Zuken Cadstar : Schematics Transfer to PCB

 

Transferring the schematic design file to PCB in Zuken CADSTAR 16 is a straightforward process. Feel free to conduct an Electrical Rules Check (ERC) before proceeding – it's all part of the smooth and confident workflow.

Multiprotocol Transceivers

Multiprotocol transceivers are very useful for projects that require RS-232, RS-485, and RS-422 serial standards. They help reduce the workload for software teams.

 There are many transceivers available in the market, and one of them is described below.

Product Link

The MAX3161/MAX3162 are programmable RS-232/RS-485/RS-422 multiprotocol transceivers. The MAX3161 can be pin-programmed as a 2TX/2RX RS-232 interface or a single RS-485/RS-422 transceiver. 

The MAX3162 is configured as a 2TX/2RX RS-232 interface and a single RS-485/RS-422 transceiver simultaneously. Both devices incorporate a proprietary low-dropout transmitter output stage and an onboard dual charge pump, allowing RS-232 and RS-485/RS-422 compliant performance from a single supply. 

These devices also feature pin-selectable transmitter slew rates for both RS-232 and RS-485/RS-422 modes. Slew-rate limiting minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 250kbps. 

Disabling slew-rate limiting allows these devices to transmit at data rates up to 10Mbps in RS-485/RS-422 mode and up to 1Mbps in RS-232 mode. The MAX3161/MAX3162 offer a flow-through pinout that facilitates board layout. They are available in tiny SSOP packages and operate from -40°C to +85°C.

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

 When reviewing designs, adding an image to the schematics can be incredibly valuable because a picture is worth a thousand words. Below, you'll find the recommended method for incorporating a PNG file

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, a 60R resistor is cost effective and a choice of 60.4R with 1% tolerance is better.

If CAN-BUS communication is chosen for long distances of more than 50m, it is advised to reduce the bitrate to minimize 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  

A varistor should be added near the connectors to enhance CAN Bus reliability.

If the device is intended to be used in a harsh environment and requires isolation due to ground potential differences between subsystems, a Galvanic isolation barrier can be placed between the CAN-BUS transceiver and the MCU. Using an isolated DC-DC power supply for the transceiver is important.

Working with Surface Mount Components

Simple Capacitive Touch Sensor Controller

Looking for a reliable capacitive touch sensor for your project? Look no further than Microchip's CAP1203. This calibrated multi-channel capacitive touch sensor controller is designed to compensate for system parasitic capacitance and automatically recalibrate to adapt to gradual environmental changes. Notably, it consumes very little power in deep sleep mode and can be used as a touch slider, working with materials up to 6mm thick including plastic, wood, and almost any other material.

PCB pad Design as below.

Check out the remade module by Sparkfun and give it a try!

Altium Designer : PCB Planes Pullback implementation

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

Alternatively,  a keep-out layer to define polygon pullback can be used.

If you believe in 20H rules to implement for Internal plane pullback, Layer Stack Manager can be used for internal planes.

WORKMANSHIP STANDARD FOR POLYMERIC APPLICATION ON ELECTRONIC ASSEMBLIES

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

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

STAKING: Staking usually be performed before conformal coating and staking 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 circuit 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 for 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 can be connected in parallel with each LED in a string; it will shunt current around an open-failed LED to keep the rest of the string lit. When the LED fails, it becomes open-circuit, and 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

 The voltage-tracking low dropout regulator (LDO) is commonly used in automotive off-board sensors and small current off-the-board modules due to its off-board protection and high voltage-tracking accuracy advantages. The output of the device is precisely regulated by the ADJ reference voltage.

To obtain accurate sensor readings, a power supply always requires better stability and accuracy. This device offers a 4-mV ultralow tracking tolerance between the ADJ and FB pins across temperatures, meeting the voltage accuracy requirements for off-board modules.

Below is a recommended PCB layout sample by TI for your reference

Altium Designer : Solving the Component Management Challenge with Alticve BOM

 

ActiveBOM offers a robust Bill of Materials management editor, leveraging Altium's advanced part-information aggregation technologies to effortlessly tackle the component selection challenge.