LT6274/LT6275 90MHz, 2200V/µs 30V Low Power Op Amps FEATURES DESCRIPTION 2200V/μs Slew Rate nn 90MHz –3dB Bandwidth (A = +1) V nn 40MHz Gain-Bandwidth Product nn 1.6mA Supply Current per Amplifier nn C-Load™ Op Amp Drives All Capacitive Loads nn ±4.5V to ±16V Operating Supply Range nn Unity-Gain Stable nn 10nV/√Hz Input Noise Voltage nn 400µV Maximum Input Offset Voltage nn 500nA Maximum Input Bias Current nn 30nA Maximum Input Offset Current nn ±13.25V Minimum Output Swing into 1k (±15V Supply) nn ±3.5V Minimum Output Swing into 500Ω (±5V Supply) nn 74dB Minimum Open-Loop Gain, R = 1k L nn 40ns Settling Time to 1%, 10V Step nn Specified at ±5V and ±15V nn Single in 5-Lead TSOT-23 Package nn Dual in 8-Lead MSOP Package The LT®6274/LT6275 are single/dual low power, high speed, very high slew rate operational amplifiers with outstanding AC and DC performance. The circuit topology is a voltage feedback amplifier with matched high impedance inputs plus the enhanced slewing performance of a current feedback amplifier. The high slew rate and single stage design provide excellent settling characteristics that make the circuit an ideal choice for data acquisition systems. Each output drives a 1k load to ±13.25V with ±15V supplies and a 500Ω load to ±3.5V on ±5V supplies. The LT6274/LT6275 are stable with any capacitive load making them useful in buffer or cable driving applications. nn APPLICATIONS The LT6274 single op amp is available in a 5-lead TSOT‑23 package, and the LT6275 dual op amp is available in an 8-lead MSOP package. They operate with guaranteed specifications over the –40°C to 85°C and –40°C to 125°C temperature ranges. All registered trademarks and trademarks are the property of their respective owners. All other trademarks are the property of their respective owners. Wideband Large Signal Amplification Cable Drivers nn Buffers nn Automated Test Equipment nn Data Acquisition Systems nn High Fidelity Video and Audio Amplification nn nn TYPICAL APPLICATION Undistorted Output Swing vs Frequency 30 Wideband Large Signal Amplification + 10V VIN –10V 1k 10V LT6274 VOUT – –10V –15V 1k AV = –1 FPBW = 3MHz 6275 TA01 OUTPUT VOLTAGE (VP-P) 25 15V AV = –1 20 15 10 AV = –10 AV = +1 5 VS = ±15V RL = 1k 1% MAX DISTORTION 0 100k 1M 10M FREQUENCY (Hz) 100M 6275 G31 6275fa For more information www.linear.com/LT6275 1 LT6274/LT6275 ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage (V+ – V–)....................................................................34V Differential Input Voltage (Transient Only) (Note 2)......................................... ±10V Input Voltage....................................................... V– to V+ Input Current (+IN, –IN) (Note 3)................................................ ±10mA Output Current (Note 12)................................115mARMS Output Short-Circuit Current Duration (Note 4)...........................................Thermally Limited Operating Temperature Range (Note 5) LT6274I/LT6275I...................................–40°C to 85°C LT6274H/LT6275H.............................. –40°C to 125°C Specified Temperature Range (Note 6) LT6274I/LT6275I...................................–40°C to 85°C LT6274H/LT6275H.............................. –40°C to 125°C Maximum Junction Temperature........................... 150°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec).................... 300°C PIN CONFIGURATION TOP VIEW – + OUTA –INA +INA V– +IN 3 4 –IN – + 8 7 6 5 V+ OUTB –INB +INB MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, qJA = 163°C/W S5 PACKAGE 5-LEAD PLASTIC TSOT-23 θJA = 215°C/W ORDER INFORMATION 1 2 3 4 + – V– 2 TOP VIEW 5 V+ OUT 1 http://www.linear.com/product/LT6275#orderinfo TUBE TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LT6274IS5#PBF LT6274IS5 #TRPBF LTHCY 5-Lead Plastic TSOT-23 –40°C to 85°C LT6274HS5#PBF LT6274HS5 #TRPBF LTHCY 5-Lead Plastic TSOT-23 –40°C to 125°C LT6275IMS8#PBF LT6275IMS8 #TRPBF LTFYV 8-Lead Plastic MSOP –40°C to 85°C LT6275HMS8#PBF LT6275HMS8 #TRPBF LTFYV 8-Lead Plastic MSOP –40°C to 125°C *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges. Parts ending with PBF are RoHS and WEEE compliant. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through designated sales channels with #TRMPBF suffix. 2 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Unless noted otherwise, VCM = 0V, and specifications apply at both VS = (V+ – V–) = ±5V and ±15V. SYMBOL PARAMETER VOS CONDITIONS MIN Input Offset Voltage (Note 7) TYP MAX UNITS ±0.15 ±0.4 ±1.2 mV mV ±4 ±10 µV/°C ±100 ±500 ±1000 nA nA ±3 ±30 ±50 nA nA l ∆VOS/∆T Input Offset Voltage Drift (Note 8) IB Input Bias Current l l IOS Input Offset Current l en Input Voltage Noise Density Low Frequency Integrated Voltage Noise 1/f 1/f Noise Corner Frequency f = 1kHz 10 nV/√Hz 0.1Hz to 10Hz 1 µVP-P Voltage Noise Current Noise 30 70 Hz Hz in Input Current Noise Density f = 1kHz RIN Input Resistance Common Mode, VCM = ±12V, VS = ±15V Differential Mode CIN Input Capacitance Common Mode Differential Mode VINCM Input Voltage Range + (Note 9) VS = ±15V VS = ±5V l l Input Voltage Range – (Note 9) VS = ±15V VS = ±5V l l CMRR Common Mode Rejection Ratio VS = ±15V, VCM = ±12V VS = ±5V, VCM = ±2.5V l l 90 80 110 102 PSRR Power Supply Rejection Ratio VS = ±4.5V to ±16V l 90 115 VS Supply Voltage Range (Note 10) l 9 l 100 12 2.5 0.5 pA/√Hz 700 20 MΩ MΩ 3 0.4 pF pF 13.4 3.4 V V –13.2 –3.2 –12 –2.5 V V dB dB dB 32 V Channel Separation VS = ±15V, VOUT = ±1V, AV = 1, RL = 1kΩ l 100 126 dB AVOL Open-Loop Voltage Gain VS = ±15V, VOUT = ±12V, RL = 1kΩ VS = ±5V, VOUT = ±2.5V, RL = 500Ω l l 74 68 90 84 dB dB VOUT Maximum Output Voltage Swing ±40mV Input Overdrive VS = ±15V, RL = 1kΩ VS = ±5V, RL = 500Ω l l ±13.25 ±3.5 ±13.5 ±3.8 V V IOUT Output Current VS = ±15V, VOUT = ±12V, VIN = ±40mV VS = ±5V, VOUT = ±2.5V, VIN = ±40mV l l ±15 ±12 ±35 ±30 mA mA ISC Output Short-Circuit Current VS = ±15V, VOUT = 0V, VIN = ±3V VS = ±5V, VOUT = 0V, VIN = ±3V l l ±35 ±30 ±90 ±80 mA mA IS Supply Current Per Amplifier, VS = ±15V 1.6 l SR Slew Rate (Note 11) VS = ±15V, AV = 1 VS = ±15V, AV = –1 VS = ±15V, AV = –2 VS = ±5V, AV = –2 FPBW Full Power Bandwidth VS = ±15V, 10V Peak, AV = –1, <1% THD VS = ±5V, 1V Peak, AV = –1, <1% THD GBW Gain-Bandwidth Product fTEST = 200kHz VS = ±15V VS = ±5V f–3dB Unity Gain –3dB Bandwidth VOUT = 100mVP-P, VS = ±15V l l l l 900 270 28 25 1.7 2.3 mA mA 2200 1600 1250 400 V/µs V/µs V/µs V/µs 3 8 MHz MHz 40 36 MHz MHz 90 MHz 6275fa For more information www.linear.com/LT6275 3 LT6274/LT6275 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. Unless noted otherwise, VCM = 0V, and specifications apply at both VS = (V+ – V–) = ±5V and ±15V. SYMBOL PARAMETER CONDITIONS tR, tF Small Signal Rise/Fall Time AV = 1, 10% – 90%, 100mV Input Step 4 ns tPD Propagation Delay 50% VIN to 50% VOUT, 100mV Input Step 4 ns ts Settling Time 1% of 10V Step, AV = 1, VS = ±15V 0.1% of 10V Step, AV = 1, VS = ±15V 1% of 5V Step, AV = 1, VS = ±5V 40 185 65 ns ns ns Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. 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: The inputs are protected by ESD protection diodes to each power supply. The Input current should be limited to less than 10mA. Note 4: A heat sink may be required to keep the junction temperature below the absolute maximum rating when the output is shorted indefinitely. Note 5: The LT6274I/LT6275I are guaranteed functional over the operating temperature range of –40°C to 85°C. The LT6274H/LT6275H are guaranteed functional over the operating temperature range of –40°C to 125°C. 4 MIN TYP MAX UNITS Note 6: The LT6274I/LT6275I are guaranteed to meet specified performance from –40°C to 85°C. The LT6274H/LT6275H are guaranteed to meet specified performance from –40°C to 125°C. Note 7: Input offset voltage is pulse tested and is exclusive of warm-up drift. Note 8: This parameter is not 100% tested. Note 9: Input voltage range is guaranteed by common mode rejection ratio test. Note 10: Supply voltage range is guaranteed by power supply rejection ratio test. Note 11: Slew rate is measured between 20% and 80% of output step with ±6V input (at AV = –2) and ±10V input (at AV = ±1) for ±15V supplies, and between 35% and 65% of output step with ±1.75V input (at AV = –2) for ±5V supplies. Note 12: Current density limitations within the IC require the continuous RMS current supplied by the output (sourcing or sinking) over the operating lifetime of the part be limited to under 115mA (Absolute Maximum). Proper heat sinking may be required to keep the junction temperature below the absolute maximum rating. 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 TYPICAL PERFORMANCE CHARACTERISTICS Input Offset Voltage vs Input Common Mode Voltage 200 35 2.5 100 30 25°C 1.5 –40°C 1.0 0.5 0 25°C –100 –200 –300 125°C 0 5 10 15 20 25 30 TOTAL SUPPLY VOLTAGE (V) –500 –15 35 VS = ±15V –10 –5 0 5 10 INPUT COMMON MODE VOLTAGE (V) 6275 G01 100 300 –100 25°C –200 –300 125°C –10 –5 0 5 10 INPUT COMMON MODE VOLTAGE (V) 0 –100 –200 15 80 75 –400 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 70 –50 125 75 6275 G07 0 25 50 75 TEMPERATURE (°C) 16 VS = ±15V 90 VS = ±5V 85 80 75 70 60 125 6275 G06 100 TA = 25°C 95 VOUT = ±100mV 100 Output Voltage Swing vs Resistive Load 65 125 –25 6275 G05 OPEN-LOOP GAIN (dB) 80 100 VS = ±15V VOUT = ±12V RL = 1k 85 Open-Loop Gain vs Resistive Load 85 0 25 50 75 TEMPERATURE (°C) 10 Open-Loop Gain vs Temperature 90 100 VS = ±5V VOUT = ±2.5V RL = 500Ω –25 1 2 3 4 5 6 7 8 9 INPUT OFFSET VOLTAGE DRIFT (µV/°C) 6275 G03 VS = ±15V 200 Open-Loop Gain vs Temperature 70 –50 0 95 6275 G04 90 10 –300 VS = ±15V 95 15 0 15 OPEN-LOOP GAIN (dB) –40°C INPUT BIAS CURRENT (nA) INPUT BIAS CURRENT (nA) 400 –500 –15 20 Input Bias Current vs Temperature 200 –400 25 6275 G02 Input Bias Current vs Input Common Mode Voltage 0 VS = ±15V 36 UNITS 5 –400 OUTPUT VOLTAGE SWING (±V) 0 –40°C PERCENTAGE OF UNITS (%) 125°C 2.0 OPEN-LOOP GAIN (dB) Typical Distribution of Input Offset Voltage Drift 3.0 INPUT OFFSET VOLTAGE (µV) SUPPLY CURRENT (mA) Supply Current vs Supply Voltage and Temperature (per Amplifier) VS = ±15V 14 VIN = ±20mV TA = 25°C 12 10 8 6 4 2 10 100 1k 10k 100k LOAD RESISTANCE (Ω) 1M 6275 G08 0 10 100 1k 10k LOAD RESISTANCE (Ω) 100k 6275 G09 6275fa For more information www.linear.com/LT6275 5 LT6274/LT6275 TYPICAL PERFORMANCE CHARACTERISTICS Output Voltage Swing vs Supply Voltage V+ VS = ±5V 4.0 VIN = ±20mV TA = 25°C 3.5 3.0 2.5 2.0 1.5 1.0 3 RL = 500Ω 2 0 – V 100k RL = 500Ω –3 1 100 1k 10k LOAD RESISTANCE (Ω) 0 5 10 15 20 25 30 TOTAL SUPPLY VOLTAGE (V) OUTPUT SHORT-CIRCUIT CURRENT (mA) OUTPUT VOLTAGE SWING (V) 125°C 125°C –40°C –40°C 2 1 SINK 100 V– –50 –40 –30 –20 –10 0 10 20 30 40 50 OUTPUT CURRENT (mA) 90 70 –25 0 25 50 75 TEMPERATURE (°C) 1 100 1k FREQUENCY (Hz) 10k SOURCE 90 80 SINK 70 60 –25 0 25 50 75 TEMPERATURE (°C) 0.1 100k 125 Settling Time vs Output Step VS = ±15V AV = 1 RL = 2k SETTLING TIME (ns) 200 0.1% 150 100 1% 50 TIME (1s/DIV) 100 6275 G15 250 6275 G17 0 2 4 6 8 OUTPUT STEP (V) 10 6275 G18 6275 G16 6 VS = ±5V VIN = ±3V 50 –50 125 INPUT VOLTAGE NOISE (200nV/DIV) INPUT VOLTAGE NOISE (nV/√Hz) 1 10 100 100 VS = ±15V INPUT CURRENT NOISE (pA/√Hz) 10 en 1 6275 G12 6275 G14 100 in –40°C 2 0.1Hz to 10Hz Input Voltage Noise 100 10 VS = ±15V VIN = ±3V 80 60 –50 Input Noise Spectral Density VS = ±15V –40°C 125°C 3 Output Short-Circuit Current vs Temperature SOURCE 6275 G13 1k 125°C 25°C V– –50 –40 –30 –20 –10 0 10 20 30 40 50 OUTPUT CURRENT (mA) 35 OUTPUT SHORT-CIRCUIT CURRENT (mA) 110 25°C –2 3 –3 Output Short-Circuit Current vs Temperature V+ 25°C –2 6275 G11 Output Voltage Swing vs Load Current VS = ±5V –1 VIN = ±20mV 25°C 1 RL = 1k 6275 G10 –3 VS = ±15V –1 VIN = ±20mV RL = 1k –2 0.5 10 V+ TA = ±25°C VIN = ±20mV –1 OUTPUT VOLTAGE SWING (V) OUTPUT VOLTAGE SWING (±V) 4.5 Output Voltage Swing vs Load Current OUTPUT VOLTAGE SWING (V) Output Voltage Swing vs Resistive Load 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 TYPICAL PERFORMANCE CHARACTERISTICS Closed-Loop Output Impedance vs Frequency 70 100 PHASE 60 GAIN (dB) 40 –120 GAIN 30 –150 20 10 1k –180 –10 10k 100k 1M FREQUENCY (Hz) 10M –20 10k 100M 100k 1M 10M FREQUENCY (Hz) 6275 G20 50 45 45 GAIN-BANDWIDTH PRODUCT 40 0 5 C=0 –10 10 15 20 25 30 TOTAL SUPPLY VOLTAGE (V) 35 –20 100k 30 POWER SUPPLY REJECTION RATIO (dB) CROSSTALK (dB) –80 –90 VS = ±5V RL = 500Ω VS = ±15V RL = 1k 100k 1M 10M FREQUENCY (Hz) 100M 6275 G26 0 25 50 75 TEMPERATURE (°C) 100 1M 10M 100M FREQUENCY (Hz) C = 5nF C = 1nF C = 500pF C = 100pF C = 50pF 0 C=0 –10 –20 100k 1G VS = ±15V TA = 25°C 100 –PSRR 80 60 +PSRR 40 20 0 –20 100 1k 30 125 VS = ±5V TA = 25°C AV = 1 120 TA = 25°C –60 AV = 1 VIN = 2VP–P –70 –130 10k –25 C = 10nF 1M 10M 100M FREQUENCY (Hz) 10k 100k 1M FREQUENCY (Hz) 10M 100M 6275 G27 1G 6275 G25 Power Supply Rejection Ratio vs Frequency –50 –120 35 GAIN-BANDWIDTH PRODUCT VS = ±5V 6275 G24 Crosstalk vs Frequency –110 35 40 Closed-Loop Frequency Response vs Load Capacitance VS = ±15V TA = 25°C AV = 1 6275 G23 –100 40 10 C = 50pF 0 35 35 45 6275 G22 C = 500pF C = 10nF 50 GAIN-BANDWIDTH PRODUCT VS = ±15V C = 100pF GAIN MAGNITUDE (dB) 50 30 C = 5nF C = 1nF 55 PHASE MARGIN 40 10 60 PHASE MARGIN (DEG) GAIN-BANDWIDTH PRODUCT (MHz) 55 45 Closed-Loop Frequency Response vs Load Capacitance TA = 25°C 55 PHASE MARGIN VS = ±5V 50 6275 G21 Gain-Bandwidth Product and Phase Margin vs Supply Voltage 60 55 30 –50 –210 1G 100M GAIN MAGNITUDE (dB) 0.01 100 VS = ±5V 0 AV = 1 Common Mode Rejection Ratio vs Frequency 120 COMMON MODE REJECTION RATIO (dB) 0.1 A = 10 V 60 PHASE MARGIN VS = ±15V PHASE MARGIN (DEG) AV = 100 1 –90 VS = ±15V 50 10 60 –60 TA = 25°C GAIN-BANDWIDTH PRODUCT (MHz) 80 VS = ±15V TA = 25°C PHASE (DEG) OUTPUT IMPEDANCE (Ω) 1k Gain-Bandwidth Product and Phase Margin vs Temperature Gain/Phase vs Frequency VS = ±15V TA = 25°C 100 80 60 40 20 0 100 1k 10k 100k 1M FREQUENCY (Hz) 10M 100M 6275 G28 6275fa For more information www.linear.com/LT6275 7 LT6274/LT6275 TYPICAL PERFORMANCE CHARACTERISTICS 2nd and 3rd Harmonic Distortion vs Frequency (AV = 1) –50 –60 –70 –80 3RD HARMONIC –90 –100 –110 –120 2ND HARMONIC 1k 10k 100k FREQUENCY (Hz) 1M 25 –50 –60 –70 –80 3RD HARMONIC –90 –100 –110 2ND HARMONIC –120 –140 100 10M 1k 10k 100k FREQUENCY (Hz) 1M Undistorted Output Swing vs Frequency SLEW RATE (V/µs) OUTPUT VOLTAGE (VP-P) TA = 25°C AV = –1 RG = RF = 2k 2000 20% to 80% OF STEP AV = –10 AV = –1 4 2 10M 1M 10M FREQUENCY (Hz) 100M OUTPUT FALLING VS = ±15V 1000 OUTPUT RISING VS = ±15V 0 0 2 4 OUTPUT FALLING VS = ±15V ±12V OUTPUT STEP OUTPUT RISING VS = ±15V ±12V OUTPUT STEP 1000 0 –50 6 8 10 12 14 16 18 20 INPUT LEVEL (VP-P) VS = ±5V ±3.5V OUTPUT STEP –25 0 25 50 75 TEMPERATURE (°C) 6275 G33 100 125 6275 G34 Step Response Overshoot vs Capacitive Load 80 70 1000 VS = ±15V 100mV STEP 60 OVERSHOOT (%) SLEW RATE (V/µs) AV = –2 RG = 2k, RF = 4k 20% to 80% OF STEP 1500 VS = ±5V 10000 100 10 10p AV = 1 40 30 20 VS = ±15V AV = –1 RG = RF = 2k 20% to 80% of ±10V STEP 1p 50 AV = –1 RG = RF = 2k 10 100p 1n 10n 100n LOAD CAPACITANCE (F) 1µ 0 10p 6275 G35 8 100M 500 Slew Rate vs Capacitive Load 0.1 2000 1500 6275 G32 1 AV = +1 Slew Rate vs Temperature 2500 500 VS = ±5V RL = 1k 1% MAX DISTORTION 0 100k 10 6275 G31 2500 AV = +1 AV = –10 15 Slew Rate vs Input Level 10 6 20 6275 G30 6275 G29 8 AV = –1 5 VS = ±15V RL = 1k 1% MAX DISTORTION 0 100k 1M 10M FREQUENCY (Hz) –130 –130 –140 100 30 V = ±15V –30 VS = 10V IN P–P –40 RG = RF = 1k OUTPUT VOLTAGE (VP-P) –40 –20 VS = ±15V VIN = 10VP–P RL = 1k SLEW RATE (V/µs) HARMONIC DISTORTION (dBc) –30 HARMONIC DISTORTION (dBc) –20 Undistorted Output Swing vs Frequency 2nd and 3rd Harmonic Distortion vs Frequency (AV = –1) 100p 1n 10n 100n LOAD CAPACITANCE (F) 1µ 6275 G36 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 TYPICAL PERFORMANCE CHARACTERISTICS Small-Signal Step Response (AV = 1) Small-Signal Step Response (AV = –1) VS = ±15V Small-Signal Step Response (AV = 1, CL = 10nF) VS = ±15V 20mV/DIV 20mV/DIV 20mV/DIV VS = ±15V RG = RF = 2k 20ns/DIV 500ns/DIV 20ns/DIV 6275 G37 6275 G39 6275 G38 Large-Signal Step Response (AV = 1) Large-Signal Step Response (AV = –1) Large-Signal Step Response (AV = 1, CL = 10nF) VS = ±15V RG = RF =2k 5V/DIV 5V/DIV VS = ±15V 5V/DIV VS = ±15V 50ns/DIV 50ns/DIV 6275 G40 5µs/DIV 6275 G41 6275 G42 6275fa For more information www.linear.com/LT6275 9 LT6274/LT6275 SIMPLIFIED SCHEMATIC (ONE AMPLIFIER SHOWN) V+ –IN R1 1k +IN RC C V– 10 OUT CC 6275 SS01 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 PIN FUNCTIONS V –: Negative Supply Voltage. Total supply voltage (V+ – V–) ranges from 9V to 32V. –IN: Inverting Input of Amplifier. +IN: Noninverting Input of Amplifier. V+: Positive Supply Voltage. Total supply voltage (V+ – V–) ranges from 9V to 32V. OUT: Amplifier Output. 6275fa For more information www.linear.com/LT6275 11 LT6274/LT6275 APPLICATIONS INFORMATION Circuit Operation Comparison to Current Feedback Amplifiers The LT6274/LT6275 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 that drive a 1k resistor. The input voltage appears across the resistor generating currents that are mirrored into the high impedance node. Complementary followers form an output stage that buffers the gain node from the load. The bandwidth is set by the internal 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. This important characteristic gives the LT6274/LT6275 superior slew performance compared to conventional voltage feedback amplifiers in which the slew rate is constrained by a fixed current (biasing the input transistors) available to charge the gain node capacitance (independent of the magnitude of the differential input voltage). Therefore, in the LT6274/LT6275, highest slew rates are 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 LT6274/ LT6275 are tested in production for slew rate in a gain of –2 so higher slew rates can be expected in gains of 1 and –1, with lower slew rates in higher gain configurations. The LT6274/LT6275 enjoy the high slew rates of Current Feedback Amplifiers (CFAs) while maintaining the characteristics of a true voltage feedback amplifier. The primary differences are that the LT6274/LT6275 have two high impedance inputs, and the closed loop bandwidth decreases as the gain increases. CFAs have a low impedance inverting input and maintain relatively constant bandwidth with increasing gain. The LT6274/LT6275 can be used in all traditional op amp configurations including integrators and applications such as photodiode amplifiers and I-to-V converters where there may be significant capacitance on the inverting input. The frequency compensation is internal and does not depend on the value of the external feedback resistor. For CFAs, by contrast, the feedback resistance is fixed for a given bandwidth, and capacitance on the inverting input can cause peaking or oscillations. The slew rate of the LT6274/LT6275 in noninverting gain configurations is also superior to that of CFAs in most cases. Special compensation across the output buffer allows the LT6274/LT6275 to be stable with any capacitive load. 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 by lowering the dominant pole frequency, improving the phase margin. The zero created by the RC combination adds phase to ensure that even for very large load capacitances, the total phase lag does not exceed 180° (zero phase margin), and the amplifier remains stable. 12 Input Considerations Each of the LT6274/LT6275 inputs is the base of an NPN and a PNP transistor whose base currents are of opposite polarity and provide first-order input bias current cancellation. Because of differences between 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 therefore 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 in other open-loop applications with large, sustained differential inputs. Under normal, closed-loop operation, an increase of power dissipation is only noticeable in applications with 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 APPLICATIONS INFORMATION large slewing outputs, and the increased power 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. combination of the feedback resistor and gain setting resistor on the inverting input combines with the total capacitance on that node, CIN, 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 × CIN/RF Capacitive Loading The LT6274/LT6275 are stable with any capacitive load. As previously stated in the Circuit Operation section of this data sheet, this is accomplished by dynamically sensing the load-induced output pole and adjusting the compensation at the amplifier’s internal gain node. As the capacitive load increases, the bandwidth will decrease. The phase margin may increase or decrease with different capacitive loads, and so there may be peaking in the frequency domain and overshoot in the transient response for some capacitive loads as shown in the Typical Performance curves. The Small-Signal Step Response curve with 10nF load shows 30% overshoot. For large load capacitance, the slew rate of the LT6274/LT6275 can be limited by the output current available to charge the load capacitor according to: I SR = SC CL The Large-Signal Step Response with 10nF load shows the output slew rate being limited to 9V/µs by the output short-circuit current. Coaxial cable can be driven directly, but for best pulse fidelity the cable should be properly terminated by placing a resistor of value equal to the characteristic impedance of the cable (e.g. 50Ω) in series with the output. The other end of the cable should be terminated with the same value resistor to ground. Layout and Passive Components 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. Power Dissipation The LT6274/LT6275 combine 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), the device’s power dissipation (PD), and the thermal resistance of the device (θJA) as follows: TJ = TA + (PD × θJA) Worst case power dissipation occurs at the maximum supply current and when the output voltage is at 1/2 of either V+ or V– (on split rails), or at the maximum output swing (if less than 1/2 of the rail voltage). Therefore PDMAX (per amplifier) is: PDMAX = (V+ – V–)(ISMAX) + (V+/2)2/RL Example: For an LT6274 with thermal resistance of 215°C/W, operating on ±15V supplies and driving a 1kΩ load to 7.5V, the maximum power dissipation is calculated to be: PDMAX = (30V)(2.3mA) + (7.5V)2/1kΩ = 125mW This leads to a die temperature rise above ambient of: The LT6274/LT6275 are easy to use and tolerant of less than ideal layouts. For maximum performance use a ground plane, short lead lengths, and RF-quality ceramic bypass capacitors (0.01µF to 0.1µF). For high drive current applications use low ESR bypass capacitors (1µF to 10µF ceramic or tantalum). The resistance of the parallel TRISE = (125mW)(215°C/W) = 27°C This implies that the maximum ambient temperature at which the LT6274 should operate under the above conditions is: TA = 150°C – 27°C = 123°C 6275fa For more information www.linear.com/LT6275 13 LT6274/LT6275 TYPICAL APPLICATIONS Noninverting Amplifier Slew Rate and Step Response RG RF Figure 1 shows a noninverting amplifier with closed-loop gain of 11V/V. The closed-loop bandwidth of this amplifier is approximately GBW/11 (GBW = Gain-Bandwidth Product). For a step input, the output follows an exponential curve: 200 2k ⎞⎞ ⎟ ⎠⎟ ⎟⎟ ⎠ 1/2 LT6275 VIN VOUT –15V 6275 TA06 (1) where τ = time constant associated with the closed-loop bandwidth. The maximum slew rate occurs in the beginning of the output response: 1 (2) VOUTSRMAX = A V • VINPUSTEP • τ Keep in mind that the closed-loop bandwidth and the closed-loop gain are related (τ = τo AV), so Equation (2) is simplified to: 1 (3) VOUTSRMAX = VINPUTSTEP • τo Figure 1. LT6275 Configured in a Noninverting Gain of AV = +11V/V 15 12 AV = +11 9 OUTPUT VOLTAGE (V) ⎛t ⎛ –⎜ ⎜ VOUT = VINITIAL + A V • VINPUTSTEP • ⎜1– e ⎝ τ ⎜ ⎝ +15V 6 3 0 –3 –6 –9 –12 –15 50ns/DIV 6275 TA07 Figure 2. Noninverting Amplifier Step Response (AV = +11V/V) where τo = time constant associated with the LT6274/ LT6275 GBW. capability ensures that the output response is never slew rate limited despite the very high excursion. Interestingly, Equation (3) reveals that the maximum slew rate is nominally related only to the input step size and the op amp’s inherent GBW. Closing the loop to implement AV > 1 gain configurations slows down the response, but increases the excursion. The resulting maximum slew rate remains the same. Figure 2 shows the output response to varying input step amplitudes. Note that none of the exponential responses is limited by the initial slew rate (which increases with increasing amplitude). The LT6274/LT6275 feature ample slew rate capability with low power consumption. Because the input stage architecture allows high slew rate with low input stage quiescent currents, the overall power consumption when amplifying pulses is very low; additional power is only drawn from the supplies during the highest slew rate moments of the exponential response. Since GBW of the LT6274/LT6275 is 40MHz, Equation (3) suggests that the maximum slew rate in a step response whose output swings 25V (implying VINPUTSTEP = 25/11 = 2.27V) is 571V/µs. The LT6274/LT6275 high slew 14 As a particular example, with AV = +11V/V, 15V output excursion, and 40 MHz GBW, Equation (3) predicts a maximum slew rate of 343V/μs. Measurement on the corresponding curve in Figure 2 shows 390V/μs, which is in good agreement with the prediction. As another example, with an 18.5V output excursion, the predicted maximum slew rate is 423V/μs; measurement shows 460V/μs. As the peak to peak voltage of the input step changes, the maximum initial slew rate changes. The 63% rise time of the closed loop response, however, does not change (as seen in Figure 2), because the closed loop bandwidth stays constant for all input amplitudes. 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 TYPICAL APPLICATIONS Using the LT6274/LT6275 to Create a Composite Amplifier with High Gain, High Bandwidth and Large Output Signal Capability While the LT6274/LT6275 provide ample slew rate and large output swing capability, the GBW is not so large as to achieve high gain, high bandwidth, and high amplitude at the same time. The circuit of Figure 3 harnesses the high slew rate capability of the LT6275 by placing it under control of the LTC6252, an op amp with greater than 700MHz GBW. The LTC6252 offers high bandwidth at low supply current, but with limited slew rate and limited output swing (since it is a 5V op amp). By creating a composite amplifier adding the LT6275 as a high-voltage, high-slew secondary op amp, this composite amplifier enables large output swing at high frequencies with relatively low power dissipation. Circuit Description R4 and R1 realize inverting gain of –11V/V from VIN to VOUT. The LT6275 op amp drives the output based on whatever is commanded by the middle node, VMID. The LTC6252 is very fast relative to the LT6275. As a consequence, the LTC6252 controlling first stage can force the LT6275 output to move quickly by providing sufficient differential input voltage to the LT6275. With the inverting input of the LT6275 tied to a DC bias voltage, the LTC6252 needs merely to drive the noninverting input. Unlike the LTC6252, the LT6275 slew rate increases linearly with its differential input voltage. Hence, the LTC6252 benefits from using the LT6275 as a slew enhancer. reduces the LTC6252 phase shift, but it also adds to the gain burden of the LT6275. R2 was selected to take a gain of 2V/V in the LTC6252, implying a gain of 5.5V/V being taken in the LT6275. The 5.5V/V gain is required to translate the 5V maximum output swing of the LTC6252 to the 27.5V maximum output swing of the LT6275 (when operated at ±15V supplies). It may be possible to achieve even higher bandwidth in the composite amplifier if a high speed ±5V (rather than 5V, 0V) op amp replaces the LTC6252 as the first stage, with the resulting increased first-stage output swing lowering the gain that has to be taken in the LT6275. Capacitor C7 in Figure 3 is adjusted to create a favorable looking transient response. Figure 4 shows the transient response at the output of the LT6275 as C7 varies. C7 = 3pF was chosen. DC Biasing In the circuit of Figure 3, LTC6252 supplies were chosen to be 5V and 0V, which are more practical than split ±2.5V supplies. R5 and R6 form a resistive divider to bias the noninverting input of LTC6252 and the inverting input of LT6275 at the middle of this rail, 2.5V. Note that this approach results in the output of LT6275 having a DC offset of 2.5V, which reduces the potential peak to peak output excursion of the composite amplifier since LT6275 is powered up from split ±15V supplies. C1 1µ VIN R1 1k R4 C7 Optimizing the Loop Larger R2 increases the local gain taken by the LTC6252. Since the total gain is fixed by the global feedback around the composite amplifier (AV = –R4/R1 = –11V/V), raising the gain in the LTC6252 lowers the gain requirement of the LT6275, increasing the overall bandwidth of the composite amplifier. Care must be taken to not take too much gain in the LTC6252, as the reduction in the LTC6252 bandwidth and the resulting additional phase shift seen at the output of the LTC6252 can lower the stability margins of the composite amplifier. Conversely, smaller R2 R2 2k 11k 3p +15V 5V 5V LTC6252 1/2 LT6275 VMID –15V C2 1µ VOUT R3 10k R5 10k R6 10k 6275 TA08 C5 1µ Figure 3. Composite Amplifier Using LTC6252 and LT6275 (AV = –11V/V) 6275fa For more information www.linear.com/LT6275 15 LT6274/LT6275 TYPICAL APPLICATIONS Pulse Response 15 Sine Waves 9 OUTPUT VOLTAGE (V) 6 3 0 –3 –6 –9 –12 –15 200ns/DIV 6275 TA12 Figure 5. Composite Amplifier Step Response at Various Output Step Amplitudes (AV = –11V/V) 25 225 20 180 15 135 10 90 5 45 0 0 –5 –45 –10 –90 PHASE (DEG) The composite amplifier of Figure 3 was also tested with sine waves. Figure 6 shows the small signal closed-loop gain and phase response. Distortion was also evaluated for this circuit: for a 20VP-P output signal at 1MHz, HD2/ HD3 were measured to be –55dBc/–47dBc, respectively. These numbers are more impressive when considering the very low power dissipation of the composite amplifier, as illustrated in Figure 7. For example, for the 20VP-P/1MHz output condition mentioned above, the 5V rail supply current is 3.75mA, for 1/2 LT6275 the ±15V rails supply current is 2.2mA, resulting in a total power dissipation of 85mW. 12 GAIN (dB) Figure 5 shows the output step response of the composite amplifier (measured at the output of the LT6275) at many different amplitudes. At 15V output excursion, the initial slope is measured to be 725V/μs. This slope is faster than the 390V/μs measured with a 15V output excursion using the simple noninverting amplifier of Figure 1. According to Equation (3), this improvement has been made possible because the effective bandwidth of the composite amplifier is higher (and thus has a lower τo), as intended. –135 –15 –20 –25 0.1 GAIN PHASE –180 –225 100 1 10 FREQUENCY (MHz) 6275 TA14 Figure 6. Composite Amplifier Closed-Loop Gain/Phase vs Frequency 10 150 5 8 USING 1/2 LT6275 2 0 –2 SUPPLY CURRENT (mA) 8pF 5pF 3pF 1pF NO CAP 4 –4 –6 250ns/DIV 6275 TA09 Figure 4. Composite Amplifier Step Response vs LTC6252 Feedback Capacitance (AV = –11V/V) 16 120 3 90 2 60 5V SUPPLY CURRENT ±15V SUPPLY CURRENT TOTAL POWER 1 –8 –10 4 0 30 OUTPUT = 20VP–P 0 0.5 1 1.5 FREQUENCY (MHz) POWER (mW) OUTPUT VOLTAGE (V) 6 2 0 6275 TA15 Figure 7. Composite Amplifier Supply Current and Total Power Dissipation 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LT6274#packaging for the most recent package drawings. S5 Package 5-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1635) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 TYP 5 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 (NOTE 3) NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 1.90 BSC S5 TSOT-23 0302 6275fa For more information www.linear.com/LT6275 17 LT6274/LT6275 PACKAGE DESCRIPTION Please refer to http://www.linear.com/product/LT6275#packaging for the most recent package drawings. MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660 Rev G) 0.889 ±0.127 (.035 ±.005) 5.10 (.201) MIN 3.20 – 3.45 (.126 – .136) 3.00 ±0.102 (.118 ±.004) (NOTE 3) 0.65 (.0256) BSC 0.42 ± 0.038 (.0165 ±.0015) TYP 8 7 6 5 0.52 (.0205) REF RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 3.00 ±0.102 (.118 ±.004) (NOTE 4) 4.90 ±0.152 (.193 ±.006) DETAIL “A” 0° – 6° TYP GAUGE PLANE 0.53 ±0.152 (.021 ±.006) DETAIL “A” 1 2 3 4 1.10 (.043) MAX 0.86 (.034) REF 0.18 (.007) SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP 0.65 (.0256) BSC 0.1016 ±0.0508 (.004 ±.002) MSOP (MS8) 0213 REV G NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 18 6275fa For more information www.linear.com/LT6275 LT6274/LT6275 REVISION HISTORY REV DATE DESCRIPTION A 12/17 Added LT6274 Updated Power Dissipation section PAGE NUMBER All 13 6275fa Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. For more information www.linear.com/LT6275 19 LT6274/LT6275 TYPICAL APPLICATION Composite Amplifier Provides 18-Bit Precision and Fast Settling 15V 12V IN LTC6655-5 + OUT LT1012 0.1µF 10µF – –15V 1 14 10k 23 10k 17 25 4 19 20 21 22 VDD ROFS 5 3 RIN RCOM 100pF 2 REF RFB LDAC IOUT1 27, 28 VOUT 1k 26 LTC2756 CLR 10k VOSADJ M-SPAN S0 – 1µF LTC2054HV S2 9 SDI SCK 10 11 SRO 15V + + 10Ω –5V CCOMP 1/2 LT6275 – –5V 5pF 1µF 6275 TA13 12 SPI BUS 1k 5V LTC6240HV + IOUT2 7 6, 8, 13, 15, 16, 24 GND S1 CS/LD 5V 10k GEADJ – –15V 4.02k DAC with Composite Amplifier Output Response (Varying Compensation Capacitance) 1k 14 12 OUTPUT RESPONSE (V) 10 8 6 4 CCOMP 2 100pF 68pF 30pF 22pF 15pF 10pF 0 –2 –4 –6 –8 –10 –2 –1 0 1 2 3 4 TIME (µs) 5 6 7 6275 TA14 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1351/LT1352/LT1353 Single/Dual/Quad 3MHz, 200V/µs, C-Load Amplifiers 250µA Supply Current, 600µV Max VOS, 5V to 30V Supply Operation LT1354/LT1355/LT1356 Single/Dual/Quad 12MHz, 400V/μs, C-Load Amplifiers 1mA Supply Current, 800µV Max VOS, 5V to 30V Supply Operation LT1357/LT1358/LT1359 Single/Dual/Quad 25MHz, 600V/μs, C-Load Amplifiers 2mA Supply Current, 600µV Max VOS, 5V to 30V Supply Operation LT1360/LT1361/LT1362 Single/Dual/Quad 50MHz, 800V/μs, C-Load Amplifiers 4mA Supply Current, 1mV Max VOS, 5V to 30V Supply Operation LT1363/LT1364/LT1365 Single/Dual/Quad 70MHz, 1000V/μs, C-Load Amplifiers 6.3mA Supply Current, 1.5mV Max VOS, 5V to 30V Supply Operation LT1812/LT1813/LT1814 Single/Dual/Quad 100MHz, 750V/μs Op Amps 3mA Supply Current, 1.5mV Max VOS, 4V to 11V Supply Operation LTC6261/LTC6262/LTC6263 Single/Dual/Quad 30MHz, 7V/µs Op Amps 240µA Supply Current, 400µV Max VOS, 1.8V to 5.25V Supply Operation LTC6246/LTC6247/LTC6248 Single/Dual/Quad 180MHz, 90V/µs Op Amps 0.95mA Supply Current, 500µV Max VOS, 2.5V to 5.25V Supply Operation LTC6252/LTC6253/LTC6254 Single/Dual/Quad 720MHz, 280V/µs Op Amps 3.3mA Supply Current, 350µV Max VOS, 2.5V to 5.25V Supply Operation 20 6275fa LT 1217 REV A • PRINTED IN USA For more information www.linear.com/LT6275 www.linear.com/LT6275 ANALOG DEVICES, INC. 2017