Pcb

Reducing Design Cycle Times

Chris — Wed, 02 Apr 2008 20:44:24 +0200

By John Isaac, Mentor Graphics [ Courtesy of Assipe ]
In today’s competitive electronics industry, getting to market ahead of the competition can mean the difference between a successful product and one that misses its market window. Design cycle time plays a big part in determining a product launch schedule and the PCB layout portion of this process often is called upon to make up for early design phase schedule slips. One designer and one computer at a time can be a limiting factor.
Traditionally, designers are pulled in from other projects to assist with meeting deadlines, usually by adopting shift-work routines or physically splitting the design into multiple pieces. Both methods incur significant overhead costs that tend to negate the advantage of design collaboration. Partitioning the design into pieces and having designers work separately on each piece can help improve the situation. But putting that design database back together is a tedious and error-prone task.

The PCBs' finishing (H.A.L. Vs Chemical's Tin)

Chris — Tue, 05 Feb 2008 10:13:33 +0100

The printed circuits boards(PCB) for the production, are realized with a finishing process named H.A.L. (Hot Air Levelling) while the prototypes' realization, usually, with a finishing process named "chemical tin".

But which are the differences and especially, considering the prices, the process' quickness and the normative in force that bans the lead employment (RoHS), which is the best to be used and why?

H.A.L.'s finishing has been developed, and now is realized without lead, in practice a thin-film of tin is realized on the printed circuit and then a warm air jet is distributed, from here has the name H.A.L. To realize this process there are some industrials machinery a little bit expensive, and these machinery inscribe on the planarity of the process. In fact the H.A.L.'s limit is this planarity of the pitches, also with the best machinery, it isn't possible to realize the footprint for the "fine pitch" smd components including the BGA.

EN5312Q/EP5352Q/EP5362Q/EP5382Q DC-DC Converters

Chris — Fri, 25 Jan 2008 08:17:34 +0100

The Enpirion EN5312Q, EP5352Q, EP5362Q and EP5382Q DC-DC converters are packaged in 5x4x1.1mm 20-pin QFN packages that have the same thermal characteristics. The QFN packages are constructed with copper lead frames that have exposed thermal pads. The recommended maximum junction temperature for continuous operation is 125°C. Continuous operation above 125°C will reduce long-term reliability.

Evaluation kit for MP230FC/MP240FC pin out

Chris — Fri, 25 Jan 2008 08:10:57 +0100

This easy-to-use kit provides a platform for the evaluation of linear power amplifiers circuits using the MP230FC/MP240FC pin out. With ample bread boarding areas it is flexible enough to analyze a multitude of standard or proprietary circuit configurations. Critical connections for power supply bypassing are pre-wired. Components not usually readily available in engineering labs are provided. External connection to the evaluation kit can be made via the terminal block and the banana jacks at the edges of the circuit board.

LNBK20D2 LNB SUPPLY AND CONTROL VOLTAGE REGULATOR (PARALLEL INTERFACE)

Chris — Fri, 25 Jan 2008 07:53:18 +0100

Intended for analog and digital satellite receivers, the LNBK20D2 is a monolithic linear voltage regulator, assembled in SO-20, specifically designed to provide the powering voltages and the interfacing signals to the LNB downconverter situated in the antenna via the coaxial cable. It has the same functionality of the LNBP1X and LNBP20 series, at a reduced output current capability.

Mechanics and Electronics as Instrument for Minimized Drive Applications

Chris — Thu, 24 Jan 2008 22:24:42 +0100

The goal of this report is to show the electrical and mechanical requirements for power modules, such as compact outline, low inductance, thermal connection to heat sink and stress relief of the electrical interconnection. The special focus is the mechanical interaction between PCB, module and heat sink.

Assembly Instructions for CQFP Packages SMT on PCB

Chris — Thu, 24 Jan 2008 22:15:47 +0100

To minimize board-level vibration failure, it is important to attach a ceramic quad flat pack (CQFP) to system boards in the correct way. Following the correct procedures will not completely eliminate vibration failure, but will help prevent initial mistakes, which can minimize vibration failure. Because each customer’s application is different, Actel recommends that the user evaluate his/her application requirements and select the right material and procedures when attaching CQFP packages on system boards.

Mounting Considerations for International Rectifier’s Power Semiconductor Packages

Chris — Thu, 24 Jan 2008 22:07:14 +0100

It is important that power semiconductors are correctly mounted if full functionality is to be achieved. Incorrect mounting may lead to both thermal and mechanical problems. The aim of this Application Note is to describe good practise in the mounting of power semiconductors.

Minimum Size Copper Sense Resistors

Chris — Thu, 24 Jan 2008 22:01:11 +0100

The Micrel MIC5156/7/8 Super LDO™ Regulator Controllers require a moderately low-value current-sensing resistor. Building the resistor from printed-circuit board (PCB) copper is attractive; arbitrary values can be provided inexpensively. The ever-shrinking world of electronic assemblies requires minimizing the physical size of this resistor, which can present a power-dissipation issue that must be resolved to provide a reliable solution.

Designing P.C. Board Heat Sinks

Chris — Thu, 24 Jan 2008 21:44:28 +0100

System designers increasingly face the restriction of using all surface-mounted components in their new designs; even including the power components. Through-hole components can dissipate excess heat with clip-on or bolt-on heat sinks keeping things cool. Surface mounted components do not have this flexibility and rely on the conductive traces or pads on the printed circuit board for heat transfer.