The pole of a PMOS present mirror is a vital parameter that determines its frequency response. The next pole frequency ends in a quicker response time, whereas a decrease pole frequency ends in a slower response time. On this article, we are going to present you calculate the pole of a PMOS present mirror. We will even present some tips about enhance the frequency response of your present mirror.
The pole frequency of a PMOS present mirror is set by the next equation:
$$f_p = frac{1}{2pi R_L C_L}$$
The place:
- $$f_p$$ is the pole frequency in Hz
- $$R_L$$ is the load resistance in ohms
- $$C_L$$ is the load capacitance in farads
With a view to enhance the frequency response of your present mirror, you’ll be able to lower the worth of RL or CL. Nevertheless, lowering the worth of RL will even lower the output present of the present mirror. Equally, lowering the worth of CL will even lower the enter capacitance of the present mirror. Due to this fact, you could fastidiously think about the trade-offs concerned when selecting the values of RL and CL.
Along with the above, there are a number of different elements that may have an effect on the frequency response of a PMOS present mirror. These elements embody the transconductance of the PMOS transistors, the parasitic capacitances of the transistors, and the format of the present mirror. By fastidiously contemplating all of those elements, you’ll be able to design a present mirror with the specified frequency response.
Analytical Derivation of Pole Frequency
The pole frequency of a PMOS present mirror may be derived analytically utilizing the small-signal mannequin of the circuit. The transconductance of the PMOS transistor is given by:
$$g_m = frac{I_D}{V_{GS}-V_{th}}$$
the place $I_D$ is the drain present, $V_{GS}$ is the gate-source voltage, and $V_{th}$ is the edge voltage.
The output resistance of the PMOS transistor is given by:
$$r_o = frac{V_{DS}}{I_D}$$
the place $V_{DS}$ is the drain-source voltage.
The pole frequency is given by:
$$f_p = frac{1}{2pi r_oC_L}$$
the place $C_L$ is the load capacitance.
The next desk summarizes the important thing equations used within the analytical derivation of the pole frequency:
| Equation | Description |
|---|---|
| $$g_m = frac{I_D}{V_{GS}-V_{th}}$$ | Transconductance of the PMOS transistor |
| $$r_o = frac{V_{DS}}{I_D}$$ | Output resistance of the PMOS transistor |
| $$f_p = frac{1}{2pi r_oC_L}$$ | Pole frequency |
How To Calculate Pole Of Pmos Curent Mirror
To calculate the pole of a PMOS present mirror, you want to know the next parameters:
- The transconductance of the PMOS transistor (gm)
- The output capacitance of the PMOS transistor (Cout)
- The load resistance (RL)
The pole frequency is given by the next equation:
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fp = gm / (2π * Cout * RL)
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For instance, if the PMOS transistor has a transconductance of 10 mA/V, an output capacitance of 100 fF, and the load resistance is 10 kΩ, the pole frequency could be:
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fp = 10 mA/V / (2π * 100 fF * 10 kΩ) = 159 kHz
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Individuals Additionally Ask About How To Calculate Pole Of Pmos Curent Mirror
What’s the function of a present mirror?
A present mirror is an digital circuit that copies a present from one place to a different. It’s usually used to create a reference present or to amplify a present.
What are the various kinds of present mirrors?
There are two principal kinds of present mirrors: the bipolar junction transistor (BJT) present mirror and the MOS field-effect transistor (MOSFET) present mirror.
What are some great benefits of utilizing a PMOS present mirror?
PMOS present mirrors provide a number of benefits over BJT present mirrors. They’ve the next enter impedance, a wider bandwidth, and a decrease output impedance.
