Datasheet OP490 (Analog Devices) - 10
| Manufacturer | Analog Devices |
| Description | Low Voltage, Micropower, Quad Operational Amplifier |
| Pages / Page | 16 / 10 — OP490. INPUT VOLTAGE PROTECTION. MICROPOWER VOLTAGE-CONTROLLED. … |
| Revision | E |
| File Format / Size | PDF / 225 Kb |
| Document Language | English |
OP490. INPUT VOLTAGE PROTECTION. MICROPOWER VOLTAGE-CONTROLLED. OSCILLATOR. 75nF. +15V. 200kΩ. 2 –. 1/4. 6 –. VCONTROL. 3 + A. SQUARE OUT. 5 +
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OP490 INPUT VOLTAGE PROTECTION
charging current symmetrically to yield positive and negative The OP490 uses a PNP input stage with protection resistors in ramps. The integrator is bounded by B, which acts as a Schmitt series with the inverting and noninverting inputs. The high trigger with a precise hysteresis of 1.67 V, set by Resistors R5, breakdown of the PNP transistors coupled with the protection R6, and R7, and the associated CMOS switches. The resulting resistors provides a large amount of input protection, allowing output of A is a triangle wave with upper and lower levels of the inputs to be taken 20 V beyond either supply without 3.33 V and 1.67 V. The output of B is a square wave with almost damaging the amplifier. rail-to-rail swing. With the components shown, frequency of operation is given by the equation
MICROPOWER VOLTAGE-CONTROLLED
f
OSCILLATOR
OUT = VCONTROL (Volts) × 10 Hz/V but this is easily changed by varying C1. The circuit operates An OP490 in combination with an inexpensive quad CMOS well up to a few hundred hertz. switch comprise the precision VCO of Figure 22. This circuit provides triangle and square wave outputs and draws only 75 μA from a 5 V supply. A acts as an integrator; S1 switches the
C1 75nF +15V +15V R1 200kΩ 2 – R5 4 200kΩ 1/4 1 6 – VCONTROL OP490 3 + A 1/4 7 11 OP490 SQUARE OUT R2 5 + B 200kΩ R4 TRIANGLE 200kΩ OUT R3 100kΩ R8 200kΩ +5V IN/OUT V R6 R7 DD +5V 1 14 200kΩ 200kΩ S1 OUT/IN CONT 2 13 OUT/IN CONT S2 3 12 IN/OUT IN/OUT 4 11 CONT OUT/IN S3 5 10 CONT OUT/IN +5V 6 9 S4 IN/OUT VSS 7 8
2 02 8- 30 00 Figure 22. Micropower Voltage Controlled Oscillator Rev. E | Page 10 of 16 Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAMS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS INFORMATION BATTERY-POWERED APPLICATIONS SINGLE-SUPPLY OUTPUT VOLTAGE RANGE INPUT VOLTAGE PROTECTION MICROPOWER VOLTAGE-CONTROLLED OSCILLATOR MICROPOWER SINGLE-SUPPLY QUAD VOLTAGE-OUTPUT 8-BIT DAC HIGH OUTPUT AMPLIFIER SINGLE-SUPPLY MICROPOWER QUAD PROGRAMMABLE GAIN AMPLIFIER OUTLINE DIMENSIONS ORDERING GUIDE
OP490 INPUT VOLTAGE PROTECTION
charging current symmetrically to yield positive and negative The OP490 uses a PNP input stage with protection resistors in ramps. The integrator is bounded by B, which acts as a Schmitt series with the inverting and noninverting inputs. The high trigger with a precise hysteresis of 1.67 V, set by Resistors R5, breakdown of the PNP transistors coupled with the protection R6, and R7, and the associated CMOS switches. The resulting resistors provides a large amount of input protection, allowing output of A is a triangle wave with upper and lower levels of the inputs to be taken 20 V beyond either supply without 3.33 V and 1.67 V. The output of B is a square wave with almost damaging the amplifier. rail-to-rail swing. With the components shown, frequency of operation is given by the equation
MICROPOWER VOLTAGE-CONTROLLED
f
OSCILLATOR
OUT = VCONTROL (Volts) × 10 Hz/V but this is easily changed by varying C1. The circuit operates An OP490 in combination with an inexpensive quad CMOS well up to a few hundred hertz. switch comprise the precision VCO of Figure 22. This circuit provides triangle and square wave outputs and draws only 75 μA from a 5 V supply. A acts as an integrator; S1 switches the
C1 75nF +15V +15V R1 200kΩ 2 – R5 4 200kΩ 1/4 1 6 – VCONTROL OP490 3 + A 1/4 7 11 OP490 SQUARE OUT R2 5 + B 200kΩ R4 TRIANGLE 200kΩ OUT R3 100kΩ R8 200kΩ +5V IN/OUT V R6 R7 DD +5V 1 14 200kΩ 200kΩ S1 OUT/IN CONT 2 13 OUT/IN CONT S2 3 12 IN/OUT IN/OUT 4 11 CONT OUT/IN S3 5 10 CONT OUT/IN +5V 6 9 S4 IN/OUT VSS 7 8
2 02 8- 30 00 Figure 22. Micropower Voltage Controlled Oscillator Rev. E | Page 10 of 16 Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAMS TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ELECTRICAL CHARACTERISTICS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION TYPICAL PERFORMANCE CHARACTERISTICS APPLICATIONS INFORMATION BATTERY-POWERED APPLICATIONS SINGLE-SUPPLY OUTPUT VOLTAGE RANGE INPUT VOLTAGE PROTECTION MICROPOWER VOLTAGE-CONTROLLED OSCILLATOR MICROPOWER SINGLE-SUPPLY QUAD VOLTAGE-OUTPUT 8-BIT DAC HIGH OUTPUT AMPLIFIER SINGLE-SUPPLY MICROPOWER QUAD PROGRAMMABLE GAIN AMPLIFIER OUTLINE DIMENSIONS ORDERING GUIDE
