LT1355/LT1356 Dual and Quad 12MHz, 400V/µs Op Amps U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 12MHz Gain Bandwidth 400V/µs Slew Rate 1.25mA Maximum Supply Current per Amplifier Unity-Gain Stable C-LoadTM Op Amp Drives All Capacitive Loads 10nV/√Hz Input Noise Voltage 800µV Maximum Input Offset Voltage 300nA Maximum Input Bias Current 70nA Maximum Input Offset Current 12V/mV Minimum DC Gain, RL=1k 230ns Settling Time to 0.1%, 10V Step 280ns Settling Time to 0.01%, 10V Step ±12.5V Minimum Output Swing into 500Ω ±3V Minimum Output Swing into 150Ω Specified at ±2.5V, ±5V, and ±15V U APPLICATIO S ■ ■ ■ ■ ■ Wideband Amplifiers Buffers Active Filters Data Acquisition Systems Photodiode Amplifiers The LT1355/LT1356 are dual and quad low power high speed operational amplifiers with outstanding AC and DC performance. The amplifiers feature much lower supply current and higher slew rate than devices with comparable bandwidth. The circuit topology is a voltage feedback amplifier with matched high impedance inputs and the slewing performance of a current feedback amplifier. The high slew rate and single stage design provide excellent settling characteristics which make the circuit an ideal choice for data acquisition systems. Each output drives a 500Ω load to ±12.5V with ±15V supplies and a 150Ω load to ±3V on ±5V supplies. The amplifiers are stable with any capacitive load making them useful in buffer applications. The LT1355/LT1356 are members of a family of fast, high performance amplifiers using this unique topology and employing Linear Technology Corporation’s advanced bipolar complementary processing. For a single amplifier version of the LT1355/LT1356 see the LT1354 data sheet. For higher bandwidth devices with higher supply currents see the LT1357 through LT1365 data sheets. Bandwidths of 25MHz, 50MHz, and 70MHz are available with 2mA, 4mA, and 6mA of supply current per amplifier. 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 TYPICAL APPLICATIO AV = –1 Large-Signal Response 100kHz, 4th Order Butterworth Filter 6.81k 5.23k 100pF 6.81k 11.3k VIN 330pF – 1/2 LT1355 + 47pF 5.23k 10.2k 1000pF – 1/2 LT1355 VOUT + 1355/1356 TA01 1355/1356 TA02 1 LT1355/LT1356 W W U W ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage (V+ to V –) ............................... 36V Differential Input Voltage (Transient Only) (Note 2)................................... ±10V Input Voltage ............................................................ ±VS Output Short-Circuit Duration (Note 3) ............ Indefinite Operating Temperature Range (Note 7) .. – 40°C to 85°C Specified Temperature Range (Note 8) ... – 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 OUT A 1 –IN A 2 8 V+ 7 OUT B A +IN A 3 V– 6 B 4 5 –IN B ORDER PART NUMBER LT1355CN8 +IN B OUT A 1 –IN A 2 +IN A 3 – 4 V 2 +IN A 3 V+ 4 +IN B 5 –IN B 6 OUT B 7 14 OUT D 13 –IN D A D 12 +IN D ORDER PART NUMBER LT1356CN 11 V – 10 +IN C B 7 OUT B B 6 –IN B 5 +IN B LT1355CS8 S8 PART MARKING 1355 TJMAX = 150°C, θJA = 190°C/ W TOP VIEW –IN A V+ S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/ W 1 8 A N8 PACKAGE 8-LEAD PDIP OUT A ORDER PART NUMBER TOP VIEW C OUT A 1 –IN A 2 +IN A 3 V+ 4 +IN B 5 16 OUT D 15 –IN D A D LT1356CS 14 +IN D 13 V – 12 +IN C B C 9 –IN C –IN B 6 8 OUT C OUT B 7 10 OUT C NC 8 9 N PACKAGE 14-LEAD PDIP ORDER PART NUMBER TOP VIEW 11 –IN C NC S PACKAGE 16-LEAD PLASTIC SO TJMAX = 150°C, θJA = 110°C/ W TJMAX = 150°C, θJA = 150°C/ W Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER VOS Input Offset Voltage 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 2 Input Capacitance CONDITIONS TA = 25°C, VCM = 0V unless otherwise noted. VSUPPLY MIN TYP MAX UNITS ±15V ±5V ±2.5V 0.3 0.3 0.4 0.8 0.8 1.0 mV mV mV ±2.5V to ±15V 20 70 nA ±2.5V to ±15V 80 300 ±2.5V to ±15V 10 nV/√Hz nA 0.6 pA/√Hz 160 MΩ ±15V 11 MΩ ±15V 3 pF 70 LT1355/LT1356 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER TA = 25°C, VCM = 0V unless otherwise noted. VSUPPLY MIN TYP + ±15V ±5V ±2.5V 12.0 2.5 0.5 13.4 3.5 1.1 V V V Input Voltage Range – ±15V ±5V ±2.5V –13.2 –12.0 –3.4 –2.5 –0.9 –0.5 V V V Input Voltage Range CONDITIONS VCM = ±12V VCM = ±2.5V VCM = ±0.5V MAX UNITS ±15V ±5V ±2.5V 83 78 68 97 84 75 92 106 dB VOUT = ±12V, RL = 1k VOUT = ±10V, RL = 500Ω VOUT = ±2.5V, RL = 1k VOUT = ±2.5V, RL = 500Ω VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω ±15V ±15V ±5V ±5V ±5V ±2.5V 12 5 12 5 1 5 36 15 36 15 4 20 V/mV V/mV V/mV V/mV V/mV V/mV 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 13.3 12.5 3.5 3.0 1.3 13.8 13.0 4.0 3.3 1.7 ±V ±V ±V ±V ±V Output Current VOUT = ±12.5V VOUT = ±3V ±15V ±5V 25 20 30 25 mA mA CMRR Common Mode Rejection Ratio PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V AVOL Large-Signal Voltage Gain VOUT IOUT dB dB dB ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V 30 42 mA SR Slew Rate AV = – 2, (Note 4) ±15V ±5V 200 70 400 120 V/µs V/µs Full Power Bandwidth 10V Peak, (Note 5) 3V Peak, (Note 5) ±15V ±5V 6.4 6.4 MHz MHz GBW Gain Bandwidth f = 200kHz, RL = 2k ±15V ±5V ±2.5V 12.0 10.5 9.0 MHz MHz MHz tr, tf Rise Time, Fall Time AV = 1, 10%-90%, 0.1V ±15V ±5V 14 17 ns ns Overshoot AV = 1, 0.1V ±15V ±5V 20 18 % % Propagation Delay 50% VIN to 50% VOUT, 0.1V ±15V ±5V 16 19 ns ns Settling Time 10V Step, 0.1%, AV = –1 10V Step, 0.01%, AV = –1 5V Step, 0.1%, AV = –1 5V Step, 0.01%, AV = –1 ±15V ±15V ±5V ±5V 230 280 240 380 ns ns ns ns Differential Gain f = 3.58MHz, AV = 2, RL = 1k ±15V ±5V 2.2 2.1 % % Differential Phase f = 3.58MHz, AV = 2, RL = 1k ±15V ±5V 3.1 3.1 Deg Deg Output Resistance AV = 1, f = 100kHz ±15V Channel Separation VOUT = ±10V, RL = 500Ω ±15V Supply Current Each Amplifier Each Amplifier ±15V ±5V ts RO IS 9.0 7.5 100 0.7 Ω 113 dB 1.0 0.9 1.25 1.20 mA mA 3 LT1355/LT1356 ELECTRICAL CHARACTERISTICS 0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER VOS Input Offset Voltage Input VOS Drift The ● denotes the specifications which apply over the temperature range CONDITIONS (Note 6) VSUPPLY MIN ±15V ±5V ±2.5V ● ● ● ±2.5V to ±15V ● TYP 5 MAX UNITS 1.0 1.0 1.2 mV mV mV 8 µV/°C IOS Input Offset Current ±2.5V to ±15V ● 100 nA IB Input Bias Current ±2.5V to ±15V ● 450 nA CMRR Common Mode Rejection Ratio ±15V ±5V ±2.5V ● ● ● PSRR Power Supply Rejection Ratio VS = ±2.5V to ±15V ● 90 dB AVOL Large-Signal Voltage Gain VOUT = ±12V, RL = 1k VOUT = ±10V, RL = 500Ω VOUT = ±2.5V, RL = 1k VOUT = ±2.5V, RL = 500Ω VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω ±15V ±15V ±5V ±5V ±5V ±2.5V ● ● ● ● ● ● 10.0 3.3 10.0 3.3 0.6 3.3 V/mV 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 ● ● ● ● ● 13.2 12.0 3.4 2.8 1.2 ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±12V VOUT = ±2.8V ±15V ±5V ● ● 24.0 18.7 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V ● 24 mA SR Slew Rate AV = – 2, (Note 4) ±15V ±5V ● ● 150 60 V/µs V/µs GBW Gain Bandwidth f = 200kHz, RL = 2k ±15V ±5V ● ● 7.5 6.0 MHz MHz Channel Separation VOUT = ±10V, RL = 500Ω ±15V ● 98 dB Supply Current Each Amplifier Each Amplifier ±15V ±5V ● ● IS VCM = ±12V VCM = ±2.5V VCM = ±0.5V 81 77 67 dB dB dB 1.45 1.40 mA mA The ● denotes the specifications which apply over the temperature range – 40°C ≤ TA ≤ 85°C, VCM = 0V unless otherwise noted. (Note 8) SYMBOL VOS IOS PARAMETER Input Offset Voltage CONDITIONS Input VOS Drift (Note 6) Input Offset Current IB Input Bias Current CMRR 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 = ±2.5V, RL = 1k VOUT = ±2.5V, RL = 500Ω 4 VSUPPLY ±15V ±5V ±2.5V ● ● ● ±2.5V to ±15V ● ±2.5V to ±15V ● ±2.5V to ±15V ● ±15V ±5V ±2.5V ● ● ● 80 76 66 dB dB dB ● 90 dB ● ● ● ● 7.0 1.7 7.0 1.7 V/mV V/mV V/mV V/mV ±15V ±15V ±5V ±5V MIN TYP MAX 1.5 1.5 1.7 UNITS mV mV mV 5 8 µV/°C 200 550 nA nA LT1355/LT1356 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range – 40°C ≤ TA ≤ 85°C, VCM = 0V unless otherwise noted. (Note 8) SYMBOL PARAMETER CONDITIONS VSUPPLY VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω ±5V ±2.5V ● ● MIN 0.4 1.7 TYP MAX UNITS 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 ● ● ● ● ● 13.0 11.5 3.4 2.6 1.2 ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±11.5V VOUT = ± 2.6V ±15V ± 5V ● ● 23.0 17.3 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V ● 23 mA SR Slew Rate AV = – 2, (Note 4) ±15V ± 5V ● ● 120 50 V/µs V/µs GBW Gain Bandwidth f = 200kHz, RL = 2k ±15V ±5V ● ● 7.0 5.5 MHz MHz Channel Separation VOUT = ±10V, RL = 500Ω ±15V ● 98 dB Supply Current Each Amplifier Each Amplifier ±15V ±5V ● ● IS 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: Slew rate is measured between ±10V on the output with ±6V input for ±15V supplies and ±1V on the output with ±1.75V input for ±5V supplies. 1.50 1.45 mA mA Note 5: Full power bandwidth is calculated from the slew rate measurement: FPBW = (SR)/2πVP. Note 6: This parameter is not 100% tested. Note 7: The LT1355C/LT1356C are guaranteed functional over the operating temperature range of –40°C to 85°C. Note 8: The LT1355C/LT1356C are guaranteed to meet specified performance from 0°C to 70°C. The LT1355C/LT1356C are designed, characterized and expected to meet specified performance from – 40°C to 85°C, but are 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+ 1.4 200 TA = 25°C ∆VOS < 1mV – 0.5 125°C 1.0 25°C 0.8 – 55°C 0.6 –1.0 INPUT BIAS CURRENT (nA) COMMON MODE RANGE (V) 1.2 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 1.0 150 VS = ±15V TA = 25°C IB+ + IB– IB = ———— 2 100 50 0 0.5 0.4 0 5 10 15 SUPPLY VOLTAGE (±V) 20 1355/1356 G01 V– 0 5 10 15 SUPPLY VOLTAGE (±V) 20 1355/1356 G02 –50 –15 –10 –5 0 5 10 INPUT COMMON MODE VOLTAGE (V) 15 1355/1356 G03 5 LT1355/LT1356 U W TYPICAL PERFORMANCE CHARACTERISTICS Input Bias Current vs Temperature 125 100 75 50 25 0 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 in 10 en 1 1 10 100 1355/1356 G04 RL = 1k 92 91 90 –2 RL = 500Ω –3 3 RL = 500Ω 2 1 89 RL = 1k 100 0 125 5 10 15 SUPPLY VOLTAGE (±V) Output Short-Circuit Current vs Temperature OUTPUT SWING (V) OUTPUT SHORT-CIRCUIT CURRENT (mA) SINK 40 SOURCE –25 0 25 50 75 TEMPERATURE (°C) 100 125 1355/1356 G10 6 1.5 Settling Time vs Output Step (Inverting) VS = ±15V AV = –1 8 6 10mV 4 1mV 2 0 –2 –4 –6 25 –40°C 10 10mV 30 25°C 2.0 1355/1356 G09 6 45 20 –50 85°C 2.5 –50 –40 –30 –20 –10 0 10 20 30 40 50 OUTPUT CURRENT (mA) 20 VS = ±15V AV = 1 8 50 25°C 1.0 10 55 35 –2.5 Settling Time vs Output Step (Noninverting) VS = ±5V 60 –2.0 1355/1356 G08 1355/1356 G07 65 –40°C –1.5 V – + 0.5 V– 0 25 50 75 TEMPERATURE (°C) 85°C VS = ±5V VIN = 100mV –1.0 OUTPUT VOLTAGE SWING (V) OUTPUT VOLTAGE SWING (V) OPEN-LOOP GAIN (dB) 93 10k Output Voltage Swing vs Load Current –1 94 100 1k LOAD RESISTANCE (Ω) V +–0.5 TA = 25°C VS = ±15V RL = 1k VO = ±12V –25 10 1355/1356 G06 V+ 88 – 50 50 Output Voltage Swing vs Supply Voltage 97 95 70 1355/1356 G05 Open-Loop Gain vs Temperature 96 80 60 0.1 100k 1k 10k FREQUENCY (Hz) VS = ±5V 90 OPEN-LOOP GAIN (dB) VS = ±15V TA = 25°C OUTPUT SWING (V) INPUT BIAS CURRENT (nA) 150 VS = ±15V TA = 25°C AV = 101 RS = 100k INPUT CURRENT NOISE (pA/√Hz) 175 100 10 100 VS = ±15V IB+ + IB– IB = ———— 2 INPUT VOLTAGE NOISE (nV/√Hz) 200 Open-Loop Gain vs Resistive Load Input Noise Spectral Density 1mV 4 0 10mV –6 –8 –10 150 200 250 SETTLING TIME (ns) 1mV –4 –8 100 1mV –2 –10 50 10mV 2 300 350 1355/1356 G11 50 100 150 200 250 SETTLING TIME (ns) 300 350 1355/1356 G12 LT1355/LT1356 U W TYPICAL PERFORMANCE CHARACTERISTICS Frequency Response vs Capacitive Load Output Impedance vs Frequency 10 AV = 10 1 AV = 1 0.1 6 C = 1000pF 4 C = 500pF 2 C = 100pF 0 C = 50pF –2 C=0 –4 1M 10M FREQUENCY (Hz) 44 14 42 13 40 12 38 11 –6 9 1M 10M FREQUENCY (Hz) 4 48 3 14 44 13 42 GAIN BANDWIDTH VS = ±15V 12 40 11 38 10 GAIN BANDWIDTH VS = ± 5V 9 8 – 50 –25 0 25 50 75 TEMPERATURE (°C) 100 5 TA = 25°C AV = 1 RL = 2k 3 2 ±15V 1 0 –1 ±5V –2 –3 34 –4 GAIN (dB) VS = ±5V –10 10k 40 VS = ±5V 20 0 TA = 25°C AV = –1 RF = RG = 2k 100k 1M 10M FREQUENCY (Hz) 100M 1355/1356 G14 POWER SUPPLY REJECTION RATIO (dB) 0 60 PHASE (DEG) 10 80 VS = ±15V GAIN 20 100 VS = ±15V 30 100M ±2.5V –5 100k 1M 10M FREQUENCY (Hz) 120 +PSRR – PSRR 60 40 20 0 100 100M Common Mode Rejection Ratio vs Frequency VS = ±15V TA = 25°C 80 ±15V 1355/1356 G18 100 120 PHASE ±5V –3 Power Supply Rejection Ratio vs Frequency 70 40 –1 1355/1356 G17 Gain and Phase vs Frequency 50 0 –4 1M 10M FREQUENCY (Hz) 1355/1356 G16 60 1 –2 ±2.5V –5 100k 32 125 TA = 25°C AV = –1 RF = RG = 2k 4 2 36 20 Frequency Response vs Supply Voltage (AV = –1) GAIN (dB) 46 GAIN (dB) GAIN BANDWIDTH (MHz) 50 PHASE MARGIN (DEG) PHASE MARGIN VS = ±5V 15 5 10 15 SUPPLY VOLTAGE (±V) 1355/1356 G15 5 52 16 30 0 100M Frequency Response vs Supply Voltage (AV = 1) PHASE MARGIN VS = ±15V 32 TA = 25°C 1355/1356 G19 Gain Bandwidth and Phase Margin vs Temperature 17 34 8 1355/1356 G13 18 36 GAIN BANDWIDTH 10 –10 100k 100M 46 15 COMMON-MODE REJECTION RATIO (dB) 100k 48 PHASE MARGIN 16 –8 0.01 10k 50 17 GAIN BANDWIDTH (MHz) 100 VS = ±15V TA = 25°C AV = –1 8 VOLTAGE MAGNITUDE (dB) AV = 100 18 10 VS = ±15V TA = 25°C PHASE MARGIN (DEG) OUTPUT IMPEDANCE (Ω) 1k Gain Bandwidth and Phase Margin vs Supply Voltage VS = ±15V TA = 25°C 100 80 60 40 20 0 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1355/1356 G20 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1355/1356 G21 7 LT1355/LT1356 U W TYPICAL PERFORMANCE CHARACTERISTICS Slew Rate vs Temperature Slew Rate vs Supply Voltage TA = 25°C AV = –1 RF = RG = 2k SR+ + SR– SR = ————— 2 300 200 250 AV = –2 SR+ + SR– SR = ————— 2 200 150 VS = ±5V 100 100 0 0 5 10 SUPPLY VOLTAGE (±V) 50 –50 15 0 25 50 75 TEMPERATURE (°C) 0.001 AV = 1 15 10 VS = ±15V RL = 5k AV = 1, 1% MAX DISTORTION AV = –1, 4% MAX DISTORTION 0 100k 100k 1M FREQUENCY (Hz) 1355/1356 G25 0 100k 10M CROSSTALK (dB) –60 10M Capacitive Load Handling 100 TA = 25°C VS = ±15V TA = 25°C VIN = 0dBm RL = 500Ω AV = 1 –70 –80 –90 AV = 1 50 AV = –1 –100 2ND HARMONIC –70 –80 100k 200k 1M FREQUENCY (Hz) 1355/1356 G27 OVERSHOOT (%) –50 –60 VS = ±5V RL = 5k AV = 1, 2% MAX DISTORTION AV = –1, 3% MAX DISTORTION 4 Crosstalk vs Frequency VS = ±15V VO = 2VP-P RL = 2k AV = 2 –50 AV = 1 6 2 –40 –20 20 AV = –1 8 1355/1356 G26 2nd and 3rd Harmonic Distortion vs Frequency 3RD HARMONIC 6 8 10 12 14 16 18 INPUT LEVEL (VP-P) AV = –1 AV = 1 0.0001 –40 4 Undistorted Output Swing vs Frequency (±5V) 20 5 1k 10k FREQUENCY (Hz) 2 1355/1356 G24 OUTPUT VOLTAGE (VP-P) OUTPUT VOLTAGE (VP-P) TOTAL HARMONIC DISTORTION (%) 0 125 10 25 AV = –1 HARMONIC DISTORTION (dB) 100 30 0.01 –110 400k 1M 2M FREQUENCY (Hz) 4M 10M 1355/1356 G28 8 100 Undistorted Output Swing vs Frequency (±15V) 0.1 100 200 1355/1356 G23 Total Harmonic Distortion vs Frequency 10 300 0 –25 1355/1356 G22 TA = 25°C VO = 3VRMS RL = 2k TA = 25°C VS = ±15V AV = –1 RF = RG = 2k SR+ + SR– SR = ————— 2 400 VS = ±15V SLEW RATE (V/µs) 400 500 300 SLEW RATE (V/µs) SLEW RATE (V/µs) 500 –30 Slew Rate vs Input Level 350 600 –120 100k 1M 10M FREQUENCY (Hz) 100M 1355/1356 G29 0 10p 100p 1000p 0.01µ 0.1µ CAPACITIVE LOAD (F) 1µ 1355/1356 G30 LT1355/LT1356 U W TYPICAL PERFORMANCE CHARACTERISTICS Small-Signal Transient (AV = 1) Small-Signal Transient (AV = –1) 1355/1356 G31 Small- Signal Transient (AV = –1, CL = 1000pF) 1355/1356 G33 1355/1356 G32 Large-Signal Transient (AV = 1) Large-Signal Transient (AV = –1) 1355/1356 G34 Large-Signal Transient (AV = 1, CL = 10,000pF) 1355/1356 G35 1355/1356 G36 U W U U APPLICATIONS INFORMATION Layout and Passive Components The LT1355/LT1356 amplifiers are easy to use and tolerant of less than ideal layouts. For maximum performance (for example, fast 0.01% settling) 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). or oscillations. If feedback resistors greater than 5kΩ are used, a parallel capacitor of value CF > RG x CIN/RF 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. The parallel combination of the feedback resistor and gain setting resistor on the inverting input combine with the input capacitance to form a pole which can cause peaking 9 LT1355/LT1356 U W U U APPLICATIONS INFORMATION Capacitive Loading Circuit Operation The LT1355/LT1356 are stable with any capacitive load. 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. 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 LT1355/LT1356 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 an 800Ω 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 LT1355/ LT1356 are 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. Input Considerations Each of the LT1355/LT1356 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. 10 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. LT1355/LT1356 U W U U APPLICATIONS INFORMATION Power Dissipation The LT1355/LT1356 combine high speed and large output drive in small packages. Because of the wide supply voltage range, it is possible to exceed the maximum junction temperature under certain conditions. Maximum junction temperature (TJ) is calculated from the ambient temperature (TA) and power dissipation (PD) as follows: LT1355CN8: LT1355CS8: LT1356CN: LT1356CS: TJ = TA + (PD x 130°C/W) TJ = TA + (PD x 190°C/W) TJ = TA + (PD x 110°C/W) TJ = TA + (PD x 150°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). For each amplifier PDMAX is: PDMAX = (V+ – V–)(ISMAX) + (V+/2)2/RL Example: LT1356 in S16 at 70°C, VS = ±15V, RL = 1k PDMAX = (30V)(1.45mA) + (7.5V)2/1kW = 99.8mW TJMAX = 70°C + (4 × 99.8mW)(150°C/W) = 130°C W W SI PLIFIED SCHE ATIC V+ R1 800Ω +IN RC OUT –IN C CC V– 1355/1356 SS01 11 LT1355/LT1356 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.400* (10.160) MAX 8 7 6 5 1 2 3 4 0.255 ± 0.015* (6.477 ± 0.381) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( +0.035 0.325 –0.015 8.255 +0.889 –0.381 ) 0.045 – 0.065 (1.143 – 1.651) 0.065 (1.651) TYP 0.100 (2.54) BSC *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) 12 0.130 ± 0.005 (3.302 ± 0.127) 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 ± 0.003 (0.457 ± 0.076) N8 1098 LT1355/LT1356 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. N Package 14-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.770* (19.558) MAX 14 13 12 11 10 9 8 1 2 3 4 5 6 7 0.255 ± 0.015* (6.477 ± 0.381) 0.130 ± 0.005 (3.302 ± 0.127) 0.300 – 0.325 (7.620 – 8.255) 0.045 – 0.065 (1.143 – 1.651) 0.020 (0.508) MIN 0.065 (1.651) TYP 0.009 – 0.015 (0.229 – 0.381) +0.035 0.325 –0.015 0.005 (0.125) MIN 0.100 (2.54) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. BSC MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) ( +0.889 8.255 –0.381 ) 0.125 (3.175) MIN 0.018 ± 0.003 (0.457 ± 0.076) N14 1098 13 LT1355/LT1356 U PACKAGE DESCRIPTIO Dimensions 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) 8 7 6 5 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 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 14 2 3 4 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) BSC SO8 1298 LT1355/LT1356 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. S Package 16-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.386 – 0.394* (9.804 – 10.008) 16 15 14 13 12 11 10 9 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 1 0.010 – 0.020 × 45° (0.254 – 0.508) 2 3 4 5 6 0.053 – 0.069 (1.346 – 1.752) 0.008 – 0.010 (0.203 – 0.254) 0.014 – 0.019 (0.355 – 0.483) TYP 8 0.004 – 0.010 (0.101 – 0.254) 0° – 8° TYP 0.016 – 0.050 (0.406 – 1.270) 7 0.050 (1.270) BSC S16 1098 *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 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. 15 LT1355/LT1356 U TYPICAL APPLICATIONS Instrumentation Amplifier R5 432Ω R1 20k R2 2k – 1/2 LT1355 R3 2k – 1/2 LT1355 + – R4 20k VOUT + VIN + R4 1 R2 R3 R2 + R3 1 + = 104 + + R3 2 R1 R4 R5 TRIM R5 FOR GAIN TRIM R1 FOR COMMON-MODE REJECTION BW = 120kHz AV = 1355/1356 TA03 100kHz, 4th Order Butterworth Filter (Sallen-Key) C4 1000pF C2 330pF – 1/2 LT1355 – 1/2 LT1355 + VIN R1 2.87k R2 26.7k VOUT + R3 2.43k C1 100pF R4 15.4k C3 68pF 1355/1356 TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1354 12MHz, 400V/µs Op Amp Single Version of LT1355/LT1356 LT1352/LT1353 Dual and Quad 250µA, 3MHz, 200V/µs Op Amps Lower Power Version of LT1355/LT1356, VOS = 0.6mV, IS = 250µA/Amplifier LT1358/LT1359 Dual and Quad 25MHz, 600Vµs Op Amps Faster Version of LT1355/LT1356, VOS = 0.6mV, IS = 2mA/Amplifier 16 Linear Technology Corporation 13556fa 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