Questions tagged [digital-isolator]

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51 views

Digital inputs for analog switches (analog or digital ground?)

I'm using an analog switch, ADG1434 to switch some filter components in a circuit. My question is about general best practice for the digital signals going to analog switches. The switch is dual ...
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0answers
85 views

How to isolate both Vcc and gnd?

There are three designs of complementary switches, which means that when the button is closed only one of configurations conducts the current and activates the circuit and the other circuit will ...
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2answers
53 views

Digital isolator capacitor design

I am new to analog design and I need to design a galvanic isolator based upon the edge-based communication** described in digital isolator design guide as a part of a task. How can I start designing ...
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1answer
63 views

How to pass a signal over isolator with only one side powered?

I have a system composed of a 230VAC zone isolated from a human contact zone with a 7.5mm 2k5 space. On the human side there is a dry contact switch: I am searching for a less than 1€ solution to ...
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1answer
24 views

Did I connect the FT232 with the Digital isolator Data wired the other way?

I think I connected the Data wires from the FT232RL to the USB Isolator ADUM3160BRWZ upside down. I just want to confirm this, Data - of the one should be connected to Data + of the other ? Datasheet ...
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1answer
75 views

Digital isolator says it is bidirectional but its block diagram does not follow that statement

I am wondering if ADUM1285CRZ is Bidirectional or unidirectional digital isolator. It says it is Bidirectional, but the block diagram says otherwise. Tha datasheet block diagram shows one direction ...
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1answer
67 views

What does "Default Output State" mean for a digital isolator?

I do not understand the term "Default Output State" of the SI8422AB-D-IS digital isolator. I saw it on this datasheet at page 3: Does it mean "the default output voltage if the input ...
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0answers
64 views

DC>DC Isolated Converter (ADuM5401)

I'm in a bit of a quandary as to if I've approached something the right way or if there's an obvious solution I'm missing. (Sorry for lack of schematic, still WIP). Goal: Self-powered isolated USB >...
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1answer
75 views

Why we need gate drivers and how much they are important in power electronics applications

Generally, there are low, high side, as well as half-bridge and full-bridge gate drivers, existing in the market. I am keen to learn the basics of all such gate drivers in view of power electronics ...
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0answers
122 views

Replacing optocoupler with a more reliable and durable device

I am working on a project where I need to have some sort isolation from a machine sending out highs and lows in terms of 24vdc to 0vdc respectively. And I'm using a microcontroller like ESP32 that ...
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2answers
66 views

What does a transceiver like MAX 483 do, especially when it is connected to RS-485?

I cannot understand the principle that the transceiver uses. Why do we need to connect it to RS-485, and how is the data transmitted? I mean how does it transmit the data and why? It is like I cannot ...
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1answer
124 views

Simplify this CAN to CAN transceiver circuit?

I currently have a circuit that does this, is there a way to simplify this circuit, ossibly with isolation? Do I need the BJTs? or can I just connect RX to TX and TX to RX then have a CAN to CAN bus ...
2
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1answer
356 views

SPI Communication with multiple slaves: Problem on MISO line when both slaves are connected

----SETUP DESCRIPTION---- I'm running SPI Master VHDL code on an FPGA (Spartan 6 - XC6SLX9-3TQG144) with 2 slaves (both ADC122S021). I have one main board onto which I connect the FPGA. The first ADC (...
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0answers
99 views

Should I remove the solder mask from an isolation-barrier?

To be able to fully utilize the isolation properties of digital isolator ICs such as the ISO7731, the PCB must have an isolation barrier that is accoding to datasheets Free from planes, traces, pads, ...
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1answer
41 views

Reading isolated multichannel input with voltage drop on all channels

I am building a circuit to read atleast 22 input channels (24 vdc) using an Arduino board which essentially works on 3.3 vdc or 5 vdc. My current setup makes use of 22 PC817 optocoupler. I am sharing ...
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0answers
32 views

Is it necessary to remove ground on all layers when using isolated DIO

So, I am using uptocouplers and digital isolators for a project connected to a microcontroller GPIO. I removed the ground (ground plane cutouts) under the load side of the components, is it necessary ...
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2answers
83 views

Isolation Capacitance (Cio)

How I can find a practical value of CIO barrier capacitance (primary to secondary side) in digital isolators?
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2answers
45 views

Do digital signal isolators shift the level of the signal

I am using 2 digital signal isolators, the ISOW7841 and the ISO7730. The datasheet does not seem to explicitly say that if a signal coming from the 5V side comes out 3.3V on the other side or vice ...
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2answers
234 views

One power supply on a digital isolator

Atmega328P provides logic signals to the AQH1213 solid-state relay to control AC load (contactor). Task: Protect the Atmega328P in case the solid-state relay fails and supplies high voltage to the ...
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1answer
47 views

Isolator’s (ISO7720) recommended current

I have a design which uses an ISO7720 digital isolator, with a 3.3 V supply voltage. My output load is 500 Ω. Due to area constraints, I’d like to avoid adding a buffer on the output, if I can. The ...
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2answers
874 views

Using optocouplers at the end of a twisted pair

I am designing a dumb "isolation box" that is to sit between a computer and medical data acquisition equipment. The purpose of this box is to inject power and to provide communications and digital ...
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2answers
472 views

Bidirectional (opto?) isolators for any protocol?

I would like to isolate digital serial communication between 2 circuits. I don't know much about the protocol between two circuits. It is not a common protocol such as SPI or I2C. Shortest pulses are ...
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1answer
66 views

Data Path Routing or Switching for AFE circuit

Currently i am making the PCB (for analog front end) for the digitization of some sensors(electro-chemical and photo-ionizations). To simply the things this sensors are giving output in Milli volt(...
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1answer
210 views

SI8751 isolated mosfet driver and msofet NVD5C668NL

I need help for my very first application with power mosfet The goal is "simple..": create a SSR for switching a generic DC load with variable power supply from 5V to 48V and max 25A. Isolation isn't ...
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1answer
47 views

ADuM140x: power only one side

In my board it may happen to power only one side of the ADuM140x. All the pins on the other one will be completely floating. When the user plugs in a connector also the second side will be powered at ...
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0answers
174 views

Transformer based digital isolator vs Capacitor based digital isolator

Nowadays, digital isolator vendors all argue digital isolators are more superior to optocouplers. And they also argue their product is more superior to others in some aspect. Like TI (produce ...
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1answer
833 views

how to isolate Maxim dallas one wire interface

I would like to isolate my thermocouple amplifier using a adum1200. Given the following illustration of the chip, does this chip allow me bidirectional comms on the same pin? I hooked up power on ...
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5answers
3k views

Analog isolation vs Digital Isolation

I am designing an ADC front-end circuit that will accept a 230 Vrms mains connection. My goal is to measure the RMS voltage of the mains. Though not really necessary, I think it would make sense to ...
4
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2answers
2k views

Bidirectional digital Isolation

I have used digital Isolators before in unidirectional Designs. I am now faced with isolating a bidirectional digital signal line. Specifically I would like to isolate the 2-wire debug interface of ...
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3answers
446 views

Relation between collector current and IF current in an optocoupler?

I need to use an optocoupler to drive BJT. BJT will let 10 A current pass. BJT's have commonly 100 - 150 Bf(current gain) so for 10A transmission I need at least 100 mA current draw from the ...
3
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3answers
2k views

Optoisolator with Logic Output - How To Use IC Circuit Example?

I'm looking at an Optoisolator with a Logic Output..It's an optoisolator with a Schmitt Trigger on the output. I think the datasheet is a little bare for my comfort level, so I'm looking for some ...
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1answer
168 views

Using ADuM3150 for SPI Interface with Arduino

I am trying to use an isolator for SPI communication with the Arduino. I am presently using the ADum3150. You can find the datasheet here. There are some delays associated with this arrangement and ...
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4answers
4k views

Sensing analog voltage on Arduino without loading the input circuit

I want to design a voltage divider for my Arduino Analog input pin, to be able to sense the change in voltage in a 9V, 250mA circuit (without loading it). Ive programmed the Arduino so that as soon ...
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4answers
3k views

When do we prefer isolator over optocoupler?

Today I have learned that a device called "isolator" exists (eg: SI8712CC-B-IS). Its function is very similar to the optocoupler's. On the good side, it is much much faster. While it is very hard to ...
5
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2answers
6k views

RS-485 isolation required?

I would like to confirm my understanding. Suppose I want to have two battery-powered MCUs inside an (unmanned) aircraft communicate with each other via RS-485. If those MCUs are powered from the same ...
4
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1answer
305 views

ADuM1301 digital isolator - PCB layout question

We are using the ADuM1301 digital isolator in one of our designs. The PCB layout section from the data sheet states: In applications involving high common-mode transients, care should be taken ...