Single or dual differential?

[Elso Kwak]

ppl,
Oops my U440s are from Intersil.
No U440 on www.fairchildsemi.com
Linear Systems did not bother to send me a sample....
I understand the boss of LS run away from Intersil.
HA-5142, HA2640, HA5160 f. a.
I do not hear much difference bewtween a U440 and a 2N3958A....
2SK389 is a completely different beast though. Hahahahaha

 

[GEirin]

Phase Linear

Hi all.

I am very interested in to know the topology dual diff input the Phase Linear 400-700?
What is yours opinions?

Thanks
GEirin

 

[john curl]

This is a single diff input with a differential 2'nd stage.

 

[GEirin]

Thanks Mr. Curl.

Input: 2 diff.
Vas: single transistor

What is the purpose of the two diff.? Why?

 

[john curl]

Common mode rejection and maybe lower distortion.

 

[GEirin]

Un single differential stage, suffers from the disadvantage of asymmetrical clipping characteristics. In the Phase Linear, the configuration topology input produced symmetrical clipping?

 

[lumanauw]

This schematic is from 1974 RCA book. 2xRCA 1A11 performs input differential. 2xRCA 1A10 makes a differential level shifter. between bases of these 2xRCA 1A10 there are diode back to back, performing anti-clipping circuit (differential input is limited to 1 dioda drop each way). The left 1A10 has the collector grounded, the right 1A10 performs as VAS.
I think it is the anti-clipping mechanism that is aimed with this CCT.