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Questions tagged [integrated-circuit]

An integrated circuit (IC) is an electronic circuit built onto a single plate of a semiconductor material, normally silicon. Modern ICs may contain billions of transistors and they have played a major part in the miniaturization and performance improvements of modern electronic systems.

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Probing with oscilloscope causes current drop

We are testing a fabricated chip with expected output current of around 4mA which is then used to charge a button cell. The input is from a PV cell. However, when we attach an oscilloscope probe onto ...
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3answers
824 views

What is a Power on Reset IC?

I'm making a prototype based on the W7500P reference design, the latest version (updated 6 months ago) specifies the need for a Power over Reset IC. I do not understand the point of this component ...
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BQ2002, LM317 NiMH charging circuit. How to control the current output?

I have designed a charging circuit utilising the BQ2002 and LM317 for 2x 1.2V NiMH batteries, and it is to be charged using a 5V USB input, I need the output current to be between 550 mA and 1A. I ...
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85 views

What chips can be used to design an Anti-Counterfeit /Authentication circuit? [on hold]

I am an intern within the R&D branch of a company that designs tools that must operate with low noise at extremely high external temperatures (upwards of 175C). My boss asked that I look into ...
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60 views

Texas Instruments SN502 [on hold]

My father is Bob Cook, an engineer that worked at TI with Jack Kilby in the 50’s/60’s. He has in his possession an SN 502 IC given to him by Jack Kilby. How rare is this chip?
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Reading signal from 190v magnetic pickup

I am using a magnetic pickup to detect the phase and RPM of a rotating assembly. The magnetic pickup produces a pulse once per rotation when a ferrous interrupter passes the pickup. Dependent on the ...
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1answer
31 views

Help identifying an IC - Motorola SC42604P

I found an old board in my stash which seems to be from a smoke detector. Trying to convert it into a doorbell I can hear way out in the yard. I tried Googling the numbers marked on the IC but I can't ...
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29 views

how to calculate sampling rate for DAC from its data sheet

I need to find the sampling rate of the DAC from its data sheet, could you please suggest me any formulae to find the sampling rate from settling time, no of bits, bandwidth. As I didn't find ...
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Combined a 555 dimming circuit with a 555 blinking circuit into a 556, LED flickers during dimming

As the title says, I have put together 2 555 circuits (dimming and blinking) into an NE556. I added a switch to toggle between blinking and dimming and used it to drive an LED. However, I noticed ...
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0answers
135 views

Could i get some circuit design feedback?

I have a computer science background and this is the first circuit I've ever designed. It is a lot of fun designing these circuits, but it also always feels like I'm missing a lot of "obvious" common ...
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1answer
22 views

Multi-cell LiFePO4 charger ICs

I've been looking for a monolithic battery charging / load sharing PMIC that is designed to work with up to 3 or 4 LiFePO4 cells. I had a search on Digikey and could only find one ($6!) chip and that ...
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2answers
88 views

Directly connecting LEDs to IC outputs

Forgive the amateur question - I don't know anything about electronics. I was not able to find any similar questions on this board, but that probably has to do with the fact that I know so little ...
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1answer
150 views

Making a lock system with a 7-segment circuit

I got an assignment in my university to create a lock system using a 7-segment LED, a 7-segment decoder IC and a bi-color LED. The idea of the assignment is that the password is stored somewhere. ...
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5answers
2k views

What is the criteria of choosing a given pin pattern in ICs?

For example, why in the Atmega328P or other MCUs, the group of ports are not contiguous? Like PORTC and PORTB in the Atmega example: Another example is this MC9S12ZV: In particular, checking the PPn ...
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1answer
65 views

How do integrated charger ICs dissipate differences in VCC and the battery voltage?

I was looking at a couple of charging ICs (BQ2002 for instance) and some of the fast charger ICs can charge up to 2A whilst running of a 5v supply. In this case charging a empty 1v NiMH cell means ...
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58 views

Everything seems fine, but SPI Read/Write simply doesn't work. (Hardware-related)

Made a working breadboard Made a working protoboard Printed PCB - same exact schematic and code. Having issues. It appears to be just fine. The SS lines are working from the Pi all the way to the ...
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1answer
31 views

Will this SR NOR latch based 4 digit lock work? [closed]

I designed this to make a lock that requires pressing the correct buttons in correct order to power the LED. My intend was to make the 1st push button set the first latch and reset the remaining ...
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1answer
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Why does this rising edge detector using a capacitor and a resistor work?

So in this video from Ben Eater he makes a rising edge detector using a capacitor and a resistor like the one below. simulate this circuit – Schematic created using CircuitLab In the video Ben ...
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1answer
125 views

555 IC - Transistor Tester

Why are Pins 7 and 5 floating for this 555 IC and how does an NPN and PNP transistor when connected to E B C act a switch? Without the use of Pin 7 surely the capacitor cannot discharge which would ...
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2answers
110 views

drawing a circuit, nand gates

Task: Construct an AND circuit with 8 inputs, a circuit which implements the expression a∧b∧c∧d∧e∧f∧g∧h. Condition: Use only NAND-Gates with two inputs to solve this task. Could anyone explain to me ...
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1answer
72 views

Need help identifying this chip on a old board

Hi Can any body assist in identifying this chip (I think its Ram) probably an easy
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0answers
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Subthreshold Analog Accelerator - How is current derived through two sub-threshold transistors in series?

Was browsing the following paper: Fick, Laura, et al. "Analog in-memory subthreshold deep neural network accelerator." 2017 IEEE Custom Integrated Circuits Conference (CICC). IEEE, 2017. When I ran ...
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1answer
77 views

KV7RF SMD Datasheet

Can someone identify a 5-Pin IC SMD with the marking code KV7RF? Searching in Google I didn't find anything. Any help on this?
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1answer
102 views

Can anyone tell me what the IC is?

I am working on the re-design of an old board, but due to many reasons, the original design document is incomplete. So I sometimes have to figure out what an IC is. Here is one I couldn't figure out, ...
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28 views

Please help identifying smd component marked A76 and 3CCAA

Please help me to identify this device marked "A76" and 3CCAA.
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64 views

Need help decoding part number for SOT23-5 chip

I have a circuit board that has come out of a smart plug-in lamp dimmer/switch module. I would like to find the part number of a small SOT23-5 integrated circuit chip that is on this board. The SMT ...
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1answer
105 views

Why is this circuit not working?

I was making this automatic street light project with a slight change i.e replacing LDR with vibration sensor on proteus. While using LDR it worked well as it changed color depending upon light (red ...
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0answers
29 views

Line driver circuit with with MC3487 not clear

I am looking at an old Heindenhain LS623 optical slide with with a LM339N comparator and an MC3487p line driver. This slide is about 20 or more old and can not be repaired anymore by Heidenhain. I ...
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1answer
42 views

Logic behind this automatic gate light

I was doing this circuit which I found on the Internet. My question is what is the logic behind the functioning of this circuit? Thanks!
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6answers
136 views

AND gate - 4 inputs, 12V

I want to make multiple AND gate input device. I have 4 locks (3 wires each; common, lock and unlock state) I want to monitor those states from locks and connect them to inputs (IC inputs) so when I ...
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0answers
28 views

Add IR (infrared) remote control to simple audio amp?

is it possible to add some kind of a remote control receiver to a basic audio amp board that only has a manual volume knob? The IC chip in the amp board is a TDA7498. A general view of the board is in ...
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2answers
49 views

Can not get the IC version of some gates to show up in KiCad

I don't know if this is a problem with the software i am running, or the way i am trying to go about doing this. But every time i try to place the 74LS04 IC in Eschema it only shows the option to ...
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2answers
46 views

High level present in a pin of a non-powered IC can damage it?

I'm using a TXS0108E to convert from 5V to 3.3V and vice versa. The schematic is below: In the datasheet, in section 6, I read the following: Voltage applied to any output in the high-impedance or ...
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1answer
38 views

Can I leave it unconnected pins in the level shifter?

My concern is that pins are connected between DB25 and TXS0108E, but are not connected between TXS0108E and the Header 5x2. There is only the tracks between TXS0108 and the Header 5x2, but there is no ...
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2answers
70 views

ADC0808 IC working correctly occasionally

I am using ADC0808CCN for a project on converting analog signal to digital signal. It has an inbuilt multiplexer using which we have to provide an analog signal to one of the pin. However what happens ...
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1answer
67 views

Both sides of a voltage level shifter connected

The TXS 0108E is a level shifter circuit, performing, in my project, a shift level voltage from 3.3V to 5V . Because of a design error in the wiring diagram, I left some pins with the same name on the ...
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2answers
70 views

ASK modulator using transistor not working properly at high frequencies

I am trying to make a simple ASK modulator circuit using an npn transistor. It works acceptably at lower frequencies. However at higher frequencies, it doesn't work properly. The amplitude of output ...
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1answer
50 views

Phase Noise In a Voltage Controlled Oscillator

I am particularly new in VCO design. I am required to build a negative gm oscillator with f=7.4 GHz with a tuning range of 300 MHz. The phase noise should be -110 dBc/Hz at 1 MHz offset. I sized the ...
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1answer
81 views

How bad are bent pins from ICs?

Regularly I buy ICs from China so I know there can be differences in shipping. Mostly ICs are sent in either plastic IC storage tubes, and mostly stuck on foam. However, today I got them without any ...
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3answers
162 views

Is there an IC that will output randomly?

Recently I've started collecting those tiny arcades boxes, and found some information to wire them so they stay on the demo mode. This way they can be used as a decoration. Here's an example vid of ...
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1answer
69 views

Part identification, or alternative part - 63 613 Power Management chip [closed]

I have this part, which is the only component that has discernable discolouration, and which I would like to replace: on the PCB of a non-functioning SMPS (12 V 3 A): The only markings on it are '63 ...
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2answers
109 views

Looking to identify an old National 8-pin DIP (M8440)

I have a rail of these 8-pin DIP's that I'm guessing was bought 15 - 20 years ago. My guess is that they could be op-amps or comparators. There are 3 printed lines on these chips: N M8440 28930 35-...
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0answers
31 views

Resources for learning about transistor configurations?

I'm currently taking a circuits class that discusses various transistor amplifier configurations eventually culminating in building an op-amp. This includes various configurations such as the ...
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1answer
42 views

Pspice simulation of NE5234 op-amp internal circuit. Currently getting zero voltage gain

I'm attempting to simulate the NE5234 op-amp via internal circuits. I'm not currently getting any errors, and so the AC sweep simulation does run, but I am getting 0 V on the output nodes. I'd ...
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1answer
63 views

Will a diode change how my IC works?

If I have an IC, any IC, with a V+ and a V- that has a minimum voltage requirement of 3V to operate. Say I supply that exact 3V, but I want to add a silicon diode to the V- to prevent a reverse ...
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1answer
23 views

Using internal regulator DVDD pin to power up external devices

I am designing a H-Bridge PCB and using DRV8323 as the driver. This chip has a pin name DVDD which from my understanding, from the below statement, is used to ...
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3answers
77 views

Control GPIO pins using USB [closed]

What is the easiest way to make a device that can control GPIO pins using USB? Can I make a device similar to this on my own without any special hardware?
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1answer
70 views

Artec QDD2 reverse voltage problem

I have an Artec QDD2 overdrive circuit and I recently powered it up with reverse voltage by accident and it doesn't give any sound on the stages of distortion, however it is allowing the bypass on ...
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1answer
36 views

Multiple Open Drain Outputs to one MCU-pin

i want to use two DRV8844 (http://www.ti.com/lit/ds/symlink/drv8844.pdf) Motor Drivers. It has an Open-Drain output, that indicates an error, when it is LOW (nFault). What happens, when i connect ...
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2answers
92 views

Why Positive-going clock transitions used in certain ICs

Why do certain ICs like 74ALS174 use an inverter so as to make a Positive-going clock transitions occur instead of Negative-going ? Why can't we just save expense of an inverter by removing it and ...