Rigid needle adapter

Rigid needle adapter serve the testing of electronic assemblies. They allow by thin rigid needles contacting finer structures assembled and bare boards, than is possible with a conventional adapter with spring pins. Furthermore, allow rigid needle adapter also contacting of low-speed micro plugs by the adapter is passed over the housing into the connector and there contact the rigid probes the plug.

Construction

In the rigid needle adapter guided rigid probes from the grid head to a Kontaktierpunkt ( Prüfpad ) are deflected in several adapter plates. Upon contacting the adapter is compressed in a certain height adapter to this Kontaktierhub. The rigid probes are thereby pressed around this hub in the corresponding spring pins ( pogo pins ) in the grid header, whereby the bonding force is established. Via these guide plates can be deflected 2 to 3 mm, which can be contacted on the specimen contact pitches down to 150 microns.

The grid head a spring contact pin is embedded per test point. This spring pins are arranged in a grid (hence comes the name), so that as large a test density can be achieved. Fine grid heads can so a 0.6 mm pitch have up to 280 spring pins / cm ². At a Kontaktierhub of about 2.5 mm, depending on the spring pin acting force of 0.4 N to 1.5 N per Kontaktierpunkt.

Life of rigid needle adapters

The Kontaktierspitze the rigid needle is flattened by the contact with time. The service life depends primarily on the material to be contacted. Under optimal conditions, approximately 500,000 contacts are achieved.

The embedded in the grid head spring pins are protected from larger lateral forces and dirt and so have a service life of more than one million contact cycles.

Combination of finest spring pins and needles Starr

The combination of spring pins and needles Starr are selected according to requirements.

Rigid needle adapter for very fine structures are also called Micro Adapter (English Contacting Micro Adapter, MCA ) respectively. The table shows an example, which spring pins can be used with which rigid probes combined in Micro adapters. You tried to use the thickest possible rigid probes, as these are more stable. The selection of the maximum rigid needle diameter is determined primarily by the existing Kontaktierabständen.

The maximum transmissible power is limited mostly by the spring pin or needle Kontakübergang ↔ specimen. It is defined by measuring the power (P = I ² · R ) in the spring pins and the rigid pins. For large currents, the rigid probes and spring pins may become hot and damage the device under test and the adaptation. The values ​​given in the following table are based on laboratory tests and benchmarks to give.

Continuous current ( ID) and pulse current (II ) at 10 ms:

  • A: ID = 0.3 A / II = 0.9 A
  • B: ID = 0.6 A / II = 1.8 A
  • C: ID = 1.0 A / II = 3.0 A
  • D: ID = 2.0 A / II = 6.0 A
  • E: ID = 3.0 A / II = 9.0 A

The possible test voltage can only be roughly calculated, since the influence of the humidity plays a big role. A rule of thumb: a voltage of 1000 V requires a distance of approximately 1 mm. With this rule of thumb, the following formula can be set up for the Needle distance:

For example, a pitch of 0.2 mm is contacted with a pin diameter of 0.13 mm. The maximum test voltage is then: 1000 V / mm × ( 0.2 mm - 0.13 mm) = 70 volts

Applications of rigid needle adapters

By miniaturizing the circuit traces on circuit boards are becoming narrower. They can be contacted by conventional spring pin adapters often then not. Rigid needle adapter can be applied in the following manner:

Use in a vacuum adapter

If the rigid needle adapter built compact, it can be integrated into a conventional vacuum adapter. The vacuum is used for the stroke, the specimen itself is in a vacuum- free zone. The adapter can be removed one or both sides and also as a 2- Stufenkontaktierung for separate in-circuit test and functional test.

Features:

  • Contact on Microvias, test pads, micro plug
  • Single-and double -sided bonding
  • Contact pad > 400 microns ( In centering on fishing pins )
  • Up to 100 test points / cm ² with a 1 -mm grid

Inline use

The rigid needle adapter can be used in semi-and fully automatic handling systems for the testing of bare and assembled printed circuit boards. The Kontaktierpitch is <0.4 mm.

Features:

  • Contact on Microvias, test pads, micro plug
  • Single-and double -sided bonding
  • Contact pad > 70 microns ( with optical centering)
  • Contact pad > 300 microns ( without optical centering)
  • Up to 280 test points / cm ² ( with a 0.6 -mm grid )

Use as a chip adapter

The rigid needle adapter can also be used as a module in combination with conventional adapter technology or with individual stroke control. The combination has the advantage that the coarser structures can be tapped on the specimens with a conventional spring pin adapter and the more expensive rigid needle insert is used only for the fine structure of the chip integrated circuits in production.

Features:

  • Contact on test pads
  • Single-and double -sided bonding
  • Contact pad > 250 microns
  • Kontaktierpitch > 400 microns
  • Up to 280 test points / cm ²

Use as a plug adapter

When contacting small connectors on circuit boards, the guide of the adapter is usually done via the connector housing, thus the tolerances of the support and installation shall be repealed. The advantage is that the smallest plugs can be contacted directly and the contacts must not be taken from a mating connector that needs to be replaced often after 20 to 30 mating cycles.

Features:

  • Direct contact with the connector contacts
  • Single-and double -sided bonding
  • Plug contact width > 150 microns
  • Up to 200 test points / cm ²
  • Pneumatic stroke initiation

Use in laser trimmer

The rigid needle adapter can also be used in the laser trimmer. In this case, the adapter moves underneath the substrate and supports it from below. From above the seal is pressed onto the substrate and then built up in the pressure chamber, the necessary counter-pressure to the rigid pins. Is this pressure exists, the adapter can contact on the component side, all measuring points at once. Through the pressure chamber all the resistors within the pressure chamber can be contacted at the same time, so that the laser trimming is more efficient.

Features:

  • Simultaneous contacting of all measuring points
  • Trim all resistors with no new contact positioning
  • Contact pad > 70 microns
  • Kontaktierpitch > 150 microns
  • Up to 280 test points / cm ²

Staggering

The goal of Staggering is to be able to check the finest structures with thick as possible rigid probes. When Staggering the Kontaktierpunkte are offset from each other on the boards so that they are as far away from each other. Here (thickness of the needles and isolation distance ), a relatively small distance A (distance between the contact points ) are achieved according to the Pythagorean theorem at a large distance C. The pitch, which can be realized in such an application, is made up of the outlined distances A and B:

Substituting this staggering at an MCA Micro adapter, contacting the following intervals is possible:

  • Rigid needle diameter 0.10 mm → pitch from 0.15 mm
  • Rigid needle diameter 0.13 mm → pitch from 0.20 mm
  • Rigid needle diameter 0.18 mm → pitch from 0.25 mm
  • Rigid needle diameter 0.30 mm → pitch from 0.40 mm
  • Rigid needle diameter 0.45 mm → pitch from 0.55 mm
  • Rigid needle diameter 0.60 mm → pitch from 0.70 mm
Electric power
590751
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