LT1396

LT1395/LT1396/LT1397 Single/Dual/Quad 400MHz Current Feedback Amplifier FEATURES s s s s s s s s DESCRIPTIO 400MHz Bandwidth on ± 5V (AV = 1) 350MHz Bandwidth on ± 5V (AV = 2, –1) 0.1dB Gain Flatness: 100MHz (AV = 1, 2 and –1) High Slew Rate: 800V/µs Wide Supply Range: ± 2V(4V) to ± 6V(12V) 80mA Output Current Low Supply Current: 4.6mA/Amplifier LT1395: SO-8 Package LT1396: SO-8 and MSOP Packages LT1397: SO-14 and SSOP-16 Packages The LT ®1395/LT1396/LT1397 are single/dual/quad 400MHz current feedback amplifiers with an 800V/µs slew rate and the ability to drive up to 80mA of output current. The LT1395/LT1396/LT1397 operate on all supplies from a single 4V to ± 6V. At ± 5V, they draw 4.6mA of supply current per amplifier. The LT1395/LT1396/LT1397 are manufactured on Linear Technology’s proprietary complementary bipolar process. They have standard single/dual/quad pinouts and they are optimized for use on supply voltages of ± 5V. , LTC and LT are registered trademarks of Linear Technology Corporation. APPLICATIO S s s s s s Cable Drivers Video Amplifiers MUX Amplifiers High Speed Portable Equipment IF Amplifiers TYPICAL APPLICATIO R G1 1.02k R F1 255Ω Unity-Gain Video Loop-Through Amplifier R G2 63.4Ω R F2 255Ω 10 0 – 3.01k VIN – 1/2 LT1396 – 3.01k VIN+ 1/2 LT1396 –10 GAIN (dB) VOUT –20 –30 –40 COMMON MODE SIGNAL –50 –60 100 + 0.67pF + 1% RESISTORS FOR A GAIN OF G: VOUT = G (VIN+ – VIN – ) R F1 = RF2 R G1 = (G + 3) RF2 R RG2 = F2 G+3 TRIM CMRR WITH RG1 1395/6/7 TA01 0.67pF 12.1k 12.1k BNC INPUTS HIGH INPUT RESISTANCE DOES NOT LOAD CABLE EVEN WHEN POWER IS OFF U Loop-Through Amplifier Frequency Response NORMAL SIGNAL 1k 10k 100k 1M 10M 100M 1G 1395/6/7 TA02 U U FREQUENCY (Hz) 1 LT1395/LT1396/LT1397 ABSOLUTE AXI U RATI GS Total Supply Voltage (V + to V –) ........................... 12.6V Input Current (Note 2) ....................................... ± 10mA Output Current ................................................. ±100mA Differential Input Voltage (Note 2) ........................... ± 5V Output Short-Circuit Duration (Note 3) ........ Continuous PACKAGE/ORDER I FOR ATIO TOP VIEW NC 1 –IN 2 +IN 3 V– 4 – + 8 7 6 5 NC V+ OUT NC OUT A –IN A +IN A V– 1 2 3 4 MS8 PACKAGE 8-LEAD PLASTIC MSOP S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 150°C/W TJMAX = 150°C, θJA = 250°C/W ORDER PART NUMBER LT1395CS8 S8 PART MARKING 1395 TOP VIEW OUT A 1 –IN A 2 +IN A 3 V+ 4 + – – + 14 OUT D – 13 –IN D + 12 +IN D 11 V– ORDER PART NUMBER LT1396CMS8 MS8 PART MARKING LTDY +IN B 5 –IN B 6 OUT B 7 + 10 +IN C – 9 –IN C 8 OUT C S PACKAGE 14-LEAD PLASTIC SO TJMAX = 150°C, θJA = 100°C/W ORDER PART NUMBER LT1397CS Consult factory for Industrial and Military grade parts. 2 U U W WW U W (Note 1) Operating Temperature Range (Note 4) . – 40°C to 85°C Specified Temperature Range (Note 5) .. – 40°C to 85°C Storage Temperature Range ................ – 65°C to 150°C Junction Temperature (Note 6) ............................ 150°C Lead Temperature (Soldering, 10 sec)................. 300°C TOP VIEW – + TOP VIEW – + 8 7 6 5 V+ OUT B –IN A +IN B OUT A 1 –IN A 2 +IN A 3 V– 4 – + 8 7 – + 6 5 V+ OUT B –IN A +IN B S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 150°C/W ORDER PART NUMBER LT1396CS8 S8 PART MARKING 1396 TOP VIEW OUT A –IN A +IN A V+ +IN B –IN B OUT B NC 1 2 3 4 5 6 7 8 + – – + 16 OUT D – 15 –IN D + 14 +IN D 13 V – + 12 +IN C – 11 –IN C 10 OUT C 9 NC GN PACKAGE 16-LEAD PLASTIC SSOP TJMAX = 150°C, θJA = 135°C/W ORDER PART NUMBER LT1397CGN GN PART MARKING 1397 LT1395/LT1396/LT1397 The q denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25°C. For each amplifier: VCM = 0V, VS = ± 5V, pulse tested, unless otherwise noted. (Note 5) SYMBOL VOS ∆VOS/∆T IIN+ IIN– en + in – in RIN CIN VINH VINL VOUTH PARAMETER Input Offset Voltage q ELECTRICAL CHARACTERISTICS CONDITIONS MIN TYP 1 MAX ± 10 ± 12 ± 25 ± 30 ± 50 ± 60 UNITS mV mV µV/°C µA µA µA µA nV/√Hz pA/√Hz pA/√Hz MΩ pF V V Input Offset Voltage Drift Noninverting Input Current q q 15 10 10 Inverting Input Current q Input Noise Voltage Density Noninverting Input Noise Current Density Inverting Input Noise Current Density Input Resistance Input Capacitance Input Voltage Range, High Input Voltage Range, Low Output Voltage Swing, High f = 1kHz, RF = 1k, RG = 10Ω, RS = 0Ω f = 1kHz f = 1kHz VIN = ± 3.5V VS = ± 5V VS = 5V, 0V VS = ± 5V VS = 5V, 0V VS = ± 5V VS = ± 5V VS = 5V, 0V VS = ± 5V VS = ± 5V VS = 5V, 0V VS = ± 5V, RL = 150Ω VS = ± 5V, RL = 150Ω VS = 5V, 0V; RL = 150Ω VS = ± 5V, RL = 150Ω VS = ± 5V, RL = 150Ω VS = 5V, 0V; RL = 150Ω VCM = ± 3.5V VCM = ± 3.5V VCM = ± 3.5V VS = ± 2V to ± 5V VS = ± 2V to ± 5V q q 4.5 6 25 0.3 3.5 1 2.0 q q 4.0 4.0 – 4.0 1.0 – 3.5 V V V V V q 3.9 3.7 4.2 4.2 – 4.2 VOUTL Output Voltage Swing, Low q – 3.9 – 3.7 0.8 q V V V V V V VOUTH Output Voltage Swing, High 3.4 3.2 3.6 3.6 – 3.6 VOUTL Output Voltage Swing, Low q – 3.4 – 3.2 0.6 q q q V V V dB µA/V µA/V dB µA/V µA/V µA/V dB kΩ mA CMRR – ICMRR PSRR + IPSRR – IPSRR AV ROL IOUT IS SR – 3dB BW 0.1dB BW Common Mode Rejection Ratio Inverting Input Current Common Mode Rejection Power Supply Rejection Ratio Noninverting Input Current Power Supply Rejection Inverting Input Current Power Supply Rejection Large-Signal Voltage Gain Transimpedance, ∆VOUT/∆IIN– Maximum Output Current Supply Current per Amplifier Slew Rate (Note 7) –3dB Bandwidth 0.1dB Bandwidth 42 52 10 16 22 2 3 7 56 70 1 VS = ± 2V to ± 5V VOUT = ± 2V, RL = 150Ω VOUT = ± 2V, RL = 150Ω RL = 0Ω AV = – 1, RL = 150Ω AV = 1, RF = 374Ω, RL = 100Ω AV = 2, RF = RG = 255Ω, RL = 100Ω AV = 1, RF = 374Ω, RL = 100Ω AV = 2, RF = RG = 255Ω, RL = 100Ω q 2 50 40 65 100 4.6 500 800 400 300 100 100 q q 80 6.5 mA V/µs MHz MHz MHz MHz 3 LT1395/LT1396/LT1397 The q denotes specifications which apply over the specified operating temperature range, otherwise specifications are at TA = 25°C. For each amplifier: VCM = 0V, VS = ± 5V, pulse tested, unless otherwise noted. (Note 5) SYMBOL tr, tf tPD os tS dG dP PARAMETER Small-Signal Rise and Fall Time Propagation Delay Small-Signal Overshoot Settling Time Differential Gain (Note 8) Differential Phase (Note 8) CONDITIONS RF = RG = 255Ω, RL = 100Ω, VOUT = 1VP-P RF = RG = 255Ω, RL = 100Ω, VOUT = 1VP-P RF = RG = 255Ω, RL = 100Ω, VOUT = 1VP-P 0.1%, AV = – 1, RF = RG = 280Ω, RL = 150Ω RF = RG = 255Ω, RL = 150Ω RF = RG = 255Ω, RL = 150Ω MIN TYP 1.3 2.5 10 25 0.02 0.04 MAX UNITS ns ns % ns % DEG ELECTRICAL CHARACTERISTICS Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: This parameter is guaranteed to meet specified performance through design and characterization. It has not been tested. Note 3: A heat sink may be required depending on the power supply voltage and how many amplifiers have their outputs short circuited. Note 4: The LT1395C/LT1396C/LT1397C are guaranteed functional over the operating temperature range of – 40°C to 85°C. Note 5: The LT1395C/LT1396C/LT1397C are guaranteed to meet specified performance from 0°C to 70°C. The LT1395C/LT1396C/LT1397C are designed, characterized and expected to meet specified performance from – 40°C and 85°C but is not tested or QA sampled at these temperatures. For guaranteed I-grade parts, consult the factory. Note 6: TJ is calculated from the ambient temperature TA and the power dissipation PD according to the following formula: LT1395CS8: TJ = TA + (PD • 150°C/W) LT1396CS8: TJ = TA + (PD • 150°C/W) LT1396CMS8: TJ = TA + (PD • 250°C/W) LT1397CS14: TJ = TA + (PD • 100°C/W) LT1397CGN16: TJ = TA + (PD • 135°C/W) Note 7: Slew rate is measured at ± 2V on a ± 3V output signal. Note 8: Differential gain and phase are measured using a Tektronix TSG120YC/NTSC signal generator and a Tektronix 1780R Video Measurement Set. The resolution of this equipment is 0.1% and 0.1°. Ten identical amplifier stages were cascaded giving an effective resolution of 0.01% and 0.01°. TYPICAL AC PERFOR A CE VS (V) ±5 ±5 ±5 AV 1 2 –1 RL (Ω) 100 100 100 RF (Ω) 374 255 280 RG (Ω) – 255 280 SMALL SIGNAL – 3dB BW (MHz) 400 350 350 SMALL SIGNAL 0.1dB BW (MHz) 100 100 100 SMALL SIGNAL PEAKING (dB) 0.1 0.1 0.1 TYPICAL PERFOR A CE CHARACTERISTICS Closed-Loop Gain vs Frequency (AV = 1) Closed-Loop Gain vs Frequency (AV = 2) Closed-Loop Gain vs Frequency (AV = – 1) 0 GAIN (dB) GAIN (dB) –2 –4 –6 GAIN (dB) 1M 10M 100M VS = ± 5V FREQUENCY (Hz) VIN = – 10dBm RF = RG = 255Ω RL = 100Ω 1G 1397 G02 1M 10M 100M VS = ± 5V FREQUENCY (Hz) VIN = – 10dBm RF = 374Ω RL = 100Ω 1G 1397 G01 4 UW UW 6 4 2 0 0 –2 –4 –6 1M 10M 100M VS = ± 5V FREQUENCY (Hz) VIN = – 10dBm RF = RG = 280Ω RL = 100Ω 1G 1397 G03 LT1395/LT1396/LT1397 TYPICAL PERFOR A CE CHARACTERISTICS Large-Signal Transient Response (AV = 1) Large-Signal Transient Response (AV = 2) Large-Signal Transient Response (AV = – 1) OUTPUT (1V/DIV) OUTPUT (1V/DIV) VS = ± 5V VIN = ± 2.5V RF = 374Ω RL = 100Ω TIME (10ns/DIV) 1395/6/7 G04 VS = ± 5V TIME (10ns/DIV) VIN = ± 1.25V RF = RG = 255Ω RL = 100Ω 1395/6/7 G05 OUTPUT (1V/DIV) 2nd and 3rd Harmonic Distortion vs Frequency 30 TA = 25°C 40 RF = RG = 255Ω RL = 100Ω 50 VS = ± 5V VOUT = 2VPP 60 70 80 90 100 110 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1397 G07 OUTPUT VOLTAGE (VP-P) DISTORTION (dB) 5 4 3 2 1M 10M FREQUENCY (Hz) 100M 1397 G08 PSRR (dB) HD3 HD2 Input Voltage Noise and Current Noise vs Frequency 1000 INPUT NOISE (nV/√Hz OR pA/√Hz) 100 OUTPUT IMPEDANCE (Ω) 100 CAPACITIVE LOAD (pF) –in 10 en +in 1 10 30 100 300 1k 3k 10k 30k 100k FREQUENCY (Hz) 1397 G10 UW VS = ± 5V TIME (10ns/DIV) VIN = ± 2.5V RF = RG = 280Ω RL = 100Ω 1395/6/7 G06 Maximum Undistorted Output Voltage vs Frequency 8 7 AV = +1 6 AV = +2 80 70 60 50 40 30 20 10 PSRR vs Frequency – PSRR + PSRR TA = 25°C RF = 374Ω (AV = 1) RF = RG = 255Ω (AV = 2) RL = 100Ω VS = ± 5V 0 10k TA = 25°C RF = RG = 255Ω RL = 100Ω AV = + 2 100k 1M 10M FREQUENCY (Hz) 100M 1397 G09 Output Impedance vs Frequency RF = RG = 255Ω RL = 50Ω AV = + 2 VS = ± 5V 1000 Maximum Capacitive Load vs Feedback Resistor 10 100 1 10 RF = RG AV = + 2 VS = ± 5V PEAKING ≤ 5dB 900 1500 2100 2700 FEEDBACK RESISTANCE (Ω) 3300 1397 G13 0.1 0.01 10k 100k 1M 10M FREQUENCY (Hz) 100M 1397 G11 1 300 5 LT1395/LT1396/LT1397 TYPICAL PERFOR A CE CHARACTERISTICS Capacitive Load vs Output Series Resistor 40 OUTPUT SERIES RESISTANCE (Ω) SUPPLY CURRENT (mA) 30 OUTPUT VOLTAGE SWING (V) RF = RG = 255Ω VS = ± 5V OVERSHOOT < 2% 20 10 0 10 100 CAPACITIVE LOAD (pF) 1000 1397 G14 Positive Supply Current per Amplifier vs Temperature POSITIVE SUPPLY CURRENT PER AMPLIFIER (mA) 5.00 4.95 4.90 4.85 4.80 4.75 4.70 4.65 4.60 4.55 VS = ± 5V INPUT OFFSET VOLTAGE (mV) 2.0 1.5 1.0 0.5 0 – 0.5 INPUT BIAS CURRENT (µA) 4.50 –50 –25 75 100 50 25 AMBIENT TEMPERATURE (°C) 0 Square Wave Response OUTPUT (200mV/DIV) INPUT (100mV/DIV) RL = 100Ω RF = RG = 255Ω f = 10MHz TIME (10ns/DIV) 1395/6/7 G22 tPD = 2.5ns AV = + 2 TIME (500ps/DIV) RL = 100Ω RF = RG = 255Ω VOUT (200mV/DIV) 6 UW 1397 G17 Supply Current vs Supply Voltage 6 5 4 3 2 1 0 0 1 2 7 3 5 6 4 SUPPLY VOLTAGE (± V) 8 9 5 4 3 2 1 0 –1 –2 –3 –4 Output Voltage Swing vs Temperature RL = 100k RL = 150Ω VS = ± 5V RL = 100k RL = 150Ω –5 50 25 0 75 100 –50 –25 AMBIENT TEMPERATURE (°C) 125 1397 G15 1397 G16 Input Offset Voltage vs Temperature 3.0 2.5 12 VS = ± 5V 15 Input Bias Currents vs Temperature VS = ± 5V IB+ 9 IB – 6 3 125 –1.0 – 50 – 25 75 100 50 25 AMBIENT TEMPERATURE (°C) 0 125 0 –50 –25 50 100 25 75 0 AMBIENT TEMPERATURE (°C) 125 1397 G18 1397 G19 Propagation Delay Rise Time and Overshoot OS = 10% OUTPUT (200mV/DIV) 1395/6/7 G20 tr = 1.3ns AV = + 2 TIME (500ps/DIV) RL = 100Ω RF = RG = 255Ω 1395/6/7 G21 LT1395/LT1396/LT1397 PIN FUNCTIONS LT1395CS8 NC (Pin 1): No Connection. – IN (Pin 2): Inverting Input. + IN (Pin 3): Noninverting Input. V – (Pin 4): Negative Supply Voltage, Usually – 5V. NC (Pin 5): No Connection. OUT (Pin 6): Output. V + (Pin 7): Positive Supply Voltage, Usually 5V. NC (Pin 8): No Connection. LT1396CMS8, LT1396CS8 OUT A (Pin 1): A Channel Output. – IN A (Pin 2): Inverting Input of A Channel Amplifier. + IN A (Pin 3): Noninverting Input of A Channel Amplifier. V – (Pin 4): Negative Supply Voltage, Usually – 5V. + IN B (Pin 5): Noninverting Input of B Channel Amplifier. – IN B (Pin 6): Inverting Input of B Channel Amplifier. OUT B (Pin 7): B Channel Output. V + (Pin 8): Positive Supply Voltage, Usually 5V. LT1397CS OUT A (Pin 1): A Channel Output. – IN A (Pin 2): Inverting Input of A Channel Amplifier. + IN A (Pin 3): Noninverting Input of A Channel Amplifier. V + (Pin 4): Positive Supply Voltage, Usually 5V. + IN B (Pin 5): Noninverting Input of B Channel Amplifier. – IN B (Pin 6): Inverting Input of B Channel Amplifier. OUT B (Pin 7): B Channel Output. OUT C (Pin 8): C Channel Output. – IN C (Pin 9): Inverting Input of C Channel Amplifier. + IN C (Pin 10): Noninverting Input of C Channel Amplifier. V – (Pin 11): Negative Supply Voltage, Usually – 5V. + IN D (Pin 12): Noninverting Input of D Channel Amplifier. – IN D (Pin 13): Inverting Input of D Channel Amplifier. OUT D (Pin 14): D Channel Output. LT1397CGN OUT A (Pin 1): A Channel Output. – IN A (Pin 2): Inverting Input of A Channel Amplifier. + IN A (Pin 3): Noninverting Input of A Channel Amplifier. V + (Pin 4): Positive Supply Voltage, Usually 5V. + IN B (Pin 5): Noninverting Input of B Channel Amplifier. – IN B (Pin 6): Inverting Input of B Channel Amplifier. OUT B (Pin 7): B Channel Output. NC (Pin 8): No Connection. NC (Pin 9): No Connection. OUT C (Pin 10): C Channel Output. – IN C (Pin 11): Inverting Input of C Channel Amplifier. + IN C (Pin 12): Noninverting Input of C Channel Amplifier. V – (Pin 13): Negative Supply Voltage, Usually – 5V. + IN D (Pin 14): Noninverting Input of D Channel Amplifier. – IN D (Pin 15): Inverting Input of D Channel Amplifier. OUT D (Pin 16): D Channel Output. APPLICATI S I FOR ATIO Feedback Resistor Selection The small-signal bandwidth of the LT1395/LT1396/LT1397 is set by the external feedback resistors and the internal junction capacitors. As a result, the bandwidth is a function of the supply voltage, the value of the feedback U W U U UO U U resistor, the closed-loop gain and the load resistor. The LT1395/LT1396/LT1397 have been optimized for ± 5V supply operation and have a – 3dB bandwidth of 400MHz at a gain of 1 and 350MHz at a gain of 2. Please refer to the resistor selection guide in the Typical AC Performance table. 7 LT1395/LT1396/LT1397 APPLICATI S I FOR ATIO Capacitance on the Inverting Input Current feedback amplifiers require resistive feedback from the output to the inverting input for stable operation. Take care to minimize the stray capacitance between the output and the inverting input. Capacitance on the inverting input to ground will cause peaking in the frequency response (and overshoot in the transient response). Capacitive Loads The LT1395/LT1396/LT1397 can drive many capacitive loads directly when the proper value of feedback resistor is used. The required value for the feedback resistor will increase as load capacitance increases and as closed-loop gain decreases. Alternatively, a small resistor (5Ω to 35Ω) can be put in series with the output to isolate the capacitive load from the amplifier output. This has the advantage that the amplifier bandwidth is only reduced when the capacitive load is present. The disadvantage is that the gain is a function of the load resistance. See the Typical Performance Characteristics curves. Power Supplies The LT1395/LT1396/LT1397 will operate from single or split supplies from ± 2V (4V total) to ± 6V (12V total). It is not necessary to use equal value split supplies, however the offset voltage and inverting input bias current will change. The offset voltage changes about 2.5mV per volt of supply mismatch. The inverting bias current will typically change about 10µA per volt of supply mismatch. Slew Rate Unlike a traditional voltage feedback op amp, the slew rate of a current feedback amplifier is not independent of the amplifier gain configuration. In a current feedback amplifier, both the input stage and the output stage have slew rate limitations. In the inverting mode, and for gains of 2 or more in the noninverting mode, the signal amplitude between the input pins is small and the overall slew rate is that of the output stage. For gains less than 2 in the noninverting mode, the overall slew rate is limited by the input stage. The input slew rate of the LT1395/LT1396/LT1397 is approximately 600V/µs and is set by internal currents and capacitances. The output slew rate is set by the value of 8 U the feedback resistor and internal capacitance. At a gain of 2 with 255Ω feedback and gain resistors and ± 5V supplies, the output slew rate is typically 800V/µs. Larger feedback resistors will reduce the slew rate as will lower supply voltages. Differential Input Signal Swing To avoid any breakdown condition on the input transistors, the differential input swing must be limited to ± 5V. In normal operation, the differential voltage between the input pins is small, so the ± 5V limit is not an issue. Buffered RGB to Color-Difference Matrix An LT1397 can be used to create buffered color-difference signals from RGB inputs (Figure 1). In this application, the R input arrives via 75Ω coax. It is routed to the noninverting input of LT1397 amplifier A1 and to a 845Ω resistor R8. There is also an 82.5Ω termination resistor R11, which yields a 75Ω input impedance at the R input when considered in parallel with R8. R8 connects to the inverting input of a second LT1397 amplifier (A2), which also sums the weighted G and B inputs to create a –0.5 • Y output. LT1397 amplifier A3 then takes the –0.5 • Y output and amplifies it by a gain of –2, resulting in the Y output. Amplifier A1 is configured in a noninverting gain of 2 with the bottom of the gain resistor R2 tied to the Y output. The output of amplifier A1 thus results in the color-difference output R-Y. The B input is similar to the R input. It arrives via 75Ω coax, and is routed to the noninverting input of LT1397 amplifier A4, and to a 2320Ω resistor R10. There is also a 76.8Ω termination resistor R13, which yields a 75Ω input impedance when considered in parallel with R10. R10 also connects to the inverting input of amplifier A2, adding the B contribution to the Y signal as discussed above. Amplifier A4 is configured in a noninverting gain of 2 configuration with the bottom of the gain resistor R4 tied to the Y output. The output of amplifier A4 thus results in the color-difference output B-Y. The G input also arrives via 75Ω coax and adds its contribution to the Y signal via a 432Ω resistor R9, which is tied to the inverting input of amplifier A2. There is also a 90.9Ω termination resistor R12, which yields a 75Ω W U UO LT1395/LT1396/LT1397 APPLICATI S I FOR ATIO termination when considered in parallel with R9. Using superposition, it is straightforward to determine the output of amplifier A2. Although inverted, it sums the R, G and B signals in the standard proportions of 0.3R, 0.59G and 0.11B that are used to create the Y signal. Amplifier A3 then inverts and amplifies the signal by 2, resulting in the Y output. 75Ω SOURCES R R11 82.5Ω G R12 90.9Ω B R13 76.8Ω R10 2320Ω R9 432Ω R7 255Ω + R8 845Ω A1 1/4 LT1397 R-Y R1 255Ω – A2 1/4 LT1397 R6 127Ω R5 255Ω A3 1/4 LT1397 ALL RESISTORS 1% VS = ± 5V A4 1/4 LT1397 1395/6/7 F01 Figure 1. Buffered RGB to Color-Difference Matrix Buffered Color-Difference to RGB Matrix An LT1395 combined with an LT1396 can be used to create buffered RGB outputs from color-difference signals (Figure 2). The R output is a back-terminated 75Ω signal created using resistor R5 and amplifier A1 configured for a gain of +2 via 255Ω resistors R3 and R4. The noninverting input of amplifier A1 is connected via 1k resistors R1 and R2 to the Y and R-Y inputs respectively, resulting in cancellation of the Y signal at the amplifier input. The remaining R signal is then amplified by A1. The B output is also a back-terminated 75Ω signal created using resistor R16 and amplifier A3 configured for a gain of +2 via 255Ω resistors R14 and R15. The noninverting input of amplifier A3 is connected via 1k resistors R12 and R13 to the Y and B-Y inputs respectively, resulting in cancellation of the Y signal at the amplifier input. The remaining B signal is then amplified by A3. The G output is the most complicated of the three. It is a weighted sum of the Y, R-Y and B-Y inputs. The Y input U is attenuated via resistors R6 and R7 such that amplifier A2’s noninverting input sees 0.83Y. Using superposition, we can calculate the positive gain of A2 by assuming that R8 and R9 are grounded. This results in a gain of 2.41 and a contribution at the output of A2 of 2Y. The R-Y input is amplified by A2 with the gain set by resistors R8 and R10, giving an amplification of –1.02. This results in a contribution at the output of A2 of 1.02Y – 1.02R. The B-Y input is amplified by A2 with the gain set by resistors R9 and R10, giving an amplification of – 0.37. This results in a contribution at the output of A2 of 0.37Y – 0.37B. If we now sum the three contributions at the output of A2, we get: A2OUT = 3.40Y – 1.02R – 0.37B It is important to remember though that Y is a weighted sum of R, G and B such that: Y = 0.3R + 0.59G + 0.11B R3 255Ω B-Y R2 255Ω Y R4 255Ω W + + – – U UO + – If we substitute for Y at the output of A2 we then get: A2OUT = (1.02R – 1.02R) + 2G + (0.37B – 0.37B) = 2G The back-termination resistor R11 then halves the output of A2 resulting in the G output. R1 1k Y R2 1k R-Y + A1 1/2 LT1396 R5 75Ω R R3 267Ω – R6 205Ω R7 1k R8 261Ω R9 698Ω B-Y R12 1k R13 1k ALL RESISTORS 1% VS = ± 5V R4 267Ω + A2 LT1395 R11 75Ω G R10 267Ω – + A3 1/2 LT1396 R16 75Ω B R14 267Ω – R15 267Ω 1395/6/7 F02 Figure 2. Buffered Color-Difference to RGB Matrix 9 LT1395/LT1396/LT1397 SI PLIFIED SCHE ATIC , each amplifier V+ PACKAGE DESCRIPTIO 0.007 – 0.0098 (0.178 – 0.249) 0.016 – 0.050 (0.406 – 1.270) * DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 10 U W W +IN –IN OUT V– 1395/6/7 SS Dimensions in inches (millimeters) unless otherwise noted. GN Package 16-Lead Plastic SSOP (Narrow 0.150) (LTC DWG # 05-08-1641) 0.189 – 0.196* (4.801 – 4.978) 16 15 14 13 12 11 10 9 0.009 (0.229) REF 0.229 – 0.244 (5.817 – 6.198) 0.150 – 0.157** (3.810 – 3.988) 1 0.015 ± 0.004 × 45° (0.38 ± 0.10) 0° – 8° TYP 0.053 – 0.068 (1.351 – 1.727) 23 4 56 7 8 0.004 – 0.0098 (0.102 – 0.249) 0.008 – 0.012 (0.203 – 0.305) 0.0250 (0.635) BSC GN16 (SSOP) 1098 LT1395/LT1396/LT1397 PACKAGE DESCRIPTIO U Dimensions in inches (millimeters) unless otherwise noted. MS8 Package 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) 0.118 ± 0.004* (3.00 ± 0.102) 0.040 ± 0.006 (1.02 ± 0.15) 0.007 (0.18) 0.021 ± 0.006 (0.53 ± 0.015) 0° – 6° TYP SEATING PLANE 0.012 (0.30) 0.0256 REF (0.65) BSC 0.034 ± 0.004 (0.86 ± 0.102) 8 76 5 0.006 ± 0.004 (0.15 ± 0.102) 0.193 ± 0.006 (4.90 ± 0.15) 0.118 ± 0.004** (3.00 ± 0.102) MSOP (MS8) 1098 * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 1 23 4 S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.189 – 0.197* (4.801 – 5.004) 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0°– 8° TYP 0.053 – 0.069 (1.346 – 1.752) 8 0.004 – 0.010 (0.101 – 0.254) 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0.157** (3.810 – 3.988) 7 6 5 0.014 – 0.019 (0.355 – 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.016 – 0.050 (0.406 – 1.270) 0.050 (1.270) BSC 1 2 3 4 SO8 1298 S Package 14-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.337 – 0.344* (8.560 – 8.738) 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.053 – 0.069 (1.346 – 1.752) 0° – 8° TYP 14 0.004 – 0.010 (0.101 – 0.254) 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0.157** (3.810 – 3.988) 13 12 11 10 9 8 0.014 – 0.019 (0.355 – 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.016 – 0.050 (0.406 – 1.270) 0.050 (1.270) BSC S14 1298 1 2 3 4 5 6 7 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. 11 LT1395/LT1396/LT1397 TYPICAL APPLICATI Single Supply RGB Video Amplifier The LT1395 can be used with a single supply voltage of 6V or more to drive ground-referenced RGB video. In Figure 3, two 1N4148 diodes D1 and D2 have been placed in series with the output of the LT1395 amplifier A1 but within the feedback loop formed by resistor R8. These diodes effectively level-shift A1’s output downward by 2 diodes, allowing the circuit output to swing to ground. Amplifier A1 is used in a positive gain configuration. The feedback resistor R8 is 255Ω. The gain resistor is created from the parallel combination of R6 and R7, giving a Thevenin equivalent 63.5Ω connected to 3.75V. This gives an AC gain of + 5 from the noninverting input of amplifier A1 to the cathode of D2. However, the video input is also attenuated before arriving at A1’s positive VIN RELATED PARTS PART NUMBER LT1227/LT1229/LT1230 LT1252/LT1253/LT1254 LT1398/LT1399 LT1675 LT1363/LT1364/LT1365 DESCRIPTION 140MHz Single/Dual/Quad Current Feedback Amplifier Low Cost Video Amplifiers Dual/Triple Current Feedback Amplifiers Triple 2:1 Buffered Video Mulitplexer 70MHz Single/Dual/Quad Op Amps COMMENTS 1100V/µs Slew Rate, Single Adds Shutdown Pin Single, Dual and Quad 100MHz Current Feedback Amplifiers 300MHz Bandwidth, 0.1dB Flatness > 150MHz with Shutdown 2.5ns Switching Time, 250MHz Bandwidth 1000V/µs Slew Rate, Voltage Feedback 139567f LT/TP 0100 4K • PRINTED IN USA 12 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com UO input. Assuming a 75Ω source impedance for the signal driving VIN, the Thevenin equivalent signal arriving at A1’s positive input is 3V + 0.4VIN, with a source impedance of 714Ω. The combination of these two inputs gives an output at the cathode of D2 of 2 • VIN with no additional DC offset. The 75Ω back termination resistor R9 halves the signal again such that VOUT equals a buffered version of VIN. It is important to note that the 4.7µF capacitor C1 has been added to provide enough current to maintain the voltage drop across diodes D1 and D2 when the circuit output drops low enough that the diodes might otherwise turn off. This means that this circuit works fine for continuous video input, but will require that C1 charge up after a period of inactivity at the input. 5V VS 6V TO 12V C1 4.7µF D2 D1 1N4148 1N4148 R1 1000Ω R2 1300Ω R3 160Ω R4 75Ω R5 2.32Ω R6 84.5Ω + A1 LT1395 R9 75Ω VOUT – R8 255Ω 1395/6/7 TA03 R7 255Ω Figure 3. Single Supply RGB Video Amplifier (1 of 4 Channels) © LINEAR TECHNOLOGY CORPORATION 1999