltage can be set to zero and composite blanking can be used to drive the select pin of the LT67 in order to provide a more precise blanking level. RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT3/LT MHz Video MUX -Input and -Input, 9dB Channel Separation, Wide Supply Range LT -Input Video MUX with 7MHz Current Feedback Amp Drives Cables, Adjustable Gain, 9dB Channel Separation LT6 Low Cost Dual and Triple 3MHz Current Feedback Amp Drives Cables, Wide Supply Range, µa Shutdown Current with Shutdown LT398/LT399 Low Cost Dual and Triple 3MHz Current Feedback Amp Performance Upgrade for the LT9/LT6 with Shutdown 6 Linear Technology Corporation 63 McCarthy Blvd., Milpitas, CA (8)3-9 FAX: (8) f LT/TP 99 K PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 998

FEATURES TYPICAL APPLICATIO. LT1194 Video Difference Amplifier DESCRIPTIO APPLICATIO S

FEATURES TYPICAL APPLICATIO. LT1194 Video Difference Amplifier DESCRIPTIO APPLICATIO S FEATURES Differential or Single-Ended Gain Block: ± (db) db Bandwidth: MHz Slew Rate: /µs Low Cost Output Current: ±ma Settling Time: ns to.% CMRR at MHz: db Differential Gain Error:.% Differential Phase