LTC6268-10/LTC6269-10 4GHz Ultra-Low Bias Current FET Input Op Amp FEATURES DESCRIPTION Gain Bandwidth Product: 4GHz nn Low Input Bias Current: nn ±3fA Typ. Room Temperature nn 4pA Max at 125°C nn Current Noise (100kHz): 7fA/√Hz nn Voltage Noise (1MHz): 4.0nV/√Hz nn Extremely Low C 0.45pF IN nn Rail-to-Rail Output nn A ≥10 V nn Slew Rate: +1500V/µs, –1000V/µs nn Supply Range: 3.1V to 5.25V nn Quiescent Current: 16.5mA nn Operating Temp Range: –40°C to 125°C nn Single in 8-Lead SO-8, 6-Lead TSOT-23 Packages nn Dual in 8-Lead MS8, 3mm × 3mm 10-Lead DFN 10 Packages The LTC®6268-10/LTC6269-10 is a single/dual 4GHz FETinput operational amplifier with extremely low input bias current and low input capacitance. It also features low input-referred current noise and voltage noise making it an ideal choice for high speed transimpedance amplifiers, and high-impedance sensor amplifiers. It is a decompensated op amp that is gain-of-10 stable. nn APPLICATIONS It operates on 3.1V to 5.25V supply and consumes 16.5mA per amplifier. A shutdown feature can be used to lower power consumption when the amplifier is not in use. The LTC6268-10 single op amp is available in 8-lead SOIC and 6-lead SOT-23 packages. The SOIC package includes two unconnected pins which can be used to create an input pin guard ring to protect against board leakage currents. The LTC6269-10 dual op amp is available in 8-lead MSOP with exposed pad and 3mm × 3mm 10-lead DFN packages. They are fully specified over the –40°C to 85°C and the –40°C to 125°C temperature ranges. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Transimpedance Amplifiers nn ADC Drivers nn Photomultiplier Tube Post-Amplifier nn Low I BIAS Circuits nn TYPICAL APPLICATION 20kΩ TIA Frequency Response 20kΩ Gain 210MHz Transimpedance Amplifier 90 87 2.5V 81 2.5V PD – IPD 84 PARASITIC FEEDBACK C LTC6268-10 + VOUT = –IPD • 20k BW = 210MHz GAIN (dBΩ) 20kΩ 78 75 72 69 66 –2.5V 63 626810 TA01 PD = OSI OPTOELECTRONICS, FCI-125G-006 60 10k 100k 1M 10M FREQUENCY (Hz) 100M 1G 626810 TA01b 626810f For more information www.linear.com/LTC6268-10 1 LTC6268-10/LTC6269-10 ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage V+ to V–............................................5.5V Input Voltage ................................V– – 0.2V to V+ + 0.2V Input Current (+IN, –IN) (Note 2)............................ ±1mA Input Current (SHDN)............................................. ±1mA Output Current (IOUT ) (Note 8, 9)..........................135mA Output Short-Circuit Duration (Note 3).... Thermally Limited Operating Temperature Range LTC6268-10I/LTC6269-10I....................–40°C to 85°C LTC6268-10H/LTC6269-10H............... –40°C to 125°C Specified Temperature Range (Note 4) LTC6268-10I/LTC6269-10I....................–40°C to 85°C LTC6268-10H/LTC6269-10H............... –40°C to 125°C Maximum Junction Temperature........................... 150°C Storage Temperature Range................... –65°C to 150°C Lead Temperature S8, S6 and MS8E (Soldering, 10 sec).................................. 300°C PIN CONFIGURATION TOP VIEW TOP VIEW NC 1 8 SHDN –IN 2 7 V+ +IN 3 6 OUT NC 4 5 V– 6 V+ OUT 1 V– 2 5 SHDN +IN 3 4 –IN S6 PACKAGE 6-LEAD PLASTIC TSOT-23 S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 120°C/W (NOTE 5) TJMAX = 150°C, θJA = 192°C/W (NOTE 5) TOP VIEW TOP VIEW OUTA –INA +INA V– 1 2 3 4 9 V– 8 7 6 5 V+ OUTB –INB +INB OUTA 1 –INA 2 +INA 3 V– 4 SDA 5 MS8E PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 40°C/W (NOTE 5) EXPOSED PAD (PIN 9) IS V–, IT IS RECOMMENDED TO SOLDER TO PCB 10 V+ 11 V– 9 OUTB 8 –INB 7 +INB 6 SDB DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 150°C, θJA = 43°C/W (NOTE 5) EXPOSED PAD (PIN 11) IS V–, IT IS RECOMMENDED TO SOLDER TO PCB 2 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION SPECIFIED TEMPERATURE RANGE LTC6268IS6-10#TRMPBF LTC6268IS6-10#TRPBF LTGQT 6-Lead Plastic TSOT-23 –40°C to 85°C LTC6268HS6-10#TRMPBF LTC6268HS6-10#TRPBF LTGQT 6-Lead Plastic TSOT-23 –40°C to 125°C LTC6268IS8-10#PBF LTC6268IS8-10#TRPBF 626810 8-Lead Plastic SOIC –40°C to 85°C LTC6268HS8-10#PBF LTC6268HS8-10#TRPBF 626810 8-Lead Plastic SOIC –40°C to 125°C LTC6269IMS8E-10#PBF LTC6269IMS8E-10#TRPBF LTGRM 8-Lead Plastic MSOP –40°C to 85°C LTC6269HMS8E-10#PBF LTC6269HMS8E-10#TRPBF LTGRM 8-Lead Plastic MSOP –40°C to 125°C LTC6269IDD-10#PBF LTC6269IDD-10#TRPBF LGRK 10-Lead Plastic DD –40°C to 85°C LTC6269HDD-10#PBF LTC6269HDD-10#TRPBF LGRK 10-Lead Plastic DD –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. 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/ 5.0V ELECTRICAL CHARACTERISTICS The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VSUPPLY = 5.0V (V+ = 5V, V– = 0V, VCM = mid-supply), RL = 1kΩ, VSHDN is unconnected. SYMBOL PARAMETER VOS Input Offset Voltage CONDITIONS MIN TYP MAX VCM = 2.75V 0.2 l –0.7 –3 0.7 3 mV mV –1.0 –4.5 0.2 l 1.0 4.5 mV mV VCM = 4.0V TC VOS Input Offset Voltage Drift VCM = 2.75V IB Input Bias Current (Notes 6, 8) VCM = 2.75V LTC6268I-10/LTC6269I-10 LTC6268H-10/LTC6269H-10 –20 –900 –4 ±3 l l 20 900 4 fA fA pA VCM = 4.0V LTC6268I-10/LTC6269I-10 LTC6268H-10/LTC6269H-10 –20 –900 –4 ±3 l l 20 900 4 fA fA pA VCM = 2.75V LTC6268I-10/LTC6269I-10 LTC6268H-10/LTC6269H-10 –40 –450 –2 ±6 l l 40 450 2 fA fA pA IOS en Input Offset Current (Notes 6, 8) Input Voltage Noise Density, VCM = 2.75V f = 1MHz Input Voltage Noise Density, VCM = 4.0V Input Referred Noise Voltage Input Current Noise Density, VCM = 2.75V Input Current Noise Density, VCM = 4.0V RIN Input Resistance CIN Input Capacitance Differential (DC to 200MHz) CMRR Common Mode Rejection Ratio VCM = 0.5V to 3.2V (PNP Side) in 4 UNITS 4.0 nV/√Hz f = 1MHz 4.0 nV/√Hz f = 0.1Hz to 10Hz 12.6 μVP-P f = 100kHz 7 fA/√Hz f = 100kHz 7 fA/√Hz Differential >1000 GΩ Common Mode >1000 GΩ 0.1 pF Common Mode (DC to 100MHz) VCM = –0.1V to 4.5V IVR Input Voltage Range μV/°C Guaranteed by CMRR 0.45 pF 85 l 72 68 dB dB 64 52 82 l dB dB l –0.1 4.5 V 626810f For more information www.linear.com/LTC6268-10 3 LTC6268-10/LTC6269-10 5.0V ELECTRICAL CHARACTERISTICS The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VSUPPLY = 5.0V (V+ = 5V, V– = 0V, VCM = mid-supply), RL = 1kΩ, VSHDN is unconnected. SYMBOL PARAMETER CONDITIONS PSRR VCM = 1.0V, VSUPPLY Ranges from 3.1V to 5.25V Power Supply Rejection Ratio Supply Voltage Range AV Open Loop Voltage Gain VOUT = 0.5V to 4.5V MIN TYP 95 l 78 75 l 3.1 125 40 250 l V/mV V/mV 10 2 21 l V/mV V/mV RLOAD = 10k RLOAD = 100 VOL Output Swing Low (Input Overdrive 30mV) Measured from V– ISINK = 10mA Output Swing High (Input Overdrive 30mV) Measured from V+ ISOURCE = 10mA 140 200 mV mV 130 200 260 mV mV 70 140 200 mV mV 160 270 370 mV mV l ISOURCE = 25mA l ISC IS Output Short Circuit Current (Note 9) 60 40 90 l 15 9 16.5 l 18 25 mA mA 0.39 0.85 1.5 mA mA 2 2 12 12 µA µA 0.75 V Supply Current Per Amplifier Supply Current in Shutdown (Per Amplifier) dB dB 80 l VOH UNITS 5.25 l ISINK = 25mA MAX l ISHDN Shutdown Pin Current VSHDN = 0.75V VSHDN =1.50V l l VIL SHDN Input Low Voltage Disable l l –12 –12 mA mA VIH SHDN Input High Voltage Enable. If SHDN is Unconnected, Amp is Enabled tON Turn On Time, Delay from SHDN Toggle to Output Reaching 90% of Target SHDN Toggle from 0V to 2V 360 ns tOFF Turn Off Time, Delay from SHDN Toggle to Output High Z SHDN Toggle from 2V to 0V 183 ns GBW Gain-Bandwidth Product (Note 8) f = 10MHz l 3500 4000 MHz SR+ Slew Rate+ AV = 11 (RF = 1000, RG = 100) VOUT = 0.5V to 4.5V, Measured 20% to 80%, RLOAD = 500Ω 1100 600 1500 l V/µs V/µs AV = 11 (RF = 1000, RG = 100) VOUT = 4.5V to 0.5V, Measured 80% to 20%, l 900 500 SR– Slew Rate– FPBW Full Power Bandwidth (Note 7) 4VP-P HD Harmonic Distortion(HD2/HD3) AV = 10, 10MHz. 2VP-P, VCM = 2.25V, RL = 1k, RF = 450Ω, RG = 50Ω ILEAK Output Leakage Current in Shutdown VSHDN = 0V, VOUT = 0V VSHDN = 0V, VOUT = 5V 4 1.5 V 1000 V/µs V/µs 73 MHz –91/–96 dB 400 400 nA nA 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 3.3V ELECTRICAL CHARACTERISTICS The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VSUPPLY = 3.3V (V+ = 3.3V, V– = 0V, VCM = mid-supply), RL = 1kΩ, VSHDN is unconnected. SYMBOL PARAMETER VOS Input Offset Voltage CONDITIONS MIN TYP MAX VCM = 1.0V 0.2 l –0.7 –3 0.7 3 mV mV –1.0 –4.5 0.2 l 1.0 4.5 mV mV ±3 l l –20 –900 –4 20 900 4 fA fA pA VCM = 2.3V –20 l LTC6268I-10/LTC6269I-10 –900 l –4 LTC6268H-10/LTC6269H-10 ±3 20 900 4 fA fA pA VCM = 1.0V –40 l LTC6268I-10/LTC6269I-10 –450 l –2 LTC6268H-10/LTC6269H-10 ±6 40 450 2 fA fA pA VCM = 2.3V TC VOS Input Offset Voltage Drift VCM = 1.0V IB Input Bias Current (Notes 6, 8) VCM = 1.0V LTC6268I-10/LTC6269I-10 LTC6268H-10/LTC6269H-10 IOS Input Offset Current (Notes 6, 8) en Input Voltage Noise Density, VCM =1.0V f = 1MHz in 4 nV/√Hz Input Voltage Noise Density, VCM = 2.3V f = 1MHz 4.0 nV/√Hz Input Referred Noise Voltage 13.5 μVP-P Input Current Noise Density, VCM = 1.0V f = 100kHz 7 fA/√Hz Input Current Noise Density, VCM = 2.3V f = 100kHz 7 fA/√Hz f = 0.1Hz to 10Hz Input Resistance Differential Common Mode CIN Input Capacitance Differential (DC to 200MHz) Common Mode (DC to 100MHz) CMRR Common Mode Rejection Ratio VCM = 0.5V to 1.2V (PNP Side) VCM = –0.1V to 2.8V (Full Range) IVR Input Voltage Range Guaranteed by CMRR AV Open Loop Voltage Gain VOUT = 0.5V to 2.8V Output Swing Low (Input Overdrive 30mV). Measured from V– >1000 >1000 GΩ GΩ 0.1 0.45 pF pF 63 60 90 l dB dB 60 50 77 l dB dB l –0.1 200 l 80 40 V/mV V/mV 10 2 18 l V/mV V/mV RLOAD = 10k RLOAD = 100 ISINK = 10mA 2.8 ISINK = 25mA Output Swing High (Input Overdrive 30mV). Measured from V+ ISOURCE = 10mA 140 200 mV mV 140 200 260 mV mV 80 140 200 mV mV 170 270 370 mV mV l ISOURCE = 25mA l ISC IS Output Short Circuit Current (Note 9) 50 35 80 l 14.5 9 16 l Supply Current per Amplifier V 80 l l VOH µV/C 4.0 RIN VOL UNITS mA mA 17.5 25 mA mA 626810f For more information www.linear.com/LTC6268-10 5 LTC6268-10/LTC6269-10 3.3V ELECTRICAL CHARACTERISTICS The l denotes specifications that apply over the full operating temperature range, otherwise specifications are at TA = 25°C, VSUPPLY = 3.3V (V+ = 3.3V, V– = 0V, VCM = mid-supply) RL = 1kΩ, VSHDN is unconnected. SYMBOL PARAMETER CONDITIONS MIN Supply Current in Shutdown (Per Amplifier) TYP MAX 0.23 0.6 1.2 mA mA 2 2 12 12 µA µA 0.75 V l ISHDN Shutdown Pin Current VSHDN = 0.75V VSHDN = 1.5V l l VIL SHDN Input Low Voltage Disable l Enable. If SHDN is Unconnected, Amp Is Enabled l –12 –12 UNITS VIH SHDN Input High Voltage tON Turn On Time, Delay from SHDN Toggle SHDN Toggle from 0V to 2V to Output Reaching 90% of Target 750 ns tOFF Turn Off Time, Delay from SHDN Toggle SHDN Toggle from 2V to 0V to Output High Z 201 ns GBW Gain-Bandwidth Product (Note 8) f = 10MHz l 3500 4000 MHz SR+ Slew Rate+ AV = 11 (RF = 1000, RG = 100), VOUT = 1V to 2.3V, Measured 20% to 80%, RLOAD = 500Ω 800 600 1500 l V/µs V/µs AV = 11 (RF = 1000, RG = 100), VOUT = 1V to 2.3V, Measured 80% to 20%, RLOAD = 500Ω 600 400 1000 l V/µs V/µs 105 MHz SR– Slew Rate– FPBW Full Power Bandwidth (Note 7) 2.3VP-P HD Harmonic Distortion(HD2/HD3) A = 10, 10MHz. 2VP-P, VCM = 1.65V, RL = 1k, RF = 450Ω, RG = 50Ω 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: The inputs are protected by two series connected ESD protection diodes to each power supply. The input current should be limited to less than 1mA. The input voltage should not exceed 200mV beyond the power supply. Note 3: A heat sink may be required to keep the junction temperature below the absolute maximum rating when the output is shorted indefinitely. Note 4: The LTC6268-10I/LTC6269-10I is guaranteed to meet specified performance from –40°C to 85°C. The LTC6268-10H/LTC6269-10H is guaranteed to meet specified performance from –40°C to 125°C. 6 1.5 V –67/–78 dB Note 5: Thermal resistance varies with the amount of PC board metal connected to the package. The specified values are for short traces connected to the leads. Note 6: The input bias current is the average of the currents into the positive and negative input pins. Typical measurement is for S8 package. Note 7: Full Power Bandwidth is determined from distortion performance in a gain-of-10 configuration with HD2/HD3 < –40dB (1%) as the criteria for a valid output. Note 8: This parameter is specified by design and/or characterization and is not tested in production. Note 9: The LTC6268-10/LTC6269-10 is capable of producing peak output currents in excess of 135mA. Current density limitations within the IC require the continuous current supplied by the output (sourcing or sinking) over the operating lifetime of the part be limited to under 135mA (Absolute Maximum). 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 TYPICAL PERFORMANCE CHARACTERISTICS Input Offset Voltage Distribution 250 VS = ±2.5V VCM = 0.25V 2.0 VS = ±2.5V VCM = 1.5V VS = ±2.5V 1.5 VCM = 0.25V 200 200 150 100 1.0 0.5 150 VOS (mV) NUMBER OF UNITS 250 Input Offset Voltage vs Temperature Input Offset Voltage Distribution NUMBER OF UNITS 300 TA = 25°C, unless otherwise noted. 100 –0.5 –1.0 50 50 0 –1.5 0 –0.4 –0.3 –0.2 –01 0 0.1 0.2 0.3 0.4 0.5 0.6 VOS (mV) 0 –0.4 –0.3 –0.2 –01 0 0.1 0.2 0.3 0.4 0.5 0.6 VOS (mV) 626810 G01 626810 G02 Input Offset Drift Distribution Input Offset Voltage vs Common Mode Voltage VS = ±2.25V VCM = 0.25V 1 H–GRADE I–GRADE 0.8 15 VOS (mV) NUMBER OF UNITS 20 10 5 0 –15 –10 626810 G03 –5 0 5 DISTRIBUTION (µV/°C) 10 1 VS = ±2.5V VS = 3.1V to 5.25V 0.8 VCM = 1V 0.6 0.6 0.4 0.4 0.2 0.2 0 –0.2 0 –0.2 –0.4 –0.4 –0.6 –0.6 –0.8 –0.8 –1 –2.5 15 Input Offset Voltage vs Supply Voltage VOS (mV) 25 –2.0 –50 –30 –10 10 30 50 70 90 110 130 TEMPERATURE (°C) –1.25 0 1.25 –1 2.5 VCM (V) 626810 G04 3 3.5 4 4.5 VS (V) 5 626810 G06 626810 G05 Input Offset Voltage vs Output Current 1.40 PSRR vs Frequency 100 VS = ±2.5V 1.20 0.80 VCM = 1.5V PSRR (dB) VOS (mV) 1.00 0.60 CMRR vs Frequency 100 +PSRR –PSRR 80 80 60 60 CMRR (dB) 1.60 5.5 40 40 0.40 0.20 0.00 VCM = 0.25V –0.20 –100 –80 –60 40 –20 0 20 40 60 80 100 OUTPUT CURRENT (mA) 20 VS = ±2.5V, VCM = 0.25V 0 0.01 0.1 1 10 FREQUENCY (MHz) 20 100 1000 626810 G08 Vs = ±2.5V, VCM = 0.25V 0 0.01 0.1 1 10 FREQUENCY (MHz) 100 1000 626810 G09 626810 G07 626810f For more information www.linear.com/LTC6268-10 7 LTC6268-10/LTC6269-10 TYPICAL PERFORMANCE CHARACTERISTICS Input Bias Current vs Common Mode Voltage Input Bias Current vs Supply Voltage 8.0 –1 6.0 –2 4.0 100 +IN 2.0 0 0.0 –2.0 –IN –100 –4.0 –6.0 –200 INPUT BIAS CURRENT (fA) INPUT BIAS CURRENT (fA) 200 0 –10.0 5.0 1.0 2.0 3.0 4.0 COMMON MODE VOLTAGE (V) VS = ±2.5V 1400 VCM = 0.25V +IN 1200 –IN –3 –4 +IN –5 –6 200 0 120 80 TA = 125°C TA = 25°C TA = –55°C 10.0 15.0 20.0 LOAD CURRENT (mA) 25.0 –40 –120 –160 2 0.1 FREQUENCY(MHz) 1 626810 G16 8 100 SINKING 50 TA = 125°C TA = 25°C TA = –55°C 0 –50 SOURCING –100 –240 –150 VS = ±2.5V VCM = 0.25V –280 0.0 5.0 10.0 15.0 20.0 LOAD CURRENT (mA) 25.0 –200 3.0 3.5 4.0 4.5 VS (V) 5.0 5.5 626810 G15 626810 G14 10 0.1Hz to 10Hz Input Referred Voltage Noise 20 VS = ±2.5V VCM = 0.25V VS = ±2.5V AV = 11 VCM = –0.25V 16 8 12 VOLTAGE NOISE (µV) 4 0 0.01 150 Wide Band Input Referred Voltage Noise 6 125 200 –200 VOLTAGE NOISE DENSITY (nV/√Hz) VOLTAGE NOISE DENSITY (nV/√Hz) 8 65 85 105 TEMPERATURE (°C) Output Short Circuit Current vs Supply Voltage –80 Input Referred Voltage Noise Density VS = ±2.5V VCM = 0.25V 45 626810 G12 TA = 125°C TA = 25°C TA = –55°C 626810 G13 10 –200 25 5.5 ISC (mA) OUTPUT SATURATION VOLTAGE (mV) OUTPUT SATURATION VOLTAGE (mV) 0 160 5.0 400 Output Saturation Voltage vs Load Current (Output High) VS = ±2.5V VCM = 0.25V 0 0.0 600 626810 G11 Output Saturation Voltage vs Load Current (Output Low) 40 800 –IN –8 626810 G10 200 1000 –7 –9 VS = 3.2V TO 5.25V VCM = 1.0V –10 3.5 4.0 4.5 5.0 3.0 SUPPLY VOLTAGE (V) –8.0 –300 0.0 Input Bias Current vs Temperature 1600 CURRENT (fA) VS = 5V 10.0 INPUT BIAS CURRENT (fA) 300 TA = 25°C, unless otherwise noted. 6 4 2 8 4 0 –4 –8 –12 –16 0 0 100 200 300 FREQUENCY (MHz) 400 500 626810 G17 –20 0 1 2 3 4 5 6 TIME (s) 7 8 9 10 626810 G18 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 TYPICAL PERFORMANCE CHARACTERISTICS Input Referred Current Noise 0.1Hz to 10Hz Input Referred Voltage Noise 8 0 –4 –8 –12 –16 –20 0 1 2 3 4 5 6 TIME (s) 7 8 9 10 VS = ±2.5V VCM = 0.25V 12 9 6 3 0 0 50 100 150 FREQUENCY(MHz) Output Impedance vs Frequency 10 1 0.1 –45 20.0 –90 0.1 100 1 10 FREQUENCY(MHz) –60 626810 G21 100 HD2 0 –100 HD3 –200 –140 0.1 1000 Small Signal Step Response –80 –100 1 FREQUENCY (MHz) 626810 G22 –135 100 200 –120 0.1 1 10 FREQUENCY(MHz) 40.0 0 0.01 200 VS = ±2.5V VOUT = 2VP–P RL = 1kΩ RF = 450Ω RG = 50Ω AV = 10V VCM = –0.25V –40 DISTORTION (dB) OUTPUT IMPEDANCE (Ω) –20 AV = 10V AV = 100V 0.01 0 Harmonic Distortion vs Frequency 1000 0.01 0.001 60.0 626810 G20 626810 G19 100 45 GAIN PHASE 10 VS = ±2.5V VCM = 0.25V 0 40 AV = 10V/V, 20mV STEP RL = 1kΩ 80 120 160 626810 G24 Small Signal Step Response Small Signal Step Response 200 TIME (ns) 626810 G23 Large Signal Step Response 200 200 PHASE 4 Gain/Phase vs Frequency 80.0 VOUT (mV) 12 CURRENT NOISE DENSITY (ρA/√Hz) VS = ±2.5V AV = 11 VCM = 1.5V 16 VOLTAGE NOISE (µV) 15 GAIN (dB) 20 TA = 25°C, unless otherwise noted. 2.0 1.5 100 0 0.5 0 –100 –100 –200 1.0 VOUT (V) VOUT (mV) VOUT (mV) 100 VS = ±2.5V VCM = 0.25V 0 40 AV = 10V/V, 20mV STEP RL = 1kΩ, CL = 2.7pF 80 120 TIME (ns) 160 200 626810 G25 –200 0.0 –0.5 –1.0 VS = ±2.5V VCM = 1.25V 0 40 –1.5 AV = 10V/V, 20mV STEP RL = 1kΩ, CL = 2.7pF 80 120 TIME (ns) 160 200 626810 G26 –2.0 VS = ±2.5V VCM = 0.25V –0 40 AV = 10V/V, 200mV STEP RL = 1kΩ 80 120 TIME (ns) 160 200 626810 G27 626810f For more information www.linear.com/LTC6268-10 9 LTC6268-10/LTC6269-10 TYPICAL PERFORMANCE CHARACTERISTICS 1.5 1.0 1.0 0.5 0.5 0.0 –0.5 30 VCM = 1V 27 AV = 1 24 SUPPLY CURRENT (mA) 1.5 VOUT (V) VOUT (V) 2.0 0.0 –0.5 –1.0 –1.0 –2.0 Supply Current vs Supply Voltage Large Signal Step Response Large Signal Step Response 2.0 –1.5 TA = 25°C, unless otherwise noted. VS = ±2.5V VCM = 0.25V –0 40 80 120 TIME (ns) 160 200 –2.0 18 15 12 9 6 –1.5 AV = 10V/V, 200mV STEP RL = 1kΩ, CL = 2.7pF 21 VS = ±2.5V VCM = 1.25V –0 40 AV = 10V/V, 200mV STEP RL = 1kΩ, CL = 2.7pF 80 120 TIME (ns) 160 3 0 3.0 200 TA = 125°C TA = 25°C TA = –55°C 3.5 4.0 4.5 5.0 SUPPLY VOLTAGE (V) 5.5 626810 G29 626810 G28 626810 G30 Supply Current vs Shutdown Voltage Supply Current vs Shutdown Voltage 25 VS = 5V VCM = 2.75V AV = 1 20 TA = 125°C TA = 25°C TA = –55°C 15 20 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) 25 10 10 5 5 0 0.0 15 VS = 3.1V VCM = 1V AV = 1 TA = 125°C TA = 25°C TA = –55°C 0.5 1.0 1.5 SHUT DOWN VOLTAGE (V) 2.0 0 0.0 0.5 1.0 1.5 SHUT DOWN VOLTAGE (V) 2.0 626810 G32 626810 G31 PIN FUNCTIONS –IN: Inverting Input of the Amplifier. The voltage range of this pin is from V– to V+ –0.5V. +IN: Non-Inverting Input. The voltage range of this pin is from V– to V+ –0.5V. V+: Positive Power Supply. Total supply (V+ – V–) voltage is from 3.1V to 5.25V. Split supplies are possible as long as the total voltage between V+ and V– is between 3.1V and 5.25V. A bypass capacitor of 0.1µF should be used between V+ to ground as close to the pin as possible. V–: Negative Power Supply. Normally tied to ground, it can also be tied to a voltage other than ground as long 10 as the voltage difference between V+ and V– is between 3.1V and 5.25V. If it is not connected to ground, bypass it to ground with a capacitor of 0.1µF as close to the pin as possible. SHDN, SDA, SDB: Active Low op amp shutdown, threshold is 0.75V above the negative supply, V–. If left unconnected, the amplifier is enabled. OUT: Amplifier Output. NC: Not connected. May be used to create a guard ring around the input to guard against board leakage currents. See Applications Information section for more details. 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 SIMPLIFIED SCHEMATIC LTC6268-10 Simplified Schematic Diagram V+ C0 I0 D2 COMPLEMENTARY INPUT STAGE Q1 INPUT REPLICA +IN Q9 D4 Q4 CASCODE STAGE Q3 D0 CMOS INPUT BUFFER –IN Q5 Q6 BUFFER OUT D1 Q7 D6 Q8 INPUT REPLICA Q2 D5 D3 SHDN REFERENCE GENERATION D7 V– 626810 BD (ONE POLARITY SHOWN IN INPUT PINS) 626810f For more information www.linear.com/LTC6268-10 11 LTC6268-10/LTC6269-10 OPERATION The LTC6268-10/LTC6269-10 input signal range is specified from the negative supply to 0.5V below the positive power supply, while the output can swing from rail-to-rail. The schematic above depicts a simplified schematic of the amplifier. The input pins drive a CMOS buffer stage. The CMOS buffer stage creates replicas of the input voltages to boot strap the protection diodes. In turn, the buffer stage drives a complementary input stage consisting of two differential amplifiers, active over different ranges of input common mode voltage. The main differential amplifier is active with input common mode voltages from the negative power supply to approximately 1.55V below the positive supply, with the second amplifier active over the remaining range to 0.5V below the positive supply rail. The buffer and output bias stage uses a special compensation technique ensuring stability of the op amp. The common emitter topology of output transistors Q1/Q2 enables the output to swing from rail-to-rail. APPLICATIONS INFORMATION Noise To minimize the LTC6268-10’s noise over a broad range of applications, careful consideration has been placed on input referred voltage noise (eN), input referred current noise (iN) and input capacitance CIN. For a transimpedance amplifier (TIA) application such as shown in Figure 1, all three of these op amp parameters, plus the value of feedback resistance RF, contribute to noise behavior in different ways, and external components and traces will add to CIN. It is important to understand the impact of each parameter independently. Input referred CF RF IN – CIN OUT 626810 F01 + voltage noise (eN) consists of flicker noise (or 1/f noise), which dominates at lower frequencies, and thermal noise which dominates at higher frequencies. For LTC6268‑10, the 1/f corner, or transition between 1/f and thermal noise, is at 40kHz. The iN and RF contributions to input referred noise current at the minus input are relatively straight forward, while the eN contribution is amplified by the noise gain. Because there is no gain resistor, the noise gain is calculated using feedback resistor(RF) in conjunction with impedance of CIN as (1 + 2π RF • CIN • Freq), which increases with frequency. All of the contributions will be limited by the closed loop bandwidth. The equivalent input current noise is shown in Figure 2 and Figure 3, where eN represents contribution from input referred voltage noise (eN), iN represents contribution from input referred current noise (iN), and RF represents contribution from feedback resistor (RF). TIA gain (RF) and capacitance at input (CIN) are also shown on each figure. Comparing Figure 2 and Figure 3, iN dominates at higher frequencies. At lower frequencies, the RF contribution dominates. Since average wide band eN is 4.0nV/√Hz (see typical performance characteristics), RF contribution will become a lesser factor at lower frequencies if RF is less than 860Ω as indicated by the following equation: eN /RF 4kT /RF 1 GND Figure 1. Simplified TIA Schematic 12 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 APPLICATIONS INFORMATION 10 100 RF = 20kΩ, CIN = 1pF, CF = 60fF CURRENT NOISE DENSITY pA/√Hz) CURRENT NOISE DENSITY pA/√Hz) 100 1 0.1 TOTAL eN iN RN 0.01 0.001 0.01 0.1 1 10 FREQUENCY (MHz) 100 10 RF = 499kΩ, CIN = 1pF, CF = 13fF 1 0.1 0.001 0.01 1000 TOTAL eN iN RN 0.01 0.1 1 10 FREQUENCY (MHz) Figure 2 Figure 3 Optimizing the Bandwidth for TIA Application The capacitance at the inverting input node can cause amplifier stability problems if left unchecked. When the feedback around the op amp is resistive (RF), a pole will be created with RF ||CIN. This pole can create excessive phase shift and possibly oscillation. Referring to Figure 1, the response at the output is: RF 2 1+ 2 s + S 2 Where RF is the DC gain of the TIA, ω is the natural frequency of the closed loop, which can be expressed as: = 2 GBW RF (CIN +CF ) GBW 2 RF (CIN ) ζ is the damping factor of the loop, which can be expressed as: = 1 2 1 2 GBW •RF (CIN +CF ) CIN +CF • + RF CF + 1+ A O 2 GBW RF (CIN +CF ) Where CIN is the total capacitance at the inverting input node of the op amp, GBW is the gain bandwidth of the op amp, and AO is the DC open loop gain of the op amp. The small capacitor CF in parallel with RF can introduce enough damping to stabilize the loop. By assuming CIN >> CF, the following condition needs to be met for CF, Hence the maximum achievable bandwidth of TIA is: fTIA (Hz) = 1000 6268-10 F03 626810 F02 100 CF > CIN •GBW •RF Since LTC6268-10 is a decompensated op amp with gainof-10 stable, it requires that CIN/CF ≥ 10. Table 1 shows the minimum and maximum CF for RF of 20k and 402k and CIN of 1pF and 5pF. Table 1. Min/Max CF RF 20kΩ 402kΩ CIN = 1pF 60fF/100fF 13fF/100fF CIN = 5pF 140fF/500fF 31fF/500fF 626810f For more information www.linear.com/LTC6268-10 13 LTC6268-10/LTC6269-10 APPLICATIONS INFORMATION Achieving Higher Bandwidth with Higher Gain TIAs Good layout practices are essential to achieving best results from a TIA circuit. The following two examples show drastically different results from an LTC6268-10 in a 402k TIA. (See Figure 4.) The first example is with an 0805 resistor in a basic circuit layout. In a simple layout, without expending a lot of effort to reduce feedback capacitance, the rise time achieved is about 87ns (Figure 5), implying a bandwidth of 4MHz (BW = 0.35/tr). In this case, the bandwidth of the TIA is limited not by the GBW of the LTC6268-10, but rather by the fact that the feedback capacitance is reducing the actual feedback impedance (the TIA gain itself) of the TIA. Basically, it’s a resistor bandwidth limitation. The impedance of the 402kΩ is being reduced by its own parasitic capacitance at high frequency. From the 4MHz bandwidth and the 402k low frequency gain, we can estimate the total feedback capacitance as C = 1/(2π • 4MHz • 402kΩ) = 0.1pF. That’s fairly low, but it can be reduced further. With some extra layout techniques to reduce feedback capacitance, the bandwidth can be increased. Note that PARASITIC FEEDBACK C – K PD CASE A OUTPUT (500MV/DIV) +2.5 LTC6268-10 VOUT + –2.5 Figure 7 shows the dramatic increase in bandwidth simply by careful attention to low capacitance methods around the feedback resistance. Bandwidth and rise time went from 4MHz (87ns) to 34MHz (10.3ns), a factor of 8. The ground trace used for LTC6268-10 was much wider than that used in the case of the LTC6268 (see LTC6268 data sheet), extending under the entire resistor dielectric. Assuming all the bandwidth limit is due to feedback capacitance (which isn't fair), we can calculate an upper limit of Cf = 1/(2π • 402kΩ • 34MHz) = 11.6fF. LASER DRIVE (2mA/DIV) 402k IPD we are increasing the effective “bandwidth” of the 402k resistance. A very powerful method to reduce feedback capacitance is to shield the E field paths that give rise to the capacitance. In this particular case, the method is to place a ground trace between the resistor pads. Such a ground trace shields the output field from getting to the summing node end of the resistor and effectively shunts the field to ground instead. The trace increases the output load capacitance very slightly. See Figure 6 for a pictorial representation. 20ns/DIV 626810 F05 Figure 5. Time Domain Response of 402kΩ TIA without Extra Effort to Reduce Feedback Capacitance. Rise Time Is 87ns and BW Is 4MHz –2.5 626810 F04 PD: OSI FCI-125G-006 Figure 4. LTC6268-10 and Low Capacitance Photodiode in a 402kΩ TIA 14 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 APPLICATIONS INFORMATION CERAMIC R SUBSTRATE E RESISTIVE ELEMENT ENDCAP IPD K G A FR4 K LTC6268-10 VOUT G A E FIELD ⇒ C –2.5 E RESISTIVE ELEMENT ENDCAP IPD – + CERAMIC R SUBSTRATE – FR4 LTC6268-10 + –2.5 EXTRA GND TRACE UNDER RESISTOR VOUT TAKE E FIELD TO GND, MUCH LOWER C 626810 F06 Figure 6. A Normal Layout at Left and a Field-Shunting Layout at Right. Simply Adding a Ground Trace Under the Feedback Resistor Does Much to Shunt Field Away from the Feedback Side and Dumps It to Ground. Note That the Dielectric Constant of Fr4 and Ceramic Is Typically 4, so Most of the Capacitance Is in the Solids and Not Through the Air. Feedback C is Reduced from 100fF at Left to 11.6fF at Right Maintaining Ultralow Input Bias Current Leakage currents into high impedance signal nodes can easily degrade measurement accuracy of fA signals. High temperature applications are especially susceptible to these issues. For humid environments, surface coating may be necessary to provide a moisture barrier. There are several factors to consider in a low input bias current circuit. At the femtoamp level, leakage sources can come from unexpected sources including adjacent signals on the PCB, both on the same layer and from internal layers, any form of contamination on the board from the assembly process or the environment, other components on the signal path and even the plastic of the device package. Care taken in the design of the system can mitigate these sources and achieve excellent performance. LASER DRIVE (2mA/DIV) OUTPUT (500MV/DIV) 20ns/DIV 626810 F07 Figure 7. LTC6268-10 in a 402kΩ TIA with Extra Layout Effort to Reduce Feedback Capacitance Achieves 10.3ns Total System Rise Time, or 34MHz Total System Bandwidth The choice of device package should be considered because although each has the same die internally, the pin spacing and adjacent signals influence the input bias current. The LTC6268-10/LTC6269-10 is available in SOIC, MSOP, DFN and SOT-23 packages. Of these, the SOIC has been designed as the best choice for low input bias current. It has the largest lead spacing which increases the impedance of the package plastic and the pinout is such that the two input pins are isolated on the far side of the package from the other signals. The gull-wing leads on this package also allow for better cleaning of the PCB and reduced contamination-induced leakage. The other packages have advantages in size and pin count but do so by reducing the input isolation. Leadless packages such as the DFN offer the minimum size but have the smallest pin spacing and may trap contaminants under the package. The material used in the construction of the PCB can sometimes influence the leakage characteristics of the design. Exotic materials such as Teflon can be used to improve leakage performance in specific cases but they are generally not necessary if some basic rules are applied in the design of conventional FR4 PCBs. It is important to keep the high impedance signal path as short as possible on the board. A node with high impedance is susceptible to picking up any stray signals in the system so keeping it as short as possible reduces this effect. In some cases, it may be necessary to have a metallic shield over this portion of the circuit. However, metallic shielding increases capacitance. Another technique for avoiding leakage paths is to cut slots in the PCB. High impedance circuits are also 626810f For more information www.linear.com/LTC6268-10 15 LTC6268-10/LTC6269-10 APPLICATIONS INFORMATION susceptible to electrostatic as well as electromagnetic effects. The static charge carried by a person walking by the circuit can induce an interference on the order of 100’s of femtoamps. A metallic shield can reduce this effect as well. The layout of a high impedance input node is very important. Other signals should be routed well away from this signal path and there should be no internal power planes under it. The best defense from coupling signals is distance and this includes vertically as well as on the surface. In cases where the space is limited, slotting the board around the high impedance input nodes can provide additional isolation and reduce the effect of contamination. In electrically noisy environments the use of driven guard rings around these nodes can be effective (see Figure 8). Adding any additional components such as filters to the high impedance input node can increase leakage. The leakage current of a ceramic capacitor is orders of magnitude larger than the bias current of this device. Any filtering will need to be done after this first stage in the signal chain. RF§ SD NC VBIAS –IN ‡ V–IN LEAKAGE CURRENT LTC6268-10 S8 V+ OUT +IN NC V– NO SOLDER MASK OVER GUARD RING LOW IMPEDANCE ‡ NO LEAKAGE CURRENT. V–IN = VGRD NODE ABSORBS § AVOID DISSIPATING SIGNIFICANT AMOUNTS OF POWER IN THIS RESISTOR. LEAKAGE CURRENT IT WILL GENERATE THERMAL GRADIENTS WITH RESPECT TO THE INPUT PINS AND LEAD TO THERMOCOUPLE-INDUCED ERROR. (a) GUARD RING VBIAS RF HIGH-Z SENSOR VIN –+ V+ RIN – LEAKAGE CURRENT LTC6268-10 VOUT + V– LEAKAGE CURRENT IS ABSORBED BY GROUND INSTEAD OF CAUSING A MEASUREMENT ERROR. 626810 F8 (b) Figure 8. Example Layout of Inverting Amplifier (or Transimpedance) with Leakage Guard Ring Driving Capacitive Load The layout of the output node is also very important since LTC6268-10/LTC6269-10 is very sensitive to capacitive loading due to the very high gain-bandwidth-product. Appreciable ringing will be observed when capacitive loading is more than 5pF. Low Input Offset Voltage The LTC6268-10 has a maximum offset voltage of ±2.5mV (PNP region) over temperature. The low offset voltage is essential for precision applications. There are 2 different input stages that are used depending on the input common mode voltage. To increase the versatility of the LTC6268-10, the offset voltages are trimmed for both regions of operation. 16 GUARD RING HIGH-Z SENSOR (RIN) Rail-to-Rail Output The LTC6268-10 has a rail-to-rail output stage that has excellent output drive capability. It is capable of delivering over ±40mA of output drive current over temperature. Furthermore, the output can reach within 200mV of either rail while driving ±10mA. Attention must be paid to keep the junction temperature of the IC below 150°C. Input Protection To prevent breakdown of internal devices in the input stage, the two op amp inputs should NOT be separated by more than 2.0V. To help protect the input stage, internal circuitry will engage automatically if the inputs are separated by >2.0V and input currents will begin to flow. In all cases, care should be taken so that these currents remain less than 1mA. Additionally, if only one input is driven, internal circuitry will prevent any breakdown condition under 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 APPLICATIONS INFORMATION transient conditions. The worst-case differential input voltage usually occurs when the +input is driven and the output is accidentally shorted to ground while in a unity gain configuration. ESD ESD Protection devices can be seen in the simplified schematic. The +IN and –IN pins use a sophisticated method of ESD protection that incorporates a total of 4 reversebiased diodes connected as 2 series diodes to each rail. To maintain extremely low input bias currents, the center node of each of these series diode chains is driven by a buffered copy of the input voltage. This maintains the two diodes connected directly to the input pins at low reverse bias, minimizing leakage current of these ESD diodes to the input pins. Shutdown The LTC6268-10S6, LTC6268-10S8, and LTC6268-10DD have SHDN pins that can shut down the amplifier to less than 1.2mA supply current per amplifier. The SHDN pin voltage needs to be within 0.75V of V– for the amplifier to shut down. During shutdown, the output will be in a high output resistance state, so the LTC6268-10 is suitable for multiplexer applications. The internal circuitry is kept in a low current active state for fast recovery. When left floating, the SHDN pin is internally pulled up to the positive supply and the amplifier is enabled. The remaining pins have traditional ESD protection, using reverse-biased ESD diodes connected to each power supply rail. Care should be taken to make sure that the voltages on these pins do not exceed the supply voltages by more than 100mV or these diodes will begin to conduct large amounts of current. 626810f For more information www.linear.com/LTC6268-10 17 LTC6268-10/LTC6269-10 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 2.90 BSC (NOTE 4) 0.95 REF 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.30 – 0.45 6 PLCS (NOTE 3) 0.95 BSC 0.80 – 0.90 0.20 BSC 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 18 0.01 – 0.10 1.00 MAX DATUM ‘A’ 1.90 BSC S6 TSOT-23 0302 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610 Rev G) .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 .050 BSC 8 .245 MIN .160 ±.005 .010 – .020 × 45° (0.254 – 0.508) NOTE: 1. DIMENSIONS IN 5 .150 – .157 (3.810 – 3.988) NOTE 3 1 RECOMMENDED SOLDER PAD LAYOUT 2 .053 – .069 (1.346 – 1.752) 0°– 8° TYP .016 – .050 (0.406 – 1.270) 6 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP .008 – .010 (0.203 – 0.254) 7 .014 – .019 (0.355 – 0.483) TYP INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) 4. PIN 1 CAN BE BEVEL EDGE OR A DIMPLE 3 4 .004 – .010 (0.101 – 0.254) .050 (1.270) BSC SO8 REV G 0212 626810f For more information www.linear.com/LTC6268-10 19 LTC6268-10/LTC6269-10 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. MS8E Package 8-Lead Plastic MSOP, Exposed Die Pad (Reference LTC DWG # 05-08-1662 Rev K) BOTTOM VIEW OF EXPOSED PAD OPTION 1.88 (.074) 1 1.88 ±0.102 (.074 ±.004) 0.29 REF 1.68 (.066) 0.889 ±0.127 (.035 ±.005) 0.05 REF 5.10 (.201) MIN DETAIL “B” CORNER TAIL IS PART OF DETAIL “B” THE LEADFRAME FEATURE. FOR REFERENCE ONLY NO MEASUREMENT PURPOSE 1.68 ±0.102 3.20 – 3.45 (.066 ±.004) (.126 – .136) 8 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 (MS8E) 0213 REV K 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 6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL NOT EXCEED 0.254mm (.010") PER SIDE. 20 626810f For more information www.linear.com/LTC6268-10 LTC6268-10/LTC6269-10 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699 Rev C) 0.70 ±0.05 3.55 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 3.00 ±0.10 (4 SIDES) R = 0.125 TYP 6 0.40 ±0.10 10 1.65 ±0.10 (2 SIDES) PIN 1 NOTCH R = 0.20 OR 0.35 × 45° CHAMFER PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF 0.75 ±0.05 0.00 – 0.05 5 1 (DD) DFN REV C 0310 0.25 ±0.05 0.50 BSC 2.38 ±0.10 (2 SIDES) BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 626810f 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 representaFor more information www.linear.com/LTC6268-10 tion that the interconnection of its circuits as described herein will not infringe on existing patent rights. 21 LTC6268-10/LTC6269-10 TYPICAL APPLICATION 100kΩ Gain 90MHz Transimpedance Amplifier 100kΩ TIA Frequency Response 109 100kΩ 2.5V 103 100 – LTC6268-10 + VOUT = –IPD • 100k BW = 90MHz GAIN (dBΩ) 2.5V PD IPD 106 PARASITIC FEEDBACK C 97 94 91 88 –2.5V 85 626810 TA02 PD = OSI OPTOELECTRONICS, FCI-125G-006 OUTPUT NOISE = 20mVP-P MEASURED ON A 100MHz BW 82 79 1M 10M FREQUENCY(Hz) 100M 626810 TA3 RELATED PARTS PART NUMBER Op Amps LTC6268/LTC6269 LTC6244 LTC6240/LTC6241/ LTC6242 LTC6252/LTC6253/ LTC6254 LTC6246/LTC6247/ LTC6248 LT1818 LT6236 LT6411 SAR ADC LTC2376-18/ LTC2377-18/ LTC2378-18/ LTC2379-18 DESCRIPTION COMMENTS 500MHz Ultra-Low Bias Current FET Input Op Amp Dual 50MHz, Low Noise, Rail-to-Rail, CMOS Op Amp 18MHz, Low Noise, Rail-to-Rail Output, CMOS Op Amp Unity Gain Stable, Ultra Low Input Bias Current (3fA), 500MHz GBW Unity Gain Stable, 1pA Input Bias Current, 100μV Max Offset. 18MHz GBW, 0.2pA Input Current, 125μV Max Offset. 720MHz, 3.5mA Power Efficient Rail-to-Rail I/O Op Amp 720MHz GBW, Unity Gain Stable, Low Noise 180MHz, 1mA Power Efficient Rail-to-Rail I/O Op Amps 180MHz GBW, Unity Gain Stable, Low Noise 400MHz, 2500V/µs, 9mA Single Operational Amplifier Unity Gain Stable, 6nV/√Hz Unity Gain Stable 215MHz, Rail-to-Rail Output, 1.1nV/√Hz, 3.5mA Op Amp Family 350μV Max Offset Voltage, 3V to 12.6V Supply 650MHz Differential ADC Driver/Dual Selectable Amplifier SR 3300V/µs, 6ns 0.1% Settling. 18-Bit, 250ksps to 1.6Msps, Low Power SAR ADC, 102dB SNR 22 Linear Technology Corporation 18mW at 1.6Msps, 3.4μW at 250sps, –126dB THD. 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTC6268-10 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTC6268-10 626810f LT 0415 • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2015