LT1793ACN8

LT1793 Low Noise, Picoampere Bias Current, JFET Input Op Amp FEATURES s s s s s s s s s DESCRIPTIO Input Bias Current, Warmed Up: 10pA Max 100% Tested Low Voltage Noise: 8nV/√Hz Max A Grade 100% Temperature Tested Offset Voltage Over Temp: 1mV Max Input Resistance: 1013Ω Very Low Input Capacitance: 1.5pF Voltage Gain: 1 Million Min Gain-Bandwidth Product: 4.2MHz Typ Guaranteed Specifications with ± 5V Supplies APPLICATIO S s s s s s s Photocurrent Amplifiers Hydrophone Amplifiers High Sensitivity Piezoelectric Accelerometers Low Voltage and Current Noise Instrumentation Amplifier Front Ends Two and Three Op Amp Instrumentation Amplifiers Active Filters , LTC and LT are registered trademarks of Linear Technology Corporation. The LT®1793 achieves a new standard of excellence in noise performance for a JFET op amp. For the first time low voltage noise (6nV/√Hz) is simultaneously offered with extremely low current noise (0.8fA/√Hz), providing the lowest total noise for high impedance transducer applications. Unlike most JFET op amps, the very low input bias current (3pA typ) is maintained over the entire common mode range which results in an extremely high input resistance (1013Ω). When combined with a very low input capacitance (1.5pF) an extremely high input impedance results, making the LT1793 the first choice for amplifying low level signals from high impedance transducers. The low input capacitance also assures high gain linearity when buffering AC signals from high impedance transducers. The LT1793 is unconditionally stable for gains of 1 or more, even with 1000pF capacitive loads. Other key features are 250µV VOS and a voltage gain over 4 million. Each individual amplifier is 100% tested for voltage noise, slew rate (3.4V/µs) and gain-bandwidth product (4.2MHz). Specifications at ± 5V supply operation are also provided. For an even lower voltage noise please see the LT1792 data sheet. TYPICAL APPLICATIO Low Noise Light Sensor with DC Servo C1 2pF TOTAL 1kHz VOLTAGE NOISE DENSITY (nV/√Hz) 10k V+ R3 1k LT1097 2N3904 HAMAMATSU S1336-5BK (908) 231-0960 V– R5 10k R4 1k 1793 TA01 V– R2C2 > C1R1 CD = PARASITIC PHOTODIODE CAPACITANCE VOUT = 100mV/µWATT FOR 200nm WAVE LENGTH 330mV/µWATT FOR 633nm WAVE LENGTH – CD D1 1N914 + + D2 1N914 3 – 2 7 LT1793 4 V– V+ 6 R1 1M VOUT 1k C2 0.022µF 100 R2 100k 10 1 100 U 1kHz Output Voltage Noise Density vs Source Resistance – + RSOURCE VN U U VN SOURCE RESISTANCE ONLY 1k TA = 25°C VS = ±15V 10k 100k 1M 10M 100M 1G SOURCE RESISTANCE (Ω) VN = √(VOP AMP)2 + 4kTRS + 2qIBRS2 1793 TA02 1 LT1793 ABSOLUTE AXI U RATI GS Supply Voltage ..................................................... ± 20V Differential Input Voltage ...................................... ± 40V Input Voltage (Equal to Supply Voltage) ............... ± 20V Output Short-Circuit Duration ........................ Indefinite Operating Temperature Range ............... – 40°C to 85°C PACKAGE/ORDER I FOR ATIO TOP VIEW VOS ADJ 1 – IN A 2 + IN A 3 V – ORDER PART NUMBER 8 NC 7V + A 6 OUT 5 VOS ADJ N8 PACKAGE 8-LEAD PDIP 4 LT1793ACN8 LT1793CN8 LT1793AIN8 LT1793IN8 TJMAX = 150°C, θJA = 80°C/W Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS SYMBOL VOS IOS IB en PARAMETER Input Offset Voltage VS = ± 5V Input Offset Current Input Bias Current Input Noise Voltage Input Noise Voltage Density in RIN Input Noise Current Density Input Resistance Differential Mode Common Mode Input Capacitance VS = ± 5V Input Voltage Range (Note 5) Common Mode Rejection Ratio Power Supply Rejection Ratio VCM = – 10V to 13V TA = 25°C, VS = ±15V, VCM = 0V, unless otherwise noted. LT1793AC/LT1793AI MIN TYP MAX 0.25 0.45 1.5 0.5 3 1 2.4 11.5 6 0.8 1014 1013 1.5 2.0 13.0 – 10.5 83 85 13.5 – 11.0 102 98 13.0 – 10.5 81 83 8 0.8 1.4 7 2 10 3 LT1793C/LT1793I MIN TYP MAX 0.25 0.45 2.5 0.7 4.0 1.5 2.4 11.5 6 1 1014 1013 1.5 2.0 13.5 – 11.0 96 95 8 0.9 1.6 15 4 20 5 UNITS mV mV pA pA pA pA µVP-P nV/√Hz nV/√Hz fA/√Hz Ω Ω pF pF V V dB dB CONDITIONS (Note 2) Warmed Up (Note 3) TJ = 25°C (Note 6) Warmed Up (Note 3) TJ = 25°C (Note 6) 0.1Hz to 10Hz fO = 10Hz fO = 1000Hz fO = 10Hz, fO = 1kHz (Note 4) VCM = – 10V to 13V CIN VCM CMRR PSRR VS = ± 4.5V to ± 20V 2 U U W WW U W (Note 1) Specified Temperature Range Commercial (Note 8) ......................... – 40°C to 85°C Industrial ........................................... – 40°C to 85°C Storage Temperature Range ................ – 65°C to 150°C Lead Temperature (Soldering, 10 sec) ................ 300°C TOP VIEW VOS ADJ 1 –IN A 2 +IN A 3 V– 4 A ORDER PART NUMBER 8 NC 7 V+ 6 OUT 5 VOS ADJ LT1793ACS8 LT1793CS8 LT1793AIS8 LT1793IS8 S8 PART MARKING 1793A 1793 1793AI 1793I S8 PACKAGE 8-LEAD PLASTIC SO TJMAX = 160°C, θJA = 190°C/W LT1793 ELECTRICAL CHARACTERISTICS SYMBOL AVOL VOUT SR GBW IS PARAMETER Large-Signal Voltage Gain Output Voltage Swing Slew Rate Gain-Bandwidth Product Supply Current VS = ± 5V Offset Voltage Adjustment Range TA = 25°C, VS = ±15V, VCM = 0V, unless otherwise noted. LT1793AC/LT1793AI MIN TYP MAX 1000 500 ± 13.0 ± 12.0 2.3 2.5 4500 3500 ± 13.2 ± 12.3 3.4 4.2 4.2 4.2 13 5.20 5.15 LT1793C/LT1793I MIN TYP MAX 900 400 ± 13.0 ± 12.0 2.3 2.5 4400 3000 ± 13.2 ± 12.3 3.4 4.2 4.2 4.2 13 5.20 5.15 UNITS V/mV V/mV V V V/µs MHz mA mA mV CONDITIONS (Note 2) VO = ± 12V, RL = 10k VO = ± 10V, RL = 1k RL = 10k RL = 1k RL ≥ 2k (Note 7) fO = 100kHz RPOT (to VEE) = 10k The q denotes specifications which apply over the temperature range 0°C ≤ TA ≤ 70°C, otherwise specifications are at TA = 25°C. VS = ±15V, VCM = 0V, unless otherwise noted. (Note 9) SYMBOL VOS ∆VOS ∆Temp IOS IB VCM CMRR PSRR AVOL VOUT SR GBW IS PARAMETER Input Offset Voltage VS = ± 5V Average Input Offset Voltage Drift Input Offset Current Input Bias Current Input Voltage Range (Note 5) Common Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain Output Voltage Swing Slew Rate Gain-Bandwidth Product Supply Current VS = ± 5V VCM = – 10V to 12.9V VS = ± 4.5V to ± 20V VO = ± 12V, RL = 10k VO = ± 10V, RL = 1k RL = 10k R L = 1k RL ≥ 2k (Note 7) fO = 100kHz (Note 6) CONDITIONS (Note 2) q q q q q q q q q q q q q q q q q MIN LT1793AC TYP MAX 0.50 0.75 5 15 130 1.0 1.6 13 100 400 MIN LT1793C TYP MAX 1.0 1.6 8 20 150 3.5 4.2 50 130 500 UNITS mV mV µV/°C pA pA V V dB dB V/mV V/mV V V V/µs MHz 12.9 – 10.0 79 83 900 500 13.4 – 10.8 100 97 3600 2600 12.9 – 10.0 77 81 800 400 13.4 – 10.8 95 94 3400 2400 ± 12.9 ± 13.2 ± 11.9 ± 12.15 2.2 2.2 3.3 3.3 4.2 4.2 5.30 5.25 ± 12.9 ± 13.2 ± 11.9 ± 12.15 2.2 2.2 3.3 3.3 4.2 4.2 5.30 5.25 mA mA 3 LT1793 The q denotes specifications which apply over the temperature range – 40°C ≤ TA ≤ 85°C. VS = ±15V, VCM = 0V, unless otherwise noted. (Notes 8, 9) SYMBOL VOS ∆VOS ∆Temp IOS IB VCM CMRR PSRR AVOL VOUT SR GBW IS PARAMETER Input Offset Voltage VS = ± 5V Average Input Offset Voltage Drift Input Offset Current Input Bias Current Input Voltage Range (Note 5) Common Mode Rejection Ratio Power Supply Rejection Ratio Large-Signal Voltage Gain Output Voltage Swing Slew Rate Gain-Bandwidth Product Supply Current VS = ± 5V VCM = – 10V to 12.6V VS = ± 4.5V to ± 20V VO = ± 12V, RL = 10k VO = ± 10V, RL = 1k RL = 10k RL = 1k RL ≥ 2 k fO = 100kHz (Note 6) CONDITIONS (Note 2) q q q q q q q q q q q q q q q q q ELECTRICAL CHARACTERISTICS LT1793AC/LT1793AI MIN TYP MAX 0.65 1.00 5 80 700 12.6 – 10.0 78 81 850 400 ± 12.8 ± 11.8 2.1 2 13.0 – 10.5 99 96 3300 2200 ± 13.1 ± 12.1 3.2 3.1 4.2 4.2 5.40 5.35 1.3 1.9 13 300 2400 LT1793C/LT1793I MIN TYP MAX 1.6 2.0 9 100 800 12.6 – 10.0 76 79 750 300 ± 12.8 ± 11.8 2.1 2 13.0 – 10.5 94 93 3000 2000 ± 13.1 ± 12.1 3.2 3.1 4.2 4.2 5.40 5.35 4.8 5.5 50 400 3000 UNITS mV mV µV/°C pA pA V V dB dB V/mV V/mV V V V/µs MHz mA mA Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: Typical parameters are defined as the 60% yield of parameter distributions of individual amplifiers. Note 3: IB and IOS readings are extrapolated to a warmed-up temperature from 25°C measurements and 32°C characterization data. Note 4: Current noise is calculated from the formula: in = (2qIB)1/2 where q = 1.6 • 10 –19 coulomb. The noise of source resistors up to 200M swamps the contribution of current noise. Note 5: Input voltage range functionality is assured by testing offset voltage at the input voltage range limits to a maximum of 2.3mV (A grade) to 2.8mV (C grade). Note 6: This parameter is not 100% tested. Note 7: Slew rate is measured in AV = – 1; input signal is ± 7.5V, output measured at ± 2.5V. Note 8: The LT1793AC and LT1793C are guaranteed to meet specified performance from 0°C to 70°C and are designed, characterized and expected to meet these extended temperature limits, but are not tested at – 40°C and 85°C. The LT1793I is guaranteed to meet the extended temperature limits. The LT1793AC and LT1793AI grade are 100% temperature tested for the specified temperature range. Note 9: The LT1793 is measured in an automated tester in less than one second after application of power. Depending on the package used, power dissipation, heat sinking, and air flow conditions, the fully warmed-up chip temperature can be 10°C to 50°C higher than the ambient temperature. 4 LT1793 TYPICAL PERFOR A CE CHARACTERISTICS 0.1Hz to 10Hz Voltage Noise 50 VOLTAGE NOISE (1µV/DIV) 40 PERCENT OF UNITS (%) 30 RMS VOLTAGE NOISE DENSITY (nV/√Hz) 0 2 4 6 TIME (SEC) Voltage Noise vs Chip Temperature 10 V+ 0 –0.5 9 COMMON MODE LIMIT (V) REFERRED TO POWER SUPPLY –1.0 –1.5 –2.0 V = 5V TO 20V + COMMON MODE REJECTION RATIO (dB) VOLTAGE NOISE (AT 1kHz) (nV/√Hz) VS = ± 15V 8 7 6 5 4 3 2 –75 –50 –25 0 25 50 75 TEMPERATURE (°C) 100 125 1793 G04 Power Supply Rejection Ratio vs Frequency 120 POWER SUPPLY REJECTION RATIO (dB) 100 +PSRR VOLTAGE GAIN (dB) TA = 25°C VOLTAGE GAIN (dB) 80 –PSRR 60 40 20 0 10 100 1k 10k 100k FREQUENCY (Hz) UW 8 10 1793 G01 1kHz Input Noise Voltage Distribution 100 TA = 25°C VS = ± 15V 510 OP AMPS TESTED Voltage Noise vs Frequency TA = 25°C VS = ±15V 10 1/f CORNER 30Hz 20 10 0 4.2 4.6 5.0 5.4 5.8 6.2 6.6 7.0 7.4 7.8 8.2 INPUT VOLTAGE NOISE (nV/√Hz) 1793 G02 1 1 10 100 1k FREQUENCY (Hz) 10k 1793 G03 Common Mode Limit vs Temperature 120 100 80 60 40 20 0 –20 60 100 20 TEMPERATURE (°C) 140 1793 G05 Common Mode Rejection Ratio vs Frequency TA = 25°C VS = ± 15V 4.0 3.5 3.0 2.5 V – = – 5V TO – 20V V – +2.0 –60 1k 10k 100k 1M FREQUENCY (Hz) 10M 1793 G06 Voltage Gain vs Frequency 180 160 140 120 100 80 60 40 20 0 TA = 25°C VS = ±15V CL = 10pF Gain and Phase Shift vs Frequency 50 40 30 PHASE 20 10 GAIN 0 –10 180 200 100 1793 G09 TA = 25°C VS = ± 15V CL = 10pF 80 100 PHASE SHIFT (DEG) 120 140 160 1M 10M 1793 G07 – 20 0.01 1 10k 100 FREQUENCY (Hz) 1M 100M 1793 G08 0.1 1 10 FREQUENCY (MHz) 5 LT1793 TYPICAL PERFOR A CE CHARACTERISTICS Small-Signal Transient Response Large-Signal Transient Response V + – 0.8 –1.0 OUTPUT VOLTAGE SWING (V) –1.2 –1.4 –1.6 2.0 1.8 1.6 1.4 1.2 V – +1.0 –10 –8 –6 –4 –2 0 2 4 6 8 10 ISINK ISOURCE OUTPUT CURRENT (mA) 1793 G12 20mV/DIV 5V/DIV AV = 1 CL = 10pF VS = ±15V, ± 5V 1µs/DIV Capacitive Load Handling 50 CHANGE IN OFFSET VOLTAGE (µV) TOTAL HARMONIC DISTORTION + NOISE (%) 40 OVERSHOOT (%) 30 VS = ± 15V TA = 25°C RL ≥ 10k VO = 100mVP-P AV = 10 RF = 10k CF = 20pF 20 AV = 1 10 AV = 10 0 0.1 1 100 1000 10 CAPACITIVE LOAD (pF) THD and Noise vs Frequency for Inverting Gain TOTAL HARMONIC DISTORTION + NOISE (%) TOTAL HARMONIC DISTORTION + NOISE (%) 1 ZL = 2k  15pF VO = 20VP-P AV = – 1, – 10, – 100 MEASUREMENT BANDWIDTH = 10Hz TO 80kHz AV = – 100 0.01 AV = – 10 0.001 NOISE FLOOR 20 100 1k FREQUENCY (Hz) 10k 20k 1793 G16 0.1 0.1 ZL = 2k  15pF, fO = 1kHz AV = – 1, –10, –100 MEASUREMENT BANDWIDTH = 10Hz TO 22kHz TOTAL HARMONIC DISTORTION + NOISE (%) 0.0001 6 UW 1793 G10 Output Voltage Swing vs Load Current 25°C –55°C 125°C VS = ± 5V TO ± 20V 125°C –55°C 25°C AV = 1 CL = 10pF RL = 2k VS = ±15V 5µs/DIV 1793 G11 Warm-Up Drift 90 75 60 45 N8 PACKAGE 30 15 0 VS = ± 15V TA = 25°C SO-8 PACKAGE 1 THD and Noise Frequency for Noninverting Gain ZL = 2k  15pF VO = 20VP-P AV = 1, 10, 100 MEASUREMENT BANDWIDTH = 10Hz TO 80kHz AV = 100 0.1 0.01 AV = 10 0.001 AV = 1 NOISE FLOOR 0.0001 20 100 1k FREQUENCY (Hz) 10k 20k 1793 G15 10000 1793 G13 0 5 2 3 4 1 TIME AFTER POWER ON (MINUTES) 6 1793 G14 THD and Noise vs Output Amplitude for Inverting Gain 1 1 THD and Noise vs Output Amplitude for Noninverting Gain ZL = 2k  15pF, fO = 1kHz AV = 1, 10, 100 MEASUREMENT BANDWIDTH = 10Hz TO 22kHz 0.1 AV = – 100 0.01 AV = – 10 0.001 AV = – 1 AV = 100 0.01 AV = 10 0.001 AV = 1 AV = – 1 0.0001 0.3 1 10 OUTPUT SWING (VP-P) 30 1793 G17 0.0001 0.3 1 10 OUTPUT SWING (VP-P) 30 1793 G18 LT1793 TYPICAL PERFOR A CE CHARACTERISTICS Short-Circuit Output Current vs Temperature 40 35 OUTPUT CURRENT (mA) SUPPLY CURRENT PER AMPLIFIER (mA) INPUT BIAS AND OFFSET CURRENTS (A) VS = ± 15V 30 SINK 25 20 15 10 – 75 – 50 – 25 0 25 50 75 TEMPERATURE (°C) SOURCE APPLICATI S I FOR ATIO LT1793 vs the Competition With improved noise performance, the LT1793 in the PDIP directly replaces such JFET op amps as the OPA111 and the AD645. The combination of low current and voltage noise of the LT1793 allows it to surpass most dual and single JFET op amps. The LT1793 can replace many of the lowest noise bipolar amps that are used in amplifying low level signals from high impedance transducers. The best bipolar op amps (with higher current noise) will eventually lose out to the LT1793 when transducer impedance increases. 100 80 INPUT BIAS CURRENT (pA) 60 40 20 0 AD822 OP215 LT1793 CURRENT NOISE = √2qIB 6 5 1 50k – 15V –40 –60 –80 ∆VOS = ±13mV –100 –15 –10 0 5 10 –5 COMMON MODE RANGE (V) 15 1793 F01 Figure 1. Comparison of LT1793, OP215, and AD822 Input Bias Current vs Common Mode Range (a) Figure 2 + + –20 3 4 3 – – U W UW 1793 G19 Supply Current vs Temperature 5 30n 10n 3n 1n 300p 100p 30p 10p 3p 1p 0.3p Input Bias and Offset Currents vs Chip Temperature VS = ± 15V VCM = –10 TO 13V VS = ± 15V 4 VS = ± 5V BIAS CURRENT OFFSET CURRENT 100 125 3 – 75 – 50 – 25 0 25 50 75 TEMPERATURE (°C) 100 125 1793 G20 0 25 75 100 50 TEMPERATURE (°C) 125 1793 G21 U UO The extremely high input impedance (1013Ω) assures that the input bias current is almost constant over the entire common mode range. Figure 1 shows how the LT1793 stands up to the competition. Unlike the competition, as the input voltage is swept across the entire common mode range the input bias current of the LT1793 hardly changes. As a result the current noise does not degrade. This makes the LT1793 the best choice in applications where an amplifier has to buffer signals from a high impedance transducer. Offset nulling will be compatible with these devices with the wiper of the potentiometer tied to the negative supply (Figure 2a). No appreciable change in offset voltage drift 15V 2 7 2 15V 7 6 4 5 1 10k 10k ∆VOS = ± 1.3mV 50k – 15V 1793 F02 (b) 7 LT1793 APPLICATI S I FOR ATIO with temperature will occur when the device is nulled with a potentiometer ranging from 10k to 200k. Finer adjustments can be made with resistors in series with the potentiometer (Figure 2b). Amplifying Signals from High Impedance Transducers The low voltage and current noise offered by the LT1793 makes it useful in a wide range of applications, especially where high impedance, capacitive transducers are used such as hydrophones, precision accelerometers and photodiodes. The total output noise in such a system is the gain times the RMS sum of the op amp’s input referred 10k CS LT1007* RS VO CS INPUT NOISE VOLTAGE (nV/√Hz)  1k LT1793* 100 RS LT1007† LT1793 10 LT1793† LT1007 RESISTOR NOISE ONLY 1k 10k 100k 1M 10M 100M SOURCE RESISTANCE (Ω) 1G 1 100 1793 F03 SOURCE RESISTANCE = 2RS = R * PLUS RESISTOR † PLUS RESISTOR  1000pF CAPACITOR Vn = AV √ Vn2(OP AMP) + 4kTR + 2qIBR2 Figure 3. Comparison of LT1793 and LT1007 Total Output 1kHz Voltage Noise vs Source Resistance RF CF CS RS OUTPUT R1 TRANSDUCER RB CB CB = CF CS RB = RF RS dQ dV Q = CV; = I = C dt dt CS RS TRANSDUCER Figure 4. Inverting and Noninverting Gain Configurations 8 + – U voltage noise, the thermal noise of the transducer, and the op amp’s input bias current noise times the transducer impedance. Figure 3 shows total input voltage noise versus source resistance. In a low source resistance (< 5k) application the op amp voltage noise will dominate the total noise. This means the LT1793 is superior to most JFET op amps. Only the lowest noise bipolar op amps have the advantage at low source resistances. As the source resistance increases from 5k to 50k, the LT1793 will match the best bipolar op amps for noise performance, since the thermal noise of the transducer (4kTR) begins to dominate the total noise. A further increase in source resistance, above 50k, is where the op amp’s current noise component (2qIBR2) will eventually dominate the total noise. At these high source resistances, the LT1793 will out perform the lowest noise bipolar op amps due to the inherently low current noise of FET input op amps. Clearly, the LT1793 will extend the range of high impedance transducers that can be used for high signal-to-noise ratios. This makes the LT1793 the best choice for high impedance, capacitive transducers. Optimization Techniques for Charge Amplifiers The high input impedance JFET front end makes the LT1793 suitable in applications where very high charge sensitivity is required. Figure 4 illustrates the LT1793 in its inverting and noninverting modes of operation. A charge amplifier is shown in the inverting mode example; the gain depends on the principal of charge conservation at the input of the LT1793. The charge across the transducer capacitance CS is transferred to the feedback capacitor CF R2 CB RB OUTPUT CB ≅ CS RB = RS RS > R1 OR R2 1793 F04 W + – U UO + – LT1793 APPLICATI S I FOR ATIO resulting in a change in voltage dV, which is equal to dQ/CF. The gain therefore is CF/CS. For unity-gain, the CF should equal the transducer capacitance plus the input capacitance of the LT1793 and RF should equal RS. In the noninverting mode example, the transducer current is converted to a change in voltage by the transducer capacitance, CS. This voltage is then buffered by the LT1793 with a gain of 1 + R1/R2. A DC path is provided by RS, which is either the transducer impedance or an external resistor. Since RS is usually several orders of magnitude greater than the parallel combination of R1 and R2, R B is added to balance the DC offset caused by the noninverting input bias current and RS. The input bias currents, although small at room temperature, can create significant errors at higher temperature, especially with transducer resistances of up to 1000M or more. The optimum value Input: ± 5.2V Sine Wave LT1793 F05a Figure 5. Voltage Follower with Input Exceeding the Common Mode Range (VS = ± 5V) U for RB is determined by equating the thermal noise (4kTRS) to the current noise (2qIB) times RS2. Solving for RS results in RB = RS = 2VT/IB (VT = 26mV at 25°C). A parallel capacitor CB, is used to cancel the phase shift caused by the op amp input capacitance and RB. Reduced Power Supply Operation To take full advantage of a wide input common mode range, the LT1793 was designed to eliminate phase reversal. Referring to the photographs in Figure 5, the LT1793 is shown operating in the follower mode (AV = 1) at ± 5V supplies with the input swinging ± 5.2V. The output of the LT1793 clips cleanly and recovers with no phase reversal. This has the benefit of preventing lockup in servo systems and minimizing distortion components. LT1793 Output LT1793 F05b W U UO 9 LT1793 PACKAGE DESCRIPTIO 0.300 – 0.325 (7.620 – 8.255) 0.009 – 0.015 (0.229 – 0.381) ( +0.035 0.325 –0.015 8.255 +0.889 –0.381 ) *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.010 INCH (0.254mm) 10 U Dimensions in inches (millimeters) unless otherwise noted. N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) 0.400* (10.160) MAX 8 7 6 5 0.255 ± 0.015* (6.477 ± 0.381) 1 2 3 4 0.130 ± 0.005 (3.302 ± 0.127) 0.045 – 0.065 (1.143 – 1.651) 0.065 (1.651) TYP 0.125 (3.175) 0.020 MIN (0.508) MIN 0.018 ± 0.003 (0.457 ± 0.076) N8 1197 0.100 ± 0.010 (2.540 ± 0.254) LT1793 PACKAGE DESCRIPTIO U Dimensions in inches (millimeters) unless otherwise noted. S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) 0.189 – 0.197* (4.801 – 5.004) 8 7 6 5 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) 0°– 8° TYP 0.053 – 0.069 (1.346 – 1.752) 2 3 4 0.004 – 0.010 (0.101 – 0.254) 0.016 – 0.050 0.406 – 1.270 0.014 – 0.019 (0.355 – 0.483) 0.050 (1.270) 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 SO8 0996 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. 11 LT1793 TYPICAL APPLICATIONS N 10Hz Fourth Order Chebyshev Lowpass Filter (0.01dB Ripple) R2 237k VIN C2 100nF LT1793 –15V TYPICAL OFFSET ≈ 0.8mV 1% TOLERANCES FOR VIN = 10VP-P, VOUT = –121dB AT f > 330Hz = – 6dB AT f = 16.3Hz LOWER RESISTOR VALUES WILL RESULT IN LOWER THERMAL NOISE AND LARGER CAPACITORS Accelerometer Amplifier with DC Servo C1 1250pF R1 100M R3 2k C2 2µF R4 20M R5 20M C3 2µF 6 1793 TA03 R2 18k 2 1 5V TO 15V 1/2 LT1464 3 RELATED PARTS PART NUMBER LT1113 LT1169 LT1467 LT1792 DESCRIPTION Low Noise, Dual JFET Op Amp Low Noise, Dual JFET Op Amp Micropower Dual JFET Op Amp Low Noise, Single JFET Op Amp COMMENTS Dual Version of LT1792, VNOISE = 4.5nV/√Hz Dual Version of LT1793, VNOISE = 6nV/√Hz, IB = 10pA 1MHz, 2pA Max IB, 200µA Max IS Lower VNOISE Version of LT1793, VNOISE = 4.2nV/√Hz 1793f LT/TP 0599 4K • PRINTED IN USA 12 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408)432-1900 q FAX: (408) 434-0507 q www.linear-tech.com + 3 – ACCELEROMETER B & K MODEL 4381 OR EQUIVALENT (800) 442-1030 2 7 LT1793 4 –5V TO –15V R4C2 = R5C3 > R1 (1 + R2/R3) C1 OUTPUT = 0.8mV/pC* = 8.0mV/g** DC OUTPUT ≤ 1.9mV OUTPUT NOISE = 8nV/Hz AT 1kHz √ *PICOCOULOMBS **g = EARTH’S GRAVITATIONAL CONSTANT + – + + 3 4 C4 330nF 3 – – R1 237k U R5 154k 15V 2 7 C1 33nF 6 R3 249k R4 154k R6 249k 2 C3 10nF LT1793 6 VOUT 1793 TA04 OUTPUT © LINEAR TECHNOLOGY CORPORATION 1999