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Tuesday, 17 September 2013

Android Media Player Dongle

Qmax Systems India Pvt Ltd offers the Android Media player dongle which is suitable in particular for ambitious newcomers who are looking for an inexpensive, diverse world of multimedia technology, without compromising highly innovative features and highest quality standards. For a digital all-rounder, Qmax systems have made  Android Media player dongle which  comes in series with the functions of a DVB-receiver, a media player, a multimedia server & client – all of these features being highly user-friendly.

Android Media player dongle comes in four different stylish casing designs, all being highly flexible- a single tuner model (DVB-C or DVB-T) comes with delivery – and as an introductory bonus retailers placing their first order of the Android Media player dongle(Android Hardware Development) receive two DVB-S-tuners for the price of one!


If customers’ demands increase, simply add elements, for example by installing a hard drive to create a personal video recorder. You can select from virtually all common optical drives available – from a simple DVD-Rom to a dual-layer burner – anything is connectable. 

A free slot is available to add a tuner module of choice. You can upgrade your Android Media player dongle with Twin-tuners to receive up to four programs via four different satellite transponders. Or take the Android Media player dongle to your vacation domicile.(Embedded Product development) Through the ability to adapt to satellite, cable or terristric reception – you are geared for all possible forms of reception – all with just one device.

For Pc-Pros looking for an individually created media center solution, the Android Media player dongle is ideal: previously owned existing large storage devices or DVD-burners do not have to be replaced. The installation of additional components becomes easy as 1-2-3, thanks to the user-friendly casing structure.
A variety of interchangeable displays in trendy color combinations ensures more individual expression, which is particularly attractive for so called case-modders(Hardware design services ).

And to assure easy communication with other home entertainment devices networked to the Android Media player dongle a Mini-PCI-base comes included in delivery – by adding the WLAN accessory, the Android Media player dongle  is also able to communicate within cordless networks.

Damarias Rodriguez has created video on Android Tutorial

PCB Documentation

The PCB’s documents should include the hardware dimensional drawings, schematic, BOM, layout file, component placement file, assembly drawings and instructions, and Gerber file set. User guides also are useful but aren’t required. The Gerber file set is PCB jargon for the output files of the layout that are used by PCB Design Services manufacturers to create the PCB. A complete set of Gerber files includes output files generated from the board layout file:
·         Silkscreen top and bottom
·         Solder mask top and bottom
·         All metal layers
·         Paste mask top and bottom
·         Component map (X-Y coordinates)
·         Assembly drawing top and bottom
·         Drill file
·         Drill legend
·         FAB outline (dimensions, special features)
·         Netlist file
The special features included in the FAB outline include but are not limited to notches, cutouts, bevels, back-filled vias-in-pad (used for BGA-type IC packages that have an array of pins under the device), blind/buried vias, surface finish and leveling, hole tolerances, layer count, and more.

Schematic Details
Schematics control the project, so accuracy and completeness are critical for success. PCB Layout Services  include information that is necessary for the proper operation of the circuit. A schematic should include adequate design details, such as pin numbers, names, component values, and ratings.
Embedded within each schematic symbol is the manufacturer part number used to determine price and specifications. The package specification determines the size of the footprint for each component. The first step should be to make sure the exposed copper for each pin is in the proper location and is slightly larger than the component pins (3 to 20 mils) depending on available area and soldering method.
Consider assembly when designing footprints, and follow the manufacturer’s recommended PCB (PCB CAD Services) footprint. Some components come in microscopic packages and do not allow room for extra copper. Even in these cases, a stripe of 2.5 to 3 mils of solder mask should be applied between every pin on the board.
Follow the rule of 10. Small vias have a finished hole size of 10 mils with 10 additional mils of pad ring. Traces should be 10 mils or further from the edge of the board. Trace-to-trace pitch is 10 mils (5-mil air-gap, 5-mil trace width, 1-oz copper). Vias with 40-mil diameter holes or larger should have a pad ring added for reliability. PCB Service Bureau  An additional 15 to 25 mils of clearance beyond the design rule should be instated for copper planes on outer layers from plane to pins. This reduces the risk of solder bridging at all solder points.
Component Placement
Component placement is next in the process and determined based on thermal management, function, and electrical noise considerations. A first-pass component placement step commences after the outline of component and interconnect position has been assigned. Printed Circuit Design Immediately after the individual components are placed, a placement review should be held and adjustments made to facilitate routing and optimize performance.
Placement and package sizes are often reconsidered and Electronic Product development changes are made at this point based on size and cost. Components absorbing greater than 10 mW or conducting more than 10 mA should be considered powerful enough for additional thermal and electrical considerations. Sensitive signals should be shielded from noise sources with planes and be kept impedance-controlled.  
Power management components should utilize ground planes or power planes for heat flow. Make high-current connections according to the acceptable voltage drop for the connection. Layer transitions for high current paths should be made with two to four vias at each layer transition.Place multiple vias at layer transitions to increase reliability, reduce resistive and inductive losses, and improve thermal conductivity.

Copper Pouring

The POLYGON command enables you to define areas which belong to a signal, connecting all of the related pads to this signal with thermal symbols. Such a signal retains a user-defined distance to any other signal path.

You can PCB design layers that contain multiple polygons such as different ground areas, and you can design polygons on multiple layers.

To demonstrate this feature of EAGLE, let’s fill the Top layer of a board with the GND signal. Reload the board demo2.brd once again, enlarge the window, and ripup the GND signal:


Use the DISPLAY command to switch on the layer 1Top, 17 Pads, 18 Vias, and 20 Dimension. Use the button None, in the menu, to switch off the display of all other layers first.

Click the POLYGON icon in the command toolbar and type:


to provide the name GND for the polygon to be defined. PCB Layout Design Only then will it belong to the GND signal.
Select the LayerTop from the combo box in the parameter toolbar. Then:

• left hand upper corner of the board outlines,
• right hand upper corner,
• right hand lower corner,
•  left hand lower corner.

The double click closes the polygon.

To start the calculation of the filled area, click the RATSNEST icon.

Since this is a very complex operation it can take some time.

As before, the pads belonging to the GND signal are connected with thermal symbols. Check this with:

In this case everything shown in the layer color is copper, since this layer is not plotted inversely (only supply layers defined with $name).

After a board has been loaded, polygons are displayed with their outlines.PCB Design Services  filled areas are displayed only after the RATSNEST command has been executed. Inversely, the RIPUP command and a single click on the edge of a polygon results in the outline display of this particular polygon.

Tuesday, 23 July 2013

High Frequency Design Techniques

High frequency design is where you really need to consider the effects of parasitic inductance, capacitance and impedance of your PCB layout. If your signal is too fast, and your track is too long, then the track can take on the properties of a transmission line. If you don’t use proper transmission line techniques in these situations then you can start to get reflections and other signal integrity problems.

A “critical length” track is one in which the propagation time of the signal starts to get close to the length of the track. On standard FR4 copper boards, a signal will travel roughly 6 inches every nano second. A rule of thumb states that you need to get really concerned when your track length approaches half of this figure. But in reality it can actually be much less than this. pcb design Remember that digital square wave signals have a harmonic content, so a 100MHz square wave can actually have signal components extending into the GHz region.
In high speed design, the ground plane is fundamental to preserving the integrity of your signals, and also reducing EMI emissions. It allows you to create “controlled impedance” traces, which match your electrical source and load. It also allows you to keep signals coupled “tight” to their return path (ground).

There are many ways to create controlled impedance “transmission” lines on a PCB. But the two most basic and popular ways are called Microstrip and Stripline.

A Microstrip is simply a trace on the top layer, with a ground plane below. The calculation involved to find the characteristic impedance of a Microstrip is relatively complex. trace, the height above the ground plane, and the relative permittivity of the PCB material.pcb design services  This is why it is important to keep the ground plane as close as possible to (usually) the top layer.

A Stripline is similar to the Microstrip, but it has an additional ground plane on top of the trace. So in this case, the trace would have to be on one of the inner layers. The advantage of stripline over microstrip is that most of the EMI radiation will be contained within the ground planes.

There are many free programs and spreadsheets available that will calculate all the variations of Microstrip and Stripline for you.

Some useful information and rules of thumb for high frequency design are:

·         Keep your high frequency signal tracks as short as possible.

·         Avoid running critical high frequency signal tracks over any cutout in your ground plane. This causes discontinuity in the signal return path, and can lead to EMI problems. Avoid cutouts in your ground plane wherever possible. A cutout is different to a split plane, which is fine, provided you keep your high frequency signal tracks over the relevant continuous plane.

·         Have one decoupling capacitor per power pin.

·         If possible, track the IC power pin to the bypass capacitor first, and then to the power plane. This will reduce switching noise on your power plane. For very high frequency designs, taking your power pindirectly to the power plane provides lower inductance, which may be more beneficial than lower noise on your plane.
·         Be aware that vias will cause discontinuities in the characteristic impedance of a transmission line.

·         To minimise crosstalk between two traces above a ground plane, minimise the distance between the plane and trace, and maximise the distance between traces. The coefficient of coupling between two traces is given by 1/(1+(Distance between traces / height from plane)^2))

·         Smaller diameter vias have lower parasitic inductance, and are thus preferred the higher in frequency you go.
·         Do not connect your main power input connector directly to your power planes, take it via your main filter capacitor(s).

     Double Sided Loading

Loading components on both sides of a PCB can have many benefits. Indeed, it is becoming an increasingly popular and necessary option when laying out a board. There are two main driving factors behind a decision to go with double sided loading. high speed pcb design The first is that of board size. If you require a particular board size, and all your components won’t fit on one side, then double sided load is an obvious way to go. The second reason is that it is required to meet certain electrical requirements. 

Often these days, with dense high speed surface mount devices packed onto a board, there is either no room for the many bypass capacitors required, multi layer pcb design or they cannot be placed close enough to the device to be effective. Ball Grid Array (BGA) devices are one such component that benefit from having the bypass capacitors on the bottom of the board. 

Friday, 25 January 2013

Looking for PCB Design

A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board (PWB) or etched wiring board. Printed circuit boards are used in virtually all but the simplest commercially produced electronic devices.

A PCB populated with electronic components is called a printed circuit assembly (PCA), printed circuit board assembly or PCB Assembly (PCBA). In informal use the term "PCB" is used both for bare and assembled boards, the context clarifying the meaning.

Circuit properties of the PCB

Each trace consists of a flat, narrow part of the copper foil that remains after etching. The resistance, determined by width and thickness, of the traces must be sufficiently low for the current the conductor will carry. Power and ground traces may need to be wider than signal traces. In a multi-layer board one entire layer may be mostly solid copper to act as a ground plane for shielding and power return. For microwave circuits, transmission lines can be laid out in the form of stripline and microstrip with carefully controlled dimensions to assure a consistent impedance. In radio-frequency and fast switching circuits the inductance and capacitance of the printed circuit board conductors become significant circuit elements, usually undesired; but they can be used as a deliberate part of the circuit design, obviating the need for additional discrete components.

Printed circuit assembly

After the printed circuit board (PCB) is completed, electronic components must be attached to form a functional printed circuit assembly,or PCA (sometimes called a "printed circuit board assembly" PCBA). In through-hole construction, component leads are inserted in holes. In surface-mount construction, the components are placed on pads or lands on the outer surfaces of the PCB. In both kinds of construction, component leads are electrically and mechanically fixed to the board with a molten metal solder.
There are a variety of soldering techniques used to attach components to a PCB. High volume production is usually done with SMT placement machine and bulk wave soldering or reflow ovens, but skilled technicians are able to solder very tiny parts (for instance 0201 packages which are 0.02 in. by 0.01 in.)by hand under a microscope, using tweezers and a fine tip soldering iron for small volume prototypes. Some parts may be extremely difficult to solder by hand, such as BGA packages.

Often, through-hole and surface-mount construction must be combined in a single assembly because some required components are available only in surface-mount packages, while others are available only in through-hole packages. Another reason to use both methods is that through-hole mounting can provide needed strength for components likely to endure physical stress, while components that are expected to go untouched will take up less space using surface-mount techniques.

After the board has been populated it may be tested in a variety of ways:
While the power is off, visual inspection, automated optical inspection. JEDEC guidelines for PCB component placement, soldering, and inspection are commonly used to maintain quality control in this stage of PCB manufacturing.

While the power is off, analog signature analysis, power-off testing.
While the power is on, in-circuit test, where physical measurements (i.e. voltage, frequency) can be done.
While the power is on, functional test, just checking if the PCB does what it had been designed to do.
To facilitate these tests, PCBs may be designed with extra pads to make temporary connections. Sometimes these pads must be isolated with resistors. The in-circuit test may also exercise boundary scan test features of some components. In-circuit test systems may also be used to program nonvolatile memory components on the board.

In boundary scan testing, test circuits integrated into various ICs on the board form temporary connections between the PCB traces to test that the ICs are mounted correctly. Boundary scan testing requires that all the ICs to be tested use a standard test configuration procedure, the most common one being the Joint Test Action Group (JTAG) standard. The JTAG test architecture provides a means to test interconnects between integrated circuits on a board without using physical test probes. JTAG tool vendors provide various types of stimulus and sophisticated algorithms, not only to detect the failing nets, but also to isolate the faults to specific nets, devices, and pins.

When boards fail the test, technicians may desolder and replace failed components, a task known as rework.


Printed circuit board artwork generation was initially a fully manual process done on clear mylar sheets at a scale of usually 2 or 4 times the desired size. The schematic diagram was first converted into a layout of components pin pads, then traces were routed to provide the required interconnections. Pre-printed non-reproducing mylar grids assisted in layout, and rub-on dry transfers of common arrangements of circuit elements (pads, contact fingers, integrated circuit profiles, and so on) helped standardize the layout. Traces between devices were made with self-adhesive tape. The finished layout "artwork" was then photographically reproduced on the resist layers of the blank coated copper-clad boards.
Modern practice is less labor intensive since computers can automatically perform many of the layout steps. The general progression for a commercial printed circuit board design would include:
Schematic capture through an Electronic design automation tool.

Card dimensions and template are decided based on required circuitry and case of the PCB Design. Determine the fixed components and heat sinks if required.

Deciding stack layers of the PCB. 1 to 12 layers or more depending on design complexity. Ground plane and power plane are decided. Signal planes where signals are routed are in top layer as well as internal layers.

Line impedance determination using dielectric layer thickness, routing copper thickness and trace-width. Trace separation also taken into account in case of differential signals. Microstrip, stripline or dual stripline can be used to route signals.

Placement of the components. Thermal considerations and geometry are taken into account. Vias and lands are marked.

Routing the signal traces. For optimal EMI performance high frequency signals are routed in internal layers between power or ground planes as power planes behave as ground for AC.
Gerber file generation for manufacturing.

Multi-Layer PWBs

 Option for dedicating layers to ground
 Forms reference planes for signals
 EMI Control
 Simpler impedance control
 Option for dedicating layers to Supply Voltages
 Low ESL/ESR power distribution
 More routing resources for signals

Electrical Considerations in Selecting Material

 Dielectric Constant (permittivity)
 The more stable, the better
 Lower values may be more suitable for high layer counts
 Higher values may be more suitable for some RF structures
 Loss Tangent
 The lower, the better
 Becomes more of an issue at higher frequencies
 Moisture Absorption
 The lower, the better
 Can effect dielectric constant and loss tangent
 Voltage Breakdown
 The higher, the better
 Typically not an issue, except in high voltage applications
 The higher, the better
 Typically not an issue, except in low leakage applications

Through-hole manufacture adds to board cost by requiring many holes to be drilled accurately, and limits the available routing area for signal traces on layers immediately below the top layer on multilayer boards since the holes must pass through all layers to the opposite side.pcb design service bureau Once surface-mounting came into use, small-sized SMD components were used where possible, with through-hole mounting only of components unsuitably large for surface-mounting due to power requirements or mechanical limitations, or subject to mechanical stress which might damage the PCB.