Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Versatile High Speed Coaxial for Package and Device Testing

IP.com Disclosure Number: IPCOM000099179D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-14
Document File: 3 page(s) / 165K

Publishing Venue

IBM

Related People

Arjavalingam, G: AUTHOR [+4]

Abstract

A novel high frequency coaxial "bird-beak" probe design is disclosed. A method is shown for building impedance test systems in-line with 50 L terminations in sampling oscilloscopes, utilizing these tips. the tips are incorporated in a new high performance source for supplying the input to wide bandwidth diodes and current-driven semiconductor devices.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Versatile High Speed Coaxial for Package and Device Testing

       A novel high frequency coaxial "bird-beak" probe design is
disclosed.  A method is shown for building impedance test systems
in-line with 50 L terminations in sampling oscilloscopes, utilizing
these tips. the tips are incorporated in a new high performance
source for supplying the input to wide bandwidth diodes and
current-driven semiconductor devices.

      Bird-beak-shaped probe tips are attached to semi-rigid cables.
The beryllium-copper tips bring the signal ground leads to the test
pads.  The tapered design is in Fig. 1.  The actual tip ends are 25 m
wide, which be accommodated on test pads as as 50 mm.  The coaxial
design allows for the testing a wide range of structures which can be
planar or  The photolithographically defined and etched tips make the
in-line transition from a inch diameter coaxial cable (RG 405/U, for
example). bird-beak shape was chosen in order to maintain the 50 L
environment when going from a dielectric constant of e 2.0 to air, e
= 1.  The large overlapping area reduces the (Z0 = ) since C = eAK/h,
where A = area, h = plate separation K = fringe factor.  The ground
return inductance is since the two leads are very close to each
other.

      Three-dimensional modelling of the probe-tip inductance
capacitance resulted in the following: L = 0.1625 nh and = 0.03 pf,
which represents a very small load on any test  Measurements on a 70
GHz sampling oscilloscope have that these probes are extendible to 24
GHz (14.5 risetime).  The calculated probe delay of about   LC  =
psec agrees fairly well with measured 4 psec delay, which includes
the effect of field in going from a coaxial structure to a parallel
configuration.

      A second embodiment represents a high input impedance system.
A 500 L probe provides a 10 times larger than any of the commonly
encountered 50 L  Such probes allow characterization of propagation
on unterminated lossy  transmission at intermediate points in
multi-drop networks, and study of switching-induced noise on power
supply leads. the 500 L is created by the series circuit of a
discrete (450 L) and the internal 50 L termination in the amplifier,
the m...