差動(dòng)放大器計(jì)算器

時(shí)間:2013-02-15  來(lái)源:  作者:
關(guān)鍵字:差動(dòng)放大器   計(jì)算器      

這個(gè)計(jì)算器計(jì)算偏置電壓和電流,以及增益和頻率響應(yīng)。 

R1 (KΩ) 
R2 (KΩ)
RC (Collector resistor)集電極電阻 (KΩ) 
RE (Emitter resistor)發(fā)射極電阻 (KΩ) 
VP (Supply Voltage)電源電壓 (V)
Beta (DC Current Gain)直流電流增益
VBE (Base to emitter drop)基極-發(fā)射極壓降 (V)
Rs (Source Resistance): 電源內(nèi)阻 (Ω)
RL (Load resistor)負(fù)載電阻 (Ω) 
fT (Current Gain BW Product):電流增益帶寬 (MHz)
CCB (Cu Collector-Base Cap.): 集電極與基極間電容 (pF)
CBE (Cπ, Base-Emitter Cap.):基極和發(fā)射極之間的電容(可選)  (pF)

VC (Collector Voltage)集電極電壓 (V) 
VE (Emitter Voltage)發(fā)射極電壓 (V) 
VB (Base Voltage)基極電壓 (V) 
IE (Emitter Voltage)發(fā)射極電壓 (mA) 
IC (Collector Voltage)集電極電壓 (mA) 
IB (Base Voltage)基極電壓 (mA) 
gm (Transconductance)跨導(dǎo)
rπ (Input Resistance of BJT at low freq)晶體管輸入阻抗,低頻率的 (Ω)
re  (Ω)
RIN (Input Resistance of Amp)放大器輸入阻抗 (KΩ)

 

A (Amplifier Voltage Gain)放大器的電壓增益
fP1 (MHz)
fP2 (MHz)

Equations

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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