® INA117 INA 117 INA 117 High Common-Mode Voltage DIFFERENCE AMPLIFIER FEATURES APPLICATIONS ● COMMON-MODE INPUT RANGE: ±200V (VS = ±15V) ● PROTECTED INPUTS: ±500V Common-Mode ±500V Differential ● UNITY GAIN: 0.02% Gain Error max ● NONLINEARITY: 0.001% max ● CMRR: 86dB min ● ● ● ● ● CURRENT MONITOR BATTERY CELL-VOLTAGE MONITOR GROUND BREAKER INPUT PROTECTION SIGNAL ACQUISITION IN NOISY ENVIRONMENTS ● FACTORY AUTOMATION DESCRIPTION The INA117 is a precision unity-gain difference amplifier with very high common-mode input voltage range. It is a single monolithic IC consisting of a precision op amp and integrated thin-film resistor network. It can accurately measure small differential voltages in the presence of common-mode signals up to ±200V. The INA117 inputs are protected from momentary common-mode or differential overloads up to ±500V. In many applications, where galvanic isolation is not essential, the INA117 can replace isolation amplifiers. This can eliminate costly isolated input-side power supplies and their associated ripple, noise and quiescent current. The INA117’s 0.001% nonlinearity and 200kHz bandwidth are superior to those of conventional isolation amplifiers. 21.11kΩ RefB 1 –In 2 +In 3 V– 4 380kΩ 8 Comp 7 V+ 6 VO 5 RefA 380kΩ 380kΩ 20kΩ The INA117 is available in 8-pin plastic mini-DIP and SO-8 surface-mount packages, specified for the –40°C to +85°C temperature range. The metal TO-99 models are available specified for the –40°C to +85°C and –55°C to +125°C temperature range. International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 © 1987 Burr-Brown Corporation PDS-748G Printed in U.S.A. August, 1999 SPECIFICATIONS ELECTRICAL At TA = +25°C, VS = ±15V, unless otherwise noted. INA117AM, SM PARAMETER CONDITIONS MIN GAIN Initial (1) Error vs Temperature Nonlinearity (2) OUTPUT Rated Voltage Rated Current Impedance Current Limit Capacitive Load IO = +20mA, –5mA VO = 10V 10 +20, –5 To Common Stable Operation INPUT Impedance Differential Common-Mode Differential Common-Mode, Continuous Voltage Range Common-Mode Rejection DC AC, 60Hz vs Temperature, DC AM, BM, P, KU SM INA117BM TYP MAX 1 0.01 2 0.0002 0.05 10 0.001 MIN ✻ ✻ ✻ ✻ ✻ 12 TYP INA117P, KU MAX MIN ✻ ✻ ✻ ✻ 0.02 ✻ ✻ ✻ TYP ✻ ✻ MAX ✻ ✻ ✻ UNITS V/V % ppm/°C % V mA Ω mA pF 0.01 +49, –13 1000 ✻ ✻ ✻ ✻ ✻ ✻ 800 400 ✻ ✻ ✻ ✻ ✻ ✻ kΩ kΩ V V ✻ ✻ dB dB ✻ dB dB ±10 ±200 ✻ ✻ (3) VCM = 400Vp-p TA = TMIN to TMAX OFFSET VOLTAGE Initial KU Grade (SO-8 Package) vs Temperature vs Supply vs Time RTO DYNAMIC RESPONSE Gain Bandwidth, –3dB Full Power Bandwidth Slew Rate Settling Time: 0.1% 0.01% 0.01% POWER SUPPLY Rated Voltage Range Quiescent Current RTO 86 66 94 94 66 60 75 75 80 90 74 120 1000 8.5 90 200 40 80 ✻ 1000 ✻ ✻ ✻ 20 ✻ ✻ ✻ 25 550 ✻ 200 VO = 20Vp-p VCM ✻ ✻ ✻ 600 ✻ ✻ ✻ ✻ 2000 µV µV µV/°C dB µV/mo (5) 30 2 VO = 10V Step VO = 10V Step = 10V Step, VDIFF = 0V Derated Performance VO = 0V TEMPERATURE RANGE Specification: AM, BM, P, KU SM Operation Storage 80 80 (4) TA = TMIN to TMAX VS = ±5V to ±18V OUTPUT NOISE VOLTAGE fB = 0.01Hz to 10Hz fB = 10kHz 70 66 ±5 ✻ ✻ 2.6 6.5 10 4.5 ±15 1.5 –25 –55 –55 –65 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ±18 2 ✻ +85 +125 +125 +150 ✻ ✻ µVp-p nV/√Hz ✻ kHz kHz V/µs µs µs µs ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ –40 +85 ✻ ✻ ✻ ✻ –40 –55 +85 +125 ✻ ✻ ✻ ✻ V V mA °C °C °C °C ✻Specification same as for INA117AM. NOTES: (1) Connected as difference amplifier (see Figure 1). (2) Nonlinearity is the maximum peak deviation from the best-fit straight line as a percent of full-scale peak-to-peak output. (3) With zero source impedance (see discussion of common-mode rejection in Application Information section). (4) Includes effects of amplifier’s input bias and offset currents. (5) Includes effects of amplifier’s input current noise and thermal noise contribution of resistor network. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® INA117 2 PIN CONFIGURATION Top View TO-99 INA117AM, BM, SM Tab 8 Ref B –In Top View DIP/SOIC INA117P, KU Comp 1 7 V+ 2 6 3 RefB 1 8 Comp –In 2 7 V+ +In 3 6 Output V– 4 5 RefA Output 5 Ref A +In 4 V– Case internally connected to V–. Make no connection. ELECTROSTATIC DISCHARGE SENSITIVITY ABSOLUTE MAXIMUM RATINGS Supply Voltage .................................................................................. ±22V Input Voltage Range, Continuous ................................................... ±200V Common-Mode and Differential, 10s ........................................... ±500V Operating Temperature M Metal TO-99 ................................................................ –55 to +125°C P Plastic DIP and U SO-8 ................................................ –40 to +85°C Storage Temperature M Package ....................................................................... –65 to +150°C P Plastic DIP and U SO-8 .............................................. –55 to +125°C Lead Temperature (soldering, 10s) ............................................... +300°C Output Short Circuit to Common ............................................ Continuous This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. PACKAGE/ORDERING INFORMATION PRODUCT INA117P PACKAGE PACKAGE DRAWING NUMBER(1) SPECIFIED TEMPERATURE RANGE –40°C to +85°C 8-Pin Plastic DIP 006 INA117KU SO-8 Surface-Mount 182 " INA117AM TO-99 Metal 001 –25°C to +85°C INA117BM " " " INA117SM " " –55°C to +125°C PACKAGE MARKING ORDERING NUMBER(2) TRANSPORT MEDIA NOTES: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) Models with a slash (/) are available only in Tape and Reel in the quantities indicated (e.g., /2K5 indicates 2500 devices per reel). Ordering 2500 pieces of “INA117KU/2K5” will get a single 2500-piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of Burr-Brown IC Data Book. ® 3 INA117 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, unless otherwise noted. COMMON-MODE REJECTION vs FREQUENCY POWER SUPPLY REJECTION vs FREQUENCY 100 INA117BM Power Supply Rejection (dB) Common-Mode Rejection (dB) 100 90 80 INA117AM, SM, P, KU 70 60 50 40 V– 80 V+ 70 60 50 40 20 100 1k 10k 100k 2M 1 10 100 1k Frequency (Hz) Frequency (Hz) POSITIVE COMMON-MODE VOLTAGE RANGE vs POSITIVE POWER SUPPLY VOLTAGE NEGATIVE COMMON-MODE VOLTAGE RANGE vs NEGATIVE POWER SUPPLY VOLTAGE 10k –400 Negative Common-Mode Range (V) 400 Positive Common-Mode Range (V) 90 TA = –55°C 350 TA = +25°C 300 Max Rating = 200V 250 TA = +125°C 200 150 –VS = –5V to –20V 100 50 –350 TA = +25°C –300 Max Rating = –200V –250 TA = –55°C to +125°C –200 –150 +VS = +5V to +20V –100 –50 5 10 15 20 –5 Positive Power Supply Voltage (V) ® INA117 –10 –15 Negative Power Supply Voltage (V) 4 –20 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V, unless otherwise noted. SMALL SIGNAL STEP RESPONSE CL = 0 SMALL SIGNAL STEP RESPONSE CL = 1000pF LARGE SIGNAL STEP RESPONSE ® 5 INA117 APPLICATION INFORMATION Figure 1 shows the basic connections required for operation. V– Applications with noisy or high impedance power supply lines may require decoupling capacitors close to the device pins. V+ 4 The output voltage is equal to the differential input voltage between pins 2 and 3. The common mode input voltage is rejected. 2 V2 Internal circuitry connected to the compensation pin 8 cancels the parasitic distributed capacitance between the feedback resistor, R2, and the IC substrate. For specified dynamic performance, pin 8 should be grounded or connected through a 0.1µF capacitor to an AC ground such as V+. 380kΩ 6 380kΩ 3 V3 7 380kΩ VO = V3 – V2 21.1kΩ 20kΩ 8 –15V 1 +15V 5 100kΩ +15V (a) + + 1µF Tantalum 4 7 R1 380kΩ 2 10Ω 1µF Tantalum R2 380kΩ V– V+ 4 –In = V2 R3 3 2 6 380kΩ 7 380kΩ 380kΩ V2 VO = V 3 – V 2 +In = V3 R5 21.1kΩ 50kΩ ±1.5mV Range –15V R4 20kΩ 3 6 380kΩ VO = V3 – V2 V3 8 1 5 V+ 21.1kΩ 8 20kΩ 1 100µA 1/2 REF200 5 FIGURE 1. Basic Power and Signal Connections. 100Ω COMMON-MODE REJECTION (b) Common-mode rejection (CMR) of the INA117 is dependent on the input resistor network, which is laser-trimmed for accurate ratio matching. To maintain high CMR, it is important to have low source impedances driving the two inputs. A 75Ω resistance in series with pin 2 or 3 will decrease CMR from 86dB to 72dB. OPA27 ±10mV 10kΩ 100µA 1/2 REF200 Resistance in series with the reference pins will also degrade CMR. A 4Ω resistance in series with pin 1 or 5 will decrease CMRR from 86dB to 72dB. V– Most applications do not require trimming. Figures 2 and 3 show optional circuits that may be used for trimming offset voltage and common-mode rejection. FIGURE 2. Offset Voltage Trim Circuits. Some applications, however, apply voltages to the reference terminals (pins 1 and 5). A more complete transfer function is: TRANSFER FUNCTION Most applications use the INA117 as a simple unity-gain difference amplifier. The transfer function is: VO = V3 – V2 + 19 • V5 – 18 • V1 V5 and V1 are the voltages at pins 5 and 1. VO = V3 – V2 V3 and V2 are the voltages at pins 3 and 2. ® INA117 100Ω Offset adjustment is regulated— insensitive to power supply variations. 6 MEASURING CURRENT The INA117 can be used to measure a current by sensing the voltage drop across a series resistor, RS. Figure 4 shows the INA117 used to measure the supply currents of a device under test. The circuit in Figure 5 measures the output current of a power supply. If the power supply has a sense connection, it can be connected to the output side of RS to eliminate the voltage-drop error. Another common application is current-to-voltage conversion as shown in Figure 6. V– V+ (+200V max) +VS 4 7 380kΩ 2 380kΩ C RS RC* 6 380kΩ 3 VO = RS IDUT+ IDUT+ V– 4 V2 2 21.1kΩ V+ 8 7 380kΩ 380kΩ 20kΩ 1 5 Device Under Test V+ V– 6 V3 3 380kΩ 4 VO = V 3 – V2 380kΩ 2 21.1kΩ 8 20kΩ 1 RS 6 380kΩ 3 10Ω 380kΩ RC* 5 200Ω 7 IDUT– VO = RS IDUT– CMR Adjust 21.1kΩ 20kΩ 10Ω 8 –VS If offset adjust is also required, connect to offset circuit, Figure 2. 1 5 (–200V max) *Not needed if R S is less than 20Ω —see text. FIGURE 4. Measuring Supply Currents of Device Under Test. FIGURE 3. CMR Trim Circuit. V– V+ 4 7 Power Supply ±200V max 2 Out 380kΩ 380kΩ Sense RS RC* Optional Load Sense Connection (see text) 3 6 380kΩ VO = I L R S IL 21.1kΩ 20kΩ Load 8 1 5 *RC = RS not needed if RS is less than 20Ω—see text. FIGURE 5. Measuring Power Supply Output Current. ® 7 INA117 VS (±200V max) 2 380kΩ 380kΩ RS 250Ω 3 250Ω RC * 4 to 20mA 6 380kΩ VO = 1V to 5V 21.1kΩ 8 20kΩ 1 5 VS (a) (±200V max) *Not needed if RS is less than 20Ω—see text. 2 380kΩ 380kΩ 250Ω RC* RS 250Ω 3 6 380kΩ VO = –1V to –5V 4 to 20mA 21.1kΩ 8 20kΩ 1 5 (b) 4 to 20mA 2 380kΩ 380kΩ *Not needed if RS is less than 20Ω—see text. 250Ω RC* RS 250Ω 3 6 380kΩ VO = 1V to 5V 20kΩ 21.1kΩ 8 VS 1 5 (±200V max) 4 to 20mA (c) *Not needed if RS is less than 20Ω—see text. 2 380kΩ 380kΩ RS 250Ω 6 3 380kΩ VO = –1V to –5V 250Ω RC* 21.1kΩ VS (±200V max) 8 20kΩ 1 5 *Not needed if RS is less than 20Ω—see text. FIGURE 6. Current to Voltage Converter. ® INA117 8 (d) Example: For a 1V/mA transfer function, the nominal, uncorrected value for RS would be 1kΩ. A slightly larger value, RS' = 1002.6Ω, compensates for the gain error due to loading. In all cases, the sense resistor imbalances the input resistor matching of the INA117, degrading its CMR. Also, the input impedance of the INA117 loads RS, causing gain error in the voltage-to-current conversion. Both of these errors can be easily corrected. The 380kΩ term in the equation for RS' has a tolerance of ±25%, so sense resistors above approximately 400Ω may require trimming to achieve gain accuracy better than 0.02%. The CMR error can be corrected with the addition of a compensation resistor, RC, equal in value to RS as shown in Figures 4, 5, and 6. If RS is less than 20Ω, the degradation in CMR is negligible and RC can be omitted. If RS is larger than approximately 2kΩ, trimming RC may be required to achieve greater than 86dB CMR. This is because the actual INA117 input impedances have 1% typical mismatch. Of course, if a buffer amplifier is added as shown in Figure 7, both inputs see a low source impedance, and the sense resistor is not loaded. As a result, there is no gain error or CMR degradation. The buffer amplifier can operate as a unity gain buffer or as an amplifier with non-inverting gain. Gain added ahead of the INA117 improves both CMR and signal-to-noise. Added gain also allows a lower voltage drop across the sense resistor. The OPA1013 is a good choice for the buffer amplifier since both its input and output can swing close to its negative power supply. If RS is more than approximately 100Ω, the gain error will be greater than the 0.02% specification of the INA117. This gain error can be corrected by slightly increasing the value of RS. The corrected value, RS', can be calculated by— RS • 380kΩ RS' = —————— 380kΩ – RS –15V V1 +15V 4 7 I 380kΩ 2 VX V1 –21V to +10V –5V to –36V –20V to –51V +15V Ground –15V 380kΩ R2* RS 6 380kΩ 3 VO = I • RS • (1 + 1/2 OPA1013 21.1kΩ R1 * 8 –VX Op amp power can be derived with voltagedropping zener diode if –VX power is relatively constant. |VX| = (5V to 36V) + VZ e.g., If VZ is 50V then VX = –55V to –86V. R2 ) R1 20kΩ 1 5 *Or connect as buffer (R2 = 0, omit R1). Regulated power for op amp allows –VX power to vary over wide range. 180k Ω VZ VX = –30V to –200V MPS-A42 0.01µF IN4702 or –VX V– V+ 4 2 I 7 380kΩ 380kΩ RS 3 6 380kΩ VO = I • RS 1/2 OPA1013 21.1kΩ 0.1µF 8 20kΩ 1 5 –VX FIGURE 7. Current Sensing with Input Buffer. ® 9 INA117 Figure 8 shows very high input impedance buffer used to measure low leakage currents. Here, the buffer op amp is powered with an isolated, split-voltage power supply. Using an isolated power supply allows full ±200V common-mode input range. these resistors produces approximately 550nV/√Hz noise. The internal op amp contributes virtually no excess noise at frequencies above 100Hz. Many applications may be satisfied with less than the full 200kHz bandwidth of the INA117. In these cases, the noise can be reduced with a low-pass filter on the output. The twopole filter shown in Figure 9 limits bandwidth to 1kHz and reduces noise by more than 15:1. Since the INA117 has a 1/f noise corner frequency of approximately 100Hz, a cutoff frequency below 100Hz will not further reduce noise. NOISE PERFORMANCE The noise performance of the INA117 is dominated by the internal resistor network. The thermal or Johnson noise of ±200V max 1kΩ +15V 100MΩ +15V Isolated DC/DC Converter 9kΩ D1,2* PWS725 Com OPA111 –15V IL 100kΩ Device Under Test 2 *D1 and D2 are each a 2N3904 transistor base-collector junction (emitter open). 3 380kΩ 380kΩ 6 380kΩ eO = IL x 109 (1V/nA) 21.1kΩ 20kΩ INA117 8 1 5 FIGURE 8. Leakage Current Measurement Circuit. V+ V– 4 V2 V3 2 3 7 380kΩ C2 0.02µF 380kΩ 6 380kΩ R1 11.0kΩ R2 11.3kΩ OPA27 2-Pole Butterworth Low-Pass Filter C1 0.01µF 21.1kΩ 8 V O = V2 – V3 20kΩ 1 5 BUTTERWORTH LOW-PASS OUTPUT NOISE f–3dB (mVp-p) 200kHz 100kHz 10kHz 1kHz ≤100Hz(1) See Application Bulletin AB-017 for other filters. R1 11kΩ 11kΩ 11kΩ 11kΩ R2 C1 No Filter 11.3kΩ 100pF 11.3kΩ 1nF 11.3kΩ 10nF 11.3kΩ 0.1µF C2 200pF 2nF 20nF 0.2µF NOTE: (1) Since the INA117 has a 1/f noise corner frequency of approximately 100Hz, bandwidth reduction below this frequency will not significantly reduce noise. FIGURE 9. Output Filter for Noise Reduction. ® INA117 1.8 1.1 0.35 0.11 0.05 10 V2 380kΩ 380kΩ 2 V– V+ 4 V3 6 380kΩ 3 VO = 1+ 19 R7 380kΩ 2 V2 R6 21.1kΩ 7 V3 – V 2 380kΩ 20kΩ INA117 8 1 5 R7 V3 R6 6 380kΩ 3 VO = V3 – V2 + VX 21.1kΩ OPA27 Refer to Application Bulletin AB-001 for details. GAIN (V/V) R7 (kΩ) R6 (kΩ) 1/2 1/4 1/5 1.05 3.16 4.22 20 20 20 20kΩ INA117 8 1 5 OPA27 VX FIGURE 11. Summing VX in Output. FIGURE 10. Reducing Differential Gain. V2 2 R1 380kΩ 3 R3 380kΩ Refer to Application Bulletin AB-010 for details. (a) R2 380kΩ 6 VOUT = V3 – V2 V3 R5 21.1kΩ V2 V3 2 R1 380kΩ R2 380kΩ R4 20kΩ INA117 8 1 5 100pF 3 R3 380kΩ R6 5kΩ 6 VOUT = V3 – V2 R4 20kΩ R5 21.1kΩ A1 OPA27 R9 400kΩ 8 1 5 R10 10kΩ 100pF R6 5kΩ R7 10kΩ –V3 /20 100pF INA117 R8 10kΩ A2 OPA27 (b) R7 10kΩ VCM /20 A1 OPA27 FIGURE 12. Common-Mode Voltage Monitoring. ® 11 INA117 +9V 7 2 V2 380kΩ 380kΩ 7 VCM Range = +50V to +200V (VS ±9V) 3 V3 6 380kΩ 21.1kΩ (a) 2 25kΩ 25kΩ 5 6 20kΩ VO = V3 – V2 INA117 8 1 5 4 3 25kΩ –3V > VO > –6V swap A2 pins 2 and 3 for +4V > VO > 3V. INA105 25kΩ 1 4 –9V +9V 7 2 V2 380kΩ 380kΩ 7 VCM Range = –12V to +200V (VS = ±9V) 3 V3 6 380kΩ 2 25kΩ 25kΩ 5 6 21.1kΩ (b) INA117 8 VO = V3 – V2 20kΩ 1 5 4 3 25kΩ 25kΩ 1N4684 3.3V (V–) +3.3V 0V > VO > –6V swap A2 pins 2 and 3 for +4V > VO > 0V. INA105 10kΩ 1 4 –9V V2 2 380kΩ 380kΩ VCM Range = ±200V (VS = ±9V) V3 3 6 380kΩ 21.1kΩ 2 25kΩ 25kΩ 5 6 20kΩ VO = V3 – V2 INA117 8 (c) 1 5 3 R7 1MΩ 25kΩ 25kΩ INA105 1 13.7kΩ (VS = ±9V) Refer to Application Bulletin AB-015 for details. R8 1MΩ OPA602 FIGURE 13. Offsetting or Boosting Common-Mode Voltage Range for Reduced Power Supply Voltage Operation. ® INA117 12 +200V max V– V+ 4 2 7 380kΩ 380kΩ + – 3 6 380kΩ 21.1kΩ 20kΩ INA117 8 1 5 V– V+ 4 2 7 380kΩ 380kΩ + 6 – 3 380kΩ 21.1kΩ 20kΩ INA117 Repeat for each cell 8 1 eO = Cell Voltage 5 MUX V– V+ 4 2 7 380kΩ 380kΩ + – 3 6 380kΩ 21.1kΩ 20kΩ INA117 8 1 5 Cell Select V– V+ 4 2 7 380kΩ 380kΩ + – 3 6 380kΩ 21.1kΩ 20kΩ INA117 8 1 5 –200V max FIGURE 14. Battery Cell Voltage Monitor. ® 13 INA117 +15V –15V VS (200V max) 7 2 4 380kΩ 380kΩ R1 0.1Ω 3 6 380kΩ –0.1 (I1) I1 20kΩ 21.1kΩ INA117 8 1 5 Load A1 VIN ILOAD = I1 – I2 +15V +15V –15V 7 7 4 –15V 4 I2 2 380kΩ 100kΩ 380kΩ 2 R2 0.1Ω 6 6 3 380kΩ 3 –0.1 (I2) 10kΩ INA106 20kΩ INA117 8 1 5 VS (–200V max) FIGURE 15. Measuring Amplifier Load Current. V2 V3 3 R2 380kΩ R1 380kΩ R3 380kΩ 6 VOUT = V3 – V2 R4 20kΩ R5 21.1kΩ INA117 8 1 5 C1 R1 0.47µF 1MΩ OPA602 Refer to Application Bulletin AB-008 for details. FIGURE 16. AC-Coupled INA117. ® INA117 14 VO VO = I 1 – I 2 = ILOAD 100kΩ 21.1kΩ 2 5 10kΩ 1