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US 6,605,994 B2Granted
Stabilized high band width differential emitter follower amplifier
AssigneeAgere Systems Inc.
InventorsJong K. Kim, Elangovan Nainar
Life of this patent
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Abstract
A differential amplifier with an emitter follower input stage includes an RC network which provides negative common mode feedback to stabilize the emitter follower stage. The feedback network provides negative common mode feedback from collector to base of the emitter follower transistors.
Claims24
An amplifier comprising:
- a first emitter follower transistor having a base, a collector and an emitter, and exhibiting a first parasitic capacitance between its collector and its base;
- a second emitter follower transistor having a base, a collector and an emitter, and exhibiting a second parasitic capacitance between its collector and its base;
- a differential pair of transistors connected to the emitters of the first and second emitter follower transistors;
- and
- a negative feedback circuit connected to the collectors of the first and second emitter follower transistors for providing negative common mode feedback to the first and second emitter follower transistors through the first and second parasitic capacitances, respectively.
2 more elements
An amplifier comprising:
- a pair of emitter follower transistors;
- a resistance-capacitance (RC) network connected to the pair of emitter follower transistors to provide negative feedback from collector to base of the emitter follower transistors with common mode gain through parasitic capacitances of the emitter follower transistors.
An amplifier comprising:
- a first emitter follower transistor having a base, a collector and an emitter;
- a second emitter follower transistor having a base, a collector and an emitter;
- a differential pair of transistors connected to the emitters of the first and second emitter follower transistors;
- and
- a negative feedback circuit connected to the collectors of the first and second emitter follower transistors for providing negative common mode feedback to the first and second emitter follower transistors, the feedback circuit comprising:
- a resistance connected between the collectors of the first and second emitter follower transistors and a first voltage node;
- and
- a capacitance connected to the collectors of the first and second emitter follower transistors.
5 more elements
An amplifier comprising:
- a first emitter follower transistor having a base, a collector and an emitter;
- a second emitter follower transistor having a base, a collector and an emitter;
- a differential pair of transistors connected to the emitters of the first and second emitter follower transistors;
- and
- a negative feedback circuit connected to the collectors of the first and second emitter follower transistors for providing negative common mode feedback to the first and second emitter follower transistors, the feedback circuit comprising:
- a resistance connected to the collectors of the first and second emitter follower transistors;
- a capacitance connected to the collectors of the first and second emitter follower transistors;
- and
- a current source connected to the collectors of the first and second emitter follower transistors.
6 more elements
An amplifier comprising:
- a pair of emitter follower transistors;
- a resistance-capacitance (RC) network connected to a collector of each of the emitter follower transistors to provide negative feedback from collector to base of the emitter follower transistors with common mode gain;
- and
- a current source connected to the collectors of the emitter follower transistors.
1 more element
An amplifier comprising:
- a pair of emitter follower transistors each having a base, a collector and an emitter;
- and
- a resistance-capacitance (RC) network for providing negative feedback from collector to base of the emitter follower transistors with common mode gain, the RC network comprising:
- a resistance connected between the collectors of the emitter follower transistors and a first voltage node;
- and
- a capacitance connected to the collectors of the emitter follower transistors.
3 more elements
Dependencies are inferred from the claim text.