LT1363 70MHz, 1000V/µs Op Amp U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 70MHz Gain Bandwidth 1000V/µs Slew Rate 7.5mA Maximum Supply Current 9nV/√Hz Input Noise Voltage Unity-Gain Stable C-LoadTM Op Amp Drives All Capacitive Loads 1.5mV Maximum Input Offset Voltage 2µA Maximum Input Bias Current 350nA Maximum Input Offset Current 50mA Minimum Output Current ±7.5V Minimum Output Swing into 150Ω 4.5V/mV Minimum DC Gain, RL=1k 50ns Settling Time to 0.1%, 10V Step 0.06% Differential Gain, AV=2, RL=150Ω 0.04° Differential Phase, AV=2, RL=150Ω Specified at ±2.5V, ±5V, and ±15V U APPLICATIO S ■ ■ ■ ■ ■ Wideband Amplifiers Buffers Active Filters Video and RF Amplification Cable Drivers Data Acquisition Systems The LT1363 is a member of a family of fast, high performance amplifiers using this unique topology and employing Linear Technology Corporation’s advanced bipolar complementary processing. For dual and quad amplifier versions of the LT1363 see the LT1364/1365 data sheet. For 50MHz amplifiers with 4mA of supply current per amplifier see the LT1360 and LT1361/1362 data sheets. For lower supply current amplifiers with bandwidths of 12MHz and 25MHz see the LT1354 through LT1359 data sheets. Singles, duals, and quads of each amplifier are available. , LTC and LT are registered trademarks of Linear Technology Corporation. C-Load is a trademark of Linear Technology Corporation U ■ The LT1363 is a high speed, very high slew rate operational amplifier with excellent DC performance. The LT1363 features reduced supply current, lower input offset voltage, lower input bias current and higher DC gain than devices with comparable bandwidth. The circuit topology is a voltage feedback amplifier with the slewing characteristics of a current feedback amplifier. The amplifier is a single gain stage with outstanding settling characteristics which makes the circuit an ideal choice for data acquisition systems. The output drives a 150Ω load to ±7.5V with ±15V supplies and to ±3.4V on ±5V supplies. The amplifier is also capable of driving any capacitive load which makes it useful in buffer or cable driver applications. TYPICAL APPLICATIO Cable Driver Frequency Response AV = –1 Large-Signal Response 2 VS = ±15V 0 GAIN (dB) VS = ±2.5V VS = ±5V –2 VS = ±10V IN –4 + LT1363 – 510Ω –6 75Ω OUT 75Ω 510Ω –8 1 10 FREQUENCY (MHz) 100 1363 TA02 1363 TA01 1 LT1363 W W U W ABSOLUTE MAXIMUM RATINGS Total Supply Voltage (V+ to V –) ............................... (Note 1) 36V Differential Input Voltage (Transient Only) (Note 2)................................... ±10V Input Voltage ............................................................ ±VS Output Short-Circuit Duration (Note 3) ............ Indefinite Operating Temperature Range (Note 8) ...–40°C to 85°C Specified Temperature Range (Note 9) ....–40°C to 85°C Maximum Junction Temperature (See Below) Plastic Package ................................................ 150°C Storage Temperature Range ..................–65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C W U U PACKAGE/ORDER INFORMATION TOP VIEW 1 8 NULL –IN 2 7 V+ +IN 3 6 VOUT V– 4 5 NC NULL ORDER PART NUMBER LT1363CN8 ORDER PART NUMBER TOP VIEW NULL 1 8 NULL –IN 2 7 V+ +IN 3 6 VOUT V– 4 5 NC LT1363CS8 S8 PART MARKING 1363 N8 PACKAGE 8-LEAD PDIP S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/ W TJMAX = 150°C, θJA = 190°C/ W Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS TA = 25°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS VSUPPLY VOS Input Offset Voltage (Note 4) IOS Input Offset Current IB Input Bias Current en Input Noise Voltage f = 10kHz in Input Noise Current f = 10kHz ±2.5V to ±15V RIN Input Resistance VCM = ±12V ±15V Input Resistance Differential CIN Input Capacitance MAX UNITS ±15V ±5V ±2.5V 0.5 0.5 0.7 1.5 1.5 1.8 mV mV mV ±2.5V to ±15V 120 350 nA ±2.5V to ±15V 0.6 2.0 ±2.5V to ±15V 9 nV/√Hz 1 pA/√Hz MΩ ±15V 5 MΩ ±15V 3 pF 13.4 3.4 1.1 V V V Input Voltage Range – ±15V ±5V ±2.5V Common Mode Rejection Ratio VCM = ±12V VCM = ±2.5V VCM = ±0.5V PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V AVOL Large-Signal Voltage Gain VOUT = ±12V, RL = 1k VOUT = ±10V, RL = 500Ω VOUT = ±7.5V, RL = 150Ω VOUT = ±2.5V, RL = 500Ω VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω µA 50 ±15V ±5V ±2.5V CMRR 2 TYP Range + Input Voltage MIN ±15V ±5V ±2.5V ±15V ±15V ±15V ±5V ±5V ±2.5V 12 12.0 2.5 0.5 –13.2 –12.0 –3.2 –2.5 –0.9 –0.5 V V V 84 76 66 90 81 71 dB dB dB 90 100 dB 4.5 3.0 2.0 3.0 2.0 2.5 9.0 6.5 3.8 6.4 5.6 5.2 V/mV V/mV V/mV V/mV V/mV V/mV LT1363 ELECTRICAL CHARACTERISTICS TA = 25°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS VSUPPLY MIN TYP MAX UNITS VOUT Output Swing RL = 1k, VIN = ±40mV RL = 500Ω, VIN = ±40mV RL = 500Ω, VIN = ±40mV RL = 150Ω, VIN = ±40mV RL = 500Ω, VIN = ±40mV ±15V ±15V ±5V ±5V ±2.5V 13.5 13.0 3.5 3.4 1.3 14.0 13.7 4.1 3.8 1.7 ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±7.5V VOUT = ±3.4V ±15V ±5V 50 23 60 29 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V 70 105 mA SR Slew Rate AV = –2, (Note 5) ±15V ±5V 750 300 1000 450 V/µs V/µs Full Power Bandwidth 10V Peak, (Note 6) 3V Peak, (Note 6) ±15V ±5V 15.9 23.9 MHz MHz GBW Gain Bandwidth f = 1MHz ±15V ±5V ±2.5V 70 50 40 MHz MHz MHz tr , tf Rise Time, Fall Time AV = 1, 10%-90%, 0.1V ±15V ±5V 2.6 3.6 ns ns Overshoot AV = 1, 0.1V ±15V ±5V 36 23 % % Propagation Delay 50% VIN to 50% VOUT, 0.1V ±15V ±5V 4.6 5.6 ns ns Settling Time 10V Step, 0.1%, AV = –1 10V Step, 0.01%, AV = –1 5V Step, 0.1%, AV = –1 ±15V ±15V ±5V 50 80 55 ns ns ns Differential Gain f = 3.58MHz, AV = 2, RL = 150Ω ±15V ±5V ±15V ±5V 0.03 0.06 0.01 0.01 % % % % ±15V ±5V ±15V ±5V 0.10 0.04 0.05 0.25 Deg Deg Deg Deg ±15V 0.7 Ω ±15V ±5V 6.3 6.0 ts f = 3.58MHz, AV = 2, RL = 1k Differential Phase f = 3.58MHz, AV = 2, RL = 150Ω f = 3.58MHz, AV = 2, RL = 1k RO Output Resistance IS Supply Current AV = 1, f = 1MHz 7.5 7.2 mA mA The ● denotes the specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS VSUPPLY VOS Input Offset Voltage (Note 4) ±15V ±5V ±2.5V ● ● ● Input VOS Drift (Note 7) ±2.5V to ±15V ● ±2.5V to ±15V ● ±2.5V to ±15V ● ±15V ±5V ±2.5V ● ● ● IOS Input Offset Current IB Input Bias Current CMRR Common Mode Rejection Ratio VCM = ±12V VCM = ±2.5V VCM = ±0.5V MIN TYP 10 82 74 64 MAX UNITS 2.0 2.0 2.2 mV mV mV 13 µV/°C 500 nA 3 µA dB dB dB 3 LT1363 ELECTRICAL CHARACTERISTICS 0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted. The ● denotes the specifications which apply over the temperature range SYMBOL PARAMETER CONDITIONS VSUPPLY MIN TYP MAX UNITS PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V ● 88 dB AVOL Large-Signal Voltage Gain VOUT = ±12V, RL = 1k VOUT = ±10V, RL = 500Ω VOUT = ±2.5V, RL = 500Ω VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω ±15V ±15V ±5V ±5V ±2.5V ● ● ● ● ● 3.6 2.4 2.4 1.5 2.0 V/mV V/mV V/mV V/mV V/mV VOUT Output Swing RL = 1k, VIN = ±40mV RL = 500Ω, VIN = ±40mV RL = 500Ω, VIN = ±40mV RL = 150Ω, VIN = ±40mV RL = 500Ω, VIN = ±40mV ±15V ±15V ±5V ±5V ±2.5V ● ● ● ● ● 13.4 12.8 3.4 3.3 1.2 ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±12.8V VOUT = ±3.3V ±15V ±5V ● ● 25 22 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V ● 55 mA SR Slew Rate AV = – 2, (Note 5) ±15V ±5V ● ● 600 225 V/µs V/µs IS Supply Current ±15V ±5V ● ● 8.7 8.4 mA mA The ● denotes the specifications which apply over the temperature range –40°C ≤ TA ≤ 85°C, VCM = 0V unless otherwise noted. (Note 9) SYMBOL PARAMETER CONDITIONS VSUPPLY VOS Input Offset Voltage (Note 4) ±15V ±5V ±2.5V ● ● ● MIN Input VOS Drift (Note 7) ±2.5V to ±15V ● TYP 10 MAX UNITS 2.5 2.5 2.7 mV mV mV 13 µV/°C IOS Input Offset Current ±2.5V to ±15V ● 600 nA IB Input Bias Current ±2.5V to ±15V ● 3.6 µA CMRR Common Mode Rejection Ratio VCM = ±12V VCM = ±2.5V VCM = ±0.5V ±15V ±5V ±2.5V ● ● ● 82 74 64 dB dB dB PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V ● 87 dB AVOL Large-Signal Voltage Gain VOUT = ±12V, RL = 1k VOUT = ±10V, RL = 500Ω VOUT = ±2.5V, RL = 500Ω VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω ±15V ±15V ±5V ±5V ±2.5V ● ● ● ● ● 2.5 1.5 1.5 1.0 1.3 V/mV V/mV V/mV V/mV V/mV VOUT Output Swing RL = 1kΩ, VIN = ±40mV RL = 500Ω, VIN = ±40mV RL = 500Ω, VIN = ±40mV RL = 150Ω, VIN = ±40mV RL = 500Ω, VIN = ±40mV ±15V ±15V ±5V ±5V ±2.5V ● ● ● ● ● 13.4 12.7 3.4 3.2 1.2 ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±12.7V VOUT = ±3.2V ±15V ±5V ● ● 25 21 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V ● 50 mA SR Slew Rate AV = – 2, (Note 5) ±15V ±5V ● ● 550 180 V/µs V/µs IS Supply Current ±15V ±5V ● ● 4 9.0 8.7 mA mA LT1363 ELECTRICAL CHARACTERISTICS Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Differential inputs of ±10V are appropriate for transient operation only, such as during slewing. Large, sustained differential inputs will cause excessive power dissipation and may damage the part. See Input Considerations in the Applications Information section of this data sheet for more details. Note 3: A heat sink may be required to keep the junction temperature below absolute maximum when the output is shorted indefinitely. Note 4: Input offset voltage is pulse tested and is exclusive of warm-up drift. Note 5: Slew rate is measured between ±10V on the output with ±6V input for ±15V supplies and ±2V on the output with ±1.75V input for ±5V supplies. Note 6: Full power bandwidth is calculated from the slew rate measurement: FPBW = SR/2πVP. Note 7: This parameter is not 100% tested. Note 8: The LT1363C is guaranteed functional over the operating temperature range of –40°C to 85°C. Note 9: The LT1363C is guaranteed to meet specified performance from 0°C to 70°C. The LT1363C is designed, characterized and expected to meet specified performance from – 40°C to 85°C, but is not tested or QA sampled at these temperatures. For guaranteed I-grade parts, consult the factory. U W TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs Supply Voltage and Temperature V+ 10 1.0 125°C 25°C 6 –55°C 4 2 –1.0 INPUT BIAS CURRENT (µA) COMMON MODE RANGE (V) 8 VS = ±15V TA = 25°C IB+ + IB– IB = ———— 2 TA = 25°C ∆VOS < 1mV – 0.5 SUPPLY CURRENT (mA) Input Bias Current vs Input Common Mode Voltage Input Common Mode Range vs Supply Voltage –1.5 –2.0 2.0 1.5 1.0 0.8 0.6 0.4 0.5 V– 0 5 10 15 SUPPLY VOLTAGE (±V) 20 0 5 10 15 SUPPLY VOLTAGE (±V) 1363 G01 0.8 0.6 0.4 0.2 INPUT VOLTAGE NOISE (nV/√Hz) INPUT BIAS CURRENT (µA) 10 VS = ±15V TA = 25°C AV = 101 RS = 100k in 10 0 25 50 75 TEMPERATURE (°C) 100 125 1363 G04 10 TA = 25°C en 1 1 –25 100 1k 10k FREQUENCY (Hz) 85 0.1 100k 1363 G05 INPUT CURRENT NOISE (pA/√Hz) 1.0 0 – 50 Open-Loop Gain vs Resistive Load 100 1.2 15 1363 G03 Input Noise Spectral Density VS = ±15V IB+ + IB– IB = ———— 2 –10 –5 0 5 10 INPUT COMMON MODE VOLTAGE (V) 1363 G02 Input Bias Current vs Temperature 1.4 0.2 –15 20 80 OPEN-LOOP GAIN (dB) 0 VS = ±15V VS = ±5V 75 70 65 60 10 100 1k LOAD RESISTANCE (Ω) 10k 1363 G06 5 LT1363 U W TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Swing vs Supply Voltage Open-Loop Gain vs Temperature V+ V+ RL = 1k VO = ±12V VS = ±15V –0.5 OUTPUT VOLTAGE SWING (V) 80 79 78 77 76 TA = 25°C –0.5 RL = 1k –1.0 –1.5 RL = 500Ω –2.0 2.0 RL = 500Ω 1.5 RL = 1k 1.0 75 0.5 74 – 50 –25 0 25 50 75 TEMPERATURE (°C) 100 0 125 5 10 15 SUPPLY VOLTAGE (±V) 20 OUTPUT IMPEDANCE (Ω) SINK 90 0 25 50 75 TEMPERATURE (°C) 100 AV = 100 10 1 AV = 10 AV = 1 0.01 10k 125 100k 1M 10M FREQUENCY (Hz) 30 20 20 1mV 0 –2 –4 10mV 4 10mV 0 –2 –4 1mV 42 80 40 70 38 60 36 50 –8 40 –10 30 40 60 80 SETTLING TIME (ns) 100 1363 G13 0 20 40 60 80 SETTLING TIME (ns) 100 1363 G12 44 PHASE MARGIN 90 –8 20 46 100 –10 0 48 TA = 25°C 110 1mV –6 50 120 2 10mV 1mV 130 GAIN BANDWIDTH (MHz) OUTPUT STEP (V) 6 2 –6 VS = ±15V AV = –1 RF = 1k CF = 3pF 8 100M 1M 10M FREQUENCY (Hz) 34 GAIN BANDWIDTH 32 30 0 5 10 15 SUPPLY VOLTAGE (±V) 20 1363 G15 PHASE MARGIN (DEG) 10mV 100k Gain Bandwidth and Phase Margin vs Supply Voltage 10 4 0 TA = 25°C AV = –1 RF = RG = 1k 1363 G14 Settling Time vs Output Step (Inverting) VS = ±15V AV = 1 RL = 1k 6 40 VS = ±5V 1363 G11 10 60 VS = ±5V –10 10k 100M 80 VS = ±15V 40 10 0.1 100 VS = ±15V GAIN Settling Time vs Output Step (Noninverting) 6 120 50 1363 G10 8 – 40°C 1.0 PHASE 0 –25 1.5 60 80 70 – 50 2.0 Gain and Phase vs Frequency VS = ±15V TA = 25°C 130 SOURCE –40°C 25°C 70 GAIN (dB) VS = ±5V 100 25°C –2.0 PHASE (DEG) OUTPUT SHORT-CIRCUIT CURRENT (mA) 100 110 –1.5 1363 G09 Output Impedance vs Frequency 120 85°C –1.0 1363 G08 Output Short-Circuit Current vs Temperature 140 VS = ±5V VIN = 100mV 85°C 0.5 V– –50 –40 –30 –20 –10 0 10 20 30 40 50 OUTPUT CURRENT (mA) V– 1363 G07 OUTPUT STEP (V) OUTPUT VOLTAGE SWING (V) 81 OPEN-LOOP GAIN (dB) Output Voltage Swing vs Load Current LT1363 U W TYPICAL PERFORMANCE CHARACTERISTICS Gain Bandwidth and Phase Margin vs Temperature 120 PHASE MARGIN VS = ±15V 100 10 45 8 40 6 35 90 30 80 GAIN BANDWIDTH VS = ±15V 70 60 25 20 15 50 GAIN BANDWIDTH VS = ±5V 40 30 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 PHASE MARGIN (DEG) 5 TA = 25°C AV = 1 RL = 1k 0 10 –6 5 –8 –3 ±2.5V 1M 10M FREQUENCY (Hz) –5 100k 100M 9 C = 500pF C = 100pF 6 C = 50pF 3 C=0 0 –3 –6 –9 –12 –15 1M 10M FREQUENCY (Hz) POWER SUPPLY REJECTION RATIO (dB) 12 120 80 – PSRR 60 40 20 0 100 100M Slew Rate vs Supply Voltage 10k 100k 1M FREQUENCY (Hz) 10M 60 40 20 100M 1k 1200 1000 800 10M 100M Slew Rate vs Input Level AV = –2 SR+ + SR– SR = ————— 2 1600 VS = ±15V 800 TA = 25°C VS = ±15V AV = –1 RF = RG = 1k SR+ + SR – SR = ————— 2 1800 1000 600 VS = ± 5V 600 400 100k 1M FREQUENCY (Hz) 2000 1200 1400 10k 1363 G21 SLEW RATE (V/µS) 1600 80 Slew Rate vs Temperature SLEW RATE (V/µs) 1800 100 0 1k 1400 TA = 25°C AV = –1 RF = RG = 1k SR+ + SR– SR = ————— 2 VS = ±15V TA = 25°C 1363 G20 2400 2000 100M Common Mode Rejection Ratio vs Frequency VS = ±15V TA = 25°C +PSRR 1363 G19 2200 1M 10M FREQUENCY (Hz) 1363 G18 100 C = 1000pF ±2.5V –4 Power Supply Rejection Ratio vs Frequency 15 VS = ±15V TA = 25°C AV = –1 ±5V 1363 G17 Frequency Response vs Capacitive Load VOLTAGE MAGNITUDE (dB) 0 –1 –2 1363 G16 SLEW RATE (V/µs) 1 ±5V –10 100k ±15V 2 2 –4 0 125 3 ±15V 4 –2 TA = 25°C AV = –1 RF = RG = 1k 4 COMMON-MODE REJECTION RATIO (dB) GAIN BANDWIDTH (MHz) 110 50 GAIN (dB) PHASE MARGIN VS = ±5V GAIN (dB) 130 Frequency Response vs Supply Voltage (AV = –1) Frequency Response vs Supply Voltage (AV = 1) 1400 1200 1000 800 600 400 400 200 200 0 0 5 10 SUPPLY VOLTAGE (±V) 15 1363 G22 200 – 50 0 –25 0 25 50 75 TEMPERATURE (°C) 100 125 1363 G23 0 2 4 6 8 10 12 14 16 18 INPUT LEVEL (VP-P) 20 1363 G24 7 LT1363 U W TYPICAL PERFORMANCE CHARACTERISTICS Total Harmonic Distortion vs Frequency 30 TA = 25°C VO = 3VRMS RL = 500Ω 20 15 10 5 0.0001 100 1k 10k FREQUENCY (Hz) VS = ±15V RL = 1k AV = 1, 1% MAX DISTORTION AV = –1, 2% MAX DISTORTION 0 100k 100k OUTPUT VOLTAGE (VP-P) AV = 1 AV = 1 1M FREQUENCY (Hz) 3RD HARMONIC DIFFERENTIAL GAIN 2ND HARMONIC –80 –90 –100 100k 200k 400k 1M 2M FREQUENCY (Hz) 4M 10M DIFFERENTIAL PHASE (DEG) HARMONIC DISTORTION (dB) 0.1 –70 0 0.3 0.2 DIFFERENTIAL PHASE 0.1 0.0 8 TA = 25°C VS = ±15V ±5 ±10 SUPPLY VOLTAGE (V) AV = –1 50 AV = 1 ±15 0 10p 100p 1000p 0.01µ 0.1µ CAPACITIVE LOAD (F) 1µ 1363 G30 1363 G29 Small-Signal Transient (AV = –1) 1363 TA31 10M 100 AV = 2 RL = 150Ω TA = 25°C 1363 G28 Small-Signal Transient (AV = 1) 1M FREQUENCY (Hz) Capacitive Load Handling 0.2 DIFFERENTIAL GAIN (%) –60 VS = ±5V RL = 1k 2% MAX DISTORTION 1363 G27 Differential Gain and Phase vs Supply Voltage –40 VS = ±15V VO = 2VP-P RL = 500Ω AV = 2 4 1363 G26 2nd and 3rd Harmonic Distortion vs Frequency –50 AV = 1 6 0 100k 10M 1363 G25 AV = –1 8 2 OVERSHOOT (%) AV = –1 10 10 AV = –1 25 OUTPUT VOLTAGE (VP-P) TOTAL HARMONIC DISTORTION (%) 0.01 0.001 Undistorted Output Swing vs Frequency (±5V) Undistorted Output Swing vs Frequency (±15V) Small-Signal Transient (AV = –1, CL = 200pF) 1363 TA32 1363 TA33 LT1363 U W TYPICAL PERFORMANCE CHARACTERISTICS Large-Signal Transient (AV = 1) Large-Signal Transient (AV = 1, CL = 10,000pF) Large-Signal Transient (AV = –1) 1363 TA34 1363 TA35 1363 TA36 U U W U APPLICATIONS INFORMATION The LT1363 may be inserted directly into AD817, AD847, EL2020, EL2044, and LM6361 applications improving both DC and AC performance, provided that the nulling circuitry is removed. The suggested nulling circuit for the LT1363 is shown below. Offset Nulling The parallel combination of the feedback resistor and gain setting resistor on the inverting input can combine with the input capacitance to form a pole which can cause peaking or oscillations. For feedback resistors greater than 5kΩ, a parallel capacitor of value CF > RG x CIN/RF V+ 3 7 + 6 LT1363 2 4 – 8 1 10k should be used to cancel the input pole and optimize dynamic performance. For unity-gain applications where a large feedback resistor is used, CF should be greater than or equal to CIN. Capacitive Loading V– 1363 AI01 Layout and Passive Components The LT1363 amplifier is easy to apply and tolerant of less than ideal layouts. For maximum performance (for example fast settling time) use a ground plane, short lead lengths, and RF-quality bypass capacitors (0.01µF to 0.1µF). For high drive current applications use low ESR bypass capacitors (1µF to 10µF tantalum). Sockets should be avoided when maximum frequency performance is required, although low profile sockets can provide reasonable performance up to 50MHz. For more details see Design Note 50. The LT1363 is stable with any capacitive load. This is accomplished by sensing the load induced output pole and adding compensation at the amplifier gain node. As the capacitive load increases, both the bandwidth and phase margin decrease so there will be peaking in the frequency domain and in the transient response as shown in the typical performance curves.The photo of the small-signal response with 200pF load shows 62% peaking. The largesignal response with a 10,000pF load shows the output slew rate being limited to 10V/µs by the short-circuit current. Coaxial cable can be driven directly, but for best pulse fidelity a resistor of value equal to the characteristic impedance of the cable (i.e., 75Ω) should be placed in series with the output. The other end of the cable should be terminated with the same value resistor to ground. The response of a cable driver in a gain of 2 driving a 75Ω cable is shown on the front page of the data sheet. 9 LT1363 U W U U APPLICATIONS INFORMATION Input Considerations Each of the LT1363 inputs is the base of an NPN and a PNP transistor whose base currents are of opposite polarity and provide first-order bias current cancellation. Because of variation in the matching of NPN and PNP beta, the polarity of the input bias current can be positive or negative. The offset current does not depend on NPN/PNP beta matching and is well controlled. The use of balanced source resistance at each input is recommended for applications where DC accuracy must be maximized. The inputs can withstand transient differential input voltages up to 10V without damage and need no clamping or source resistance for protection. Differential inputs, however, generate large supply currents (tens of mA) as required for high slew rates. If the device is used with sustained differential inputs, the average supply current will increase, excessive power dissipation will result and the part may be damaged. The part should not be used as a comparator, peak detector or other open-loop application with large, sustained differential inputs. Under normal, closed-loop operation, an increase of power dissipation is only noticeable in applications with large slewing outputs and is proportional to the magnitude of the differential input voltage and the percent of the time that the inputs are apart. Measure the average supply current for the application in order to calculate the power dissipation. Single Supply Operation The LT1363 is specified at ±15V, ±5V, and ±2.5V supplies, but it is also well suited to single supply operation down to a single 5V supply. The symmetrical input Ccmmon mode range and output swing make the device well suited for applications with a single supply if the the input and output swing ranges are centered (i.e., a DC bias of 2.5V on the input and the output). For 5V video applications with an assymetrical swing, an offset of 2V on the input works best. Power Dissipation The LT1363 combines high speed and large output drive in a small package. Because of the wide supply voltage range, it is possible to exceed the maximum junction 10 temperature under certain conditions. Maximum junction temperature (TJ) is calculated from the ambient temperature (TA) and power dissipation (PD) as follows: LT1363CN8: TJ = TA + (PD x 130°C/W) LT1363CS8: TJ = TA + (PD x 190°C/W) Worst case power dissipation occurs at the maximum supply current and when the output voltage is at 1/2 of either supply voltage (or the maximum swing if less than 1/2 supply voltage). Therefore PDMAX is: PDMAX = (V+ – V –)(ISMAX) + (V+/2)2/RL Example: LT1363CS8 at 70°C, VS = ±15V, RL = 390Ω PDMAX = (30V)(8.7mA) + (7.5V)2/390Ω = 405mW TJMAX = 70°C + (405mW)(190°C/W) = 147°C Circuit Operation The LT1363 circuit topology is a true voltage feedback amplifier that has the slewing behavior of a current feedback amplifier. The operation of the circuit can be understood by referring to the simplified schematic. The inputs are buffered by complementary NPN and PNP emitter followers which drive a 500Ω resistor. The input voltage appears across the resistor generating currents which are mirrored into the high impedance node. Complementary followers form an output stage which buffers the gain node from the load. The bandwidth is set by the input resistor and the capacitance on the high impedance node. The slew rate is determined by the current available to charge the gain node capacitance. This current is the differential input voltage divided by R1, so the slew rate is proportional to the input. Highest slew rates are therefore seen in the lowest gain configurations. For example, a 10V output step in a gain of 10 has only a 1V input step, whereas the same output step in unity gain has a 10 times greater input step. The curve of Slew Rate vs Input Level illustrates this relationship. The LT1363 is tested for slew rate in a gain of –2 so higher slew rates can be expected in gains of 1 and –1, and lower slew rates in higher gain configurations. LT1363 U U W U APPLICATIONS INFORMATION The RC network across the output stage is bootstrapped when the amplifier is driving a light or moderate load and has no effect under normal operation. When driving a capacitive load (or a low value resistive load) the network is incompletely bootstrapped and adds to the compensation at the high impedance node. The added capacitance slows down the amplifier which improves the phase margin by moving the unity-gain frequency away from the pole formed by the output impedance and the capacitive load. The zero created by the RC combination adds phase to ensure that even for very large load capacitances, the total phase lag can never exceed 180 degrees (zero phase margin) and the amplifier remains stable. Comparison to Current Feedback Amplifiers tics of a true voltage feedback amplifier. The primary differences are that the LT1363 has two high impedance inputs and its closed loop bandwidth decreases as the gain increases. CFAs have a low impedance inverting input and maintain relatively constant bandwidth with increasing gain. The LT1363 can be used in all traditional op amp configurations including integrators and applications such as photodiode amplifiers and I-to-V converters where there may be significant capacitance on the inverting input. The frequency compensation is internal and not dependent on the value of the feedback resistor. For CFAs, the feedback resistance is fixed for a given bandwidth and capacitance on the inverting input can cause peaking or oscillations. The slew rate of the LT1363 in noninverting gain configurations is also superior in most cases. The LT1363 enjoys the high slew rates of Current Feedback Amplifiers (CFAs) while maintaining the characteris- W W SI PLIFIED SCHE ATIC V+ R1 500Ω +IN RC OUT –IN C CC V– 1363 SS01 U PACKAGE DESCRIPTION Dimension in inches (millimeters) unless otherwise noted. N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( +0.035 0.325 –0.015 +0.889 8.255 –0.381 ) 0.045 – 0.065 (1.143 – 1.651) 0.400* (10.160) MAX 0.130 ± 0.005 (3.302 ± 0.127) 0.065 (1.651) TYP 8 7 6 5 1 2 3 4 0.255 ± 0.015* (6.477 ± 0.381) 0.100 (2.54) BSC 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 ± 0.003 (0.457 ± 0.076) N8 1098 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) 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 LT1363 U TYPICAL APPLICATIONS Two Op Amp Instrumentation Amplifier R5 220Ω R1 10k 2MHz, 4th Order Butterworth Filter R4 10k 464Ω R2 1k 47pF 22pF 464Ω 1.33k – VIN R3 1k – – LT1363 + – 549Ω 1.13k + VOUT LT1363 549Ω LT1363 220pF + ( R4 1 R2 R3 R2 + R3 GAIN = 1 + + + R5 R3 2 R1 R4 TRIM R5 FOR GAIN TRIM R1 FOR COMMON-MODE REJECTION BW = 700kHz LT1363 VOUT + + VIN – 470pF 1363 TA04 ) = 102 1363 TA03 U PACKAGE DESCRIPTION Dimension in inches (millimeters) unless otherwise noted. 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) 0.053 – 0.069 (1.346 – 1.752) 0°– 8° TYP 0.016 – 0.050 (0.406 – 1.270) 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 8 7 6 5 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) BSC 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 2 3 4 SO8 1298 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1364/LT1365 Dual and Quad 70MHz, 1000V/µs Op Amps Dual and Quad Versions of LT1363 LT1360 50MHz, 800V/µs Op Amp Lower Power Version of LT1363, VOS = 1mV, IS = 4mA LT1357 25MHz, 600V/µs Op Amp Lower Power Version of LT1363, VOS = 0.6mV, IS = 2mA LT1812 100MHz, 750V/µs Op Amp Low Voltage, Low Power LT1363, VOS = 1.5mV, IS = 3mA 12 Linear Technology Corporation 1363fa LT/TP 0400 2K REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 ● FAX: (408) 434-0507 ● www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1994