LT1221

LT1221 150MHz, 250V/µ s, AV ≥ 4 Operational Amplifier FEATURES s s s s s s s s s s s s s s DESCRIPTIO Gain-Bandwidth: 150MHz Gain of 4 Stable Slew Rate: 250V/µs Input Noise Voltage: 6nV/√Hz C-LoadTM Op Amp Drives Capacitive Loads Maximum Input Offset Voltage: 600µV Maximum Input Bias Current: 300nA Maximum Input Offset Current: 300nA Minimum Output Swing Into 500Ω: ± 12V Minimum DC Gain: 50V/mV, RL = 500Ω Settling Time to 0.1%: 65ns, 10V Step Settling Time to 0.01%: 85ns, 10V Step Differential Gain: 0.08%, AV = 4, RL = 150Ω Differential Phase: 0.2°, AV = 4, RL = 150Ω The LT1221 is a very high speed operational amplifier with superior DC performance. The LT1221 is stable in a noise gain of 4 or greater. It features reduced input offset voltage, lower input bias currents and higher DC gain than devices with comparable bandwidth and slew rate. The circuit is a single gain stage that includes proprietary DC gain enhancement circuitry to obtain precision with high speed. The high gain and fast settling time make the circuit an ideal choice for data acquisition systems. The circuit is also capable of driving capacitive loads which makes it useful in buffer or cable driver applications. The LT1221 is a member of a family of fast, high performance amplifiers that employ Linear Technology Corporation’s advanced complementary bipolar processing. For unity-gain stable applications the LT1220 can be used, and for gains of 10 or greater the LT1222 can be used. and LTC are registered trademarks and LT is a trademark of Linear Technology Corporation. C-Load is a trademark of Linear Technology Cortporation. APPLICATI s s s s s s S Wideband Amplifiers Buffers Active Filters Video and RF Amplification Cable Drivers 8-, 10-, 12-Bit Data Acquisition Systems TYPICAL APPLICATION Summing Amplifier 1k VA VB VC 1k 1k Summing Amplifier Large-Signal Response – LT1221 VOUT 1k + LT1221 • TA01 VS = ±15V VIN = 10VP-P f = 2MHz U LT1221 • TA02 U UO 1 LT1221 ABSOLUTE AXI U RATI GS Operating Temperature Range LT1221C ........................................... – 40°C TO 85°C LT1221M ......................................... – 55°C to 125°C Maximum Junction Temperature (See Below) Plastic Package ............................................... 150°C Ceramic Package ............................................. 175°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec)................. 300°C Total Supply Voltage (V + to V –) ............................. 36V Differential Input Voltage ........................................ ± 6V Input Voltage .......................................................... ± VS Output Short-Circuit Duration (Note 1) ........... Indefinite Specified Temperature Range LT1221C (Note 2) ................................... 0°C to 70°C LT1221M ......................................... – 55°C to 125°C PACKAGE/ORDER I FOR ATIO TOP VIEW NULL 8 NULL 1 –IN 2 +IN 3 7 V+ 6 VOUT 5 NC 4 – ORDER PART NUMBER SPECIAL ORDER CONSULT FACTORY V H PACKAGE 8-LEAD TO-5 METAL CAN TJMAX = 175°C, θJA = 150°C/W Consult factory for Industrial grade parts. ELECTRICAL CHARACTERISTICS SYMBOL VOS IOS IB en in RIN CIN PARAMETER Input Offset Voltage Input Offset Current Input Bias Current Input Noise Voltage Input Noise Current Input Resistance Inut Capacitance Input Voltage Range (Positive) Input Voltage Range (Negative) Common-Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain Output Swing Output Current Slew Rate Full Power Bandwidth Gain-Bandwidth VS = ±15V, TA = 25°C, VCM = 0V, unless otherwise specified. MIN TYP 200 100 100 6 2 45 80 2 14 – 13 114 110 100 13 26 250 4 150 MAX 600 300 300 UNITS µV nA nA nV/√Hz pA/√Hz MΩ kΩ pF V V dB dB V/mV ±V mA V/µs MHz MHz CONDITIONS (Note 3) f = 10kHz f = 10kHz VCM = ± 12V Differential CMRR PSRR AVOL VOUT IOUT SR GBW VCM = ± 12V VS = ± 5V to ± 15V VOUT = ± 10V, RL = 500Ω RL = 500Ω VOUT = ± 12V (Note 4) 10V Peak (Note 5) f = 1MHz 2 U U W WW U W TOP VIEW NULL 1 –IN 2 +IN 3 V– 4 J8 PACKAGE 8-LEAD CERAMIC DIP 8 7 6 5 NULL V+ VOUT NC ORDER PART NUMBER LT1221CN8 LT1221MJ8 LT1221CS8 S8 PART MARKING 1221 N8 PACKAGE 8-LEAD PLASTIC DIP S8 PACKAGE 8-LEAD PLASTIC SOIC TJMAX = 175°C, θJA = 100°C/W (J) TJMAX = 150°C, θJA = 130°C/W (N) TJMAX = 150°C, θJA = 190°C/W (S) 20 12 92 90 50 12 24 200 – 12 LT1221 ELECTRICAL CHARACTERISTICS SYMBOL tr, tf PARAMETER Rise Time, Fall Time Overshoot Propagation Delay Settling Time Differential Gain Differential Phase RO IS Output Resistance Supply Current VS = ± 15V, TA = 25°C, VCM = 0V, unless otherwise specified. MIN TYP 3.2 10 5.4 65 85 0.08 0.02 0.20 0.05 0.3 8 MAX UNITS ns % ns ns ns % % DEG DEG Ω mA ts CONDITIONS AV = 4, 10% to 90%, 0.1V AV = 4, 0.1V AV = 4, 50% VIN to 50% VOUT, 0.1V 10V Step, 0.1% 10V Step, 0.01% f = 3.58MHz, RL = 150Ω (Note 6) f = 3.58MHz, RL = 1k (Note 6) f = 3.58MHz, RL = 150Ω (Note 6) f = 3.58MHz, RL = 1k (Note 6) AV = 4, f = 1MHz 10.5 VS = ± 15V, 0°C ≤ TA ≤ 70°C, VCM = 0V, unless otherwise specified. SYMBOL VOS IOS IB CMRR PSRR AVOL VOUT IOUT SR IS PARAMETER Input Offset Voltage Input VOS Drift Input Offset Current Input Bias Current Common-Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain Output Swing Output Current Slew Rate Supply Current CONDITIONS (Note 3) MIN q q q VCM = ± 12V VS = ± 5V to ± 15V VOUT = ± 10V, RL = 500Ω RL = 500Ω VOUT = ± 12V (Note 4) q q q q q q q 92 90 40 12 24 180 TYP 0.2 15 100 100 114 110 100 13 26 250 8 MAX 1.5 400 400 11 UNITS mV µV/°C nA nA dB dB V/mV ±V mA V/µs mA VS = ± 15V, – 55°C ≤ TA ≤ 125°C, VCM = 0V, unless otherwise specified. SYMBOL VOS IOS IB CMRR PSRR AVOL VOUT IOUT SR IS PARAMETER Input Offset Voltage Input VOS Drift Input Offset Current Input Bias Current Common-Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain Output Swing Output Current Slew Rate Supply Current CONDITIONS (Note 3) MIN q q q VCM = ± 12V VS = ± 5V to ± 15V VOUT = ± 10V, RL = 500Ω RL = 500Ω RL = 1k VOUT = ± 10V VOUT = ± 12V (Note 4) q q q q q q q q q 92 90 12.5 10 12 20 12 130 TYP 0.2 15 100 100 114 110 100 13 13 26 13 250 8 MAX 2 800 1000 11 UNITS mV µV/°C nA nA dB dB V/mV ±V ±V mA mA V/µs mA The q denotes specifications which apply over the full temperature range. Note 1: A heat sink may be required when the output is shorted indefinitely. Note 2: Commercial parts are designed to operate over – 40°C to 85°C, but are not tested nor guaranteed beyond 0°C to 70°C. Industrial grade parts specified and tested over – 40°C to 85°C are available on special request. Consult factory. Note 3: Input offset voltage is pulse tested and is exclusive of warm-up drift. Note 4: Slew rate is measured between ± 10V on an output swing of ± 12V. Note 5: FPBW = SR/2πVP. Note 6: Differential Gain and Phase are tested in AV = 4 with five amps in series. Attenuators of 1/4 are used as loads (36.5Ω, 110Ω and 249Ω, 750Ω). 3 LT1221 TYPICAL PERFORMANCE CHARACTERISTICS Input Common-Mode Range vs Supply Voltage 20 11 10 +VCM 10 –VCM 5 SUPPLY CURRENT (mA) 15 MAGNITUDE OF OUTPUT VOLATGE (V) MAGNITUDE OF INPUT VOLTAGE (V) TA = 25°C ∆VOS = 0.5mV 0 0 5 10 15 SUPPLY VOLTAGE (±V) 20 Output Voltage Swing vs Resistive Load 30 500 TA = 25°C ∆VOS = 30mV 400 OUTPUT VOLTAGE SWING (VP-P) 25 20 INPUT BIAS CURRENT (nA) OPEN-LOOP GAIN (dB) ±15V SUPPLIES 15 10 ±5V SUPPLIES 5 0 10 100 1k LOAD RESISTANCE (Ω) 10k LT1221 • TPC04 Output Short-Circuit Current vs Temperature 50 OUTPUT SHORT-CIRCUIT CURRENT (mA) POWER SUPPLY REJECTION RATIO (dB) VS = ± 5V 45 40 35 30 25 20 –50 INPUT NOISE VOLTAGE (nV/√Hz) –25 50 0 25 75 TEMPERATURE (°C) 4 UW LT1221 • TPC01 Supply Current vs Supply Voltage and Temperature 20 Output Voltage Swing vs Supply Voltage TA = 25°C RL = 500Ω ∆VOS = 30mV 15 +VSW 10 –VSW 5 T = 125°C 9 8 7 6 5 0 5 10 15 SUPPLY VOLTAGE (±V) 20 T = 25°C T = –55°C 0 0 5 10 15 SUPPLY VOLTAGE (±V) 20 LT1221 • TPC02 LT1221 • TPC03 Input Bias Current vs Input Common-Mode Voltage TA = 25°C VS = ± 15V 110 Open-Loop Gain vs Resistive Load TA = 25°C 100 300 200 100 0 –100 –200 –300 – 400 – 500 –15 IB+ IB– VS = ±15V 90 VS = ± 5V 80 70 60 0 5 –10 –5 10 INPUT COMMON-MODE VOLTAGE (V) 15 10 100 1k LOAD RESISTANCE (Ω) 10k LT1221 • TPC06 LT1221 • TPC05 Input Noise Spectral Density 1000 VS = ±15V TA = 25°C AV = 101 RS = 100k 100 in 10 100 100 Power Supply Rejection Ratio vs Frequency +PSRR 80 60 –PSRR 40 20 10 0 100 VS = ±15V TA = 25°C INPUT NOISE CURRENT (pA/√Hz) 10 en 1 1 100 125 10 100 1k 10k FREQUENCY (Hz) 0.1 100k 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M LT1221 • TPC07 LT1221 • TPC08 LT1221 • TPC09 LT1221 TYPICAL PERFORMANCE CHARACTERISTICS Common-Mode Rejection Ratio vs Frequency 120 COMMON-MODE REJECTION RATIO (dB) 100 80 60 40 20 0 1k 10k 1M 100k FREQUENCY (Hz) VS = ±15V TA = 25°C OUTPUT SWING (V) 2 0 –2 –4 –6 –8 10mV 1mV OUTPUT SWING (V) Voltage Gain and Phase vs Frequency 100 VS = ±15V 80 80 VOLTAGE MAGNITUDE (dB) 100 24 22 20 18 16 14 12 10 8 6 10k 1M 100k FREQUENCY (Hz) 10M –20 100M 4 OUTPUT IMPEDANCE (Ω) VOLTAGE GAIN (dB) 60 VS = ±15V 40 20 0 TA = 25°C –20 100 1k VS = ±5V VS = ±5V Gain-Bandwidth vs Temperature 180 VS = ±15V 170 325 300 TOTAL HARMONIC DISTORTION AND NOISE (%) GAIN-BANDWIDTH (MHz) 160 150 140 130 120 – 50 – 25 SLEW RATE (V/µs) 0 75 25 50 TEMPERATURE (°C) UW 10M LT1221 • TPC10 LT1221 • TPC13 Output Swing and Error vs Settling Time (Noninverting) 10 8 6 4 10mV 1mV VS = ±15V TA = 25°C 10 8 6 4 2 0 –2 –4 –6 –8 0 25 75 100 50 SETTLING TIME (ns) 125 –10 Output Swing and Error vs Settling Time (Inverting) VS = ±15V TA = 25°C 10mV 1mV 10mV 1mV 100M –10 0 25 75 100 50 SETTLING TIME (ns) 125 LT1220 • TPC11 LT1221 • TPC12 Frequency Response vs Capacitive Load 10 VS = ±15V TA = 25°C AV = – 5 C = 100pF C = 50pF Closed-Loop Output Impedance vs Frequency VS = ±15V TA = 25°C AV = 4 1 PHASE MARGIN (DEG) 60 40 20 0 0.1 C = 500pF C = 1000pF 1 10 FREQUENCY (MHz) C=0 0.01 100 LT1221 • TPC14 0.001 10k 100k 1M 10M FREQUENCY (Hz) 100M LT1221 • TPC15 Slew Rate vs Temperature 0.01 Total Harmonic Distortion vs Frequency VS = ±15V VO = 3VRMS RL = 500Ω VS = ±15V AV = – 5 (SR+) + (SR –) SR = 2 AV = 4 AV = – 4 275 250 225 200 175 – 50 –25 0.001 100 125 0 25 50 75 TEMPERATURE (°C) 100 125 0.0001 10 100 1k 10k FREQUENCY (Hz) 100k LT1220 • TPC18 LT1221 • TPC16 LT1221 • TPC19 5 LT1221 TYPICAL PERFORMANCE CHARACTERISTICS Small Signal, AV = 4 Large Signal, AV = 4 Large Signal, AV = 4, CL = 10,000pF VS = ±15V VIN = 25mV f = 5MHz Small Signal, AV = – 4 VS = ±15V VIN = 25mV f = 5MHz APPLICATIONS INFORMATION The LT1221 is stable in noise gains of 4 or greater and may be inserted directly into HA2520/2/5, HA2541/2/4, AD817, AD847, EL2020, EL2044 and LM6361 applications, provided that the nulling circuitry is removed and the amplifier configuration has a high enough noise gain. The suggested nulling circuit for the LT1221 is shown in the following figure. Offset Nulling V+ 5k 1 3 0.1µF 8 7 4 0.1µF V– LT1221 • AI01 + – LT1221 2 6 6 U W UW LT1221 • TPC19 LT1221 • TPC22 VS = ±15V VIN = 5VP-P f = 2MHz LT1221 • TPC20 VS = ±15V VIN = 5VP-P f = 20kHz LT1221 • TPC21 Large Signal, AV = – 4 Small Signal, AV = – 4, CL = 1,000pF VS = ±15V VIN = 5VP-P f = 2MHz LT1221 • TPC23 VS = ±15V VIN = 42mV f = 500kHz LT1221 • TPC24 U U Layout and Passive Components The LT1221 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. Feedback resistors greater than 5k are not recommended because a pole is formed with the input capacitance which can cause peaking or oscillations. Input Considerations Bias current cancellation circuitry is employed on the inputs of the LT1221 so the input bias current and input LT1221 APPLICATIONS INFORMATION offset current have identical specifications. For this reason, matching the impedance on the inputs to reduce bias current errors is not necessary. Capacitive Loading The LT1221 is stable with capacitive loads. 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. There will be peaking in the frequency domain as shown in the curve of Frequency Response vs Capacitive Load. The small-signal transient response will have more overshoot as shown in the photo of the small-signal response with 1000pF load. The large-signal response with a 10,000pF load shows the output slew rate being limited to 4V/µs by the short-circuit current. The LT1221 can drive coaxial cable 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. Compensation The LT1221 has a typical gain-bandwidth product of 150MHz which allows it to have wide bandwidth in high gain configurations (i.e., in a gain of 10, it will have a bandwidth of about 15MHz). The amplifier is stable in a noise gain of 4 so the ratio of the signal at the inverting input to the output must be 1/4 or less. Straightforward gain configurations of 4 or –3 are stable, but there are several others that allow the amplifier to be stable for lower signal gains (the noise gain, however, remains 4 or more). One example is the summing amplifier on the first page of this data sheet. Each input signal has a gain of –1 to the output, but it is easily seen that this configuration is equivalent to a gain of –3 as far as the amplifier is concerned. Another circuit is shown below with a DC gain of 1, but an AC gain of 5. The break frequency of the R-C combination across the amplifier inputs should be approximately a factor of 10 less than the gain-bandwidth of the amplifier divided by the high frequency gain (in this case 1/10 of 150MHz/5 or 3MHz). TYPICAL APPLICATIONS N Lag Compensation 20MHz, AV = 50 Instrumentation Amplifier VIN + VIN + LT1221 10k 100pF – – 1k 250Ω 200pF 250Ω 1k + LT1221 VOUT 1k 1k – 10k LT1221 • TA03 – LT1221 + 510Ω 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 W U U U + 500Ω LT1221 VOUT – 2k AV = 1, f < 3MHz LT1221 • TA04 Cable Driver VIN + LT1221 75Ω 75Ω CABLE VOUT 75Ω – 1.5k LT1221 • TA05 7 LT1221 SI PLIFIED SCHE ATIC V+ 7 NULL 1 8 BIAS 1 BIAS 2 +IN 3 V– 4 LT1221 • SS PACKAGE DESCRIPTION 0.040 (1.016) MAX H8 Package 8-Lead TO-5 Metal Can SEATING PLANE 0.010 – 0.045 (0.254 – 1.143) 0.016 – 0.021 (0.406 – 0.533) 0.300 BSC (0.762 BSC) J8 Package 8-Lead Ceramic Dip 0.008 – 0.018 (0.203 – 0.457) 0.385 ± 0.025 (9.779 ± 0.635) 0° – 15° NOTE: LEAD DIMENSIONS APPLY TO SOLDER DIP/PLATE OR TIN PLATE LEADS. N8 Package 8-Lead Plastic Dip S8 Package 8-Lead Plastic SOIC 0.008 – 0.010 (0.203 – 0.254) 8 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7487 (408) 432-1900 q FAX: (408) 434-0507 q TELEX: 499-3977 U W W 6 OUT 2 –IN Dimensions in inches (millimeters) unless otherwise noted. 0.335 – 0.370 (8.509 – 9.398) DIA 0.305 – 0.335 (7.747 – 8.509) 0.050 (1.270) MAX GAUGE PLANE 0.165 – 0.185 (4.191 – 4.699) REFERENCE PLANE 0.500 – 0.750 (12.700 – 19.050) 0.110 – 0.160 (2.794 – 4.064) INSULATING STANDOFF 0.405 (10.287) MAX 8 7 6 5 45°TYP 0.027 – 0.034 (0.686 – 0.864) 0.027 – 0.045 (0.686 – 1.143) 0.200 – 0.230 (5.080 – 5.842) BSC NOTE: LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE AND SEATING PLANE. CORNER LEADS OPTION (4 PLCS) 0.200 (5.080) MAX 0.015 – 0.060 (0.381 – 1.524) 0.005 (0.127) MIN 0.023 – 0.045 (0.584 – 1.143) HALF LEAD OPTION 0.045 – 0.068 (1.143 – 1.727) FULL LEAD OPTION 0.025 (0.635) RAD TYP 1 2 3 0.220 – 0.310 (5.588 – 7.874) 4 0.045 – 0.068 (1.143 – 1.727) 0.014 – 0.026 (0.360 – 0.660) 0.125 3.175 0.100 ± 0.010 MIN (2.540 ± 0.254) 0.400* (10.160) MAX 8 7 6 5 0.300 – 0.325 (7.620 – 8.255) 0.045 – 0.065 (1.143 – 1.651) 0.130 ± 0.005 (3.302 ± 0.127) 0.009 – 0.015 (0.229 – 0.381) 0.065 (1.651) TYP 0.125 (3.175) MIN 0.255 ± 0.015* (6.477 ± 0.381) 0.015 (0.380) 1 2 4 3 MIN *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTURSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm). 0.189 – 0.197* (4.801 – 5.004) ( +0.025 0.325 –0.015 +0.635 8.255 –0.381 ) 0.045 ± 0.015 (1.143 ± 0.381) 0.100 ± 0.010 (2.540 ± 0.254) 0.018 ± 0.003 (0.457 ± 0.076) 0.010 – 0.020 × 45° (0.254 – 0.508) 0°– 8° TYP 0.053 – 0.069 (1.346 – 1.752) 8 0.004 – 0.010 (0.101 – 0.254) 0.228 – 0.244 (5.791 – 6.197) 7 6 5 0.016 – 0.050 0.406 – 1.270 0.014 – 0.019 (0.355 – 0.483) 0.050 (1.270) BSC 0.150 – 0.157* (3.810 – 3.988) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006 INCH (0.15mm). 1 2 3 4 LT/GP 0894 5K REV A • PRINTED IN USA © LINEAR TECHNOLOGY CORPORATION 1992