LT1354IS8#TRPBF

LT1354 12MHz, 400V/µs Op Amp U DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LT ®1354 is a low power, high speed, high slew rate operational amplifier with outstanding AC and DC performance. The LT1354 has much lower 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 500Ω load to ±12V with ±15V supplies and a 150Ω load to ±2.5V on ±5V supplies. The amplifier is also stable with any capacitive load which makes it useful in buffer or cable driver applications. 12MHz Gain-Bandwidth 400V/µs Slew Rate 1.25mA Maximum Supply Current 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 ±12V Minimum Output Swing into 500Ω ±2.5V Minimum Output Swing into 150Ω Specified at ±2.5V, ±5V, and ±15V The LT1354 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 LT1354 see the LT1355/LT1356 data sheet. For higher bandwidth devices with higher supply current see the LT1357 through LT1365 data sheets. Singles, duals, and quads of each amplifier are available. U APPLICATIONS ■ ■ ■ ■ ■ Wideband Amplifiers Buffers Active Filters Data Acquisition Systems Photodiode Amplifiers , LTC and LT are registered trademarks of Linear Technology Corporation. C-Load is a trademark of Linear Technology Corporation U TYPICAL APPLICATION AV = –1 Large-Signal Response 100kHz, 4th Order Butterworth Filter 6.81k 5.23k 100pF 6.81k 11.3k VIN 330pF – 47pF 5.23k 10.2k LT1354 + 1000pF – LT1354 VOUT + 1354 TA01 1354 TA02 1 LT1354 W W U W ABSOLUTE MAXIMUM RATINGS Total Supply Voltage (V + to V –) ............................... 36V Differential Input Voltage (Transient Only, Note 1) ... ±10V Input Voltage ............................................................±VS Output Short-Circuit Duration (Note 2) ............ Indefinite Operating Temperature Range ................ –40°C to 85°C Specified Temperature Range (Note 6) ... –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 NULL 1 8 NULL –IN 2 7 V+ +IN 3 6 VOUT V– 4 5 NC ORDER PART NUMBER LT1354CN8 ORDER PART NUMBER TOP VIEW NULL 1 8 NULL –IN 2 7 V+ +IN 3 6 VOUT V– 4 5 NC N8 PACKAGE, 8-LEAD PLASTIC DIP S8 PACKAGE, 8-LEAD PLASTIC SOIC TJMAX = 150°C, θJA = 130°C/ W TJMAX = 150°C, θJA = 190°C/ W LT1354CS8 S8 PART MARKING 1354 Consult factory for Industrial and Military grade parts. ELECTRICAL CHARACTERISTICS TA = 25°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS 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 Differential ±15V ±15V CIN Input Capacitance 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 MIN 70 ±15V + ±15V ±5V ±2.5V Input Voltage Range – ±15V ±5V ±2.5V Input Voltage Range 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 VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω 2 VSUPPLY ±15V ±5V ±2.5V ±15V ±15V ±5V ±5V ±5V ±2.5V 12.0 2.5 0.5 nA 0.6 pA/√Hz 160 11 MΩ MΩ 3 pF 13.4 3.5 1.1 V V V –13.2 – 3.4 – 0.9 –12.0 – 2.5 – 0.5 V V V 80 78 68 97 84 75 dB dB dB 92 106 dB 12 5 12 5 1 5 36 15 36 15 4 20 V/mV V/mV V/mV V/mV V/mV V/mV LT1354 ELECTRICAL CHARACTERISTICS TA = 25°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS VSUPPLY MIN TYP 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 13.3 12.0 3.5 2.5 1.3 13.8 12.5 4.0 3.1 1.7 ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±12V VOUT = ±2.5V ±15V ±5V 24.0 16.7 30 25 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V 30 42 mA SR Slew Rate AV = –2, (Note 3) ±15V ±5V 200 70 400 120 V/µs V/µs Full Power Bandwidth 10V Peak, (Note 4) 3V Peak, (Note 4) ±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 RO Output Resistance AV = 1, f = 100kHz ±15V 0.7 IS Supply Current ±15V ±5V 1.0 0.9 1.25 1.20 mA mA TYP MAX UNITS ts 9.0 7.5 MAX UNITS Ω 0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER VOS Input Offset Voltage Input VOS Drift IOS CONDITIONS (Note 5) 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 VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω VSUPPLY MIN ±15V ±5V ±2.5V ● ● ● ±2.5V to ±15V ● ±2.5V to ±15V ● ±2.5V to ±15V ● ±15V ±5V ±2.5V ● ● ● ±15V ±15V ±5V ±5V ±5V ±2.5V 1.0 1.0 1.2 5 79 77 67 8 mV mV mV µV/°C 100 nA 450 nA dB dB dB ● 90 dB ● ● ● ● ● ● 10.0 3.3 10.0 3.3 0.6 3.3 V/mV V/mV V/mV V/mV V/mV V/mV 3 LT1354 ELECTRICAL CHARACTERISTICS 0°C ≤ TA ≤ 70°C, VCM = 0V unless otherwise noted. SYMBOL PARAMETER CONDITIONS VSUPPLY 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 11.5 3.4 2.3 1.2 MIN TYP MAX UNITS ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±11.5V VOUT = ±2.3V ±15V ±5V ● ● 23.0 15.3 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V ● 24 mA SR Slew Rate AV = –2, (Note 3) ±15V ±5V ● ● 150 60 V/µs V/µs GBW Gain-Bandwidth f = 200kHz, RL = 2k ±15V ±5V ● ● 7.5 6.0 MHz MHz IS Supply Current ±15V ±5V ● ● 1.45 1.40 mA mA MAX UNITS 1.5 1.5 1.7 mV mV mV –40°C ≤ TA ≤ 85°C, VCM = 0V unless otherwise noted. (Note 6) SYMBOL PARAMETER VOS Input Offset Voltage Input VOS Drift IOS CONDITIONS (Note 5) Input Offset Current VSUPPLY MIN TYP ±15V ±5V ±2.5V ● ● ● ±2.5V to ±15V ● ±2.5V to ±15V ● ±2.5V to ±15V ● ±15V ±5V ±2.5V ● ● ● 78 76 66 dB dB dB ● 90 dB 5 8 µV/°C 200 nA 550 nA 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 VOUT = ±2.5V, RL = 150Ω VOUT = ±1V, RL = 500Ω ±15V ±15V ±5V ±5V ±5V ±2.5V ● ● ● ● ● ● 7.0 1.7 7.0 1.7 0.4 1.7 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 ● ● ● ● ● 13.0 11.0 3.4 2.1 1.2 ±V ±V ±V ±V ±V IOUT Output Current VOUT = ±11V VOUT = ±2.1V ±15V ±5V ● ● 22 14 mA mA ISC Short-Circuit Current VOUT = 0V, VIN = ±3V ±15V ● 23 mA SR Slew Rate AV = –2, (Note 3) ±15V ±5V ● ● 120 50 V/µs V/µs GBW Gain Bandwith f = 200kHz, RL = 2k ±15V ±5V ● ● 7.0 5.5 MHz MHz IS Supply Current ±15V ±5V ● ● 4 1.50 1.45 mA mA LT1354 ELECTRICAL CHARACTERISTICS The ● denotes specifications that apply over the full specified temperature range. Note 1: 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 dutails. Note 2: A heat sink may be required to keep the junction temperature below absolute maximum when the output is shorted indefinitely. Note 3: 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 4: Full power bandwidth is calculated from the slew rate measurement: FPBW = SR/2πVP. Note 5: This parameter is not 100% tested. Note 6: The LT1354 is designed, characterized and expected to meet these extended temperature limits, but is not tested at – 40°C and at 85°C. Guaranteed I grade parts are available; consult factory. U W TYPICAL PERFORMANCE CHARACTERISTICS Supply Current vs Supply Voltage and Temperature V+ 1.4 200 125°C 1.0 25°C 0.8 –55°C 0.6 –1.0 INPUT BIAS CURRENT (nA) COMMON-MODE RANGE (V) 1.2 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  150  100 50 0 0.5 V– 0.4 5 10 15 SUPPLY VOLTAGE (±V) 20 0 5 10 15 SUPPLY VOLTAGE (±V) 1354 G01  125 100 75 50 VS = ±15V TA = 25°C AV = 101 RS = 100k in 10 TA = 25°C en 1 25 0 – 50 1 –25 0 25 50 75 TEMPERATURE (°C) 100 125 1354 G04 100 10 100 INPUT VOLTAGE NOISE (nV/√Hz) INPUT BIAS CURRENT (nA) 150 Open-Loop Gain vs Resistive Load 10 100 1k 10k FREQUENCY (Hz) 0.1 100k 1354 G05 INPUT CURRENT NOISE (pA/√Hz)  175 15 1354 G03 Input Noise Spectral Density VS = ±15V IB+ + IB– IB = ———— 2 –10 –5 0 5 10 INPUT COMMON-MODE VOLTAGE (V) 1354 G02 Input Bias Current vs Temperature 200 –50 –15 20 VS = ±15V VS = ±5V 90 OPEN-LOOP GAIN (dB) 0 80 70 60 50 10 100 1k LOAD RESISTANCE (Ω) 10k 1354 G06 5 LT1354 U W TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Swing vs Supply Voltage Open-Loop Gain vs Temperature V + – 0.5 V+ 97 RL = 1k VO = ±12V VS = ±15V RL = 1k 94 93 92 91 90 –2 RL = 500Ω –3 3 RL = 500Ω 2 1 89 88 – 50 0 25 50 75 TEMPERATURE (°C) 100 125 0 20 10 SINK 40 SOURCE 6 10mV 4 1mV 2 0 –2 –4 10mV 30 –6 25 1mV 100 150 200 250 SETTLING TIME (ns) 300 PHASE VS = ±15V GAIN 0 100k 1M 10M FREQUENCY (Hz) 100M 1354 G13 6 60 VS = ±5V 30 20 80 VS = ±15V 40 –10 10k 40 VS = ±5V 20 0 16 46 15 44 14 42 13 40 12 38 11 36 GAIN-BANDWIDTH 34 TA = 25°C 9 8 1M 10M FREQUENCY (Hz) 48 PHASE MARGIN 10 TA = 25°C AV = –1 RF = RG = 2k 100k 350 50 17 100 10 0.1 300 18 GAIN-BANDWIDTH (MHz) AV = 1 150 200 250 SETTLING TIME (ns) 1355/1356 G12 120 60 GAIN (dB) 1 100 100M 1354 G14 0 5 10 15 SUPPLY VOLTAGE (±V) 32 30 20 1354 G15 PHASE MARGIN (DEG) AV = 10 10mV Gain-Bandwidth and Phase Margin vs Supply Voltage 70 VS = ±15V TA = 25°C 10 1mV 50 Gain and Phase vs Frequency 50 0.01 10k 350 PHASE (DEG) OUTPUT IMPEDANCE (Ω) 100 –2 –4 1354 G11 Output Impedance vs Frequency AV = 100 1mV 0 –10 50 1354 G10 1k 10mV 2 –8 –10 125 4 –6 –8 100 VS = ±15V AV = –1 8 OUTPUT SWING (V) OUTPUT SWING (V) OUTPUT SHORT-CIRCUIT CURRENT (mA) 45 0 25 50 75 TEMPERATURE (°C) – 40°C 1.5 Settling Time vs Output Step (Inverting) VS = ±15V AV = 1 8 50 –25 25°C 2.0 1354 G09 6 20 – 50 85°C V – +0.5 – 50 – 40 –30 –20 –10 0 10 20 30 40 50 OUTPUT CURRENT (mA) 10 55 35 25°C 2.5 Settling Time vs Output Step (Noninverting) VS = ±5V 60 –2.5 1354 G08 Output Short-Circuit Current vs Temperature 65 –2.0 1.0 5 10 15 SUPPLY VOLTAGE (±V) 1354 G07 – 40°C –1.5 RL = 1k V– –25 85°C VS = ± 5V VIN = 100mV –1.0 –1 OUTPUT VOLTAGE SWING (V) 95 TA = 25°C OUTPUT VOLTAGE SWING (V) 96 OPEN-LOOP GAIN (dB) Output Voltage Swing vs Load Current LT1354 U W TYPICAL PERFORMANCE CHARACTERISTICS Gain-Bandwidth and Phase Margin vs Temperature PHASE MARGIN VS = ±5V 15 4 48 3 46 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 2 ±15V 1 0 –1 ±5V –2 36 –3 34 –4 –3 10M 1M FREQUENCY (Hz) 100M C = 500pF 2 C = 100pF 0 C = 50pF –2 C=0 –4 –6 –8 –10 100k 1M 10M FREQUENCY (Hz) 120 VS = ±15V TA = 25°C 80 +PSRR –PSRR 60 40 20 0 100 100M Slew Rate vs Supply Voltage 10k 100k 1M FREQUENCY (Hz) 10M 40 20 15 SR+ + SR– SR = ————— 2 150 1354 G22 50 – 50 100M VS = ±15V AV = –1 RF = RG = 2k SR+ + SR– SR = ————— 2 TA = 25°C 400 SLEW RATE (V/µs) 200 10M Slew Rate vs Input Level 250 VS = ± 5V 100 0 100k 1M FREQUENCY (Hz) 500 VS = ±15V 100 10k 1354 G21 AV = –2 SLEW RATE (V/µs) SLEW RATE (V/µs) 60 1k 300 200 5 10 SUPPLY VOLTAGE (±V) 80 Slew Rate vs Temperature 300 0 100 100M 350 400 VS = ±15V TA = 25°C 1354 G20 600 AV = –1 RF = RG = 2k SR+ + SR– SR = ————— 2 TA = 25°C 100M 0 1k 1354 G19 500 10M 1M FREQUENCY (Hz) Common-Mode Rejection Ratio vs Frequency COMMON-MODE REJECTION RATIO (dB) POWER SUPPLY REJECTION RATIO (dB) VOLTAGE MAGNITUDE (dB) 4 ±15V 1354 G18 100 C = 1000pF ±2.5V –5 100k Power Supply Rejection Ratio vs Frequency 10 6 ±5V 1354 G17 Frequency Response vs Capacitive Load VS = ±15V TA = 25°C AV = –1 0 –1 –4 1354 G16 8 1 –2 ±2.5V –5 100k 32 125 TA = 25°C AV = –1 RF = RG = 2k 4 GAIN (dB) 16 50 GAIN (dB) PHASE MARGIN VS = ±15V PHASE MARGIN (DEG) GAIN-BANDWIDTH (MHz) 5 52 18 17 Frequency Response vs Supply Voltage (AV = –1) Frequency Response vs Supply Voltage (AV = 1) 300 200 100 0 –25 0 25 50 75 TEMPERATURE (°C) 100 125 1354 G23 0 2 4 6 8 10 12 14 16 18 20 INPUT LEVEL (VP-P) 1354 G24 7 LT1354 U W TYPICAL PERFORMANCE CHARACTERISTICS Total Harmonic Distortion vs Frequency Undistorted Output Swing vs Frequency (±15V) 30 TA = 25°C VO = 3VRMS RL = 2k OUTPUT VOLTAGE (VP-P) AV = –1 0.001 AV = 1 100 AV = –1 25 0.01 0.0001 10 10 20 AV = 1 15 10 5 VS = ±15V RL = 5k AV = 1, 1% MAX DISTORTION AV = –1, 4% MAX DISTORTION 0 100k 100k 1k 10k FREQUENCY (Hz) OUTPUT VOLTAGE (VP-P) 0.1 1M FREQUENCY (Hz) Capacitive Load Handling DIFFERENTIAL PHASE (DEGREES) HARMONIC DISTORTION (dB) –60 2ND HARMONIC –70 400k 1M 2M FREQUENCY (Hz) 4M 10M 2.0 3.4 AV = 2 RL = 1k TA = 25°C 1.5 3.3 DIFFERENTIAL PHASE 3.2 3.1 ±5 ±10 SUPPLY VOLTAGE (V) 1354 G28 ±15 TA = 25°C VS = ±15V 1354 TA31 AV = 1 50 AV = –1 0 10p 100p 1000p 0.01µ 0.1µ CAPACITIVE LOAD (F) 1µ 1354 G30 1354 G29 Small-Signal Transient (AV = –1) Small-Signal Transient (AV = 1) DIFFERENTIAL PHASE (PERCENT) –50 10M 100 DIFFERENTIAL GAIN 3RD HARMONIC 1M FREQUENCY (Hz) 1354 G27 2.5 –40 8 0 100k 10M –20 –80 100k 200k VS = ±5V RL = 5k AV = 1, 2% MAX DISTORTION AV = –1, 3% MAX DISTORTION 4 Differential Gain and Phase vs Supply Voltage 2nd and 3rd Harmonic Distortion vs Frequency –30 AV = 1 6 1355/1356 G26 1354 G25 VS = ±15V VO = 2VP-P RL = 2k AV = 2 AV = –1 8 2 OVERSHOOT (%) TOTAL HARMONIC DISTORTION (%) Undistorted Output Swing vs Frequency (±5V) Small-Signal Transient (AV = –1, CL = 1000pF) 1354 TA32 1354 TA33 LT1354 U W TYPICAL PERFORMANCE CHARACTERISTICS Large-Signal Transient (AV = 1) Large-Signal Transient (AV = 1, CL = 10,000pF) Large-Signal Transient (AV = –1) 1354 TA34 1354 TA35 1354 TA36 U U W U APPLICATIONS INFORMATION The LT1354 may be inserted directly into many high speed amplifier applications improving both DC and AC performance, provided that the nulling circuitry is removed. The suggested nulling circuit for the LT1354 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 • CIN)/RF V+ 3 7 + 6 LT1354 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– 1354 AI01 Layout and Passive Components The LT1354 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 LT1354 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 1000pF load shows 43% peaking. The large signal response with a 10,000pF load shows the output slew rate being limited to 5V/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. 9 LT1354 U W U U APPLICATIONS INFORMATION Input Considerations Each of the LT1354 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. Power Dissipation The LT1354 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 temperature under certain conditions. Maximum junction temperature (TJ) is calculated from the ambient temperature (TA) and power dissipation (PD) as follows: LT1354CN8: TJ = TA + (PD • 130°C/W) LT1354CS8: TJ = TA + (PD • 190°C/W) Worst case power dissipation occurs at the maximum supply current and when the output voltage is at 1/2 of 10 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: LT1354CS8 at 70°C, VS = ±15V, RL = 100Ω (Note: the minimum short-circuit current at 70°C is 24mA, so the output swing is guaranteed only to 2.4V with 100Ω.) PDMAX = (30V • 1.45mA) + (15V–2.4V)(24mA) = 346mW TJMAX = 70°C + (346mW • 190°C/W) = 136°C Circuit Operation The LT1354 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 LT1354 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. 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 LT1354 U U W U APPLICATIONS INFORMATION 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. W W SI PLIFIED SCHE ATIC V+ R1 800Ω +IN RC OUT –IN C CC V– 1354 SS01 U PACKAGE DESCRIPTION Dimensions 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) 0.130 ± 0.005 (3.302 ± 0.127) 0.065 (1.651) TYP 0.100 ± 0.010 (2.540 ± 0.254) 0.400* (10.160) MAX 8 7 6 5 1 2 3 4 0.255 ± 0.015* (6.477 ± 0.381) 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 ± 0.003 (0.457 ± 0.076) N8 1197 *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 LT1354 U PACKAGE DESCRIPTION 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) 0.010 – 0.020 × 45° (0.254 – 0.508) 8 0.053 – 0.069 (1.346 – 1.752) 0.008 – 0.010 (0.203 – 0.254) 5 6 0.004 – 0.010 (0.101 – 0.254) 0°– 8° TYP 0.016 – 0.050 0.406 – 1.270 7 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) 0.050 (1.270) TYP 0.014 – 0.019 (0.355 – 0.483) *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 1 2 3 4 SO8 0996 U TYPICAL APPLICATIONS 100kHz, 4th Order Butterworth Filter (Sallen-Key) Instrumentation Amplifier R5 432Ω R1 20k C4 1000pF C2 330pF R2 2k – – R3 2k – LT1354 – R4 20k + + VIN – VOUT LT1354 + VIN LT1354 R1 2.87k R2 26.7k C1 100pF VOUT + LT1354 R3 2.43k R4 15.4k C3 68pF 1354 TA04 + 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 = 1354 TA03 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1355/LT1356 Dual/Quad 1mA, 12MHz, 400V/µs Op Amp Good DC Precision, Stable with All Capacitive Loads LT1357 2mA, 25MHz, 600V/µs Op Amp Good DC Precision, Stable with All Capacitive Loads LT1358/LT1359 Dual/Quad 2mA, 25MHz, 600V/µs Op Amp Good DC Precision, Stable with All Capacitive Loads 12 Linear Technology Corporation 1354fa LT/TP 0598 REV A 2K • 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