Electronic Design Blog: 2022

Thursday 2 June 2022

Altium Designer : Schematics Transfer to PCB

Import Changes from Schematics to PCB in Alitum as below.

1) Compile the Project

2) Design >> Import Changes From XXX.PrjPCB

3)Execute Changes

Wednesday 18 May 2022

Zuken Cadstar : Schematics Transfer to PCB

Transferring schematics Design file to PCB in Zunken CADSTAR 16 as below. Electrical Rules Check, ERC can be done before transferring to PCB if you like.

Multiprotocol Transceivers

Multiprotocol transceivers are very useful for those projects which require RS-232, RS-485, and RS-422 serial standards which reduce work load for software teams.

There are many transceivers available in Markets and one of them is as shown below.

Product Link

Tuesday 17 May 2022

Altium Designer : Working with an Image Object on a Schematic Sheet

As a picture speaks a thousand words, adding an image object to the schematics is very handy for design review. Prefer method of adding PNG file as below.

Monday 16 May 2022

CAN-BUS Termination and Protection

A properly terminated CAN bus is terminated at each end with the characteristic impedance of the cable, this is typically 120Ω on each end for a 60Ω load on the CAN driver. The 60Ω–60Ω split termination is preferred to reduce high-frequency noise and common-mode drift. Usually, 60R resistor is not cost effective and a choice of 60.4R with 1% tolerance is better.

If we are using CAN-BUS for long distance for more than 50m, it is advised to reduce the bitrate to minimize an errors and signal distortions.

The maximum possible CAN Bitrate depends on the total CAN bus cable length:

- 1 Mbit/s: max. 40 m

- 500 kBit/s: max. 100 m

- 125 kBit/s: max. 500 m

To enhance CAN Bus reliability, communication BUS varistor can be added near next to the connectors.

If the device is intended to be used in harsh environment and required isolation due to ground potential difference between subsystems, Galvanic isolation barrier can be placed between CAN BUS transceiver and MCU. It is also important to use isolated DC-DC power supply for transceiver.

Friday 13 May 2022

Working with Surface Mount Components

Below are prefer ways to replace Surface Mount Components. If you guys have different working methods, please write in comment section.

Thursday 12 May 2022

Simple Capacitive Touch Sensor Controller

If you need a simple capacitive touch sensor to our project, Microchip's CAP1203 is a good choice. It is a multiple channel capacitive touch sensor controller with calibrated to compensate for system parasitic capacitance and automatically recalibrated to compensate for gradual environmental changes. The best thing about this chip is low power consumption at deep sleep mode. It can be used as a touch slider and worked under 6 mm thickness of plastic or wood or almost any materials.

PCB pad Design as below.

Sparkfun has remade module to try.

Tuesday 10 May 2022

Altium Designer : PCB Planes Pullback implementation

There are many ways to implement polygon planes pullback in Altium. One of my prefer way is utilizing design rules as below.

Alternatively, we can make use of keep-out layer to define polygon pullback.

If you believe in 20H rules and to implement for Internal plane pull back, Layer Stack Manager can be used which is only for internal planes.

Thursday 5 May 2022

WORKMANSHIP STANDARD FOR POLYMERIC APPLICATION ON ELECTRONIC ASSEMBLIES

Reference : NASA-STD-8739.1B – 2016-06-30

This is a good refereence standard for staking, conformal coating, bonding and encapsulation of PCB.

STAKING: Staking usually be performed prior to conformal coating and stamking material should be free from contamination.

Default Staking for Horizontally-Mounted Sleeved or Sleeveless Cylindrical Part

Single Wire Staking

Staking for Radial Lead Components

Staking for Radial Multi-lead Rectangular Components

Default Staking of a Single Vertically-Mounted Rectangular Part

Default Staking for an Array of Vertically-Mounted Rectangular Parts

Wire Bundle Staking

Fastener Staking , Locking of Screws and Bolts with Nuts

Thread Locking of Blind Screw

Torque Striping Methods

CONFORMAL COATING, Spray Application

CONFORMAL COATING, Bubbles

CONFORMAL COATING, Scratches

CONFORMAL COATING, Liftting and Peeling

CONFORMAL COATING,Coverage Defects

COMPONENT BONDING, Excess Bonding Material

ENCAPSULATION, Encapsulating Wires at Connector

ENCAPSULATION, Modules

Open LED Protection for LED Strings

LEDs are fragile solid-state devices. An LED is essentially a diode, structured as a P-N junction that emits light when forward biased. One of the major causes of an electrical open in an LED is thermomechanical stress on the wire bonds. Other causes of LED open circuits are electrostatic discharge (ESD) events or surges induced by nearby lightning events. These threats are especially high in outdoor applications. Devices such as MOVs, fuses, and TVS diodes are essential components of a circuit protection strategy, because they can prevent transients and surges from damaging delicate LEDs. However, none of these traditional circuit protection devices can prevent an entire string of LEDs from going out if a single LED fails.

An open LED protector is can be connected in parallel with each LED in a string; it will shunt current around an openfailed LED to keep the rest of the string lit. When LED fails open-Circuit, the open LED protector goes into conduction, limiting its voltage drop to about 1.3V and keeping the rest of the string operating.

Voltage-Tracking LDO With 4-mV Tracking Tolerance

Voltage-tracking low dropout regulator (LDO) is widely used in automotive off-board sensors and small current off-board modules for its off-board protection and high voltage-tracking accuracy advantages.The output of the device is accurately regulated by a reference voltage at the ADJ pin.

To get accurate sensor readings, power supply is required to be stable and accurate. To provide an accurate power supply to the off-board modules, this device offers a 4-mV ultralow tracking

tolerance between the ADJ and FB pins across temperature. Recommend PCB layout sample by TI as below.

Altium Designer : Solving the Component Management Challenge with Alticve BOM

ActiveBOM is a powerful Bill of Materials management editor that brings comprehensive BOM management tools together with Altium's powerful part-information aggregation technologies, helping you manage the component selection challenge.

Friday 29 April 2022

Component Cross Reference Search

Nowadays, component supply chain issue is quite common and designers need to do component cross referencing from different suppliers. Here are a list of cross reference component search websites from manufacture and others.

If you guys have more useful links, please leave it in comment session.