Transimpedance amplifier for optical receiver

• US 5,455,705 A
• Filed: 03/14/1994
• Issued: 10/03/1995
• Est. Priority Date: 03/14/1994
• Status: Expired due to Term

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Gusinov, Alex
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/212,159
• Time in Patent Office: 568 Days
• Field of Search: 359/189, 359/194, 250/214 A
• US Class Current: 398/202
• CPC Class Codes: H03F 1/08 Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements wide-band amplifiers with inter-stage coupling networks incorporating these impedances H03F1/42
• CPC Class Codes: H03F 2200/264 An operational amplifier based integrator or transistor based integrator being used in an amplifying circuit
• CPC Class Codes: H03F 2200/78 A comparator being used in a controlling circuit of an amplifier
• CPC Class Codes: H03F 2203/45136 One differential amplifier in IC-block form being shown
• CPC Class Codes: H03F 2203/45494 the CSC comprising one or more potentiometers
• CPC Class Codes: H03F 2203/45528 the FBC comprising one or more passive resistors and being coupled between the LC and the IC
• CPC Class Codes: H03F 2203/45722 the LC comprising one or more source followers, as post buffer or driver stages, in cascade in the LC
• CPC Class Codes: H03F 3/08 controlled by light
• CPC Class Codes: H03F 3/087 with IC amplifier blocks H03F3/085 takes precedence
• CPC Class Codes: H03F 3/45098 PI types H03F3/45125, H03F3/45152 take precedence
• CPC Class Codes: H03F 3/45197 Pl types H03F3/45224, H03F3/45251 take precedence
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit
• CPC Class Codes: H04B 10/6932 Bandwidth control of bit rate adaptation

Abstract

A transimpedance amplifier for an optical receiver includes an integrator circuit for receiving a current input from a photodetector; an integrator capacitance between the input and output of the integrator circuit; a gain stage responsive to the output of the integrator circuit for providing an output voltage representative of the current input to the integrator circuit; and a feedback resistance connected between the output of the gain stage and the input of the integrator circuit for establishing the nominal gain of and in conjunction with the integrator circuit for setting the nominal bandwidth of the transimpedance amplifier; the gain stage may have a gain greater than unity for increasing the bandwidth by the factor of the gain and the gain stage may include a trimmable resistance for adjusting the gain both below and above unity.

Claims

1. A transimpedance amplifier for an optical receiver comprising:

an integrator circuit for receiving a current input from a photodetector;

an integrator capacitance between an input and output of said integrator circuit;

a gain stage, responsive to said output of said integrator circuit, for providing an output voltage representative of the current input to said integrator circuit; and

a feedback resistance connected between the output of said gain stage and said input of said integrator circuit for establishing the nominal gain of, and in conjunction with said integrator capacitance for setting the nominal bandwidth of, the transimpedance amplifier;

where said gain stage increases the bandwidth by the factor of the gain.

2. The transimpedance amplifier for an optical receiver of claim 1 in which said gain stage includes a trimmable resistance to adjust the gain of said gain stage.

3. The transimpedance amplifier for an optical receiver of claim 2 in which the transimpedance amplifier is fabricated as an integrated circuit and said trimmable resistance is in said integrated circuit.

4. The transimpedance amplifier for an optical receiver of claim 2 in which the transimpedance amplifier is fabricated as an integrated circuit and said trimmable resistance is external to said integrated circuit.

5. The transimpedance amplifier for an optical receiver of claim 2 in which said trimmable resistance is approximately several orders of magnitude smaller than said feedback resistance.

6. A transimpedance amplifier for an optical receiver comprising:

an integrator circuit for receiving a current input from a photodetector;

an integrator capacitance between an input and output of said integrator circuit;

a gain stage, responsive to said output of said integrator circuit, for providing an output voltage representative of the current input to said integrator circuit; and

a feedback resistance connected between the output of said gain stage and said input of said integrator circuit for establishing the nominal gain of, and in conjunction with said integrator capacitance for setting the nominal bandwidth of, the transimpedance amplifier;

said gain stage including a trimmable resistance for adjusting the gain of said gain stage to control the bandwidth of the transimpedance amplifier.

7. The transimpedance amplifier for an optical receiver of claim 6 in which the transimpedance amplifier is fabricated as an integrated circuit and said trimmable resistance is in said integrated circuit.

8. The transimpedance amplifier for an optical receiver of claim 6 in which the transimpedance amplifier is fabricated as an integrated circuit and said trimmable resistance is external to said integrated circuit.

9. The transimpedance amplifier for an optical receiver of claim 6 in which said trimmable resistance is approximately several orders of magnitude smaller than said feedback resistance.