Datasheet OP292, OP492 (Analog Devices) - 15
| Manufacturer | Analog Devices |
| Description | Dual/Quad Single-Supply Operational Amplifiers |
| Pages / Page | 20 / 15 — Data Sheet. OP292/OP492. 50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER. 5kΩ. … |
| Revision | D |
| File Format / Size | PDF / 345 Kb |
| Document Language | English |
Data Sheet. OP292/OP492. 50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER. 5kΩ. 1/2. 0.022µF. OP292. OUT. 0.01µF. 1.1kΩ 14.3kΩ. VIN
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Data Sheet OP292/OP492 50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER 5V 5V 6
Figure 39 shows a notch filter that achieves nearly 30 dB of
2 5kΩ 8 1/2 7 0.022µF OP292 V
60 Hz rejection while powered by only a single 12 V supply.
1/2 1 5 OUT 0.01µF OP292
The circuit also works well on 5 V systems. The filter uses a
3 1.1kΩ 14.3kΩ VIN 4
twin-T configuration, whose frequency selectivity depends
100µF 1.78kΩ 16.2kΩ 2200pF
heavily on the relative matching of the capacitors and resistors in
5kΩ 3300pF
040 the twin-T section. Mylar is a good choice for the capacitors of 00310- the twin-T, and the relative matching of the capacitors and resistors Figure 40. Four-Pole Bessel Low-Pass Filter Using Sallen-Key Topology determines the pass-band symmetry of the filter. Using 1%
LOW COST, LINEARIZED THERMISTOR AMPLIFIER
resistors and 5% capacitors produces satisfactory results. An inexpensive thermometer amplifier circuit can be implemented The amount of rejection and the Q of the filter is solely determined using low cost thermistors. One such implementation is shown by one resistor and is shown in the table with Figure 39. The in Figure 41. The circuit measures temperature over the range bottom amplifier is used to split the supply to bias the amplifier of 0°C to 70°C to an accuracy of ±0.3°C as the linearization to midlevel. The circuit can be modified to reject 50 Hz by simply circuit works well within a narrow temperature range. However, it changing the resistors in the twin-T section (R1 through R4) can measure higher temperatures but at a slightly reduced accuracy. from 2.67 kΩ to 3.16 kΩ and by changing R5 to ½ of 3.16 kΩ. For To achieve the aforementioned accuracy, the nonlinearity of the best results, the common value resistors can be from a resistor thermistor must be corrected. This is done by connecting the array for optimum matching characteristics. thermistor in parallel with the 10 kΩ in the feedback loop of the
R2
first stage amplifier. A constant operating current of 281 µA is
2.67kΩ
supplied by the resistor R1 with the 5 V reference from the
R1 C1 C2
REF195 such that the self-heating error of the thermistor is
12V 2.67kΩ 1µF 1µF 1/4
kept below 0.1°C.
OP492 1/4 VIN VOUT OP492
In many cases, the thermistor is placed some distance from the
R3 R4
signal conditioning circuit. Under this condition, a 0.1 µF capacitor
2.67kΩ 2.67kΩ R6
placed across R2 will help to suppress noise pickup.
C3 R5 100kΩ 2µF 1.335kΩ R7 RQ (1µF × 2) (2.67k ÷ 2) 1kΩ
This linearization network creates an offset voltage that is corrected
8kΩ
by summing a compensating current with Potentiometer P1. The
12V R8
temperature dependent signal is amplified by the second stage,
6V 100kΩ 1/4 OP492
producing a transfer coefficient of −10 mV/°C at the output.
R9 +
To calibrate, a precision decade box can be used in place of the
100kΩ C4 1µF
thermistor. For 0°C trim, the decade box is set to 32.650 kΩ, and P1 is adjusted until the output of the circuit reads 0 V. To
FILTER Q RQ (kΩ ) REJECTION (dB) VOLTAGE GAIN
trim the circuit at the full-scale temperature of 70°C, the decade
0.75 1.0 40 1.33
box is then set to 1.752 kΩ, and P2 is adjusted until the circuit
1.00 2.0 35 1.50
reads −0.70 V.
1.25 3.0 30 1.60 2.50 8.0 25 1.80 R 1 T 5.00 18 20 1.90 15V 10kΩ NTC 10.00 38 15 1.95 R12 NOTES 17.8kΩ R12 P2 1. FOR 50Hz APPLICATION CHANGE R12 TO R4 TO 3.16kΩ
039
1.0µF REF195 200Ω AND R5 TO 1.58kΩ (3.16kΩ ÷ 2) 17.8kΩ
00310-
R3 R6 70°C TRIM 1µF
Figure 39. Single-Supply 50 Hz/60 Hz Notch Filter
10kΩ 7.87kΩ 1/2 OP292 5V R4 1/2 FOUR-POLE BESSEL LOW-PASS FILTER 41.2kΩ OP292 VOUT R5 –10mV/°C
The linear phase filter in Figure 40 is designed to roll off at a
P1 806kΩ
voice-band cutoff frequency of 3.6 kHz. The four poles are
10kΩ 0°C TRIM
formed by two cascading stages of 2-pole Sallen-Key filters.
1RT = ALPHATHERMISTOR 13A1002-C3.
041
2R1 = 0.1% IMPERIAL ASTRONICS M015.
00310-
NOTES 1. ALL RESISTORS ARE 1%, 25ppm/°C EXCEPT R5 = 1%, 100ppm/°C.
Figure 41. Low Cost Linearized Thermistor Amplifier Rev. D | Page 15 of 20 Document Outline FEATURES APPLICATIONS PIN CONFIGURATIONS GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS INFORMATION PHASE REVERSAL POWER SUPPLY CONSIDERATIONS TYPICAL APPLICATIONS DIRECT ACCESS ARRANGEMENT FOR TELEPHONE LINE INTERFACE SINGLE-SUPPLY INSTRUMENTATION AMPLIFIER DAC OUTPUT AMPLIFIER 50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER FOUR-POLE BESSEL LOW-PASS FILTER LOW COST, LINEARIZED THERMISTOR AMPLIFIER SINGLE-SUPPLY ULTRASONIC CLAMPING/LIMITING RECEIVER AMPLIFIER PRECISION SINGLE-SUPPLY VOLTAGE COMPARATOR PROGRAMMABLE PRECISION WINDOW COMPARATOR OUTLINE DIMENSIONS ORDERING GUIDE
Data Sheet OP292/OP492 50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER 5V 5V 6
Figure 39 shows a notch filter that achieves nearly 30 dB of
2 5kΩ 8 1/2 7 0.022µF OP292 V
60 Hz rejection while powered by only a single 12 V supply.
1/2 1 5 OUT 0.01µF OP292
The circuit also works well on 5 V systems. The filter uses a
3 1.1kΩ 14.3kΩ VIN 4
twin-T configuration, whose frequency selectivity depends
100µF 1.78kΩ 16.2kΩ 2200pF
heavily on the relative matching of the capacitors and resistors in
5kΩ 3300pF
040 the twin-T section. Mylar is a good choice for the capacitors of 00310- the twin-T, and the relative matching of the capacitors and resistors Figure 40. Four-Pole Bessel Low-Pass Filter Using Sallen-Key Topology determines the pass-band symmetry of the filter. Using 1%
LOW COST, LINEARIZED THERMISTOR AMPLIFIER
resistors and 5% capacitors produces satisfactory results. An inexpensive thermometer amplifier circuit can be implemented The amount of rejection and the Q of the filter is solely determined using low cost thermistors. One such implementation is shown by one resistor and is shown in the table with Figure 39. The in Figure 41. The circuit measures temperature over the range bottom amplifier is used to split the supply to bias the amplifier of 0°C to 70°C to an accuracy of ±0.3°C as the linearization to midlevel. The circuit can be modified to reject 50 Hz by simply circuit works well within a narrow temperature range. However, it changing the resistors in the twin-T section (R1 through R4) can measure higher temperatures but at a slightly reduced accuracy. from 2.67 kΩ to 3.16 kΩ and by changing R5 to ½ of 3.16 kΩ. For To achieve the aforementioned accuracy, the nonlinearity of the best results, the common value resistors can be from a resistor thermistor must be corrected. This is done by connecting the array for optimum matching characteristics. thermistor in parallel with the 10 kΩ in the feedback loop of the
R2
first stage amplifier. A constant operating current of 281 µA is
2.67kΩ
supplied by the resistor R1 with the 5 V reference from the
R1 C1 C2
REF195 such that the self-heating error of the thermistor is
12V 2.67kΩ 1µF 1µF 1/4
kept below 0.1°C.
OP492 1/4 VIN VOUT OP492
In many cases, the thermistor is placed some distance from the
R3 R4
signal conditioning circuit. Under this condition, a 0.1 µF capacitor
2.67kΩ 2.67kΩ R6
placed across R2 will help to suppress noise pickup.
C3 R5 100kΩ 2µF 1.335kΩ R7 RQ (1µF × 2) (2.67k ÷ 2) 1kΩ
This linearization network creates an offset voltage that is corrected
8kΩ
by summing a compensating current with Potentiometer P1. The
12V R8
temperature dependent signal is amplified by the second stage,
6V 100kΩ 1/4 OP492
producing a transfer coefficient of −10 mV/°C at the output.
R9 +
To calibrate, a precision decade box can be used in place of the
100kΩ C4 1µF
thermistor. For 0°C trim, the decade box is set to 32.650 kΩ, and P1 is adjusted until the output of the circuit reads 0 V. To
FILTER Q RQ (kΩ ) REJECTION (dB) VOLTAGE GAIN
trim the circuit at the full-scale temperature of 70°C, the decade
0.75 1.0 40 1.33
box is then set to 1.752 kΩ, and P2 is adjusted until the circuit
1.00 2.0 35 1.50
reads −0.70 V.
1.25 3.0 30 1.60 2.50 8.0 25 1.80 R 1 T 5.00 18 20 1.90 15V 10kΩ NTC 10.00 38 15 1.95 R12 NOTES 17.8kΩ R12 P2 1. FOR 50Hz APPLICATION CHANGE R12 TO R4 TO 3.16kΩ
039
1.0µF REF195 200Ω AND R5 TO 1.58kΩ (3.16kΩ ÷ 2) 17.8kΩ
00310-
R3 R6 70°C TRIM 1µF
Figure 39. Single-Supply 50 Hz/60 Hz Notch Filter
10kΩ 7.87kΩ 1/2 OP292 5V R4 1/2 FOUR-POLE BESSEL LOW-PASS FILTER 41.2kΩ OP292 VOUT R5 –10mV/°C
The linear phase filter in Figure 40 is designed to roll off at a
P1 806kΩ
voice-band cutoff frequency of 3.6 kHz. The four poles are
10kΩ 0°C TRIM
formed by two cascading stages of 2-pole Sallen-Key filters.
1RT = ALPHATHERMISTOR 13A1002-C3.
041
2R1 = 0.1% IMPERIAL ASTRONICS M015.
00310-
NOTES 1. ALL RESISTORS ARE 1%, 25ppm/°C EXCEPT R5 = 1%, 100ppm/°C.
Figure 41. Low Cost Linearized Thermistor Amplifier Rev. D | Page 15 of 20 Document Outline FEATURES APPLICATIONS PIN CONFIGURATIONS GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS INFORMATION PHASE REVERSAL POWER SUPPLY CONSIDERATIONS TYPICAL APPLICATIONS DIRECT ACCESS ARRANGEMENT FOR TELEPHONE LINE INTERFACE SINGLE-SUPPLY INSTRUMENTATION AMPLIFIER DAC OUTPUT AMPLIFIER 50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER FOUR-POLE BESSEL LOW-PASS FILTER LOW COST, LINEARIZED THERMISTOR AMPLIFIER SINGLE-SUPPLY ULTRASONIC CLAMPING/LIMITING RECEIVER AMPLIFIER PRECISION SINGLE-SUPPLY VOLTAGE COMPARATOR PROGRAMMABLE PRECISION WINDOW COMPARATOR OUTLINE DIMENSIONS ORDERING GUIDE