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Differential amplifier - Coggle Diagram

- - - - VIN1 and VIN2 are grounded (𝑉_𝐵=0).
        
        Using Ohms Law, 𝑰𝑹𝑬=(𝑽𝒄𝒄−𝑽𝑬)/𝑹𝑬
      - Assume the transistors are well matched and large β,
      - Using KCL:
        
        𝑰𝑬=𝑰𝑹𝑬/𝟐
      - 𝑰𝑪=𝑰𝑬
        
        𝑰𝑩=𝑰𝑪/𝜷
      - 𝐼𝑅𝐶=𝐼𝐶⇒ 𝑽𝑹𝑪=𝐼𝑅𝐶 𝑅𝐶=𝑰𝑪 𝑹_𝑪
      - Using KVL, 𝑽𝑪=𝑽𝑬𝑬+𝑽_𝑹𝑪
      - VOUT1 = VOUT2 = VC
      - VEB = VB -VE
        VE = 0.7
  - - - To analysis its differential mode, the transistors are redrawn in equivalent t-model, and the following equations are obtained:
      - AC emitter resistance, 𝒓𝒆=𝑽𝑻/𝑰𝑬 =𝟐𝟓𝒎𝑽/𝑰𝑬
      - Differential Mode gain, 𝑨𝒅𝒎=𝑹𝑪/(𝟐𝒓_𝒆 )
      - To analysis its common mode, it is obtained from “half circuits”:
      - Common Mode gain, 𝑨𝒄𝒎=𝑹𝑪/(𝟐𝑹_𝑬 )
      - The ratio of the differential gain and common mode gain is:
        
        Common Mode Rejection Ratio, CMRR =𝑨𝒅𝒎/𝑨𝒄𝒎
- - - - To analysis its differential mode, the transistors are redrawn in equivalent t-model, and the following equations are obtained:
      - AC emitter resistance, re=VT/IE =25mV/IE
      - Differential Mode gain,Adm = RC/2re
      - To analysis its common mode, it is obtained from “half circuits”:
      - Common Mode gain,ACM = RC/2RE
      - The ratio of the differential gain and common mode gain is:
        
        Common Mode Rejection Ratio, CMRR =Adm/Acm
  - - - VIN1 and VIN2 are grounded (𝑉_𝐵=0).
        
        Using Ohms Law, 𝑰𝑹𝑬=(𝑽𝑬−𝑽𝑬𝑬)/𝑹𝑬
      - Assume the transistors are well matched and large β,
      - Using KCL:
        
        𝑰𝑬=𝑰𝑹𝑬/𝟐
      - 𝑰𝑪=𝑰𝑬
        
        𝑰𝑩=𝑰𝑪/𝜷
      - 𝐼𝑅𝐶=𝐼𝐶⇒ 𝑽𝑹𝑪=𝐼𝑅𝐶 𝑅𝐶=𝑰𝑪 𝑹_𝑪
      - Using KVL, 𝑽𝑪=𝑽𝑪𝑪−𝑽_𝑹𝑪
      - VOUT1 = VOUT2 = VC
      - VBE = VB -VE
        VE = -0.7
- - - - Common Mode Rejection Ratio, CMRR =𝑨𝒅𝒎/𝑨𝒄𝒎