FeaTures
n n n n n n n n n n n n n n n n n n n
LTC6246/LTC6247/LTC6248 180MHz, 1mA Power Efficient Rail-to-Rail I/O Op Amps DescripTion
The LTC®6246/LTC6247/LTC6248 are single/dual/quad low power, high speed unity gain stable rail-to-rail input/output operational amplifiers. On only 1mA of supply current they feature an impressive 180MHz gain-bandwidth product, 90V/µs slew rate and a low 4.2nV/√Hz of input-referred noise. The combination of high bandwidth, high slew rate, low power consumption and low broadband noise makes these amplifiers unique among rail-to-rail input/output op amps with similar supply currents. They are ideal for lower supply voltage high speed signal conditioning systems. The LTC6246 family maintains high efficiency performance from supply voltage levels of 2.5V to 5.25V and is fully specified at supplies of 2.7V and 5.0V. For applications that require power-down, the LTC6246 and the LTC6247 in MS10 offer a shutdown pin which disables the amplifier and reduces current consumption to 42µA. The LTC6246 family can be used as a plug-in replacement for many commercially available op amps to reduce power or to improve input/output range and performance.
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.
Gain Bandwidth Product: 180MHz –3dB Frequency (AV = 1): 120MHz Low Quiescent Current: 1mA Max High Slew Rate: 90V/µs Input Common Mode Range Includes Both Rails Output Swings Rail-to-Rail Low Broadband Voltage Noise: 4.2nV/√Hz Power-Down Mode: 42μA Fast Output Recovery Supply Voltage Range: 2.5V to 5.25V Input Offset Voltage: 0.5mV Max Input Bias Current: 100nA Large Output Current: 50mA CMRR: 110dB Open Loop Gain: 45V/mV Operating Temperature Range: –40°C to 125°C Single in 6-Pin TSOT-23 Dual in MS8, 2mm × 2mm Thin DFN,TS0T-23, MS10 Quad in MS16 Low Voltage, High Frequency Signal Processing Driving A/D Converters Rail-to-Rail Buffer Amplifiers Active Filters Video Amplifiers Fast Current Sensing Amplifiers Battery Powered Equipment
applicaTions
n n n n n n n
Typical applicaTion
Low Noise Low Distortion Gain = 2 ADC Driver
3.3V 2.5V MAGNITUDE (dB) 3.3V VIN 0 –10 –20 –30 CS SDO SCK OVDD
624678 TA01a
350kHz FFT Driving ADC
fIN = 350.195kHz fSAMP = 2.2Msps SFDR = 82dB SNR = 70dB 1024 POINT FFT
+
LTC6246 AIN 499 1% 10pF
VDD VREF LTC2366 GND
–40 –50 –60 –70 –80 –90 –100 –110 0 200 400 600 800 FREQUENCY (kHz) 1000
624678 TA01b
–
499 1%
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LTC6246/LTC6247/LTC6248 absoluTe MaxiMuM raTings
(Note 1)
Total Supply Voltage (V+ to V –) ................................5.5V Input Current (+IN, –IN, SHDN) (Note 2) .............. ±10mA Output Current (Note 3) ..................................... ±100mA Operating Temperature Range (Note 4) . –40°C to 125°C
Specified Temperature Range (Note 5) .. –40°C to 125°C Storage Temperature Range .................. –65°C to 150°C Junction Temperature ........................................... 150°C Lead Temperature (Soldering, 10 sec) (MSOP, TSOT Packages Only) ............................... 300°C
pin conFiguraTion
TOP VIEW OUT A 1 +IN A 3 V– 4
+ –
8 7 6 5 9
+ –
V+ OUT B –IN B +IN B
TOP VIEW
+ –
TOP VIEW
+ –
–IN A 2
KC PACKAGE 8-LEAD PLASTIC UTDFN (2mm 2mm) TJMAX = 125°C, θJA = 102°C/W (NOTE 9) EXPOSED PAD (PIN 9) IS V–, MUST BE SOLDERED TO PCB TOP VIEW
+ – + –
MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 163°C/W (NOTE 9)
MS PACKAGE 10-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 160°C/W (NOTE 9)
+IN 3
4 –IN
MS PACKAGE 16-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 125°C/W (NOTE 9)
S6 PACKAGE 6-LEAD PLASTIC TSOT-23 TJMAX = 150°C, θJA = 192°C/W (NOTE 9)
TS8 PACKAGE 8-LEAD PLASTIC TSOT-23 TJMAX = 150°C, θJA = 195°C/W (NOTE 9)
orDer inForMaTion
LEAD FREE FINISH LTC6246CS6#TRMPBF LTC6246IS6#TRMPBF LTC6246HS6#TRMPBF LTC6247CKC#TRMPBF LTC6247IKC#TRMPBF LTC6247CMS8#PBF LTC6247IMS8#PBF LTC6247CTS8#TRMPBF LTC6247ITS8#TRMPBF LTC6247HTS8#TRMPBF TAPE AND REEL LTC6246CS6#TRPBF LTC6246IS6#TRPBF LTC6246HS6#TRPBF LTC6247CKC#TRPBF LTC6247IKC#TRPBF LTC6247CMS8#TRPBF LTC6247IMS8#TRPBF LTC6247CTS8#TRPBF LTC6247ITS8#TRPBF LTC6247HTS8#TRPBF PART MARKING* LTDWF LTDWF LTDWF DWJT DWJT LTDWH LTDWH LTDWK LTDWK LTDWK PACKAGE DESCRIPTION 6-Lead Plastic TSOT-23 6-Lead Plastic TSOT-23 6-Lead Plastic TSOT-23 8-Lead (2mm × 2mm) UTDFN 8-Lead (2mm × 2mm) UTDFN 8-Lead Plastic MSOP 8-Lead Plastic MSOP 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 8-Lead Plastic TSOT-23 SPECIFIED TEMPERATURE RANGE 0°C to 70°C –40°C to 85°C –40°C to 125°C 0°C to 70°C –40°C to 85°C 0°C to 70°C –40°C to 85°C 0°C to 70°C –40°C to 85°C –40°C to 125°C
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+ –
+ –
+ –
V– 2
+–
5 SHDN
+ –
OUT A –IN A +IN A V+ +IN B –IN B OUT B
1 2 3 4 5 6 7 8
16 15 14 13 12 11 10 9
OUT D –IN D +IN D V– +IN C –IN C OUT C
TOP VIEW OUT 1 6V
+
TOP VIEW OUT A 1 –IN A 2 +IN A 3 V– 4 8 V+ 7 OUT B 6 –IN B 5 +IN B
+ –
+ –
OUT A –IN A +IN A V–
1 2 3 4
8 7 6 5
V+ OUT B –IN B +IN B
1 2 3 4 SHDNA 5 OUT A –IN A +IN A V–
10 9 8 7 6
V+ OUT B –IN B +IN B SHDNB
LTC6246/LTC6247/LTC6248 orDer inForMaTion
LEAD FREE FINISH LTC6247CMS#PBF LTC6247IMS#PBF LTC6248CMS#PBF LTC6248IMS#PBF LTC6248HMS#PBF TAPE AND REEL LTC6247CMS#TRPBF LTC6247IMS#TRPBF LTC6248CMS#TRPBF LTC6248IMS#TRPBF LTC6248HMS#TRPBF PART MARKING* LTDWM LTDWM 6248 6248 6248 PACKAGE DESCRIPTION 10-Lead Plastic MSOP 10-Lead Plastic MSOP 16-Lead Plastic MSOP 16-Lead Plastic MSOP 16-Lead Plastic MSOP SPECIFIED TEMPERATURE RANGE 0°C to 70°C –40°C to 85°C 0°C to 70°C –40°C to 85°C –40°C to 125°C
TRM = 500 pieces. *Temperature grades are identified by a label on the shipping container. Consult LTC Marketing for parts specified with wider operating temperature ranges. Consult LTC Marketing for information on lead based finish parts. 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/
(VS = 5V) The l denotes the specifications which apply across the specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 5V, 0V; VSHDN = 2V; VCM = VOUT = 2.5V, unless otherwise noted.
SYMBOL VOS PARAMETER Input Offset Voltage CONDITIONS VCM = Half Supply
l
elecTrical characTerisTics
MIN –500 –1000 –2.5 –3 –600 –1000 –3.5 –4 –350 –550 100 0 –250 –400 –250 –400
TYP 50 0.1 50 0.1 –2 –30 400 –10 –10 4.2 1.6 2.0 2 0.8 32 14
MAX 500 1000 2.5 3 600 1000 3.5 4 350 550 1000 1500 250 400 250 400
UNITS µV µV mV mV µV µV mV mV µV/°C nA nA nA nA nA nA nA nA nV/√Hz µVP-P pA/√Hz pF pF kΩ MΩ V/mV V/mV V/mV V/mV dB dB
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VCM = V+ – 0.5V, NPN Mode
l
∆VOS
Input Offset Voltage Match (Channel-to-Channel) (Note 8)
VCM = Half Supply
l
VCM = V+ – 0.5V, NPN Mode
l
VOS TC IB
Input Offset Voltage Drift Input Bias Current (Note 7) VCM = Half Supply
l l
VCM = V+ – 0.5V, NPN Mode
l
IOS
Input Offset Current
VCM = Half Supply
l
VCM = V+ – 0.5V, NPN Mode
l
en in CIN RIN AVOL
Input Noise Voltage Density Input 1/f Noise Voltage Input Noise Current Density Input Capacitance Input Resistance Large Signal Voltage Gain
f = 100kHz f = 0.1Hz to 10Hz f = 100kHz Differential Mode Common Mode Differential Mode Common Mode RL = 1k to Half Supply (Note 10)
l
30 14 5 2.5 78 76
45 15 110
RL = 100Ω to Half Supply (Note 10)
l
CMRR
Common Mode Rejection Ratio
VCM = 0V to 3.5V
l
LTC6246/LTC6247/LTC6248 elecTrical characTerisTics
SYMBOL ICMR PSRR PARAMETER Input Common Mode Range Power Supply Rejection Ratio Supply Voltage Range (Note 6) VOL Output Swing Low (VOUT – V–) No Load
l
(VS = 5V) The l denotes the specifications which apply across the specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 5V, 0V; VSHDN = 2V; VCM = VOUT = 2.5V, unless otherwise noted.
CONDITIONS
l
MIN 0 69 65 2.5
TYP 73
MAX VS
UNITS V dB dB
VS = 2.5V to 5.25V VCM = 1V
l l
5.25 25 70 40 55 110 160 250 450 100 150 175 225 500 750 –35 –30
V mV mV mV mV mV mV mV mV mV mV mV mV mA mA mA mA
ISINK = 5mA
l
ISINK = 25mA
l
160 70
l
VOH
Output Swing High (V+ – VOUT)
No Load ISOURCE = 5mA
l
130 300
l
ISOURCE = 25mA ISC Output Short-Circuit Current Sourcing
l
–80 60 40 100 0.95
l
Sinking
l
IS
Supply Current per Amplifier
VCM = Half Supply VCM = V+ – 0.5V
l
1 1.4 1.4 1.8 75 200 0 0 300 350 0.8
mA mA mA mA µA µA µA µA nA nA V V nA µs µs MHz MHz MHz ns ns V/µs V/µs MHz
1.25 42
l
ISD ISHDNL ISHDNH VL VH IOSD tON tOFF BW GBW tS , 0.1% tS , 0.01% SR FPBW
Disable Supply Current per Amplifier SHDN Pin Current Low SHDN Pin Current High SHDN Pin Input Voltage Low SHDN Pin Input Voltage High Output Leakage Current Magnitude in Shutdown Turn-On Time Turn-Off Time –3dB Closed Loop Bandwidth Gain-Bandwidth Product Settling Time to 0.1% Settling Time to 0.01% Slew Rate Full Power Bandwidth
VSHDN = 0.8V VSHDN = 0.8V
l
–3 –4 –300 –350 2
–1.6 35
VSHDN = 2V
l l l
VSHDN = 0.8V, Output Shorted to Either Supply VSHDN = 0.8V to 2V VSHDN = 2V to 0.8V AV = 1, RL = 1k to Half Supply f = 2MHz, RL = 1k to Half Supply
l
100 5 2 120 100 70 180 74 202
l
AV = –1, VO = 2V Step RL = 1k AV = –1, VO = 2V Step RL = 1k AV = –3.33, 4.6V Step (Note 11) VOUT = 4VP-P (Note 13) 60 50
90 4
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LTC6246/LTC6247/LTC6248 elecTrical characTerisTics
SYMBOL HD2/HD3 PARAMETER Harmonic Distortion RL = 1k to Half Supply RL = 100Ω to Half Supply ∆G ∆θ Differential Gain (Note 14) Differential Phase (Note 14) Crosstalk
(VS = 5V) The l denotes the specifications which apply across the specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 5V, 0V; VSHDN = 2V; VCM = VOUT = 2.5V, unless otherwise noted.
CONDITIONS fC = 100kHz, VO = 2VP-P fC = 1MHz, VO = 2VP-P fC = 2MHz, VO = 2VP-P fC = 100kHz, VO = 2VP-P fC = 1MHz, VO = 2VP-P fC = 2MHz, VO = 2VP-P AV = 1, RL = 1k, VS = ±2.5V AV = 1, RL = 1k, VS = ±2.5V AV = –1, RL = 1k to Half Supply, VOUT = 2VP-P, f = 1MHz MIN TYP 110/90 88/80 78/62 90/79 66/60 59/51 0.2 0.08 –90 % Deg dB MAX UNITS dBc dBc dBc
elecTrical characTerisTics
SYMBOL VOS PARAMETER Input Offset Voltage
(VS = 2.7V) The l denotes the specifications which apply across the specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 2.7V, 0V; VSHDN = 2V; VCM = VOUT = 1.35V, unless otherwise noted.
CONDITIONS VCM = Half Supply
l
MIN –100 –300 –1.75 –2.25 –700 –1000 –3.5 –4 –450 –600 50 0 –250 –350 –250 –350
TYP 500 0.75 –20 0.1 2 –100 350 –10 –10 4.6 1.7 1.8 2 0.8 32 12
MAX 1000 1400 3.25 3.75 700 1000 3.5 4 450 600 1000 1500 250 350 250 350
UNITS µV µV mV mV µV µV mV mV µV/°C nA nA nA nA nA nA nA nA nV/√Hz µVP-P pA/√Hz pF pF kΩ MΩ V/mV V/mV V/mV V/mV
VCM = V+ – 0.5V, NPN Mode
l
∆VOS
Input Offset Voltage Match (Channel-to-Channel) (Note 8)
VCM = Half Supply
l
VCM = V+ – 0.5V, NPN Mode
l
VOS TC IB
Input Offset Voltage Drift Input Bias Current (Note 7) VCM = Half Supply
l l
VCM = V+ – 0.5V, NPN Mode
l
IOS
Input Offset Current
VCM = Half Supply
l
VCM = V+ – 0.5V, NPN Mode
l
en in CIN RIN AVOL
Input Noise Voltage Density Input 1/f Noise Voltage Input Noise Current Density Input Capacitance Input Resistance Large Signal Voltage Gain
f = 100kHz f = 0.1Hz to 10Hz f = 100kHz Differential Mode Common Mode Differential Mode Common Mode RL = 1k to Half Supply (Note 12) RL = 100Ω to Half Supply (Note 12)
l l
15 7.5 2 1.3
25 7.5
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LTC6246/LTC6247/LTC6248 elecTrical characTerisTics
SYMBOL CMRR ICMR PSRR PARAMETER Common Mode Rejection Ratio Input Common Mode Range Power Supply Rejection Ratio Supply Voltage Range (Note 6) VOL Output Swing Low (VOUT – V–) No Load
l
(VS = 2.7V) The l denotes the specifications which apply across the specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 2.7V, 0V; VSHDN = 2V; VCM = VOUT = 1.35V, unless otherwise noted.
CONDITIONS VCM = 0V to 1.2V
l l
MIN 80 78 0 69 65 2.5
TYP 100
MAX
UNITS dB dB
VS 73 5.25 20 80 40 55 125 160 175 225 85 100 190 225 275 400 –20 –15
V dB dB V mV mV mV mV mV mV mV mV mV mV mV mV mA mA mA mA
VS = 2.5V to 5.25V VCM = 1V
l l
ISINK = 5mA
l
ISINK = 10mA
l
110 60
l
VOH
Output Swing High (V+ – VOUT)
No Load ISOURCE = 5mA
l
135 180
l
ISOURCE = 10mA ISC Short Circuit Current Sourcing
l
–35 25 20 50 0.89
l
Sinking
l
IS
Supply Current per Amplifier
VCM = Half Supply VCM = V+ – 0.5V
l
1 1.3 1.3 1.7 50 90 0 0 300 350 0.8
mA mA mA mA µA µA µA µA nA nA V V nA µs µs MHz MHz ns ns V/µs
1 22
l
ISD ISHDNL ISHDNH VL VH IOSD tON tOFF BW GBW tS , 0.1 tS , 0.01 SR
Disable Supply Current per Amplifier SHDN Pin Current Low SHDN Pin Current High SHDN Pin Input Voltage SHDN Pin Input Voltage
VSHDN = 0.8V VSHDN = 0.8V
l
–1 –1.5 –300 –350 2.0
–0.5 45
VSHDN = 2V
l l l
Output Leakage Current Magnitude in Shutdown VSHDN = 0.8V, Output Shorted to Either Supply Turn-On Time Turn-Off Time –3dB Closed Loop Bandwidth Gain-Bandwidth Product Settling Time to 0.1% Settling Time to 0.01% Slew Rate VSHDN = 0.8V to 2V VSHDN = 2V to 0.8V AV = 1, RL = 1k to Half Supply f = 2MHz, RL = 1k to Half Supply
l
100 5 2 100 80 50 150 119 170 55
AV = –1, VO = 2V Step RL = 1k AV = –1, VO = 2V Step RL = 1k AV = –1, 2V Step
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LTC6246/LTC6247/LTC6248 elecTrical characTerisTics
SYMBOL FPBW PARAMETER Full Power Bandwidth Crosstalk
(VS = 2.7V) The l denotes the specifications which apply across the specified temperature range, otherwise specifications are at TA = 25°C. For each amplifier VS = 2.7V, 0V; VSHDN = 2V; VCM = VOUT = 1.35V, unless otherwise noted.
CONDITIONS VOUT = 2VP-P (Note 13) AV = –1, RL = 1k to Half Supply, VOUT = 2VP-P, f = 1MHz MIN TYP 3.3 –90 MAX UNITS MHz dB
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 back-to-back diodes. If any of the input or shutdown pins goes 300mV beyond either supply or the differential input voltage exceeds 1.4V the input current should be limited to less than 10mA. This parameter is guaranteed to meet specified performance through design and/or characterization. It is not production tested. Note 3: A heat sink may be required to keep the junction temperature below the absolute maximum rating when the output current is high. Note 4: The LTC6246C/LTC6247C/LTC6248C and LTC6246I/LTC6247I/ LTC6248I are guaranteed functional over the temperature range of –40°C to 85°C. The LTC6246H/LTC6247H/LTC6248H are guaranteed functional over the temperature range of –40°C to 125°C. Note 5: The LTC6246C/LTC6247C/LTC6248C are guaranteed to meet specified performance from 0°C to 70°C. The LTC6246C/LTC6247C/ LTC6248C are designed, characterized and expected to meet specified performance from –40°C to 85°C but are not tested or QA sampled at these temperatures. The LTC6246I/LTC6247I/LTC6248I are guaranteed to meet specified performance from –40°C to 85°C. The LTC6246H/ LTC6247H/LTC6248H are guaranteed to meet specified performance from –40°C to 125°C.
Note 6: Minimum supply voltage is guaranteed by power supply rejection ratio test. Note 7: The input bias current is the average of the average of the currents through the positive and negative input pins. Note 8: Matching parameters are the difference between amplifiers A and D and between B and C on the LTC6248; between the two amplifiers on the LTC6247. Note 9: Thermal resistance varies with the amount of PC board metal connected to the package. The specified values are with short traces connected to the leads with minimal metal area. Note 10: The output voltage is varied from 0.5V to 4.5V during measurement. Note 11: Middle 80% of the output waveform is observed. RL = 1k at half supply. Note 12: The output voltage is varied from 0.5V to 2.2V during measurement. Note 13: FPBW is determined from distortion performance in a gain of +2 configuration with HD2, HD3 < –40dBc as the criteria for a valid output. Note 14: Differential gain and phase are measured using a Tektronix TSG120YC/NTSC signal generator and a Tektronix 1780R video measurement set.
Typical perForMance characTerisTics
VOS Distribution, VCM = VS/2 (MS, PNP Stage)
22 VS = 5V, 0V 20 V = 2.5V CM 18 PERCENT OF UNITS (%) 14 12 10 8 6 4 2 0 –375 –250 –150 –50 50 150 250 INPUT OFFSET VOLTAGE (µV) 350 0 –175 –125 –75 –25 25 75 125 INPUT OFFSET VOLTAGE (µV) 175 PERCENT OF UNITS (%) 16 25
VOS Distribution, VCM = VS/2 (TSOT-23, PNP Stage)
VS = 5V, 0V VCM = 2.5V PERCENT OF UNITS (%) 16
VOS Distribution, VCM = V+ – 0.5V (MS, NPN Stage)
VS = 5V, 0V 14 VCM = 4.5V 12 10 8 6 4 2 0 –2000 –1200 –400 400 1200 INPUT OFFSET VOLTAGE (µV) 2000
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20
15
10
5
624678 G01
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LTC6246/LTC6247/LTC6248 Typical perForMance characTerisTics
VOS Distribution, VCM = V+ – 0.5V (TSOT-23, NPN Stage)
18 VS = 5V, 0V 16 VCM = 4.5V PERCENT OF UNITS (%) 14 VOLTAGE OFFSET (µV) 12 10 8 6 4 2 0 –2000 –1200 –400 400 1200 INPUT OFFSET VOLTAGE (µV) 2000
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VOS vs Temperature (MS10, PNP Stage)
500 VS = 5V, 0V 400 VCM = 2.5V 6 DEVICES 300 VOLTAGE OFFSET (µV) 200 100 0 –100 –200 –300 –400 –55 –35 –15 5 25 45 65 85 105 125 TEMPERATURE (°C)
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VOS vs Temperature (MS10, NPN Stage)
2500 VS = 5V, 0V 2000 VCM = 4.5V 6 DEVICES 1500 1000 500 0 –500
–1000 –1500 –2000 –2500 –55 –35 –15 5 25 45 65 85 105 125 TEMPERATURE (°C)
624678 G06
VOS vs Temperature (MS10, PNP Stage)
1200 VS = 2.7V, 0V VCM = 1.35V 1000 6 DEVICES VOLTAGE OFFSET (µV) VOLTAGE OFFSET (µV) 800 600 400 200 0 –55 –35 –15 2500 2000 1500
VOS vs Temperature (MS10, NPN Stage)
500 400 300 OFFSET VOLTAGE (µV) 200 100 0 –100 –200 –300 –400 –500
Offset Voltage vs Input Common Mode Voltage
VS = 5V, 0V
1000 500 0 –500
–55°C 25°C
–1000
125°C
5 25 45 65 85 105 125 TEMPERATURE (°C)
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VS = 2.7V, 0V –1500 VCM = 2.2V 6 DEVICES –2000 –55 –35 –15 5 25 45 65 85 105 125 TEMPERATURE (°C)
624678 G08
0
0.5 1 1.5 2 2.5 3 3.5 4 4.5 INPUT COMMON MODE VOLTAGE (V)
5
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Offset Voltage vs Output Current
2.0 1.5 1.0 VOS (mV) 0.5 0 –0.5 –1.0 –1.5 –2.0 –100 –75 –50 –25 0 25 50 OUTPUT CURRENT (mA) 75 100 –55°C 25°C VS = ±2.5V 125°C CHANGE IN OFFSET VOLTAGE (µV) 5
Warm-Up Drift vs Time
VS = ±2.5V 0 TA = 25°C –5 –10 –15 –20 –25 –30 –35 0 20 40 60 80 100 120 140 160 TIME AFTER POWER-UP (s)
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Input Bias Current vs Common Mode Voltage
800 600 400 INPUT BIAS CURRENT (nA) 200 0 –200 –400 –600 –800 –55°C VS = 5V, 0V 25°C 125°C
–1000 –1200 –1400 –1600 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 COMMON MODE VOLTAGE (V) 5
624678 G10
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LTC6246/LTC6247/LTC6248 Typical perForMance characTerisTics
Input Bias Current vs Temperature
700 600 INPUT BIAS CURRENT (nA) 500 400 300 200 100 0 –100 –200 –55 –25 65 5 35 TEMPERATURE (°C) 95 125 VCM = 2.5V VS = 5V, 0V VOLTAGE NOISE (500nV/DIV) VCM = 4.5V 1.5 1.0 0.5 0 0.5 –1.0 –1.5 0.1 VOLTAGE NOISE (nV/√Hz) CURRENT NOISE (pA/√Hz) 100
0.1Hz to 10Hz Voltage Noise
VS = ±2.5V 1000
Input Noise Voltage and Noise Current vs Frequency
en, VCM = 4.5V en, VCM = 2.5V
10
1.0
in, VCM = 2.5V in, VCM = 4.5V
0
1
2
3
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4567 TIME (1s/DIV)
8
9
10
1
10
100
1k 10k 100k 1M FREQUENCY (Hz)
10M
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Supply Current vs Supply Voltage (Per Amplifier)
1.20 1.00 SUPPLY CURRENT (mA) 0.80 0.60 TA = –55°C 0.40 0.20 0 TA = 25°C 1.25
Supply Current Per Amplifier vs SHDN Pin Voltage
VS = 5V, 0V 0.25 125°C 25°C SHDN PIN CURRENT (µA) –55°C 0 –0.25 –0.50 –0.75 –1.00 –1.25 –1.50 –1.75 –2.00 –2.25 –2.50
SHDN Pin Current vs SHDN Pin Voltage
VS = 5V, 0V SHUTDOWN CURRENT
SUPPLY CURRENT (mA)
TA = 125°C
1.00
0.75
–55°C
0.50
0.25
25°C 125°C
0
1 3 2 4 TOTAL SUPPLY VOLTAGE (V)
5
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0
0
0.5
1
1.5 2 2.5 3 3.5 4 SHDN PIN VOLTAGE (V)
4.5
5
0
0.5
1
1.5 2 2.5 3 3.5 4 SHDN PIN VOLTAGE (V)
4.5
5
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12 10 OFFSET VOLTAGE (mV)
Minimum Supply Voltage, VCM = VS/2 (PNP Operation)
5 4 OFFSET VOLTAGE (mV) 3 2 1 0
Minimum Supply Voltage, VCM = V+ – 0.5V (NPN Operation)
OUTPUT HIGH SATURATION VOLTAGE (V) VCM = VCC – 0.5V 10
Output Saturation Voltage vs Load Current (Output High)
VS = ±2.5V
8 6 4 2 0 –2 2 2.5 3.5 3 4 4.5 5 TOTAL SUPPLY VOLTAGE (V) 5.5 –55°C
1 TA = 25°C 0.1 TA = –55°C
TA = 125°C
25°C 125°C
125°C –55°C 5.5
25°C –1 2 2.5
3.5 3 4 4.5 5 TOTAL SUPPLY VOLTAGE (V)
0.01 0.01
624678 G19
624678 G20
0.1 1 10 LOAD CURRENT (mA)
100
624678 G21
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LTC6246/LTC6247/LTC6248 Typical perForMance characTerisTics
Output Saturation Voltage vs Load Current (Output Low)
10 OUTPUT LOW SATURATION VOLTAGE (V) OUTPUT SHORT-CIRCUIT CURRENT (mA) VS = ±2.5V 120 100 80 60 40 20 0 –20 –40 –60 –80 SOURCE TA = –55°C TA = 125°C SINK
Output Short-Circuit Current vs Power Supply Voltage
TA = –55°C TA = 25°C INPUT VOLTAGE (µV) TA = 125°C 500 400 300 200 100 0 –100 –200 –300 –400 –500
Open Loop Gain
TA = 25°C VS = 5V, 0V RL = 100 TO MID SUPPLY RL = 1k TO MID SUPPLY
1 TA = 125°C 0.1 TA = 25°C
RL = 1k TO GROUND RL = 100 TO GROUND
TA = –55°C 0.01 0.01 0.1 1 10 LOAD CURRENT (mA) 100
624678 G22
TA = 25°C –100 1.25 1.45 1.65 1.85 2.05 2.25 2.45 2.65 POWER SUPPLY VOLTAGE (±V)
624678 G23
0
0.5
1
1.5 2 2.5 3 3.5 OUTPUT VOLTAGE (V)
4
4.5
5
624678 G24
Open Loop Gain
1000 900 800 700 600 500 400 300 200 100 0 –100 –200 –300 RL = 100 TO MID SUPPLY TA = 25°C VS = 2.7V, 0V 6
Gain vs Frequency (AV = 1)
12
Gain vs Frequency (AV = 2)
INPUT VOLTAGE (µV)
RL = 1k TO MID SUPPLY GAIN (dB)
0
6
RL = 1k TO GROUND
–12
GAIN (dB) VS = ±2.5V TA = 25°C RL = 1k 0.1 1 10 FREQUENCY (MHz) 100
624678 G26
–6
0
–6 VS = ±2.5V TA = 25°C RF = RG = 1k RL = 1k 0.1 1 10 FREQUENCY (MHz) 100
624678 G27
RL = 100 TO GROUND
–18
–12
0
0.5
1 1.5 2 OUTPUT VOLTAGE (V)
2.5 2.7
624678 G25
–24 0.01
–18 0.01
Open Loop Gain and Phase vs Frequency
80 TA = 25°C 70 RL = 1k 60 50 GAIN (dB) 40 30 20 10 0 –10 –20 100k 1M 10M FREQUENCY (Hz) –100 100M 300M
624678 G28
Gain Bandwidth and Phase Margin vs Supply Voltage
150 TA = 25°C RL = 1k 70 PHASE MARGIN 60 50 PHASE MARGIN (DEG)
Gain Bandwidth and Phase Margin vs Temperature
TA = 25°C RL = 1k PHASE MARGIN 300 250 200 150 100 –55 –35 –15 VS = ±1.35V 5 25 45 65 85 105 125 TEMPERATURE (°C)
624678 G30
70 60 VS = ±2.5V VS = ±1.35V 50 40 GAIN BANDWIDTH PRODUCT VS = ±2.5V
PHASE MARGIN (DEG)
PHASE GAIN VS = ±2.5V VS = ±1.35V
VS = ±2.5V
100 PHASE (DEG)
GAIN BANDWIDTH (MHz)
VS = ±1.35V
200 180 160 140 120 100 2.5
0
GAIN BANDWIDTH PRODUCT
–50
3
4 3.5 4.5 TOTAL SUPPLY VOLTAGE (V)
5
624678 G29
GAIN BANDWIDTH (MHz)
50
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0
LTC6246/LTC6247/LTC6248 Typical perForMance characTerisTics
Output Impedance vs Frequency
1000 100 OUTPUT IMPEDANCE ( ) 10 1 0.1 0.01 0.001 100k AV = 1 AV = 2 COMMON MODE REJECTION RATIO (dB) VS = ±2.5V AV = 10 110 100 90 80 70 60 50 40 30 20 10 0 –10 10 100 1k 10k 100k 1M 10M 100M 1G FREQUENCY (Hz)
624678 G31
Common Mode Rejection Ratio vs Frequency
POWER SUPPLY REJECTION RATIO (dB) TA = 25°C VS = ±2.5V 80 70 60 50 40 30 20 10 0 –10
Power Supply Rejection Ratio vs Frequency
VS = ±2.5V TA = 25°C NEGATIVE SUPPLY POSITIVE SUPPLY
1M
10M 100M FREQUENCY (Hz)
1G
624678 G31
10
100
1k
10k 100k 1M 10M 100M FREQUENCY (Hz)
624678 G33
Slew Rate vs Temperature
140 AV = –1, RL = 1k, VOUT = 4VP-P (±2.5V), 2VP-P (±1.35V) SLEW RATE MEASURED AT MIDDLE 2/3 OF OUTPUT FALLING, VS = ±2.5V OVERSHOOT (%) RISING, VS = ±2.5V FALLING, VS = ±1.35V RISING, VS = ±1.35V 80
Series Output Resistor vs Capacitive Load (AV = 1)
AV = 1 80 RS VOUT CL OVERSHOOT (%) 70 60 50 40 30 20 RS = 49.9Ω 10 100 1000 CAPACITIVE LOAD (pF) 10000
624678 G35
Series Output Resistor vs Capacitive Load (AV = 2)
500Ω
120 SLEW RATE (V/µs)
VIN RS = 10Ω RS = 20Ω RS = 49.9Ω
100
50 40 30 20 10 RS = 20Ω
80
60
40 –55 –35 –15
5 25 45 65 85 105 125 TEMPERATURE (°C)
624678 G34
0
VS = ±2.5V = 200mV V 10 ROUTR = 500P-P , F= G AV = 2 0 100 1000 10 CAPACITIVE LOAD (pF)
–40
Distortion vs Frequency (AV = 1, 5V)
VS = ±2.5V –50 VOUT = 2VP-P AV = 1 –60 DISTORTION (dBc) DISTORTION (dBc) RL = 100Ω, 3RD
–40
Distortion vs Frequency (AV = 1, 2.7V)
RL = 100Ω, 3RD
VS = ±1.35V –50 VOUT = 1VP-P AV = 1 –60
–40
Distortion vs Frequency (AV = 2, 5V)
RL = 100Ω, 3RD
VS = ±2.5V –50 VOUT = 2VP-P AV = 2 –60 DISTORTION (dBc)
–70 RL = 100Ω, 2ND –80 –90 RL = 1kΩ, 3RD RL = 1kΩ, 2ND 0.1 1 FREQUENCY (MHz) 10
624678 G37
–70 –80 –90
RL = 100Ω, 2ND
RL = 1kΩ, 2ND
–70 –80 –90
RL = 100Ω, 2ND RL = 1kΩ, 3RD
RL = 1kΩ, 3RD
–100 –110 –120 0.01
–100 –110 –120 0.01 0.1 1 FREQUENCY (MHz) 10
624678 G38
–100 –110 –120 0.01
RL = 1kΩ, 2ND
0.1 1 FREQUENCY (MHz)
+ –
+ –
VS = ±2.5V 70 VOUT = 100mVP-P AV = 1 VIN 60 RS = 10Ω
500Ω
RS AV = 2
VOUT CL
10000
624678 G36
10
624678 G39
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LTC6246/LTC6247/LTC6248 Typical perForMance characTerisTics
–40 –50
Distortion vs Frequency AV = 2, 2.7V)
RL = 100Ω, 3RD OUTPUT VOLTAGE SWING (VP-P)
Maximum Undistorted Output Signal vs Frequency
5 200
Settling Time vs Output Step (Noninverting) + –
1mV VS = ±2.5V 180 AV = 1 T = 25°C 160 A SETTLING TIME (ns) 140 120 100 80 60 40 20 10 0 –4 –3 –2 –1 0 1 2 OUTPUT STEP (V) 3 4 10mV 10mV 1mV VOUT 1k
–60 RL = 100Ω, 2ND DISTORTION (dBc) –70 –80 –90 RL = 1kΩ, 2ND RL = 1kΩ, 3RD
4
VIN
3
2
–100 VS = ±1.35V –110 VOUT = 1VP-P AV = 2 –120 0.1 1 0.01 FREQUENCY (MHz)
10
624678 G40
VS = ±2.5V TA = 25°C RL = 1kΩ 1 HD2, HD3 < –40dBc AV = 2 AV = –1 0 0.1 1 0.01 FREQUENCY (MHz)
624678 G41
624678 G42
Settling Time vs Output Step (Inverting)
200 180 160 VIN SETTLING TIME (ns) 140 120 100 80 60 40 20 0 –4 –3 –2 –1 0 1 2 OUTPUT STEP (V) 3 4 10mV 1mV 1k 1k VS = ±2.5V AV = –1 TA = 25°C VOUT 1k 0V VSHDN 2.5V/DIV 1mV 10mV VOUT 1.6V/DIV 0V
SHDN Pin Response Time
Large Signal Response
0V 25mV/DIV
+ –
0V
1V/DIV
AV = 1 VS = ±2.5V RL = 1k VIN = 1.6V
10µs/DIV
624678 G44
AV = 1 VS = ±2.5V RL = 1k
200ns/DIV
624678 G45
624678 G43
Small Signal Response
Output Overdriven Recovery
0V VIN 1V/DIV 0V VOUT 2V/DIV AV = 1 VS = ±2.5V RL = 1k 50ns/DIV
624678 G46
AV = ±2 VS = ±2.5V RL = 1k VIN = 3VP-P
100ns/DIV
624678 G47
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LTC6246/LTC6247/LTC6248 pin FuncTions
–IN: Inverting Input of Amplifier. Valid input range from V– to V+. +IN: Non-Inverting Input of Amplifier. Valid input range from V– to V+. V+ : Positive Supply Voltage. Allowed applied voltage ranges from 2.5V to 5.25V when V– = 0V. V– : Negative Supply Voltage. Typically 0V. This can be made a negative voltage as long as 2.5V ≤ (V+ – V–) ≤ 5.25V. SHDN: Active Low Shutdown. Threshold is typically 1.1V referenced to V–. Floating this pin will turn the part on. OUT: Amplifier Output. Swings rail-to-rail and can typically source/sink over 50mA of current at a total supply of 5V.
applicaTions inForMaTion
Circuit Description The LTC6246/LTC6247/LTC6248 have an input and output signal range that extends from the negative power supply to the positive power supply. Figure 1 depicts a simplified schematic of the amplifier. The input stage is comprised of two differential amplifiers, a PNP stage, Q1/Q2, and an NPN stage, Q3/Q4 that are active over different common mode input voltages. The PNP stage is active between the negative supply to nominally 1.2V below the positive supply. As the input voltage approaches the positive supply, the transistor Q5 will steer the tail current, I1, to the current mirror, Q6/Q7, activating the NPN differential pair
V+ V+ V– ESDD2 R3 R4 R5
and the PNP pair becomes inactive for the remaining input common mode range. Also, at the input stage, devices Q17 to Q19 act to cancel the bias current of the PNP input pair. When Q1/Q2 are active, the current in Q16 is controlled to be the same as the current in Q1 and Q2. Thus, the base current of Q16 is nominally equal to the base current of the input devices. The base current of Q16 is then mirrored by devices Q17 to Q19 to cancel the base current of the input devices Q1/Q2. A pair of complementary common emitter stages, Q14/Q15, enable the output to swing from rail-to-rail.
+
I2 +IN
ESDD1
+
I1
Q11
Q12
Q13
Q15 C2
D6 D5 –IN ESDD4 ESDD3
D8 D7 Q4 Q3
Q5
VBIAS CC Q1 Q2 Q10
+
V–
I3
ESDD5
OUT BUFFER AND OUTPUT BIAS Q8 C1 R1 R2 Q14
ESDD6
Q16 Q17 Q18
V–
V+
Q9
Q19
Q7
Q6
V–
624678 F01
Figure 1. LTC6246/LTC6247/LTC6248 Simplified Schematic Diagram
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LTC6246/LTC6247/LTC6248 applicaTions inForMaTion
Input Offset Voltage The offset voltage will change depending upon which input stage is active. The PNP input stage is active from the negative supply rail to approximately 1.2V below the positive supply rail, then the NPN input stage is activated for the remaining input range up to the positive supply rail with the PNP stage inactive. The offset voltage magnitude for the PNP input stage is trimmed to less than 500µV with 5V total supply at room temperature, and is typically less than 150μV. The offset voltage for the NPN input stage is typically less than 1.7mV with 5V total supply at room temperature. Input Bias Current The LTC6246 family uses a bias current cancellation circuit to compensate for the base current of the PNP input pair. When the input common mode voltage is less than 200mV, the bias cancellation circuit is no longer effective and the input bias current magnitude can reach a value above 1µA. For common mode voltages ranging from 0.2V above the negative supply to 1.2V below the positive supply, the low input bias current of the LTC6246 family allows the amplifiers to be used in applications with high source resistances where errors due to voltage drops must be minimized. Output The LTC6246 family has excellent output drive capability. The amplifiers can typically deliver over 50mA of output drive current at a total supply of 5V. The maximum output current is a function of the total supply voltage. As the supply voltage to the amplifier decreases, the output current capability also decreases. Attention must be paid to keep the junction temperature of the IC below 150°C (refer to the Power Dissipation Section) when the output is in continuous short circuit. The output of the amplifier has reverse-biased diodes connected to each supply. If the output is forced beyond either supply, extremely high current will flow through these diodes which can result in damage to the device. Forcing the output to even 1V beyond either supply could result in several hundred milliamps of current through either diode. Input Protection The input stages are protected against a large differential input voltage of 1.4V or higher by 2 pairs of back-to-back diodes to prevent the emitter-base breakdown of the input transistors. In addition, the input and shutdown pins have reverse biased diodes connected to the supplies. The current in these diodes must be limited to less than 10mA. The amplifiers should not be used as comparators or in other open loop applications. ESD The LTC6246 family has reverse-biased ESD protection diodes on all inputs and outputs as shown in Figure 1. There is an additional clamp between the positive and negative supplies that further protects the device during ESD strikes. Hot plugging of the device into a powered socket must be avoided since this can trigger the clamp resulting in larger currents flowing between the supply pins. Capacitive Loads The LTC6246/LTC6247/LTC6248 are optimized for high bandwidth and low power applications. Consequently they have not been designed to directly drive large capacitive loads. Increased capacitance at the output creates an additional pole in the open loop frequency response, worsening the phase margin. When driving capacitive loads, a resistor of 10Ω to 100Ω should be connected between the amplifier output and the capacitive load to avoid ringing or oscillation. The feedback should be taken directly from the amplifier output. Higher voltage gain configurations tend to have better capacitive drive capability than lower gain configurations due to lower closed loop bandwidth and hence higher phase margin. The graphs titled Series Output Resistor vs Capacitive Load demonstrate the transient response of the amplifier when driving capacitive loads with various series resistors.
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LTC6246/LTC6247/LTC6248 applicaTions inForMaTion
Feedback Components When feedback resistors are used to set up gain, care must be taken to ensure that the pole formed by the feedback resistors and the parasitic capacitance at the inverting input does not degrade stability. For example if the amplifier is set up in a gain of +2 configuration with gain and feedback resistors of 5k, a parasitic capacitance of 5pF (device + PC board) at the amplifier’s inverting input will cause the part to oscillate, due to a pole formed at 12.7MHz. An additional capacitor of 5pF across the feedback resistor as shown in Figure 2 will eliminate any ringing or oscillation. In general, if the resistive feedback network results in a pole whose frequency lies within the closed loop bandwidth of the amplifier, a capacitor can be added in parallel with the feedback resistor to introduce a zero whose frequency is close to the frequency of the pole, improving stability.
5pF 5k
Power Dissipation The LTC6246 and LTC6247 contain one and two amplifiers respectively. Hence the maximum on-chip power dissipation for them will be less than the maximum on-chip power dissipation for the LTC6248, which contains four amplifiers. The LTC6248 is housed in a small 16-lead MS package and typically has a thermal resistance (θJA) of 125°C/ W. It is necessary to ensure that the die’s junction temperature does not exceed 150°C. The junction temperature, TJ, is calculated from the ambient temperature, TA, power dissipation, PD, and thermal resistance, θJA: TJ = TA + (PD • θJA) The power dissipation in the IC is a function of the supply voltage, output voltage and load resistance. For a given supply voltage with output connected to ground or supply, the worst-case power dissipation PD(MAX) occurs when the supply current is maximum and the output voltage at half of either supply voltage for a given load resistance. PD(MAX) is approximately (since IS actually changes with output load current) given by: V PD(MAX) = (VS •IS(MAX) ) + S / RL 2 Example: For an LTC6248 in a 16-lead MS package operating on ±2.5V supplies and driving a 100Ω load to ground, the worst-case power dissipation is approximately given by PD(MAX)/Amp = (5 • 1.3mA) + (1.25)2/100 = 22mW If all four amplifiers are loaded simultaneously then the total power dissipation is 88mW. At the Absolute Maximum ambient operating temperature, the junction temperature under these conditions will be: TJ = TA + PD • 125°C/W = 125 + (0.088W • 125°C/W) = 136°C which is less than the absolute maximum junction temperature for the LTC6248 (150°C). Refer to the Pin Configuration section for thermal resistances of various packages.
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CPAR 5k VIN
Figure 2. 5pF Feedback Cancels Parasitic Pole
Shutdown The LTC6246 and LTC6247MS have SHDN pins that can shut down the amplifier to 42µA typical supply current. The SHDN pin needs to be taken below 0.8V above the negative supply for the amplifier to shut down. When left floating, the SHDN pin is internally pulled up to the positive supply and the amplifier remains on.
+
624678 F02
–
VOUT
2
LTC6246/LTC6247/LTC6248 Typical applicaTions
12-Bit ADC Driver Figure 3 shows the LTC6246 driving an LTC2366 12-bit A/D converter. The low wideband noise of the LTC6246 maintains a 70dB SNR even without the use of an intermediate antialiasing RC filter. On a single 3.3V supply with a 2.5V reference, a full –1dBFS output can be obtained without the amplifier transitioning between input regions, thus minimizing crossover distortion. Figure 4 shows an FFT obtained with a sampling rate of 2.2Msps and a 350kHz input waveform. Spurious free dynamic range is a quite handsome 82dB.
3.3V 2.5V 3.3V VIN
Low Noise Low Power DC-Accurate Single Supply Photodiode Amplifier Figure 5 shows the LTC6246 applied as a low power high performance transimpedance amplifier for a photodiode. A low noise JFET Q1 acts as a current buffer, with R2 and R3 imposing a low frequency gain of approximately 1. Transimpedance gain is set by feedback resistor R1 to 1MΩ. R4 and R5 set the LTC6246 inputs at 1V below the 3V rail, with C3 reducing their noise contribution. By feedback this 1V also appears across R2, setting the JFET quiescent current at 1mA completely independent of its pinchoff voltage and IDSS characteristics. It does this by placing the JFETs 1mA VGS at the gate referenced to the source, which is sitting 1V above ground. For this JFET, that will typically be about 500mV, and this voltage is imposed as a reverse voltage on the photodiode PD1. At zero IPD photocurrent, the output sits at the same voltage and rises as photocurrent increases. As mentioned before, R2 and R3 set the JFET gain to 1 at low frequency.
R1 1M, 1%
+
LTC6246 AIN 499 1% 10pF
VDD VREF LTC2366 GND
CS SDO SCK OVDD
624678 F03
–
499 1%
Figure 3. Single Supply 12-Bit ADC Driver
Q1 NXP BF862
3V R2 1k
C1 0.1pF
0 –10 –20 –30 MAGNITUDE (dB) –40 –50 –60 –70 –80 –90 –100 –110 0 200
fIN = 350.195kHz fSAMP = 2.2Msps SFDR = 82dB SNR = 70dB 1024 POINT FFT
IPD PD1 OSRAM SFH213
+ –
R3 1k C3 0.1µF R5 20k 3V LT6003
3V VOUT = VR + IPD • 1M
LTC6246
C2 6.8nF FILM OR NPO
3V R6 10M 400 600 800 FREQUENCY (kHz) 1000
624678 F04
R4 10k
+ –
R7 1k
VR C4 1µF
Figure 4. 350kHz FFT Showing 82dB SFDR
624678 F05
–3dB BW = 700kHz ICC = 2.2mA OUTPUT NOISE = 160µVRMS MEASURED ON A 1MHz BW VOUT IS REFERRED TO VR AT ZERO PHOTOCURRENT, VOUT = VR
Figure 5. Low Noise Low Power DC Accurate Single Supply Photodiode Amplifier
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LTC6246/LTC6247/LTC6248 Typical applicaTions
This is not the lowest noise configuration for a transistor, as downstream noise sources appear at the input completely unattenuated. At low frequency, this is not a concern for a transimpedance amplifier because the noise gain is 1 and the output noise is dominated by the 130nV/√Hz of the 1MΩ R1. However, at increasing frequencies the capacitance of the photodiode comes into play and the circuit noise gain rises as the 1MΩ feedback looks back into lower and lower impedance. But capacitor C2 comes to the rescue. In addition to the obvious quenching of noise source R3, capacitor C2 increases the JFET gain to about 30 at high frequency effectively attenuating the downstream noise contributions of R2 and the op amp input noise. Thus the circuit achieves low input voltage noise at high frequency where it is most needed. Amplifier LT6003 is used to buffer the output voltage of the photodiode and R7 and C4 are used to filter out the voltage noise of the LT6003. Bandwidth to 700kHz was achieved with this circuit, with integrated output noise being 160µVRMS up to 1MHz. Total supply current was a very low 2.2mA. 60dB 5.5MHz Gain Block Figure 6 shows the LTC6247 configured as a low power high gain high bandwidth block. Two amplifiers each configured with a gain of 31V/V, are cascaded in series. A 660nF capacitor is used to limit the DC gain of the block to around 30dB to minimize output offset voltage. Figure 7 shows the frequency response of the block. Mid-band voltage gain is approximately 60dB with a –3dB frequency of 5.5MHz, thus resulting in a gain-bandwidth product of 5.5GHz with only 1.9mA of quiescent supply current. Single 2.7V Supply 4MHz 4th Order Butterworth Filter Benefitting from low voltage operation and rail-to-rail output, a low power filter that is suitable for antialiasing can be built as shown in Figure 8. On a 2.7V supply the filter has a passband of approximately 4MHz with 2VP-P input signal and a stopband attenuation that is greater than –75dB at 43MHz as shown in Figure 9. The resistor and capacitor values can be scaled to reduce noise at the cost of large signal power consumption and distortion.
65 60 1.5k 50 2.5V 1k 660nF 30k 2.5V GAIN (dB) 55 50 45 40 35 VS = ±2.5V VIN = 4.5mVP-P 30 RL = 1k DC GAIN = 30dB 25 (DUE TO 660nF DC BLOCKING CAP) OUTPUT OFFSET = 4mV 20 10k 100k 1M FREQUENCY (kHz)
1/2LTC6247 VIN
–2.5V
Figure 6. 60dB 5.5MHz Gain Block
910 12pF
GAIN (dB)
1/2LTC6247
120pF
1.2V
Figure 8. Single 2.7V Supply 4MHz 4th Order Butterworth Filter
+
–
56pF
+
–
VIN
910
2.7k
2.7V 1.1k 2.3k 2.7V VOUT
624678 F08
+
–2.5V
624678 F06
–
1/2LTC6247 VOUT 1.1k 5.6pF 1/2LTC6247
+
–
10M
624678 F07
Figure 7
10 0 –10 –20 –30 –40 –50 –60 –70 –80 VS = 2.7V, 0V –90 VIN = 2VP-P RL = 1kΩ to 0V –100 10k 100k 1M 10M FREQUENCY (kHz)
100M
624678 F09
Figure 9
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LTC6246/LTC6247/LTC6248 package DescripTion
(Reference LTC DWG # 05-08-1749 Rev Ø)
1.37 0.05 0.70 0.05 2.55 0.05 0.64 0.05 1.15 0.05 2.00 0.10 R = 0.115 TYP 5 R = 0.05 TYP 1.37 0.10 8 0.40 0.10
KC Package 8-Lead Plastic UTDFN (2mm × 2mm)
2.00 0.10 PACKAGE OUTLINE 0.25 0.45 BSC 1.35 REF 0.05 0.125 REF 0.55 0.05 PIN 1 BAR TOP MARK (SEE NOTE 6)
0.64
0.10
PIN 1 NOTCH R = 0.20 OR 0.25 45 CHAMFER
(KC8) UTDFN 0107 REVØ
4
0.23 0.45 BSC 1.35 REF
1
0.05
RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED
0.00 – 0.05
BOTTOM VIEW—EXPOSED PAD
NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 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
(Reference LTC DWG # 05-08-1660 Rev F)
0.889 (.035 0.127 .005)
3.00 0.102 (.118 .004) (NOTE 3) 0.52 (.0205) REF
MS8 Package 8-Lead Plastic MSOP
8
7 65
5.23 (.206) MIN
3.20 – 3.45 (.126 – .136)
0.254 (.010)
GAUGE PLANE
DETAIL “A” 0 – 6 TYP
4.90 0.152 (.193 .006)
3.00 0.102 (.118 .004) (NOTE 4)
0.42 0.038 (.0165 .0015) TYP
0.65 (.0256) BSC
RECOMMENDED SOLDER PAD LAYOUT
0.18 (.007)
0.53 0.152 (.021 .006)
DETAIL “A”
1 1.10 (.043) MAX
23
4 0.86 (.034) REF
SEATING PLANE
0.22 – 0.38 (.009 – .015) TYP
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
0.65 (.0256) BSC
0.1016 (.004
0.0508 .002)
MSOP (MS8) 0307 REV F
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LTC6246/LTC6247/LTC6248 package DescripTion
(Reference LTC DWG # 05-08-1661 Rev E)
0.889 ± 0.127 (.035 ± .005)
MS Package 10-Lead Plastic MSOP
5.23 (.206) MIN
3.20 – 3.45 (.126 – .136)
3.00 ± 0.102 (.118 ± .004) (NOTE 3)
0.50 0.305 ± 0.038 (.0197) (.0120 ± .0015) BSC TYP RECOMMENDED SOLDER PAD LAYOUT
10 9 8 7 6
0.497 ± 0.076 (.0196 ± .003) REF
0.254 (.010)
GAUGE PLANE
DETAIL “A”
4.90 ± 0.152 (.193 ± .006)
3.00 ± 0.102 (.118 ± .004) (NOTE 4)
0° – 6° TYP 12345 0.53 ± 0.152 (.021 ± .006)
DETAIL “A”
0.18 (.007) SEATING PLANE
1.10 (.043) MAX
0.86 (.034) REF
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
0.17 – 0.27 (.007 – .011) TYP
0.50 (.0197) BSC
0.1016 ± 0.0508 (.004 ± .002)
MSOP (MS) 0307 REV E
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LTC6246/LTC6247/LTC6248 package DescripTion
(Reference LTC DWG # 05-08-1669 Rev Ø)
0.889 (.035 0.127 .005)
MS Package 16-Lead Plastic MSOP
5.23 (.206) MIN
3.20 – 3.45 (.126 – .136)
0.305 0.038 (.0120 .0015) TYP
0.50 (.0197) BSC
4.039 0.102 (.159 .004) (NOTE 3) 16151413121110 9
RECOMMENDED SOLDER PAD LAYOUT
DETAIL “A” 0 – 6 TYP
0.280 0.076 (.011 .003) REF
0.254 (.010)
GAUGE PLANE
4.90 0.152 (.193 .006)
3.00 0.102 (.118 .004) (NOTE 4)
0.53 0.152 (.021 .006)
DETAIL “A”
0.18 (.007)
SEATING PLANE
1.10 (.043) MAX
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0.86 (.034) REF
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
0.17 – 0.27 (.007 – .011) TYP
0.50 (.0197) BSC
0.1016 (.004
0.0508 .002)
MSOP (MS16) 1107 REV Ø
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0
LTC6246/LTC6247/LTC6248 package DescripTion
(Reference LTC DWG # 05-08-1636)
0.62 MAX 0.95 REF 2.90 BSC (NOTE 4)
S6 Package 6-Lead Plastic TSOT-23
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
0.95 BSC 0.80 – 0.90
0.30 – 0.45 6 PLCS (NOTE 3)
0.20 BSC DATUM ‘A’ 1.00 MAX
0.01 – 0.10
0.30 – 0.50 REF
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
0.09 – 0.20 (NOTE 3)
1.90 BSC
S6 TSOT-23 0302 REV B
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LTC6246/LTC6247/LTC6248 package DescripTion
(Reference LTC DWG # 05-08-1637)
0.52 MAX 0.65 REF 2.90 BSC (NOTE 4)
TS8 Package 8-Lead Plastic TSOT-23
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
0.65 BSC 0.80 – 0.90
0.22 – 0.36 8 PLCS (NOTE 3)
0.20 BSC DATUM ‘A’ 1.00 MAX
0.01 – 0.10
0.30 – 0.50 REF
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
0.09 – 0.20 (NOTE 3)
1.95 BSC
TS8 TSOT-23 0802
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LTC6246/LTC6247/LTC6248 revision hisTory
REV A DATE 2/10 DESCRIPTION Changes to Graph G15 PAGE NUMBER 9
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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.
LTC6246/LTC6247/LTC6248 Typical applicaTion
700kHz, 1MΩ Single Supply Photodiode Amplifier
R1 1M, 1% 3V R2 1k IPD C2 6.8nF FILM OR NPO Q1 NXP BF862 R3 1k C1 0.1pF 3V 20nV/√Hz/DIV 500mV/DIV OUTPUT WAVEFORM 0V 0 10kHz 100kHz 1MHz
624678 TA02b
Output Noise Spectrum
200 5V/DIV LED DRIVER VOLTAGE
Transient Response
+
LTC6246 VOUT ≈ 0.5V + IPD • 1M –3dB BW = 700kHz ICC = 2.2mA OUTPUT NOISE = 153µVRMS MEASURED ON A 1MHz BW
PD1 OSRAM SFH213
–
C3 0.1µF
500ns/DIV
624678 TA02c
3V
R4 10k
R5 20k
624678 TA02a
relaTeD parTs
PART NUMBER DESCRIPTION Operational Amplifiers LT1818/LT1819 Single/Dual Wide Bandwidth, High Slew Rate Low Noise and Distortion Op Amps LT6230/LT6231/ Single/Dual/Quad Low Noise Rail-to-Rail Output Op Amps LT6232 LT6202/LT6203/ Single/Dual/Quad Ultralow Noise Rail-to-Rail Op Amp LT6204 LT1468 16-Bit Accurate Precision High Speed Op Amp 400MHz, 9mA, 6nV/√Hz , 2500V/µs, 1.5mV –85dBc at 5MHz COMMENTS
LT1806/LT1807 Single/Dual Low Noise Rail-to-Rail Input and Output Op Amps 325MHz, 13mA, 3.5nV/√Hz , 140V/µs, 550µV, 85mA Output Drive 215MHz, 3.5mA, 1.1nV/√Hz , 70V/µs, 350µV
LT6200/LT6201 Single/Dual Ultralow Noise Rail-to-Rail Input/Output Op Amps 165MHz, 20mA, 0.95nV/√Hz , 44V/µs, 1mV 100MHz, 3mA, 1.9nV/√Hz , 25V/µs, 0.5mV 90MHz, 3.9mA, 5nV/√Hz , 22V/µs, 175µV, –96.5dB THD at 10VP-P, 100kHz 85MHz, 3mA, 21nV√Hz , 100V/µs, 2mV 80MHz, 2mA, 8.5nV√Hz , 25V/µs, 350µV 75MHz (–3dB), 13.5mA, 55.5nV/√Hz , 350V/µs, 20mV 75MHz, 9.5mA, 0.85nV/√Hz , 11V/µs, 40µV 60MHz, 1.2mA, 1.2nV/√Hz , 15V/µs, 0.5mV 60MHz, 1mA, 10nV/√Hz , 20V/µs, 350µV 50MHz, 7.4mA, 8nV/√Hz , 35V/µs, 100µV, Input Bias Current = 1pA 45MHz, 4.3mA, 12nV/√Hz , 45V/µs, 1.35mV 30MHz, 3.5mA, 6nV/√Hz , 10V/µs, 525µV 25MHz, 2.5mA, 8nV/√Hz , 600V/µs, 800µV, Drives All Capacitive Loads 72dB SNR, 7.8mW No Data Latency TSOT-23 Package 73dB SNR, 7.8mW No Data Latency TSOT-23 Package Single 5V or ±5V Supplies, 0V to 4.096V or ±2.048V Input Range 10mW Single 5V or ±5V Supplies, 0V to 4.096V or ±2.048V Input Range
624678fa LT 0210 REV A • PRINTED IN USA
LT1803/LT1804/ Single/Dual/Quad Low Power High Speed Rail-to-Rail Input LT1805 and Output Op Amps LT1801/LT1802 Dual/Quad Low Power High Speed Rail-to-Rail Input and Output Op Amps LT6552 LT1028 Single Supply Rail-to-Rail Output Video Difference Amplifier Ultralow Noise, Precision High Speed Op Amps
LT6233/LT6234/ Single/Dual/Quad Low Noise Rail-to-Rail Output Op Amps LT6235 LT6220/LT6221/ Single/Dual/Quad Low Power High Speed Rail-to-Rail Input LT6222 and Output Op Amps LT6244 Dual High Speed CMOS Op Amp LT1632/LT1633 Dual/Quad Rail-to-Rail Input and Output Precision Op Amps LT1630/LT1631 Dual/Quad Rail-to-Rail Input and Output Op Amps LT1358/LT1359 Dual/Quad Low Power High Speed Op Amps ADC’s LTC2366 LTC2365 LTC1417 LTC1274 3Msps, 12-Bit ADC Serial I/O 1Msps, 12-Bit ADC Serial I/O Low Power 14-Bit 400ksps ADC Parallel I/O Low Power 12-Bit 400ksps ADC Parallel I/O
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2009
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