Products
This webpage doesn't work with Internet Explorer. Please use the latest version of Google Chrome, Microsoft Edge, Mozilla Firefox or Safari.
require 3 characters or more.
The information presented in this cross reference is based on TOSHIBA's selection criteria and should be treated as a suggestion only. Please carefully review the latest versions of all relevant information on the TOSHIBA products, including without limitation data sheets and validate all operating parameters of the TOSHIBA products to ensure that the suggested TOSHIBA products are truly compatible with your design and application.
Please note that this cross reference is based on TOSHIBA's estimate of compatibility with other manufacturers' products, based on other manufacturers' published data, at the time the data was collected.
TOSHIBA is not responsible for any incorrect or incomplete information. Information is subject to change at any time without notice.
require 3 characters or more.
Even when the ideal rectangular waveform (a fast-rising signal) is applied to the input of an op-amp, its output does not provide the ideal rectangular waveform as shown in Figure 3.
A change in output voltage per 1 μs is called a slew rate.
As shown in Figure 3, in the case of an op-amp with a low slew rate, a rectangular input signal appears as a trapezoidal signal at the output, and a sinusoidal input appears as a triangular signal at the output.
As shown in Figure 2, an op-amp with a higher cut-off frequency provides a greater bandwidth with the same closed-loop gain.
If you use an op amp with a low slew rate, the shape of the waveform will change and distortion will worsen.
Its maximum output frequency (fmax) can be calculated from the slew rate.For simplicity, we will first explain the case of using op-amp in unity gain.
The slew rate (SR) is expressed as:
SR = ΔVo / Δtr or ΔVo/ Δtf
Waveform distortion occurs when the maximum value of the output signal differentiated by time becomes higher than this SR.
Let the voltage of the input sine wave with an amplitude of A be Vin = Asinωt. Then, no waveform distortion occurs if the maximum change (differential value) in the amplitude of the input signal is less than the slew rate.
Since the differential value of the input signal is dVin / dt = Aωcosωt, its maximum value is Aω. Therefore, the maximum frequency that does not cause slew-inducted waveform distortion is theoretically calculated as follows, where A is the input amplitude.
SR = Aω =2πfmaxA
fmax = SR / 2πA
If there is no unity gain, the voltage gain of the amplification circuit is multiplied by Av, then Vo = Av x Vin.
The same can be said for unity gain.
dVout / dt = AvAω cosωt
SR = AvAω =AvA2πfmax
fmax = SR / 2πAAv
In practice, it is necessary to set fmax, allowing an adequate margin for the required frequency.