## 差动放大器计算器

 R1 (KΩ) R2 (KΩ) RC(Collector resistor)集电极电阻 (KΩ) RE(Emitter resistor)发射极电阻 (KΩ) VP(Supply Voltage)电源电压 (V) Beta (DC Current Gain)直流电流增益 VBE (Base to emitter drop)基极-发射极压降 (V) Rs(Source Resistance): 电源内阻 (Ω) RL(Load resistor)负载电阻 (Ω) fT(Current Gain BW Product):电流增益带宽 (MHz) CCB(Cu Collector-Base Cap.): 集电极与基极间电容 (pF) CBE(Cπ, Base-Emitter Cap.):基极和发射极之间的电容(可选) (pF) VC(Collector Voltage)集电极电压 (V) VE(Emitter Voltage)发射极电压 (V) VB (Base Voltage)基极电压 (V) IE(Emitter Voltage)发射极电压 (mA) IC(Collector Voltage)集电极电压 (mA) IB (Base Voltage)基极电压 (mA) gm (Transconductance)跨导 rπ (Input Resistance of BJT at low freq)晶体管输入阻抗,低频率的 (Ω) re (Ω) RIN (Input Resistance of Amp)放大器输入阻抗 (KΩ) A (Amplifier Voltage Gain)放大器的电压增益 fP1 (MHz) fP2 (MHz) VB=  VP*R2/(R1+R2)

VE= VB-VBE

IE=VE/RE

Alpha= Beta/(Beta+1);

IC= Alpha*IE

VC= VP -  IC*RC/2

IB=IC/Beta

gm = Ic/25mA

re= Alpha/gm

rπ= Beta/gm

A=Alpha* rπ*RC/(Rs+2*rπ)/re

fP1=1/(2*π*(Rs||2*rπ)*(CBE/2+CBC))

fP2=1/(2*π*RC*CBC)

fT= gm/(2π*(CBE+CBC))

The lower pole is dominate:

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