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LT1355/LT1356 Dual and Quad 12MHz, 400V/s Op Amps FEATURES s s s s s s s s s s s s s s s DESCRIPTIO 12MHz Gain Bandwidth 400V/s 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 800V 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 500 3V Minimum Output Swing into 150 Specified at 2.5V, 5V, and 15V 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 500 load to 12.5V with 15V supplies and a 150 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. APPLICATIO S s s s s s Wideband Amplifiers Buffers Active Filters Data Acquisition Systems Photodiode Amplifiers TYPICAL APPLICATIO 100kHz, 4th Order Butterworth Filter 6.81k 100pF 5.23k 47pF 6.81k VIN 11.3k 330pF - 1/2 LT1355 5.23k 10.2k 1000pF - 1/2 LT1355 VOUT + + 1355/1356 TA01 U AV = -1 Large-Signal Response 1355/1356 TA02 U U 1 LT1355/LT1356 ABSOLUTE MAXIMUM RATINGS 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 PACKAGE/ORDER INFORMATION TOP VIEW OUT A -IN A +IN A V- 1 2 A 3 4 N8 PACKAGE 8-LEAD PDIP B 6 5 -IN B +IN B 8 7 V+ OUT B ORDER PART NUMBER LT1355CN8 TJMAX = 150C, JA = 130C/ W TOP VIEW OUT A 1 2 3 4 5 6 7 B C A D 14 OUT D 13 -IN D 12 +IN D 11 V - 10 +IN C 9 8 -IN C OUT C ORDER PART NUMBER LT1356CN -IN A +IN A V+ +IN B -IN B OUT B N PACKAGE 14-LEAD PDIP TJMAX = 150C, JA = 110C/ W Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS SYMBOL VOS PARAMETER Input Offset Voltage CONDITIONS TA = 25C, VCM = 0V unless otherwise noted. VSUPPLY 15V 5V 2.5V 2.5V to 15V 2.5V to 15V MIN TYP 0.3 0.3 0.4 20 80 10 0.6 70 160 11 3 MAX 0.8 0.8 1.0 70 300 UNITS mV mV mV nA nA nV/Hz pA/Hz M M pF IOS IB en in RIN CIN Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Resistance Input Resistance Input Capacitance f = 10kHz f = 10kHz VCM = 12V Differential 2 U U W WW U W (Note 1) Operating Temperature Range (Note 7) .. - 40C to 85C Specified Temperature Range (Note 8) ... - 40C to 85C Maximum Junction Temperature (See Below) Plastic Package ................................................ 150C Storage Temperature Range ................. - 65C to 150C Lead Temperature (Soldering, 10 sec).................. 300C TOP VIEW OUT A -IN A +IN A V - 1 2 A 3 4 S8 PACKAGE 8-LEAD PLASTIC SO B 8 7 6 5 V+ OUT B -IN B +IN B ORDER PART NUMBER LT1355CS8 S8 PART MARKING 1355 ORDER PART NUMBER LT1356CS TJMAX = 150C, JA = 190C/ W TOP VIEW OUT A 1 2 3 4 5 6 7 8 B C A D 16 OUT D 15 -IN D 14 +IN D 13 V - 12 +IN C 11 -IN C 10 OUT C 9 NC -IN A +IN A V+ +IN B -IN B OUT B NC S PACKAGE 16-LEAD PLASTIC SO TJMAX = 150C, JA = 150C/ W 2.5V to 15V 2.5V to 15V 15V 15V 15V LT1355/LT1356 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER Input Voltage Range + TA = 25C, VCM = 0V unless otherwise noted. VSUPPLY 15V 5V 2.5V 15V 5V 2.5V MIN 12.0 2.5 0.5 TYP 13.4 3.5 1.1 -13.2 -12.0 -3.4 -2.5 -0.9 -0.5 83 78 68 92 15V 15V 5V 5V 5V 2.5V 15V 15V 5V 5V 2.5V 15V 5V 15V 15V 5V 15V 5V 15V 5V 2.5V 15V 5V 15V 5V 15V 5V 15V 15V 5V 5V 15V 5V 15V 5V 15V 15V 15V 5V 100 9.0 7.5 12 5 12 5 1 5 13.3 12.5 3.5 3.0 1.3 25 20 30 200 70 97 84 75 106 36 15 36 15 4 20 13.8 13.0 4.0 3.3 1.7 30 25 42 400 120 6.4 6.4 12.0 10.5 9.0 14 17 20 18 16 19 230 280 240 380 2.2 2.1 3.1 3.1 0.7 113 1.0 0.9 1.25 1.20 MAX UNITS V V V V V V dB dB dB dB V/mV V/mV V/mV V/mV V/mV V/mV V V V V V mA mA mA V/s V/s MHz MHz MHz MHz MHz ns ns % % ns ns ns ns ns ns % % Deg Deg dB mA mA CONDITIONS Input Voltage Range - CMRR Common Mode Rejection Ratio VCM = 12V VCM = 2.5V VCM = 0.5V VS = 2.5V to 15V VOUT = 12V, RL = 1k VOUT = 10V, RL = 500 VOUT = 2.5V, RL = 1k VOUT = 2.5V, RL = 500 VOUT = 2.5V, RL = 150 VOUT = 1V, RL = 500 RL = 1k, VIN = 40mV RL = 500, VIN = 40mV RL = 500, VIN = 40mV RL = 150, VIN = 40mV RL = 500, VIN = 40mV VOUT = 12.5V VOUT = 3V VOUT = 0V, VIN = 3V AV = - 2, (Note 4) 10V Peak, (Note 5) 3V Peak, (Note 5) f = 200kHz, RL = 2k 15V 5V 2.5V PSRR AVOL Power Supply Rejection Ratio Large-Signal Voltage Gain VOUT Output Swing IOUT ISC SR Output Current Short-Circuit Current Slew Rate Full Power Bandwidth GBW Gain Bandwidth tr, tf Rise Time, Fall Time Overshoot Propagation Delay AV = 1, 10%-90%, 0.1V AV = 1, 0.1V 50% VIN to 50% VOUT, 0.1V 10V Step, 0.1%, AV = -1 10V Step, 0.01%, AV = -1 5V Step, 0.1%, AV = -1 5V Step, 0.01%, AV = -1 f = 3.58MHz, AV = 2, RL = 1k f = 3.58MHz, AV = 2, RL = 1k AV = 1, f = 100kHz VOUT = 10V, RL = 500 Each Amplifier Each Amplifier ts Settling Time Differential Gain Differential Phase RO IS Output Resistance Channel Separation Supply Current 3 LT1355/LT1356 0C TA 70C, VCM = 0V unless otherwise noted. SYMBOL VOS PARAMETER Input Offset Voltage ELECTRICAL CHARACTERISTICS CONDITIONS The q denotes the specifications which apply over the temperature range VSUPPLY 15V 5V 2.5V q q q q q q q q q q MIN TYP MAX 1.0 1.0 1.2 UNITS mV mV mV V/C nA nA dB dB dB dB V/mV V/mV V/mV V/mV V/mV V/mV V V V V V mA mA mA V/s V/s MHz MHz dB Input VOS Drift IOS IB CMRR Input Offset Current Input Bias Current Common Mode Rejection Ratio (Note 6) 2.5V to 15V 2.5V to 15V 2.5V to 15V 5 8 100 450 VCM = 12V VCM = 2.5V VCM = 0.5V VS = 2.5V to 15V VOUT = 12V, RL = 1k VOUT = 10V, RL = 500 VOUT = 2.5V, RL = 1k VOUT = 2.5V, RL = 500 VOUT = 2.5V, RL = 150 VOUT = 1V, RL = 500 RL = 1k, VIN = 40mV RL = 500, VIN = 40mV RL = 500, VIN = 40mV RL = 150, VIN = 40mV RL = 500, VIN = 40mV VOUT = 12V VOUT = 2.8V VOUT = 0V, VIN = 3V AV = - 2, (Note 4) f = 200kHz, RL = 2k VOUT = 10V, RL = 500 Each Amplifier Each Amplifier 15V 5V 2.5V 15V 15V 5V 5V 5V 2.5V 15V 15V 5V 5V 2.5V 15V 5V 15V 15V 5V 15V 5V 15V 15V 5V 81 77 67 90 10.0 3.3 10.0 3.3 0.6 3.3 13.2 12.0 3.4 2.8 1.2 24.0 18.7 24 150 60 7.5 6.0 98 1.45 1.40 PSRR AVOL Power Supply Rejection Ratio Large-Signal Voltage Gain q q q q q q q q q q q q q q q q q q q q q VOUT Output Swing IOUT ISC SR GBW Output Current Short-Circuit Current Slew Rate Gain Bandwidth Channel Separation IS Supply Current mA mA The q denotes the specifications which apply over the temperature range - 40C TA 85C, VCM = 0V unless otherwise noted. (Note 8) SYMBOL VOS PARAMETER Input Offset Voltage CONDITIONS VSUPPLY 15V 5V 2.5V 2.5V to 15V 2.5V to 15V 2.5V to 15V VCM = 12V VCM = 2.5V VCM = 0.5V VS = 2.5V to 15V VOUT = 12V, RL = 1k VOUT = 10V, RL = 500 VOUT = 2.5V, RL = 1k VOUT = 2.5V, RL = 500 15V 15V 5V 5V 15V 5V 2.5V MIN q q q q q q q q q q q q q q TYP MAX 1.5 1.5 1.7 8 200 550 UNITS mV mV mV V/C nA nA dB dB dB dB V/mV V/mV V/mV V/mV Input VOS Drift IOS IB CMRR Input Offset Current Input Bias Current Common Mode Rejection Ratio (Note 6) 5 80 76 66 90 7.0 1.7 7.0 1.7 PSRR AVOL Power Supply Rejection Ratio Large-Signal Voltage Gain 4 LT1355/LT1356 ELECTRICAL CHARACTERISTICS SYMBOL PARAMETER The q denotes the specifications which apply over the temperature range - 40C TA 85C, VCM = 0V unless otherwise noted. (Note 8) CONDITIONS VOUT = 2.5V, RL = 150 VOUT = 1V, RL = 500 VSUPPLY 5V 2.5V 15V 15V 5V 5V 2.5V 15V 5V 15V 15V 5V 15V 5V 15V 15V 5V q q q q q q q q q q q q q q q q q MIN 0.4 1.7 13.0 11.5 3.4 2.6 1.2 23.0 17.3 23 120 50 7.0 5.5 98 TYP MAX UNITS V/mV V/mV V V V V V mA mA mA V/s V/s MHz MHz dB VOUT Output Swing RL = 1k, VIN = 40mV RL = 500, VIN = 40mV RL = 500, VIN = 40mV RL = 150, VIN = 40mV RL = 500, VIN = 40mV VOUT = 11.5V VOUT = 2.6V VOUT = 0V, VIN = 3V AV = - 2, (Note 4) f = 200kHz, RL = 2k VOUT = 10V, RL = 500 Each Amplifier Each Amplifier IOUT ISC SR GBW Output Current Short-Circuit Current Slew Rate Gain Bandwidth Channel Separation IS Supply Current 1.50 1.45 mA mA 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. Note 5: Full power bandwidth is calculated from the slew rate measurement: FPBW = (SR)/2VP. Note 6: This parameter is not 100% tested. Note 7: The LT1355C/LT1356C are guaranteed functional over the operating temperature range of -40C to 85C. Note 8: The LT1355C/LT1356C are guaranteed to meet specified performance from 0C to 70C. The LT1355C/LT1356C are designed, characterized and expected to meet specified performance from - 40C to 85C, but are not tested or QA sampled at these temperatures. For guaranteed I-grade parts, consult the factory. TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs Supply Voltage and Temperature 1.4 V+ - 0.5 TA = 25C VOS < 1mV COMMON MODE RANGE (V) SUPPLY CURRENT (mA) 125C 1.0 25C -1.5 -2.0 INPUT BIAS CURRENT (nA) 1.2 0.8 0.6 0.4 0 5 10 15 SUPPLY VOLTAGE (V) 20 1355/1356 G01 UW - 55C Input Common Mode Range vs Supply Voltage 200 Input Bias Current vs Input Common Mode Voltage VS = 15V TA = 25C IB+ + IB- IB = -------- 2 -1.0 150 100 2.0 1.5 1.0 0.5 V- 0 5 10 15 SUPPLY VOLTAGE (V) 20 1355/1356 G02 50 0 -50 -15 -10 -5 0 5 10 INPUT COMMON MODE VOLTAGE (V) 15 1355/1356 G03 5 LT1355/LT1356 TYPICAL PERFORMANCE CHARACTERISTICS Input Bias Current vs Temperature 200 175 INPUT BIAS CURRENT (nA) INPUT VOLTAGE NOISE (nV/Hz) 125 100 75 50 25 0 -50 -25 0 25 50 75 TEMPERATURE (C) 100 125 OPEN-LOOP GAIN (dB) 150 VS = 15V IB+ + IB- IB = -------- 2 Open-Loop Gain vs Temperature 97 96 95 VS = 15V RL = 1k VO = 12V OUTPUT VOLTAGE SWING (V) OUTPUT VOLTAGE SWING (V) OPEN-LOOP GAIN (dB) 94 93 92 91 90 89 88 - 50 -25 0 25 50 75 TEMPERATURE (C) 100 125 Output Short-Circuit Current vs Temperature 65 OUTPUT SHORT-CIRCUIT CURRENT (mA) 60 55 50 45 SINK 40 35 30 25 20 -50 -25 SOURCE VS = 5V OUTPUT SWING (V) 2 0 -2 -4 10mV -6 -8 -10 1mV OUTPUT SWING (V) 0 25 50 75 TEMPERATURE (C) 6 UW 1355/1356 G04 1355/1356 G07 Input Noise Spectral Density 100 VS = 15V TA = 25C AV = 101 RS = 100k in en 1 10 Open-Loop Gain vs Resistive Load 100 TA = 25C VS = 15V VS = 5V INPUT CURRENT NOISE (pA/Hz) 90 80 10 70 60 1 10 100 1k 10k FREQUENCY (Hz) 0.1 100k 1355/1356 G05 50 10 100 1k LOAD RESISTANCE () 10k 1355/1356 G06 Output Voltage Swing vs Supply Voltage V+ TA = 25C -1 -2 RL = 500 -3 3 2 1 V- 0 5 10 15 SUPPLY VOLTAGE (V) 20 1355/1356 G08 Output Voltage Swing vs Load Current V +-0.5 -1.0 -1.5 -2.0 -2.5 85C 2.5 2.0 1.5 1.0 V - + 0.5 -50 -40 -30 -20 -10 0 10 20 30 40 50 OUTPUT CURRENT (mA) 1355/1356 G09 RL = 1k VS = 5V VIN = 100mV -40C 85C 25C RL = 500 25C -40C RL = 1k Settling Time vs Output Step (Noninverting) 10 8 6 4 10mV VS = 15V AV = 1 10 8 6 4 2 0 -2 -4 -6 -8 -10 Settling Time vs Output Step (Inverting) VS = 15V AV = -1 10mV 1mV 1mV 10mV 1mV 100 125 50 100 150 200 250 SETTLING TIME (ns) 300 350 50 100 150 200 250 SETTLING TIME (ns) 300 350 1355/1356 G10 1355/1356 G11 1355/1356 G12 LT1355/LT1356 TYPICAL PERFORMANCE CHARACTERISTICS Output Impedance vs Frequency 1k AV = 100 VS = 15V TA = 25C VOLTAGE MAGNITUDE (dB) 10 8 6 4 2 0 -2 -4 -6 -8 C=0 VS = 15V TA = 25C AV = -1 OUTPUT IMPEDANCE () 100 GAIN BANDWIDTH (MHz) 10 AV = 10 1 AV = 1 0.1 0.01 10k 100k 1M 10M FREQUENCY (Hz) Gain Bandwidth and Phase Margin vs Temperature 18 17 PHASE MARGIN VS = 15V PHASE MARGIN VS = 5V 52 50 48 5 4 3 GAIN BANDWIDTH (MHz) 16 15 14 13 12 11 10 9 GAIN BANDWIDTH VS = 5V -25 GAIN (dB) GAIN (dB) GAIN BANDWIDTH VS = 15V 8 - 50 0 25 50 75 TEMPERATURE (C) Gain and Phase vs Frequency 70 60 50 GAIN (dB) PHASE VS = 15V VS = 15V GAIN VS = 5V VS = 5V TA = 25C AV = -1 RF = RG = 2k 100k 1M 10M FREQUENCY (Hz) 100 80 60 40 20 0 PHASE (DEG) COMMON-MODE REJECTION RATIO (dB) POWER SUPPLY REJECTION RATIO (dB) 40 30 20 10 0 -10 10k UW 1355/1356 G13 Frequency Response vs Capacitive Load 18 17 C = 1000pF C = 500pF C = 100pF C = 50pF Gain Bandwidth and Phase Margin vs Supply Voltage 50 48 PHASE MARGIN 46 PHASE MARGIN (DEG) 16 15 14 13 12 11 10 9 8 44 42 40 38 GAIN BANDWIDTH 36 34 TA = 25C 0 5 10 15 SUPPLY VOLTAGE (V) 20 1355/1356 G15 32 30 100M -10 100k 1M 10M FREQUENCY (Hz) 100M 1355/1356 G19 Frequency Response vs Supply Voltage (AV = 1) 5 TA = 25C AV = 1 RL = 2k Frequency Response vs Supply Voltage (AV = -1) 4 3 2 15V TA = 25C AV = -1 RF = RG = 2k PHASE MARGIN (DEG) 46 44 42 40 38 36 34 2 1 0 -1 -2 -3 -4 -5 100k 5V 2.5V 1 0 -1 -2 -3 -4 2.5V 1M 10M FREQUENCY (Hz) 15V 100M 1355/1356 G18 5V 100 32 125 1M 10M FREQUENCY (Hz) 100M 1355/1356 G17 -5 100k 1355/1356 G16 Power Supply Rejection Ratio vs Frequency 120 100 VS = 15V TA = 25C 80 +PSRR - PSRR 60 120 100 80 60 40 20 0 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M Common Mode Rejection Ratio vs Frequency VS = 15V TA = 25C 40 20 100M 1355/1356 G14 0 100 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 1355/1356 G20 1355/1356 G21 7 LT1355/LT1356 TYPICAL PERFORMANCE CHARACTERISTICS Slew Rate vs Supply Voltage 600 500 SLEW RATE (V/s) SLEW RATE (V/s) 400 300 200 100 0 0 250 200 150 100 50 -50 AV = -2 SR+ + SR- SR = ---------- 2 SLEW RATE (V/s) TA = 25C AV = -1 RF = RG = 2k SR+ + SR- SR = ---------- 2 5 10 SUPPLY VOLTAGE (V) Total Harmonic Distortion vs Frequency 0.1 30 TA = 25C VO = 3VRMS RL = 2k 0.01 25 OUTPUT VOLTAGE (VP-P) 20 TOTAL HARMONIC DISTORTION (%) OUTPUT VOLTAGE (VP-P) AV = -1 0.001 AV = 1 0.0001 10 100 1k 10k FREQUENCY (Hz) 100k 1355/1356 G25 2nd and 3rd Harmonic Distortion vs Frequency -20 -30 -40 3RD HARMONIC -50 -60 2ND HARMONIC -70 -80 100k 200k VS = 15V VO = 2VP-P RL = 2k AV = 2 CROSSTALK (dB) HARMONIC DISTORTION (dB) -70 -80 -90 OVERSHOOT (%) 400k 1M 2M FREQUENCY (Hz) 8 UW 1355/1356 G22 Slew Rate vs Temperature 350 300 VS = 15V 500 Slew Rate vs Input Level TA = 25C VS = 15V AV = -1 RF = RG = 2k SR+ + SR- SR = ---------- 2 400 300 200 VS = 5V 100 0 -25 0 25 50 75 TEMPERATURE (C) 100 125 0 2 4 6 8 10 12 14 16 18 INPUT LEVEL (VP-P) 20 15 1355/1356 G23 1355/1356 G24 Undistorted Output Swing vs Frequency (15V) 10 AV = -1 8 Undistorted Output Swing vs Frequency (5V) AV = -1 AV = 1 AV = 1 15 10 5 VS = 15V RL = 5k AV = 1, 1% MAX DISTORTION AV = -1, 4% MAX DISTORTION 1M FREQUENCY (Hz) 10M 1355/1356 G26 6 4 2 VS = 5V RL = 5k AV = 1, 2% MAX DISTORTION AV = -1, 3% MAX DISTORTION 1M FREQUENCY (Hz) 10M 1355/1356 G27 0 100k 0 100k Crosstalk vs Frequency -40 -50 -60 TA = 25C VIN = 0dBm RL = 500 AV = 1 100 Capacitive Load Handling TA = 25C VS = 15V AV = 1 50 AV = -1 -100 -110 4M 10M -120 100k 1M 10M FREQUENCY (Hz) 100M 1355/1356 G29 0 10p 100p 1000p 0.01 0.1 CAPACITIVE LOAD (F) 1 1355/1356 G28 1355/1356 G30 LT1355/LT1356 TYPICAL PERFORMANCE CHARACTERISTICS Small-Signal Transient (AV = 1) Small-Signal Transient (AV = -1) Small- Signal Transient (AV = -1, CL = 1000pF) 1355/1356 G31 Large-Signal Transient (AV = 1) 1355/1356 G34 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 (0.01F to 0.1F). For high drive current applications use low ESR bypass capacitors (1F to 10F tantalum). 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 or oscillations. If feedback resistors greater than 5k 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. U W UW 1355/1356 G32 1355/1356 G33 Large-Signal Transient (AV = -1) Large-Signal Transient (AV = 1, CL = 10,000pF) 1355/1356 G35 1355/1356 G36 U U 9 LT1355/LT1356 APPLICATIONS INFORMATION Capacitive Loading 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., 75) should be placed in series with the output. The other end of the cable should be terminated with the same value resistor to ground. 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. Circuit Operation 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 800 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. 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. 10 U W U U LT1355/LT1356 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 130C/W) TJ = TA + (PD x 190C/W) TJ = TA + (PD x 110C/W) TJ = TA + (PD x 150C/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 70C, VS = 15V, RL = 1k PDMAX = (30V)(1.45mA) + (7.5V)2/1kW = 99.8mW TJMAX = 70C + (4 x 99.8mW)(150C/W) = 130C SI PLIFIED SCHE ATIC V+ R1 800 -IN V- 1355/1356 SS01 U W W U U W +IN C RC OUT CC 11 LT1355/LT1356 PACKAGE DESCRIPTIO 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 ) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) 12 U 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 0.255 0.015* (6.477 0.381) 1 2 3 4 0.130 0.005 (3.302 0.127) 0.045 - 0.065 (1.143 - 1.651) 0.065 (1.651) TYP 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 0.003 (0.457 0.076) N8 1098 0.100 (2.54) BSC LT1355/LT1356 PACKAGE DESCRIPTIO 0.300 - 0.325 (7.620 - 8.255) 0.009 - 0.015 (0.229 - 0.381) 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) +0.035 0.325 -0.015 +0.889 8.255 -0.381 ( ) U 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 0.255 0.015* (6.477 0.381) 1 0.130 0.005 (3.302 0.127) 0.020 (0.508) MIN 2 3 4 5 6 7 0.045 - 0.065 (1.143 - 1.651) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.018 0.003 (0.457 0.076) N14 1098 13 LT1355/LT1356 PACKAGE DESCRIPTIO 0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0- 8 TYP 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) 14 U 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 0.228 - 0.244 (5.791 - 6.197) 0.150 - 0.157** (3.810 - 3.988) 1 2 3 4 0.053 - 0.069 (1.346 - 1.752) 0.004 - 0.010 (0.101 - 0.254) 0.050 (1.270) BSC SO8 1298 LT1355/LT1356 PACKAGE DESCRIPTIO 0.010 - 0.020 x 45 (0.254 - 0.508) 0.008 - 0.010 (0.203 - 0.254) 0 - 8 TYP 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 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. U 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 0.228 - 0.244 (5.791 - 6.197) 0.150 - 0.157** (3.810 - 3.988) 1 0.053 - 0.069 (1.346 - 1.752) 2 3 4 5 6 7 8 0.004 - 0.010 (0.101 - 0.254) 0.014 - 0.019 (0.355 - 0.483) TYP 0.050 (1.270) BSC S16 1098 15 LT1355/LT1356 TYPICAL APPLICATIONS Instrumentation Amplifier R5 432 R1 20k R2 2k R4 20k 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 = VIN R1 2.87k R2 26.7k RELATED PARTS PART NUMBER LT1354 LT1352/LT1353 LT1358/LT1359 DESCRIPTION 12MHz, 400V/s Op Amp Dual and Quad 250A, 3MHz, 200V/s Op Amps Dual and Quad 25MHz, 600Vs Op Amps COMMENTS Single Version of LT1355/LT1356 Lower Power Version of LT1355/LT1356, VOS = 0.6mV, IS = 250A/Amplifier Faster Version of LT1355/LT1356, VOS = 0.6mV, IS = 2mA/Amplifier 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com U - + - 1/2 LT1355 R3 2k - 1/2 LT1355 VOUT + + 1355/1356 TA03 100kHz, 4th Order Butterworth Filter (Sallen-Key) C4 1000pF C2 330pF - - 1/2 LT1355 1/2 LT1355 VOUT + R3 2.43k R4 15.4k C3 68pF 1355/1356 TA04 + C1 100pF 13556fa LT/TP 0400 2K REV A * PRINTED IN USA (c) LINEAR TECHNOLOGY CORPORATION 1994 |
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