Unity-Gain Bandwidth of BJT Calculator

✖Transconductance is the ratio of the change in current at the output terminal to the change in the voltage at the input terminal of an active device.ⓘ Transconductance [G_m]			+10% -10%
✖Emitter-base capacitance is the capacitance between the emitter and the base.ⓘ Emitter-Base Capacitance [C_eb]			+10% -10%
✖Collector-Base Junction Capacitance in active mode is reverse biased and is the capacitance between collector and base.ⓘ Collector-Base Junction Capacitance [C_cb]			+10% -10%

✖Unity-Gain Bandwidth is simply the frequency of an input signal at which the open-loop gain is equal to 1.ⓘ Unity-Gain Bandwidth of BJT [ω_T]

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Formula

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Unity-Gain Bandwidth of BJT

Formula

`"ω"_{"T"} = "G"_{"m"}/("C"_{"eb"}+"C"_{"cb"})`

Example

`"637.037Hz"="1.72mS"/("1.5μF"+"1.2μF")`

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Unity-Gain Bandwidth of BJT Solution

STEP 0: Pre-Calculation Summary

Formula Used

Unity-Gain Bandwidth = Transconductance/(Emitter-Base Capacitance+Collector-Base Junction Capacitance)
ω_T = G_m/(C_eb+C_cb)
This formula uses 4 Variables

Variables Used

Unity-Gain Bandwidth - (Measured in Hertz) - Unity-Gain Bandwidth is simply the frequency of an input signal at which the open-loop gain is equal to 1.
Transconductance - (Measured in Siemens) - Transconductance is the ratio of the change in current at the output terminal to the change in the voltage at the input terminal of an active device.
Emitter-Base Capacitance - (Measured in Farad) - Emitter-base capacitance is the capacitance between the emitter and the base.
Collector-Base Junction Capacitance - (Measured in Farad) - Collector-Base Junction Capacitance in active mode is reverse biased and is the capacitance between collector and base.

STEP 1: Convert Input(s) to Base Unit

Transconductance: 1.72 Millisiemens --> 0.00172 Siemens (Check conversion here)
Emitter-Base Capacitance: 1.5 Microfarad --> 1.5E-06 Farad (Check conversion here)
Collector-Base Junction Capacitance: 1.2 Microfarad --> 1.2E-06 Farad (Check conversion here)

STEP 2: Evaluate Formula

Substituting Input Values in Formula

ω_T = G_m/(C_eb+C_cb) --> 0.00172/(1.5E-06+1.2E-06)

Evaluating ... ...

ω_T = 637.037037037037

STEP 3: Convert Result to Output's Unit

637.037037037037 Hertz --> No Conversion Required

FINAL ANSWER

637.037037037037 ≈ 637.037 Hertz <-- Unity-Gain Bandwidth

(Calculation completed in 00.004 seconds)

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Home » Engineering » Electronics » BJT » Analog Electronics » Internal Capacitive Effects and High Frequency Model » Unity-Gain Bandwidth of BJT

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Created by Payal Priya

Birsa Institute of Technology (BIT), Sindri

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National Institute Of Technology (NIT), Hamirpur

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< 11 Internal Capacitive Effects and High Frequency Model Calculators

Collector-Base Capacitance

Go Collector Base Capacitance = Emitter Base Junction Area*sqrt((Charge*Permittivity*Doping Density)/(2*(Built In Potential+Reverse Bias Junction)))

Collector-Base Junction Capacitance

Go Collector-Base Junction Capacitance = Collector-Base Junction Capacitance at 0 Voltage/(1+(Reverse-Bias Voltage/Built-In Voltage))^Grading Coefficient

Transition Frequency of BJT

Go Transition Frequency = Transconductance/(2*pi*(Emitter-Base Capacitance+Collector-Base Junction Capacitance))

Concentration of Electrons Injected from Emitter to Base

Go Concentration of e- Injected from Emitter to Base = Thermal Equilibrium Concentration*e^(Base-Emitter Voltage/Thermal Voltage)

Unity-Gain Bandwidth of BJT

Go Unity-Gain Bandwidth = Transconductance/(Emitter-Base Capacitance+Collector-Base Junction Capacitance)

Small-Signal Diffusion Capacitance of BJT

Go Emitter-Base Capacitance = Device Constant*(Collector Current/Threshold Voltage)

Thermal Equilibrium Concentration of Minority Charge Carrier

Go Thermal Equilibrium Concentration = ((Intrinsic Carrier Density)^2)/Doping Concentration of Base

Small-Signal Diffusion Capacitance

Go Emitter-Base Capacitance = Device Constant*Transconductance

Stored Electron Charge in Base of BJT

Go Stored Electron Charge = Device Constant*Collector Current

Transition Frequency of BJT given Device Constant

Go Transition Frequency = 1/(2*pi*Device Constant)

Base-Emitter Junction Capacitance

Go Base–Emitter Junction Capacitance = 2*Emitter-Base Capacitance

< 20 BJT Circuit Calculators

Transition Frequency of BJT

Go Transition Frequency = Transconductance/(2*pi*(Emitter-Base Capacitance+Collector-Base Junction Capacitance))

Base Current of PNP Transistor using Saturation Current

Go Base Current = (Saturation Current/Common Emitter Current Gain)*e^(Base-Emitter Voltage/Thermal Voltage)

Total Power Dissipated in BJT

Go Power = Collector-Emitter Voltage*Collector Current+Base-Emitter Voltage*Base Current

Unity-Gain Bandwidth of BJT

Go Unity-Gain Bandwidth = Transconductance/(Emitter-Base Capacitance+Collector-Base Junction Capacitance)

Reference Current of BJT Mirror

Go Reference Current = Collector Current+(2*Collector Current)/Common Emitter Current Gain

Common Mode Rejection Ratio

Go Common Mode Rejection Ratio = 20*log10(Differential Mode Gain/Common Mode Gain)

Output Resistance of BJT

Go Resistance = (Supply Voltage+Collector-Emitter Voltage)/Collector Current

Thermal Equilibrium Concentration of Minority Charge Carrier

Go Thermal Equilibrium Concentration = ((Intrinsic Carrier Density)^2)/Doping Concentration of Base

Output Voltage of BJT Amplifier

Go Output Voltage = Supply Voltage-Drain Current*Load Resistance

Total Power Supplied in BJT

Go Power = Supply Voltage*(Collector Current+Input Current)

Common-Base Current Gain

Go Common-Base Current Gain = Common Emitter Current Gain/(Common Emitter Current Gain+1)

Collector to Emitter Voltage at Saturation

Go Collector-Emitter Voltage = Base-Emitter Voltage-Base-Collector Voltage

Base Current of PNP Transistor given Emitter Current

Go Base Current = Emitter Current/(Common Emitter Current Gain+1)

Base Current of PNP Transistor using Collector Current

Go Base Current = Collector Current/Common Emitter Current Gain

Collector Current using Emitter Current

Go Collector Current = Common-Base Current Gain*Emitter Current

Base Current of PNP Transistor using Common-Base Current Gain

Go Base Current = (1-Common-Base Current Gain)*Emitter Current

Collector Current of BJT

Go Collector Current = Emitter Current-Base Current

Emitter Current of BJT

Go Emitter Current = Collector Current+Base Current

Short-Circuit Transconductance

Go Transconductance = Output Current/Input Voltage

Intrinsic Gain of BJT

Go Intrinsic Gain = Early Voltage/Thermal Voltage

Unity-Gain Bandwidth of BJT Formula

Unity-Gain Bandwidth = Transconductance/(Emitter-Base Capacitance+Collector-Base Junction Capacitance)
ω_T = G_m/(C_eb+C_cb)

What is the unity gain frequency?

The frequency at which the output signal is reduced by −3 db. The amplifier is tested in a unity-gain configuration, with a small signal applied, usually 200 mV p-p. A low-level signal is used to determine bandwidth because this eliminates the effects of the slew rate limit on the signal.

How to Calculate Unity-Gain Bandwidth of BJT?

Unity-Gain Bandwidth of BJT calculator uses Unity-Gain Bandwidth = Transconductance/(Emitter-Base Capacitance+Collector-Base Junction Capacitance) to calculate the Unity-Gain Bandwidth, The Unity-gain bandwidth of BJT formula is defined as the frequency at which the output signal is reduced by −3 db. Unity-Gain Bandwidth is denoted by ω_T symbol.

How to calculate Unity-Gain Bandwidth of BJT using this online calculator? To use this online calculator for Unity-Gain Bandwidth of BJT, enter Transconductance (G_m), Emitter-Base Capacitance (C_eb) & Collector-Base Junction Capacitance (C_cb) and hit the calculate button. Here is how the Unity-Gain Bandwidth of BJT calculation can be explained with given input values -> 637.037 = 0.00172/(1.5E-06+1.2E-06).

FAQ

What is Unity-Gain Bandwidth of BJT?

The Unity-gain bandwidth of BJT formula is defined as the frequency at which the output signal is reduced by −3 db and is represented as ω_T = G_m/(C_eb+C_cb) or Unity-Gain Bandwidth = Transconductance/(Emitter-Base Capacitance+Collector-Base Junction Capacitance). Transconductance is the ratio of the change in current at the output terminal to the change in the voltage at the input terminal of an active device, Emitter-base capacitance is the capacitance between the emitter and the base & Collector-Base Junction Capacitance in active mode is reverse biased and is the capacitance between collector and base.

How to calculate Unity-Gain Bandwidth of BJT?

The Unity-gain bandwidth of BJT formula is defined as the frequency at which the output signal is reduced by −3 db is calculated using Unity-Gain Bandwidth = Transconductance/(Emitter-Base Capacitance+Collector-Base Junction Capacitance). To calculate Unity-Gain Bandwidth of BJT, you need Transconductance (G_m), Emitter-Base Capacitance (C_eb) & Collector-Base Junction Capacitance (C_cb). With our tool, you need to enter the respective value for Transconductance, Emitter-Base Capacitance & Collector-Base Junction Capacitance and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

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