Features

Input and output swing between the rail

Low power consumption: 60 ampere/amplifier

gain bandwidth multiplication: 450 kHz

Single power operation operation : 3 V to 12 V

Low offset voltage: maximum 300 V

High open ring gain: 500 v/mv

Unit's gain stable

None Phase reverse

Application

Battery monitoring

Sensor regulator

Portable power control

Portable instrument

General description

OP196 series CBCMOS operational amplifier has micro -power operation and rail pairing input and output range.

The extremely low power requirements and the guarantee work from 3V to 12V make these amplifiers very suitable for monitoring battery usage and controlling battery charging. Its dynamic performance (including 26 NV/√Hz voltage noise density) is recommended for audio applications for battery power supply. 200 PF's capacitance load has no oscillation.

OP196/ OP296 / OP496 within the temperature range of industrial (-40 ° C to+125 ° C). 3V is stipulated in the temperature range of 0 ° C to 125 ° C.

Single OP196 and dual OP296 have 8 -line SOIC and TSSOP packaging. The four -way OP496 has 14 -line SOIC and Tssop encapsulation.

pin configuration

OP196/OP296/OP496 - Typical performance features

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Application information ] Functional description

OP196 series operational amplifier consisting of single power, micro -power, rail -to -rail input and output amplifier. The maximum value of the input offset voltage (VOS) is only 300 μV, and the output will provide ± 5 ma for load. The power supply is only 50 μA, the bandwidth is more than 450 kHz, and the conversion rate is 0.3 V/μs. TPC 36 is a simplified schematic diagram of OP196, which shows the novel circuit design technology used in this performance.

Enter overvoltage protection

OPX96 series operational amplifier uses a composite PNP/NPN input stage. FigThe electrode base voltage is 0V, if+in Vee. If+in and then exceed VEE, the knot will be pressed forward, and the large diode current will flow, which may damage the device. The same situation is also applicable to+in on the base of the transistor Q5 driven above the VCC. Therefore, unless the input current is limited, the inverter and non -inverter input shall not be driven above or below the power rail.

FIG. 1 shows the input characteristics of the OPX96 series. This photo is generated from the power pins connected to the ground and the collector of the collector connected to the input curve tracker. As shown in the figure, when the input voltage exceeds any power of more than 0.6V, the internal PN connecting power and allowing the current to flow from the input flow to the power supply. If the current is not limited, the amplifier may be damaged. To prevent damage, the input current should be limited to no more than 5 mAh.

The output phase reversed

Other calculations designed for the work of a single power supply, when the input is driven by the use -mode range that is used by its useful co -mode range The output voltage phase reverses. For a single power supply dual -type computing amplifier, the negative power source determines the lower limit of the scope of the co -mode. For these co -mode restrictions, the external diode is required to prevent the input signal from shifting off the negative power rail (ie GND) of the device and trigger the output phase reversal.

The OPX96 series operational amplifier is not affected by the output phase reversal due to its novel input structure. Figure 2 illustrates the performance of the OPX96 computing amplifier when the input is driven to the power rail. As mentioned earlier, the amplifier input current must be restricted, if the input is driven by the supply track. In the circuit in FIG. 2, the power amplitude is ± 15 V, and the power supply voltage is only ± 5 V. In this case, 2 k source resistance limits the input current to 5 mA.

Input offset voltage zero position

OP196 provides two offset adjustment terminals, which can be used to zero the internal VO of the amplifier. Generally speaking, the terminal of the computing amplifier is not used to adjust the offset voltage of the system. It is recommended to use 100 k potential meter, as shown in Figure 3 to make the offset voltage of the OP196 zero. The bias zero will not adversely affect the performance of TCVOS, provided that the temperature coefficient of fine -tuning potentiometer does not exceed ± 100 ppm/° C.

Drive capacitance load

OP196 series amplifier unconditional stability, capacitor load less than 170pf. In the driver technology shown in Figure 4, the driver technology of the capacitance load is shown in Figure 4.

A micro -power fake generator

Some single -power supply circuits are best working when the input voltage is higher than the ground, usually 1 with a power supply voltage 1 / /2. In these cases, fake ground can be generated by using the amplifier buffer. A circuit is shown in Figure 5.

The circuit will generate a wrong grounding reference voltage under the voltage of 1/2, and consumes only about 55 μA voltage from the 5 V power supply. A capacitor output allowed 1 μ to be compensated at 1 place. The advantage of large capacitors is that not only the DC resistance of the load is very low, but its AC impedance is also very low.

Single power supply semi -wave and full -wave rectifier

OP296 is configured to be configured as a voltage follower operated by a single power supply, which can be at low frequencies ( lt; 400Hz) The application is used as a simple semi -wave rectifier. The full -wave rectifier can configure a pair of OP296, as shown in Figure 6.

The working principle of the circuit is: When the input signal is higher than 0V, the output of the amplifier A1 follows the input signal. Due to the output connected to A1 by the non -reversible input of the amplifier A2, the operation of the computing amplifier control forced the reverse input of A2 to have the same potential. The results show that the two ends of R1 have the same potential, and there is no current flowing in R1. Because there is no current in R1, the same conditions must be existing in R2; therefore, the output tracking input signal of the circuit. When the input signal is lower than 0 V, the output voltage of A1 is forced to 0 V. This situation is now forcing A2 to run as a reverse voltage follower, because the non -switching terminal of A2 is also at 0 V. The output voltage of VOUTA is a full -wave rectifier version of the input signal. When the input signal reaches below the ground, the resistance to the input of the irreversible input of A1 protects the ESD diode.

Fang wave oscillator

The oscillator circuit in FIG. 7 demonstrates the effects of the rail -to -rail output swing to reduce the effect of the power change on the frequency of the oscillator. This function is particularly valuable in battery power applications. In these applications, voltage adjustment may be unavailable. When the power supply voltage changes, the output frequency remains stable, because the RC charging current generated by the rail -to -rail passing is proportional to the power supply voltage. Because Schmidt trigger threshold level is also proportional to the power supply voltage, the frequency remains relatively independent of the power voltage. When the power supply voltage changes from 9V to 5V, the output frequency is only about 4Hz. The conversion rate of the amplifier limits the maximum value of the oscillation frequency to the power supply voltage of 5V about 200Hz.

A 3V low -voltage differential stabilizer

Figure 8 shows a simple 3V voltage regulator design. The regulator can provide a load current of 50 mA, while allowing 0.2 volt voltage voltage. OP296's rail pairing output swing is easy to drive the MJE350 transistor without a special drive circuit. Its launch pole voltage is almost not extremely low than the launch when the launch is cut. Under the full load and low-emission pole-set voltage,Crystal tube β tends to decrease. The additional base current is easy to process by OP296.

AD589 provides a 1.235V reference voltage for the regulator. OP296 runs with an irreversible gain of 2.43, driving the output voltage of 3.0 V of the MJE350. Because the MJE350 works in the inverse (public launch pole) mode, the output feedback feedback is applied to the non -conversion input of OP296.

FIG. 9 shows the recovery characteristics of the regulator, when its output experience changes from a step current from 20 mia to 50 mAh.

Cushioning DAC output

Multi -channel Trimdacs #174; Such as AD8801/AD8803, is widely used in digital zero and similar applications. These DACs are swinging between rails, and the nominal output resistance is 5K . If you need lower output impedance, you can add an OP296 amplifier. Figure 10 shows two examples. A amplifier of OP296 is used as a simple buffer to reduce the output resistance of DAC A. OP296 provides rail -to -rail output drivers, and the working voltage is reduced to 3V at the same time, only 50 μA power current is required.

The next two DACs, B and C, add their output to another OP296 amplifier. In this circuit, DAC provides a rough output voltage settings, and DAC B is used for fine -tuning. The insertion of R1 and DAC B will weaken its contribution to the voltage and nodes of the DAC C output place.

High -voltage side current monitor

In the design of the power control circuit, a large number of design work is concentrated in ensuring the long -term reliability of the augmented crystal tube under extensive load current conditions. Therefore, in these designs, monitoring and restricting equipment power consumption are the most important. The circuit shown in FIG. 11 is an example of a 5V single -power high -voltage side current monitor. The monitor can be composed of a voltage regulator with a foldable flow limit function or a large current power supply with a pilot protection. The design uses an OP296 rail ring line input voltage range to detect the voltage drop through 0.1 the current downsor. The circuit uses P groove MOSFET as a feedback element to convert the differential input voltage of the computing amplifier to current. The current is then applied to R2 to generate a voltage, which is a linear representation of the load current. The transmission equation of the current monitor is as follows:

For the displayed component value, the transmission characteristics of the monitor output are 2.5 v/a.

Single -power RTD amplifier

In a operating circuit, a 49 ampel operating amplifier generates a voltageA single power supply for 49 volts.The circuit uses the wide output swing of OP496 to generate a 3.9V incentive voltage, and AD589 provides a 1.235V reference voltage for the bridge current.The computing amplifier A1 driving bridge keeps 6.19 k and 2.55 m resistors, which can generate 200 μA current sources.This water flow is evenly diverted, crossing the two -half part of the bridge.Therefore, 100 μA flows the output voltage that is proportional to its resistance by RTD.In order to improve the accuracy, it is recommended to use a 3 -wire resistor temperature detector to balance the line resistance of two 100 leg resistance.

The amplifier A2 and A3 are configured to configure the dual operation amplifier instrument amplifier amplifier.In order to facilitate measurement, the selection of IA resistors can generate 259 gains. Therefore, every 1 ° C of the temperature increases, the output voltage will increase by 10 MV.In order to reduce the measuring noise, the bandwidth of the amplifier is limited.0.1 μF capacitor and 100 k resistors on the amplifier A3 are connected in parallel to generate 16 Hz poles.

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