LT1494/LT1495/LT1496 1.5µA Max, Single, Dual and Quad Over-The-Top Precision Rail-to-Rail Input and Output Op Amps U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ DESCRIPTIO Low Supply Current: 1.5µA Max Rail-to-Rail Input and Output Low Offset Voltage: 375µV Max Operating Temperature Range: – 40°C to 125°C Over-The-TopTM Inputs Operate Above V+ Wide Supply Range: 2.2V to 36V Single Supply Input Range: – 0.3V to 36V Low Input Bias Current: 250pA Low Input Offset Current: 20pA High AVOL: 100V/mV Minimum Driving 100kΩ Load Output Sources and Sinks 500µA Load Current Reverse Battery Protected to 18V The LT®1494/LT1495/LT1496 are the lowest power (IS ≤ 1.5µA) op amps with precision specifications. The extremely low supply current is combined with excellent amplifier specifications: input offset voltage is 375µV maximum with a typical drift of only 0.4µV/°C, input offset current is 100pA maximum. A minimum open-loop gain (AVOL) of 100V/mV ensures that gain errors are small. The device characteristics change little over the supply range of 2.2V to ±15V. Supply rejection is 90dB and the common mode rejection ratio is 90dB. Operation is specified for 3V, 5V and ±15V supplies. Reverse battery protection (–18V␣ min) and inputs that operate above the positive supply make the LT1494/LT1495/LT1496 easy to use in harsh environments. U APPLICATIO S ■ ■ ■ ■ The low bias currents and offset current of the amplifier permit the use of megohm level source resistors without introducing significant errors. Voltage noise at 4µVP-P is remarkably low considering the low supply current. Battery- or Solar-Powered Systems Portable Instrumentation Remote Sensor Amplifier Micropower Filter The LT1494 is available in the 8-Pin MSOP, PDIP and SO packages.The LT1495 is available in plastic 8-Pin PDIP and SO packages with the standard dual op amp pinout. The LT1496 is available in 14-Pin SO and PDIP packages. , LTC and LT are registered trademarks of Linear Technology Corporation. Over-The-Top is a trademark of Linear Technology Corporation. U TYPICAL APPLICATION Micropower Integrating Current Sense RI 1M 30 0.1µF 25 RS 0.1Ω 1M 1/2 LT1495 – + 1/2 LT1495 IL LOAD 10M 15 VO 10 + 5 10M 1495 TA01 VCC 200k OUTPUT SWITCHES WHEN ILdt = 0.98 VCC 100 AMPLIFIERS VS = ±2.5V –40°C TO 85°C 20 – UNITS VCC TC VOS Distribution RESET ( ) 0 – 2.0 –1.6 –1.2 –0.8 –0.4 0 0.4 0.8 1.2 1.6 2.0 TC VOS (µV/°C) 1495 TA02 RI C = (4.9A)(SEC) FOR VCC = 5V RS IS = 3µA DURING INTEGRATION; IS = 5µA END OF INTEGRATION 1 LT1494/LT1495/LT1496 U W W W ABSOLUTE MAXIMUM RATINGS (Note 1) Total Supply Voltage (V + to V –) .............................. 36V Differential Input Voltage ......................................... 36V Input Current ...................................................... ±10mA Output Short-Circuit Duration ....................... Continuous Operating Temperature Range (Note 2) LT1494C/LT1495C/LT1496C .............. – 40°C to 85°C LT1494I/LT1495I/LT1496I ................. – 40°C to 85°C LT1494H/LT1495H/LT1496H ........... – 40°C to 125°C Specified Temperature Range (Note 3) LT1494C/LT1495C/LT1496C .............. – 40°C to 85°C LT1494I/LT1495I/LT1496I ................. – 40°C to 85°C LT1494H/LT1495H/LT1496H ........... – 40°C to 125°C Storage Temperature Range ................. – 65°C to 150°C Junction Temperature ........................................... 150°C Lead Temperature (Soldering, 10 sec).................. 300°C U W U PACKAGE/ORDER INFORMATION ORDER PART NUMBER TOP VIEW NC –IN +IN V– 8 NC 7 V+ 6 OUT 5 NC 1 2 3 4 LT1494CMS8 LT1494IMS8 MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 250°C/ W MS8 PART MARKING LTFF LTFG NC 1 8 NC –IN 2 7 V+ +IN 3 6 OUT V– 4 5 NC N8 PACKAGE 8-LEAD PDIP S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/ W (N8) TJMAX = 150°C, θJA = 190°C/ W (S8) ORDER PART NUMBER TOP VIEW OUT A 1 8 –IN A 2 A +IN A 3 V– 4 N8 PACKAGE 8-LEAD PDIP V+ 7 OUT B 6 –IN B 5 +IN B B S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/ W (N8) TJMAX = 150°C, θJA = 190°C/ W (S8) LT1495CN8 LT1495CS8 LT1495IN8 LT1495IS8 LT1495HS8 S8 PART MARKING 1495 1495I 1495H Consult LTC Marketing for parts specified with wider operating temperature ranges. 2 ORDER PART NUMBER TOP VIEW LT1494CN8 LT1494CS8 LT1494IN8 LT1494IS8 LT1494HS8 S8 PART MARKING 1494 1494I 1494H ORDER PART NUMBER TOP VIEW OUT A 1 –IN A 2 +IN A 3 12 +IN D V+ 4 11 V – +IN B 5 –IN B 6 OUT B 7 14 OUT D A D 13 –IN D 10 +IN C B N PACKAGE 14-LEAD PDIP C 9 –IN C 8 OUT C S PACKAGE 14-LEAD PLASTIC SO TJMAX = 150°C, θJA = 130°C/ W (N) TJMAX = 150°C, θJA = 160°C/ W (S) LT1496CN LT1496CS LT1496IN LT1496IS LT1496HS LT1494/LT1495/LT1496 ELECTRICAL CHARACTERISTICS TA = 25°C, VS = 5V, 0V; VS = 3V, 0V; VCM = VO = half supply, unless otherwise noted. SYMBOL PARAMETER Input Offset Voltage VOS IB Input Bias Current IOS en in AVOL Input Offset Current Input Noise Voltage Input Noise Voltage Density Input Noise Current Density Large-Signal Voltage Gain CMRR Input Voltage Range Common Mode Rejection Ratio PSRR VOL Power Supply Rejection Ratio Minimum Operating Supply Voltage Output Voltage Swing LOW VOH Output Voltage Swing HIGH ISC IS Short-Circuit Current Supply Current per Amplifier Reverse Supply Voltage Slew Rate Gain Bandwidth Product SR GBW CONDITIONS VS = 5V VS = 3V VS = 5V, MS8 Package VS = 3V, MS8 Package (Note 5) VCM = 10V (Note 6) (Note 5) 0.1Hz to 10Hz f = 100Hz f = 100Hz VS = 5V, VO = 0.25V to 4.5V, RL = 100k VS = 3V, VO = 0.25V to 2.5V, RL = 100k VCM = 0V to 4V, VS = 5V VCM = 0V to 10V, VS = 5V VS = 2.2V to 12V, VCM = VO = 0.5V No Load ISINK = 100µA No Load ISOURCE = 100µA (Note 5) (Note 6) IS = 10µA per Amplifier AV = –1, VS = ±5V f = 100Hz MIN 100 50 0 90 74 90 V+ – 0.07 V+ – 0.32 0.7 –18 0.4 TYP 150 200 150 200 250 180 20 4 185 10 500 250 MAX 375 475 475 575 1000 360 100 36 106 95 99 2.1 50 210 V+ – 0.035 V+ – 0.160 1.3 1.0 1.0 2.7 2.2 100 410 1.5 UNITS µV µV µV µV pA nA pA µVP-P nV/√Hz fA/√Hz V/mV V/mV V dB dB dB V mV mV V V mA µA V V/ms kHz 3 LT1494/LT1495/LT1496 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C, VS = 5V, 0V; VS = 3V, 0V; VCM = VO = half supply, unless otherwise noted. (Note 3) SYMBOL PARAMETER Input Offset Voltage VOS VOS TC IB Input Offset Voltage Drift Input Bias Current IOS AVOL Input Offset Current Large-Signal Voltage Gain CMRR Input Voltage Range Common Mode Rejection Ratio PSRR VOL Power Supply Rejection Ratio Minimum Operating Supply Voltage Output Voltage Swing LOW VOH Output Voltage Swing HIGH ISC IS Short-Circuit Current Supply Current per Amplifier CONDITIONS VS = 5V VS = 3V VS = 5V, MS8 Package VS = 3V, MS8 Package (Note 4) (Note 5) VCM = 10V (Note 6) (Note 5) VS = 5V, VO = 0.25V to 4.5V, RL = 100k VS = 3V, VO = 0.25V to 2.5V, RL = 100k MIN ● ● ● ● ● ● ● ● ● ● ● VCM = 0.2V to 4V, VS = 5V VCM = 0.2V to 10V, VS = 5V VS = 2.4V to 12V, VCM = VO = 0.5V ● ● ● 75 40 0.2 89 64 89 ● No Load ISINK = 100µA No Load ISOURCE = 100µA (Note 5) (Note 6) ● ● ● ● ● V+ – 0.08 V+ – 0.36 0.6 ● TYP 175 225 175 225 0.4 250 240 20 280 150 MAX 425 525 525 625 2 1200 500 120 36 106 85 99 2.3 55 225 V+ – 0.04 V+ – 0.18 1.1 1.2 2.4 110 450 1.8 UNITS µV µV µV µV µV/°C pA nA pA V/mV V/mV V dB dB dB V mV mV V V mA µA The ● denotes the specifications which apply over the temperature range of – 40°C ≤ TA ≤ 85°C, VS = 5V, 0V; VS = 3V, 0V; VCM = VO = half supply, unless otherwise noted. (Note 3) SYMBOL PARAMETER Input Offset Voltage VOS VOS TC IB Input Offset Voltage Drift Input Bias Current IOS AVOL Input Offset Current Large-Signal Voltage Gain CMRR Input Voltage Range Common Mode Rejection Ratio PSRR VOL Power Supply Rejection Ratio Minimum Operating Supply Voltage Output Voltage Swing LOW VOH Output Voltage Swing HIGH ISC IS Short-Circuit Current Supply Current per Amplifier 4 CONDITIONS VS = 5V VS = 3V VS = 5V, MS8 Package VS = 3V, MS8 Package (Note 4) (Note 5) VCM = 10V (Note 6) (Note 5) VS = 5V, VO = 0.25V to 4.5V, RL = 100k VS = 3V, VO = 0.25V to 2.5V, RL = 100k MIN ● ● ● ● ● ● ● ● ● ● ● VCM = 0.2V to 4V, VS = 5V VCM = 0.2V to 10V, VS = 5V VS = 2.7V to 12V, VCM = VO = 0.5V ● ● ● 55 30 0.2 88 88 ● No Load ISINK = 100µA No Load ISOURCE = 100µA (Note 5) (Note 6) ● ● ● ● ● ● V+ – 0.10 V+ – 0.38 0.4 TYP 200 250 200 250 0.4 250 275 20 215 115 MAX 475 575 575 675 2 1700 170 36 106 75 99 2.6 60 245 V+ – 0.05 V+ – 0.19 0.9 1.5 2.7 120 490 2.3 UNITS µV µV µV µV µV/°C pA nA pA V/mV V/mV V dB dB dB V mV mV mV mV mA µA LT1494/LT1495/LT1496 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range of – 40°C ≤ TA ≤ 125°C. VS = 5V, 0V; VS = 3V, 0V; VCM = VO = half supply, unless otherwise noted. (Note 3) SYMBOL PARAMETER Input Offset Voltage VOS VOS TC IB Input Offset Voltage Drift Input Bias Current IOS AVOL Input Offset Current Large-Signal Voltage Gain CMRR Input Voltage Range Common Mode Rejection Ratio PSRR VOL Power Supply Rejection Ratio Minimum Operating Supply Voltage Output Voltage Swing LOW VOH Output Voltage Swing HIGH IS Supply Current per Amplifier CONDITIONS VS = 5V VS = 3V (Note 4) (Note 5) VCM = 10V (Note 6) (Note 5) VS = 5V, VO = 0.25V to 4.5V, RL = 100k VS = 3V, VO = 0.25V to 2.5V, RL = 100k ● ● ● ● ● ● ● ● ● VCM = 0.5V to 4V, VS = 5V VCM = 0.5V to 10V, VS = 5V VS = 2.7V to 12V, VCM = VO = 0.5V ● ● ● ● No Load ISINK = 100µA No Load ISOURCE = 100µA (Note 6) LT1494H/LT1495H/LT1496H TYP MAX 225 875 275 975 0.4 3 3.8 10 0.300 2 0.3 2 4 25 2 17 0.5 36 72 95 85 86 105 2.7 70 160 275 550 V+ – 140 V+ – 45 V+ – 450 V+ – 225 2 5 MIN ● ● ● ● ● UNITS µV µV µV/°C nA µA nA V/mV V/mV V dB dB dB V mV mV mV mV µA TA = 25°C, VS = ±15V, VCM = VO = 0V, unless otherwise noted. SYMBOL PARAMETER VOS Input Offset Voltage CONDITIONS MIN MS8 Package IB IOS AVOL CMRR PSRR VOL Input Bias Current Input Offset Current Large-Signal Voltage Gain Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing LOW VOH Output Voltage Swing HIGH ISC IS Short-Circuit Current Supply Current per Amplifier VO = ±10V, RL = 100k VCM = – 15V to 14V VS = ±5V to ±15V RL = 1M RL = 100k RL = 1M RL = 100k 100 – 15 100 96 14.78 14.62 0.7 TYP 200 200 25 20 360 MAX 575 675 1000 100 21 120 120 –14.85 –14.75 14.89 14.81 1.5 1.4 –14.70 –14.50 2.0 UNITS µV µV pA pA V/mV V dB dB V V V V mA µA 5 LT1494/LT1495/LT1496 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range of 0°C ≤ TA ≤ 70°C, VS = ±15V, VCM = VO = 0V, unless otherwise noted. (Note 3) SYMBOL PARAMETER VOS Input Offset Voltage CONDITIONS MS8 Package IB IOS AVOL CMRR PSRR VOL Input Bias Current Input Offset Current Large-Signal Voltage Gain Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing LOW VOH Output Voltage Swing HIGH ISC IS Short-Circuit Current Supply Current per Amplifier MIN ● ● ● ● VO = ±10V, RL = 100k ● ● VCM = –14.8V to 14V VS = ±5V to ±15V RL = 1M RL = 100k RL = 1M RL = 100k ● ● 60 – 14.8 98 94 ● ● ● ● ● 14.76 14.58 0.6 ● TYP 225 225 250 20 240 MAX 625 725 1200 120 21 120 120 –14.84 –14.73 14.88 14.79 1.3 1.6 –14.67 –14.46 2.4 UNITS µV µV pA pA V/mV V dB dB V V V V mA µA The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 85°C, VS = ±15V, VCM = VO = 0V, unless otherwise noted. (Note 3) SYMBOL PARAMETER VOS Input Offset Voltage CONDITIONS MS8 Package IB IOS AVOL CMRR PSRR VOL Input Bias Current Input Offset Current Large-Signal Voltage Gain Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing LOW VOH Output Voltage Swing HIGH ISC IS Short-Circuit Current Supply Current per Amplifier 6 MIN ● ● ● ● VO = ±10V, RL = 100k ● ● VCM = –14.8V to 14V VS = ±5V to ±15V RL = 1M RL = 100k RL = 1M RL = 100k ● ● 50 – 14.8 96 92 ● ● ● ● ● ● 14.74 14.54 0.4 TYP 250 250 250 20 200 MAX 675 775 1700 170 21 114 120 –14.83 –14.72 14.87 14.77 1.1 2.0 –14.66 –14.44 3.0 UNITS µV µV pA pA V/mV V dB dB V V V V mA µA LT1494/LT1495/LT1496 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the temperature range of –40°C ≤ TA ≤ 125°C. VS = ±15V, VCM = VO = half supply, unless otherwise noted. (Note 3) SYMBOL VOS IB IOS AVOL CMRR PSRR VOL PARAMETER Input Offset Voltage Input Bias Current Input Offset Current Large-Signal Voltage Gain Input Voltage Range Common Mode Rejection Ratio Power Supply Rejection Ratio Output Voltage Swing LOW VOH Output Voltage Swing HIGH IS Supply Current per Amplifier LT1494H/LT1495H/LT1496H TYP MAX 275 1100 3.8 10 0.3 2 21 70 –14.5 21 69 90 89 115 –14.80 –14.4 –14.69 –14.2 14.5 14.85 14.3 14.73 3 6 CONDITIONS MIN ● ● ● VO = ±10V, RL = 100k ● ● VCM = –14.5V to 14V VS = ±5V to ±15V RL = 1M RL = 100k RL = 1M RL = 100k ● ● ● ● ● ● ● UNITS µV nA nA V/mV V dB dB V V V V µA –40°C to 85°C but are not tested or QA sampled at these temperatures. The LT1494I/LT1495I/LT1496I are guaranteed to meet specified performance from –40°C to 85°C. The LT1494H/LT1495H/LT1496H are guaranteed to meet specified performance from –40°C to 125°C. Note 4: This parameter is not 100% tested. Note 5: VS = 5V limits are guaranteed by correlation to VS = 3V and VS = ±15V tests. Note 6: VS = 3V limits are guaranteed by correlation to VS = 5V and VS = ±15V tests. Note 1: Absolute Maximum Ratings are those values beyond which the life of the device may be impaired. Note 2: The LT1494C/LT1495C/LT1496C and LT1494I/LT1495I/LT1496I are guaranteed functional over the operating temperature range of – 40°C to 85°C. The LT1494H/LT1495H/LT1496H are guaranteed functional over the operating temperature range of –40°C to 125°C. Note 3: The LT1494C/LT1495C/LT1496C are guaranteed to meet specified performance from 0°C to 70°C. The LT1494C/LT1495C/LT1496C are designed, characterized and expected to meet specified performance from U W TYPICAL PERFORMANCE CHARACTERISTICS Distribution of Input Offset Voltage PERCENT OF UNITS (%) 16 VS = 5V, 0V LT1494/LT1495/ LT1496 5700 OP AMPS 14 12 10 8 6 4 2 0 –400 –300 –200 –100 0 100 200 300 400 INPUT OFFSET VOLTAGE (µV) 1495 G01 Minimum Supply Voltage 200 CHANGE IN OFFSET VOLTAGE (µV) 18 Supply Current vs Temperature 2.5 SUPPLY CURRENT PER AMPLIFIER (µA) 20 2.0 1.5 VS = ±15V 1.0 VS = ±2.5V 0.5 0 – 40 – 20 150 TA = 25°C TA = – 40°C 100 TA = 85°C 50 0 – 50 40 20 0 60 TEMPERATURE (°C) 80 100 1495 G02 1 3 2 4 TOTAL SUPPLY VOLTAGE (V) 5 1495 G03 7 LT1494/LT1495/LT1496 U W TYPICAL PERFORMANCE CHARACTERISTICS Output Saturation Voltage vs Load Current (Output Low) TA = 85°C 100 TA = 25°C TA = – 40°C 10 0.1 1 10 100 LOAD CURRENT (µA) 100 TA = 85°C TA = 25°C TA = – 40°C 10 0.1 1000 300 VS = 5V, 0V 1 10 100 LOAD CURRENT (µA) 1495 G04 80 PHASE 20 60 10 40 GAIN 0 20 –10 0 – 20 – 20 – 30 1 FREQUENCY (kHz) 200 150 100 50 TA = – 40°C –1 0 10 FREQUENCY (Hz) 40 20 1 40 1.5 30 1.0 20 0.5 10 30 1495 G11 VS = ± 2.5V 70 60 AV = 1 50 40 30 AV = 5 20 AV = 10 10 0 0 25 100 Capacitive Load Handling OVERSHOOT (%) 2.0 PHASE MARGIN (DEG) 50 0 10 FREQUENCY (Hz) 1495 G09 80 OUTPUT VOLTAGE (2µV/DIV) 60 20 15 10 SUPPLY VOLTAGE (V) 60 100 VS = ±15V VCM = 0V GBW 9 10 VS = ± 2.5V 1495 G08 PHASE MARGIN 2.5 1 2 3 4 5 6 7 8 COMMON MODE VOLTAGE (V) 0 1 70 3.0 TA = 85°C 80 0.1Hz to 10Hz Output Voltage Noise 3.5 FREQUENCY (kHz) TA = 25°C 0.5 0 10 Gain Bandwidth and Phase Margin vs Supply Voltage 8 1.5 Noise Current Spectrum VS = ± 2.5V 1495 G10 5 TA = – 40°C 100 250 – 40 0 100 1495 G06 CURRENT NOISE (fA/√Hz) 30 NOISE VOLTAGE (nV/√Hz) 100 PHASE SHIFT (DEG) VOLTAGE GAIN (dB) 40 0.1 TA = 25°C Noise Voltage Spectrum 300 120 VS = ± 2.5V TA = 85°C 200 – 0.5 1000 VS = 5V, 0V 1495 G05 Gain and Phase Shift vs Frequency 50 INPUT BIAS CURRENT (nA) 1000 VS = 5V, 0V SATURATION VOLTAGE (mV) SATURATION VOLTAGE (mV) 1000 Input Bias Current vs Common Mode Voltage Output Saturation Voltage vs Load Current (Output High) 10 TIME (1s/DIV) 1495 G07 100 1000 10000 CAPACITIVE LOAD (pF) 100000 1495 G12 LT1494/LT1495/LT1496 U W TYPICAL PERFORMANCE CHARACTERISTICS VS = ± 2.5V 90 80 70 60 50 40 30 20 10 0 0.01 0.1 1 FREQUENCY (kHz) 100 POWER SUPPLY REJECTION RATIO (dB) COMMON MODE REJECTION RATIO (dB) 100 Power Supply Rejection Ratio vs Frequency POSITIVE SUPPLY 80 70 60 50 NEGATIVE SUPPLY 40 30 20 0.1 1 FREQUENCY (kHz) 20 OFFSET VOLTAGE CHANGE (µV) OFFSET VOLTAGE CHANGE (µV) 30 VS = ±2.5V –10 –20 –30 – 40 80 10 5 RL = 1M 0 RL = 100k –5 –10 VS = ±15V RL = 1M CL = 100pF 0 1 2 4 3 OUTPUT VOLTAGE (V) 5 6 40 RL = 100k 20 0 RL = 1M –20 – 40 – 80 –20 –15 –10 –5 0 5 10 OUTPUT VOLTAGE (V) 1495 G17 Small-Signal Response VS = 5V, 0V 1495 G19 VS = ± 15V 60 – 60 1495 G16 Small-Signal Response VS = ±15V 10 1495 G15 VS = 5V, 0V 15 – 20 20 40 60 80 100 120 140 160 180 200 TIME AFTER POWER-UP (SEC) 0.1 1 FREQUENCY (kHz) Open-Loop Gain VS = ±15V –15 0 0.1 0.01 10 OFFSET VOLTAGE CHANGE (µV) 40 10 AV = 1 1 Open-Loop Gain VS = 5V, 0V VS = ±15V AV = 10 10 1495 G14 Warm-Up Drift vs Time 0 100 10 1495 G13 20 1000 VS = ± 2.5V 90 0 0.01 10 Output Impedance vs Frequency OUTPUT IMPEDANCE (kΩ) Common Mode Rejection Ratio vs Frequency VS = 5V, 0V RL = 1M CL = 100pF 15 20 1495 G18 Large-Signal Response VS = 5V, 0V 1495 G20 VS = 5V, 0V RL = 1M CL = 100pF 1495 G21 9 LT1494/LT1495/LT1496 U W U U APPLICATIONS INFORMATION Start-Up Characteristics Reverse Battery Micropower op amps are sometimes not micropower during start-up, wreaking havoc on low current supplies. In the worst case, there may not be enough supply current available to take the system up to nominal voltages. Figure 1 is a graph of LT1495 supply current vs supply voltage for the three limit cases of input offset that could occur during start-up. The circuits are shown in Figure 2. One circuit creates a positive offset, forcing the output to come up saturated high. Another circuit creates a negative offset, forcing the output to come up saturated low, while the last brings up the output at half supply. In all cases, the supply current is well behaved. Supply current is highest with the output forced high, so if one amplifier is unused, it is best to force the output low or at half supply. The LT1494/LT1495/LT1496 are protected against reverse battery voltages up to 18V. In the event a reverse battery condition occurs, the supply current is typically less than 100nA (inputs grounded and outputs open). For typical single supply applications with ground referred loads and feedback networks, no other precautions are required. If the reverse battery condition results in a negative voltage at either the input pins or output pin, the current into the pin should be limited by an external resistor to less than 10mA. SUPPLY CURRENT PER AMPLIFIER (µA) 5 4 OUTPUT HIGH 3 2 Inputs While the LT1494/LT1495/LT1496 will function normally with its inputs taken above the positive supply, the common mode range does not extend beyond approximately 300mV below the negative supply at room temperature. The device will not be damaged if the inputs are taken lower than 300mV below the negative supply as long as the current out of the pin is limited to less than 10mA. However, the output phase is not guaranteed and the supply current will increase. OUTPUT LOW Output 1 OUTPUT VS /2 The graph, Capacitive Load Handling, shows amplifier stability with the output biased at half supply. If the output is to be operated within about 100mV of the positive rail, the allowable load capacitance is less. With this output voltage, the worst case occurs at AV = 1 and light loads, where the load capacitance should be less than 500pF with a 5V supply and less than 100pF with a 30V supply. 0 0 1 2 3 4 SUPPLY VOLTAGE (V) 5 1495 F01 Figure 1. Start-Up Characteristics VS VS VS Rail-to-Rail Operation + + – – VS /2 + – 1495 F02 OUTPUT HIGH OUTPUT LOW OUTPUT AT VS /2 Figure 2. Circuits for Start-Up Characteristics 10 The simplified schematic, Figure 3, details the circuit design approach of the LT1494/LT1495/LT1496. The amplifier topology is a three-stage design consisting of a rail-to-rail input stage, that continues to operate with the inputs above the positive rail, a folded cascode second stage that develops most of the voltage gain, and a rail-torail common emitter stage that provides the current gain. LT1494/LT1495/LT1496 U U W U APPLICATIONS INFORMATION V+ D1 D2 D3 Q10 D7 Q13 Q14 Q15 Q20 + I1 IN IN – Q1 Q2 Q3 Q4 Q7 Q5 0.5 Q6 0.5 0.5 0.5 (V +) – 0.8V Q16 OUT Q19 Q17 Q11 Q21 + C1 + D4 Q12 D5 D6 Q18 Q22 + Q9 R1 Q8 R2 I2 1495 F03 Figure 3. Simplified Schematic The input stage is formed by two diff amps Q1-Q2 and Q3Q6. For signals with a common mode voltage between VEE and (VCC – 0.8V), Q1 and Q2 are active. When the input common mode exceeds (VCC – 0.8V), Q7 turns on, diverting the current from diff amp Q1-Q2 to current mirror Q8-Q9. The current from Q8 biases on the other diff amp consisting of PNP’s Q5-Q6 and NPN’s Q3-Q4. Though Q5-Q6 are driven from the emitters rather than the base, the basic diff amp action is the same. When the common mode voltage is between (VCC – 0.8V) and VCC, devices Q3 and Q4 act as followers, forming a buffer between the amplifier inputs and the emitters of the Q5-Q6. If the common mode voltage is taken above VCC, Schottky diodes D1 and D2 reverse bias and devices Q3 and Q4 then act as diodes. The diff amp formed by Q5-Q6 operates normally, however, the input bias current increases to the emitter current of Q5-Q6, which is typically 180nA. The graph, Input Bias Current vs Common Mode Voltage found in the Typical Performance Characteristics section, shows these transitions at three temperatures. The collector currents of the two-input pairs are combined in the second stage consisting of Q11 to Q16, which furnishes most of the voltage gain. Capacitor C1 sets the amplifier bandwidth. The output stage is configured for maximum swing by the use of common emitter output devices Q21 and Q22. Diodes D4 to D6 and current source Q15 set the output quiescent current. 11 LT1494/LT1495/LT1496 U TYPICAL APPLICATIONS N 13µA, 0kHz to 10kHz Voltage to Frequency Converter 270k 10M* 3.9M* 5V – 390Ω 562k* 1µF – 0.0082µF + VIN 0V TO 2.5V 1/2 LT1495 + 100k 3.9M 20M 5V LTC®1440 + 1.2 REFERENCE LTC1440 12pF 1N5712 3.6M TYP SELECT FOR 100Hz AT VIN = 0.025V 1N4148 360k 39k 15k 10M 100pF† OUTPUT 0kHz TO 10kHz Q1 0.05µF – Q1: ZTX-849 *1% METAL FILM † POLYSTYRENE 1/2 LT1495 0V – 2.5V = 0kHz – 10kHz SUPPLY CURRENT = 6.2µA QUIESCENT = 13.3µA AT f = 10kHz LINEARITY: ± 0.03% PSRR (4.4V TO 36V): 10ppm/V TEMPERATURE DRIFT: 250ppm/°C + 1495 TA07 6µA, AV = 1000, Chopper Stabilized Amplifier 0.2µF 1µF φ1 5V + INPUT 1µF φ2 1/2 LT1495 1M – φ2 1M – 1/2 LT1495 10M φ1 – 5V OUTPUT + 10k 10M 10k 10M φ1 – 0.047µF – 1/2 LTC1441 + 1/2 10M 10M 12 5V +LTC1441 – 5V φ2 GAIN: 1000 OFFSET: 1µV DRIFT: 50nV/°C SUPPLY CURRENT: 5.5µA BANDWIDTH: 0.2Hz CLOCK RATE: 4Hz CD4016 QUAD 1495 TA08 LT1494/LT1495/LT1496 U TYPICAL APPLICATIONS N Filter Frequency Response 6th Order 10Hz Elliptic Lowpass Filter 10k 100k 15nF 215k 215k 30nF 100nF –10 + –20 1/2 LT1495 215k 100nF GAIN (dB) e in 15nF 0 – 200k –30 –40 10nF 100k VS = 5V, 0V IS = 2µA + ein /150k ZEROS AT 50Hz AND 60Hz –50 –60 15nF 15nF 169k 169k 1 10k 80.6k 10 100 FREQUENCY (Hz) 100nF 1000 LT1495/96 • TA04 + 169k 100nF OUTPUT 1/2 LT1495 – 30nF 200k 10nF 100k 1495 TA03 U PACKAGE DESCRIPTION MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660) 0.118 ± 0.004* (3.00 ± 0.102) 8 7 6 5 0.118 ± 0.004** (3.00 ± 0.102) 0.193 ± 0.006 (4.90 ± 0.15) 1 2 3 4 0.043 (1.10) MAX 0.007 (0.18) 0.034 (0.86) REF 0° – 6° TYP 0.021 ± 0.006 (0.53 ± 0.015) SEATING PLANE 0.009 – 0.015 (0.22 – 0.38) 0.0256 (0.65) BSC 0.005 ± 0.002 (0.13 ± 0.05) MSOP (MS8) 1100 * DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE ** DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE 13 LT1494/LT1495/LT1496 U PACKAGE DESCRIPTION N8 Package 8-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) 0.400* (10.160) MAX 8 7 6 5 1 2 3 4 0.255 ± 0.015* (6.477 ± 0.381) 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( 0.130 ± 0.005 (3.302 ± 0.127) 0.045 – 0.065 (1.143 – 1.651) 0.065 (1.651) TYP +0.035 0.325 –0.015 +0.889 8.255 –0.381 ) 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 ± 0.003 0.100 (2.54) BSC (0.457 ± 0.076) N8 1098 *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) S8 Package 8-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) 0.189 – 0.197* (4.801 – 5.004) 8 7 6 5 0.150 – 0.157** (3.810 – 3.988) 0.228 – 0.244 (5.791 – 6.197) SO8 1298 1 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 0.053 – 0.069 (1.346 – 1.752) 0°– 8° TYP 0.016 – 0.050 (0.406 – 1.270) 0.014 – 0.019 (0.355 – 0.483) TYP *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 14 2 3 4 0.004 – 0.010 (0.101 – 0.254) 0.050 (1.270) BSC LT1494/LT1495/LT1496 U PACKAGE DESCRIPTION N Package 14-Lead PDIP (Narrow .300 Inch) (Reference LTC DWG # 05-08-1510) 0.770* (19.558) MAX 14 13 12 11 10 9 8 1 2 3 4 5 6 7 0.255 ± 0.015* (6.477 ± 0.381) 0.130 ± 0.005 (3.302 ± 0.127) 0.300 – 0.325 (7.620 – 8.255) 0.045 – 0.065 (1.143 – 1.651) 0.020 (0.508) MIN 0.065 (1.651) TYP 0.009 – 0.015 (0.229 – 0.381) +0.035 0.325 –0.015 0.005 (0.125) MIN 0.100 (2.54) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. BSC MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) ( +0.889 8.255 –0.381 ) 0.018 ± 0.003 (0.457 ± 0.076) 0.125 (3.175) MIN N14 1098 S Package 14-Lead Plastic Small Outline (Narrow .150 Inch) (Reference LTC DWG # 05-08-1610) 0.337 – 0.344* (8.560 – 8.738) 14 13 12 11 10 9 8 0.228 – 0.244 (5.791 – 6.197) 0.150 – 0.157** (3.810 – 3.988) 1 0.010 – 0.020 × 45° (0.254 – 0.508) 0.008 – 0.010 (0.203 – 0.254) 2 3 4 5 6 0.053 – 0.069 (1.346 – 1.752) 0.004 – 0.010 (0.101 – 0.254) 0° – 8° TYP 0.016 – 0.050 (0.406 – 1.270) 0.014 – 0.019 (0.355 – 0.483) TYP 7 0.050 (1.270) BSC *DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 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. S14 1298 15 LT1494/LT1495/LT1496 U TYPICAL APPLICATIONS N 0nA to 200nA Current Meter Battery Current Monitor IL CHARGE 100pF RSENSE 0.1Ω DISCHARGE – A2 1/2 LT1495 RA RA RA R4 10k – A1 1/2 LT1495 RA + DISCHARGE OUT 1.5V 1/2 LT1495 R3 2k FULL-SCALE ADJUST ( ) RB 1/2 LT1495 + R2 9k + R VO = IL B RSENSE RA CHARGE OUT RB – – INPUT CURRENT + 2N3904 2N3904 R1 10M 12V 5V FOR RA = 1k, RB = 10k VO = 1V/A IL 1495 TA05 µA 1.5V IS = 3µA WHEN IIN = 0 NO ON/OFF SWITCH REQUIRED 0µA TO 200µA 1495 TA06 High Side Current Sense VS = 2.7V TO 36V RA 1k VO = IL – RSENSE 1Ω FOR RA = 1k, RB = 10k, RS = 1Ω VO = 10 V/A IL LT1494 + + LOAD IL ( RRBA )RS RB 10k OUTPUT OFFSET ≈ IS • RB ≈ 10mV OUTPUT CLIPS AT VS – 2.4V VO _ 1495 TA09 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC 1440/41/42 Micropower Single/Dual Comparators with 1% Reference LTC1440: Single, LTC1441/42: Dual LTC1443/44/45 Micropower Quad Comparators with 1% Reference LTC1443: 1.182 Reference LTC1444/45: 1.221V Reference and Adjustable Hysteresis LT1466/LT1467 75µA Dual/Quad Rail-to-Rail Input and Output Op Amps 390µV VOS(MAX), Gain Bandwidth = 120kHz LT1490A/LT1491A 50µA Dual/Quad Rail-to-Rail Input and Output Op Amps 950µV VOS(MAX), Gain Bandwidth = 200kHz LTC1540 Nanopower Single Comparator with 1% Reference 350nA Supply Current LT1636 Single Over-The-Top Micropower, Rail-to-Rail Input and Output Op Amp 225µV VOS(MAX), IS = 55µA (MAX), Gain-Bandwidth = 200kHz Shutdown Pin, MSOP LT1672/LT1673/LT1674 2µA MAX, A V ≥ 5 Single/Dual/Quad Over-The-Top Precision Rail-to-Rail Input and Output Op Amps Decompensated Version of the LT1494/LT1495/LT1496 AV ≥ 5, Gain-Bandwidth = 12kHz LT2078/LT2079 55µA Dual/Quad Single Supply Op Amps 120µV VOS(MAX), Gain Bandwidth = 200kHz LT2178/LT2179 17µA Dual/Quad Single Supply Op Amps 120µV VOS(MAX), Gain Bandwidth = 60kHz LT1782 Micropower, Over-The-Top, SOT-23, Rail-to-Rail Input and Output Op Amp SOT-23, 800µV VOS(MAX) , IS = 55µA (Max), Gain-Bandwidth = 200kHz, Shutdown Pin LT1783 1.2MHz, Over-The-Top, Micropower, Rail-to-Rail Input and Output Op Amp in SOT-23 SOT-23, 800µV VOS(MAX) , IS = 300µA (Max), Gain-Bandwidth = 1.2MHz, Shutdown Pin ® 16 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417● (408) 432-1900 FAX: (408) 434-0507 ● TELEX: 499-3977 ● www.linear.com 149456fb LT/TP 0801 1.5K REV B • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 1997