Piezo-electric device cut at a specific resonance frequency, mostly used in oscillators.

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8
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2answers
906 views

Strange extra frequency in crystal oscillator

I have inherited a circuit from another designer using a 12.288 MHz crystal as the source for an audio clock. We recently had supply chain issues and I was asked to approve an alternate part with ...
3
votes
1answer
68 views

Routing over 8 MHz crystal traces

I am routing a development board for STM32F030R8T6 which can use external 8 MHz crystal. Here are the schematics and board for the crystal part: Crystal traces are routed on bottom layer (blue ...
0
votes
1answer
56 views

Non-standard frequency crystal replacement [on hold]

I'm new to DIY electronics therefore this might well be a noob question. I'm trying to upcycle a brushless DC motor salvaged from a printer and I accidentally broke a crystal's pin [edit: on the ...
1
vote
1answer
61 views

How to overcome 3.2 mm x 2.5 mm smd crystal pinout differences

As i am currently designing a project involving a stm32f446ve that requires semi good timing, I am looking into using a crystal oscillator. As this is still an early prototype, I would like to be ...
3
votes
1answer
57 views

Parallel and series cut crystal difference

Section 2.2.2 of pic18f4550 datasheet says: In HS, HSPLL, XT and XTPLL Oscillator modes, a crystal or ceramic resonator is connected to the OSC1 and OSC2 pins to establish oscillation. Figure ...
10
votes
4answers
1k views

When should one use an external crystal for this MCU given that the internal oscillator is much faster?

I am looking at this MCU and was wondering if it makes sense to use an external crystal. Extracted from the datasheet pg1, *Clock management – 4 to 32 MHz crystal oscillator – 32 kHz oscillator for ...
5
votes
2answers
106 views

“Standard” Footprint for SMD Crystal [duplicate]

I want my design to use as many common footprints as possible (eg. 0805/0603 for capacitors and resistors, powerSO8 for big switching MOSFETs, etc) so that I am less restricted by manufacturers and ...
1
vote
3answers
28 views

How does the ELPF and XTAL inputs on the ADV7180 recommended circuit work?

I am looking at the recommended circuit for the ADV7180 by Analog Devices and trying to understand some of the reasoning behind the design choices. I realize some of these questions may be a lack of ...
0
votes
1answer
40 views

I found what looks like a crystal oscillator with an xdl stamp I haven't seen before

I found an old transmitter with a crystal oscillator on it, when I looked at this I saw that it had "xdl 17.734475m" stamped onto it, I've only ever seen oscillators with just their frequency written ...
1
vote
2answers
357 views

What kind of oscillator is this circuit?(processor oscillator)

I was just seeing the datasheet of a motherboard and saw this oscillator circuit: What kind of oscillator is this circuit? what are the usage of those resistors? As you can see it has two input ...
1
vote
3answers
76 views

Understanding available frequencies of quartz crystal from datasheet

I would like to make an order of crystals from digikey.com. The crystal product series datasheet is at https://support.epson.biz/td/api/doc_check.php?dl=brief_C-2-TYPE_en.pdf However, I am having ...
2
votes
4answers
121 views

About using a crystal as notch filter

I am looking to create a high q passive notch filter using a crystal. I am not very familiar with crystals, hoping that someone who's had a similar experience can enlighten. I know crystals are mostly ...
0
votes
1answer
46 views

ATmega328 external crystal capacitor requirements

I am reading this guide and it states that, in order to use an external 16 MHz crystal for an ATmega328, I need two 22 pF capacitors. I found this bundle of two 20 pF capacitors and the crystal (sold ...
0
votes
1answer
118 views

Crystal marking

Please help me to find out the value of a crystal
4
votes
1answer
354 views

RC oscillator ageing

I know that a crystal oscillator has a particular ageing curve, that shall be taken into account when designing a long-term application. But what about the RC internal to the MCUs? I did not find ...
4
votes
1answer
88 views

32.768 kHz crystal for RTC, should the case be soldered to GND? [duplicate]

I've seen this on a few boards, but I don't know if it's the right thing to do. Should the case be soldered to GND? It is the common cylindrical package:
0
votes
4answers
91 views

Can I only use a crystal earpiece for my crystal radio?

I am building a crystal radio for my science fair project, and I am having some issues. For my earpiece, I am using a telephone receiver which may be the issue. For my ground, I am using a water ...
1
vote
2answers
95 views

resonator or Crystal Oscillator for atmega2560

I've received the PCB that I have designed. This PCB has an atmega2560 on it. I have designed it to use a Crystal Oscillator such as this figure shows : Is this designed supposed to work on an ...
1
vote
1answer
46 views

Will this crystal-driven inverter successfully produce AC current?

The basic idea of this is that the crystal X1 and filtering caps C1 and C2, will produce a simple square wave that feeds into the NPN transistor Q1. When Q1 is on, the input voltage that Q2 and Q4 ...
0
votes
0answers
79 views

Is there a way to fine tune the frequency of a crystal oscillator?

I have a cheap alarm clock at home. I notified that it got about 10 min of delay every two weeks (I have to re-setup time again and again). I tear it down and found out it is driven by a crystal and ...
-1
votes
2answers
102 views

Why is an 80MHz PIC32 using an 8MHz AND a 32,768Hz crystal?

I saw this schematic, and they are using a PIC32 microprocessor that can do 80MHz, but they are using an 8MHz crystal on OSC1 and OSC2. Are they running the processor at 8MHz or is there some sort of ...
3
votes
2answers
157 views

Choosing crystal, strangely narrow requirements in MCU datasheet?

I am making a prototype using the Atmel ATSAM4S2B microcontroller, but I am having trouble choosing a crystal. I need a 12MHz crystal to use the integrated USB module. The problem is, in the ...
3
votes
2answers
619 views

The classic 1N34A Ge Diode has a Vf of 1V… how could a diode with such a high Vf work in crystal sets they were packaged in?

Back when I was younger I got a crystal radio set kit which included a 1N34A Ge diode (as far as I can remember, I don't have it anymore). I wanted to build one again recently and all I had a was a ...
0
votes
2answers
44 views

drive strength of OCXO

I am trying to find the drive level of an OCXO. The OCXO I am using is the OCXO. I am trying to find the max drive strength. I find only the minimum peak power in dBm. The screen shot is as shown ...
-3
votes
1answer
73 views

Saw resonator vs quartz

I see some data sheets of some saw resonators with a nominal frequency at the GHz range, whereas normal AT quartz cuts are limited to some hundreds of MHz. What is really the difference here, ...
1
vote
1answer
103 views

Oscillator will not start up reliably

I have designed a PCB using a PIC18F6520 and a 32MHz crystal. Using a breadboard with a PIC16F877A, my code works great. But when I load a simple LED blinking program onto my PCB, the LED flickers ...
5
votes
2answers
640 views

Using CMOS Schmitt trigger inverters in quartz crystal oscillator circuit

In all sources I've seen about quartz crystal oscillators using CMOS inverters there's a note like this: But why Schmitt inverter is needed? Won't classic 74HC04 work?
0
votes
3answers
96 views

Where are the external oscillator pins on PIC12LF1572

I have searched the whole datasheet, but couldn't find where are the OSC1 and OSC2 pins are. I've found the CLKOUT (which is CMOS output) on RA4 and CLKIN (which is TTL input) on RA5. But I need the ...
3
votes
1answer
90 views

Does thhis crystal circuit works?

I need a tiny oscillator circuit for testing an application. Now I haven't much experience in creating oscillators so I would like to use this Collpits-circuit: I only need the carrier wave so I ...
5
votes
1answer
64 views

Placement of two independent crystals

This one is completely about PCB layout. I have two 26MHz crystals in the design, one for each processor on the board (TXC 7M-26.000MEEQ-T, datasheet: http://www.txccrystal.com/images/pdf/number-...
1
vote
1answer
150 views

Need Help In Creating and Debugging a 8Mhz CLK Circuit

I want to create a CLK generator circuit that will work at 8Mhz. I'm following this design (from http://www.electronics-tutorials.ws/oscillator/crystal.html): My crystal is 8Mhz HC49/US, with 20pF ...
1
vote
1answer
90 views

26MHz crystal not oscillating - strange capacitor behavior

I am using this 26MHz crystal from NDK. The specified load capacitance is 10pF, I am using two 18pF capacitors in series accordingly. The circuit is shown in figure below. The problem is that the ...
6
votes
1answer
317 views

Using crystal in LTspice (where to get values for RCL)?

I'd like to simulate a schematic in LTspice driven by a crystal. An capacitor representing the crytal (as a resonant circuit) however it needs some specific values. Is there a table of common values ...
12
votes
6answers
1k views

Why are crystal oscillators used in clocks instead of RLC circuits?

The timing of quartz clocks is regulated by a crystal oscillator. This crystal oscillator effectively forms an RLC circuit. If this is so, what properties does a crystal oscillator have that makes ...
0
votes
1answer
52 views

Will a parallel crystal toggle on its own?

I'm having trouble with this part of my circuit. I have this crystal connected, but I see only a 3.3V DC signal on Pin 1 and 3 of the Crystal, and a 0V signal on Pin 2 and 4 of the crystal. I'm ...
1
vote
1answer
173 views

How can a diode act as a detector in a crystal receiver?

I was reading about old crystal radios and read that in a crystal receiver the radio signal in the air is first selected by a tuning coil and then converted to audio signal by a diode. I am confused ...
6
votes
1answer
148 views

JFET - Ceramic Resonator - Oscillator Phenomonom going in and out of oscillation

An oscillator using a ceramic resonator is going in and out of oscillation. I have an oscillator circuit with a peculiar phenomonon. The oscillator does work (mostly). The “crystal” I am ...
2
votes
1answer
131 views

How to test a crystal with multimeter

I have a PCB in which I need to change the crystal. I don't have scope right now with me. So is there any way I can check if the crystal is working or not after soldering it in PCB. I am not good in ...
0
votes
2answers
90 views

10 USB Hub ICs from 1 Crystal Oscillator?

I am designing a PCB with 10 individual USB hub ICs onboard. They all require a clock input and I am wondering if it is possible to drive all the clocks from a single crystal oscillator? The hub IC ...
2
votes
1answer
165 views

Abracon RTCC - no startup oscillation, no SPI

I'm trying an Abracon AB1815 Real-Time Clock/Calendar (SPI interface) in a "fun" QFN16 package. It has a 17th VSS pad which is grounded. It is on a QFN17-to-DIP expander for prototyping at 1.8v. I ...
3
votes
2answers
165 views

Additional Resistor For Pierce Oscillator

I want to build SIM Card Reader by following a schematic from here as follow: I realized that the clock generator (upper center) form a Pierce oscillator but with an additional resistor (R2 symbol ...
0
votes
1answer
133 views

Strange ADC sampling frequency / clock frequency on STM32F401 board

I use a timer to trigger ADC sampling on STM32F401, and the interrupt service routine of ADC will toggle a GPIO pin so that I can measure the ADC sampling frequency using an oscilloscope (which should ...
0
votes
1answer
93 views

Can I replace a 27.12MHZ by a 13.56MHZ Xtal on PN532

I have a prototype of NFC reader which is attached to my Board. But it seem it doesn't work ... the only change I made was the Xtal because I don't find 27.12MHZ. Some people told me I can replace it ...
-2
votes
1answer
79 views

Run an atmega328 using an 16Mhz crystal with 22nF caps

Can you run an ATmega328 using an 16Mhz crystal with 22nF capacitors instead 22pF?
2
votes
1answer
94 views

What is going on in this VCXO circuit?

Here's a schematic of the VCXO oscillator section from a Siemens S55 mobile phone. AFC signal coming from the processor tunes the crystal via a varicap. There's also a thermistor going back to the ...
0
votes
3answers
564 views

How does one get the common PC frequencies (33.33 MHz, 48.000 MHz) from 14.318 MHz?

I see that a lot ICs for PC use a single 14.318 MHz crystal oscillator (which is an NTSC standard frequency, so very widely available in terms of parts) to generate the clocks for PCI, USB, etc. ...
2
votes
1answer
84 views

How to measure parastic capacitance of a trace

I have a 24 MHz, crystal on my board and datasheet of IC defines the load capacitance between 5-9pF. The reference design I follow don't use any load capacitor. My traces look like this: shorter ...
1
vote
1answer
87 views

Crystal grounds and minimal trace distance to leads

Some questions have already been asked about crystals but there's a few competing designs and I have a few "obsessive" type questions on layout. Here's a almost completed layout with a PIC16F ...
1
vote
1answer
356 views

AVR unable to enter programming mode

I have an ATMega88PB on a PCB which won't enter programming mode after changing the fuse settings to EXTFSXTAL_16KCK_14CK_0MS. Prior to this, the AVRISP MkII was able to communicate with the ...
11
votes
4answers
748 views

Why are crystal capacitors considered to be in series?

I'm trying to pick a crystal and capacitors for the clocking of a MCU, and, from what I've understood, my crystal needs a load capacitance of 30pF (its specified in the datasheet) in order to properly ...