Probe for combined signals

• US 7,205,784 B2
• Filed: 05/25/2006
• Issued: 04/17/2007
• Est. Priority Date: 11/13/2002
• Status: Expired due to Fees

• Current Assignee: Cascade Microtech Incorporated (FormFactor Incorporated)
• Original Assignee: Cascade Microtech Incorporated (FormFactor Incorporated)
• Inventors: Andrews, Mike, Hayden, Leonard, Rumbaugh, Scott
• Primary Examiner(s): Nguyen; Ha Tran
• Assistant Examiner(s): Nguyen; Trung Q.
• Application Number:
  US11/442,503
• Publication Number:
  US 20060214677A1
• Time in Patent Office: 327 Days
• Field of Search: None
• US Class Current: 324/754.07
• CPC Class Codes: G01R 1/06738 related to tip portion
• CPC Class Codes: G01R 1/06766 Input circuits therefor
• CPC Class Codes: G01R 1/06772 High frequency probes

Abstract

A direct current and a modulation signal are simultaneously applied to contact pads on a device under test, such as a laser diode, with a probe that reduces signal distortion and power dissipation by transmitting a modulated signal through an impedance matching resistor and transmitting of a direct current over a second signal path that avoids the impedance matching resistor.

Claims

1. A probing system for interconnecting a source of a modulated signal and a source of a direct current to a terminal of a device under test having a device impedance, said probing system comprising:

(a) a capacitor;

(b) a resistor connected in series with said capacitor, said resistor and said capacitor interconnecting said source of said modulated signal and said terminal of said device under test; and

(c) an inductor interconnecting said source of direct current and said terminal of said device under test.

2. The probing system of claim 1 wherein an impedance of said inductor is substantially greater than said device impedance at a frequency of said modulated signal.

3. The probing system of claim 1 wherein an impedance of said resistor is substantially equal to an impedance of an interconnection of said resistor and said source of said modulated signal.