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For most current data sheet and other product information, visit www. They are also well suited for cell phone PA control loops and video processing 75?
Single, dual, and quad versions have identical specifications for maximum design flexibility. The OPA series operates on a single supply as low as 2. Output voltage swing is to within 10mV of the supply rails with a 10k?
Dual and quad designs feature completely independent circuitry for lowest crosstalk and freedom from interaction. Street Address: S. Tucson Blvd. Tel: Twx: ? Telex: ? FAX: ? Immediate Product Info: ? See Figure 6 for test circuit. Continuous Operating Temperature Exposure to absolute maximum conditions for extended periods may degrade device reliability. Input signals that can swing more than 0. 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.
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. Voltage Gain dB 80 60 40 20 0 0. They are unity-gain stable and suitable for a wide range of general purpose applications. They are also well suited for controlling the output power in cell phones.
These applications often require high speed and low noise. In addition, the OPA series offers a low cost solution for general purpose and consumer video applications 75? Excellent ac performance makes the OPA series well suited for audio applications. The class AB output stage is capable of driving ? Rail-to-rail input and output swing significantly increases dynamic range, especially in low voltage supply applications. Rail-to-Rail Input and Output.
The input is a 5Vp-p sinusoid. Output voltage swing is approximately 4. Power supply pins should be bypassed with 0. F ceramic capacitors. Parameters are guaranteed over the specified supply range—a unique feature of the OPA series. Most behavior remains virtually unchanged throughout the full operating voltage range. Parameters which vary significantly with operating voltage or temperature are shown in the typical performance curves. This is achieved with a complementary input stage—an N-channel input differential pair in parallel with a P-channel differential pair see Figure 2.
Simplified Schematic. A double-folded cascode adds the signal from the two input pairs and presents a differential signal to the class AB output stage. Normally, input bias current is approximately fA. Momentary voltages greater than mV beyond the power supply can be tolerated if the current on the input pins is limited to 10mA.
This is easily accomplished with an input resistor as shown in Figure 3. Many input signals are inherently current-limited to less than 10mA, therefore, a limiting resistor is not required. Increasing load resistance improves capacitive load drive capability. The effect becomes more significant with higher impedance networks. With heavier resistive loads ? However, all op amps under certain conditions may become unstable.
Op amp configuration, gain, and load value are just a few of the factors to consider when determining stability. An op amp in unity gain configuration is the most susceptible to the effects of capacitive load. In unity gain, OPA series op amps perform well with very large capacitive loads. The typical RIN? Feedback Capacitor Improves Dynamic Performance. It is suggested that a variable capacitor be used for the feedback capacitor since input capacitance may vary between op amps and layout capacitance is difficult to determine.
For the circuit shown in Figure 4, the value of the variable feedback capacitor should be chosen so that the input resistance times the input capacitance of the OPA typically 9pF plus the estimated parasitic layout capacitance equals the feedback capacitor times the feedback resistor: RIN?
The capacitor can be varied until optimum performance is obtained. However, they also offer excellent performance for higher speed converters.
When used with the miniature package options of the OPA series, the combination is ideal for space-limited applications. For further information, consult the ADS data sheet. When the op amp is connected with feedback, this value is reduced significantly by the loop gain of the op amp. For example, with dB of open-loop gain, the output impedance is reduced in unity-gain to less than 0.
At higher frequencies, the output impedance will rise as the open-loop gain of the op amp drops. However, at these frequencies the output also becomes capacitive due to parasitic capacitance. This prevents the output impedance from becoming too high, which can cause stability problems when driving capacitive loads.
As mentioned previously, the OPA has excellent capacitive load drive capability for an op amp with its bandwidth. The synchronized outputs of a composite video line driver extend below ground. As shown, the input to the op amp should be ac-coupled and shifted positively to provide adequate signal swing to account for these negative signals in a single-supply configuration.
The input is terminated with a 75? F capacitor to a voltage divider that provides the dc bias point to the input. Setting the optimal bias point requires some understanding of the nature of composite video signals. Refer to the discussion of rail-to-rail input. CB1 2k? VIN B1 2k? VIN B0 2k? VIN A1 2k? Video In C1 ? F C2 47? F R1 R2 75? C3 10? Single-Supply Video Line Driver.
RG R2 25k? R4 k? VIN R2 OPA C2 1nF —2. RL 20k?
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