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

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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 ...
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1answer
65 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 ...
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0answers
39 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 ...
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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 ...
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1answer
47 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 ...
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1answer
142 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 ...
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1answer
96 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 ...
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1answer
72 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 ...
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2answers
75 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 ...
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1answer
149 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 ...
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2answers
59 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 ...
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1answer
58 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 ...
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1answer
77 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 ...
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1answer
60 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?
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53 views

Crystal routing in layout

We started production for a project with RFID reader (13.56Mhz) which have an external crystal of 13.56Mhz. The layout was designed by a Chinese design house which I'm afraid that did a small mistake ...
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1answer
57 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 ...
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3answers
480 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. ...
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1answer
67 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 ...
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1answer
62 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 ...
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1answer
134 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 ...
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4answers
632 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 ...
3
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1answer
50 views

PIC16 LP drive level - do I need a damping resistor?

I'm using a 32kHz crystal oscillator with timer1 on a PIC16F1825 to provide more accurate timing for events (I want to do something every 20 minutes). The crystal circuit looks easy enough to design ...
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1answer
43 views

Run two boards with different crystals (MCP2515 specifically)

I have one CAN bus interface that's using a 16 MHz crystal, and I want to set up my own interface to talk / simulate CAN packets with first one. I do have 20 MHz crystals for my own ...
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42 views

Troubleshoot load capacitance (crystal not starting)

I am using a MAX11060 ADC in a project, I have established SPI communications and am able to read and write registers, however I am unable to get any readings, I believe this is due to the crystal not ...
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2answers
38 views

difference between crystals in applications

I am trying to use a crystal for a MCU. The xtal is 32.768KHz. This will be scaled up by the internal PLL or FLL to a much more higher level. I was looking at some crystals of the same value in some ...
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69 views

Using “oscillator” rather than crystal for MCU

I'm kinda new to this so the name is based on Digikey. I have a PIC24FV32KA304 and I want to put an external oscillator of 32mhz. I found out that an oscillator like this one is a bit cheaper than ...
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1answer
39 views

8253 / 82C54 timer, clock input

I'm experimenting on a breadboard how to use the programmable interval timer 8253 (actually I'm using the new 82C54, it's the same thing). datasheet: ...
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1answer
176 views

Can I replace watch quartz with DS3231 32 kHz output?

I'd like to know if it's possible to synchronize classical quartz clock by replacing inbuilt quartz crystal with DS3231's 32 kHz output. I need to synchronize my analog watch with RTC DS3231. Am I ...
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1answer
92 views

Can I use 8pF 200ohm 10MHz crystal with ATMega88 w/o caps?

I'm trying to save board space. I know crystals typically have 20-30 pF ratings, and need 20-ish pF caps to ground. I found this crystal: ...
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0answers
50 views

Can Two Or More ATTinys Share One External Crystal? [duplicate]

I've got two I2C Slave ATTiny85 chips both running at 16MHz with external crystals. Can they both share a single crystal with the 22pf caps? Is there anything wrong with this? I don't have any free ...
3
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2answers
1k views

What generates the clock signal in a fast CPU and how does it work?

Often, for integrated circuits, a quartz crystal is used to generate the clock signal. However, this only reaches speeds in MHz. What component, or what circuit, generates signals up to 5 GHz ...
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97 views

Why LED signboards shake when I eat an apple? [duplicate]

while I was sitting in city center with so many LED (especially red ones mounted) signboards and I was bitting an apple, the signboards suddenly begin to shake for only a second while my head is ...
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33 views

Charge Cap Crystal - Package

I got an external crystal for a MCU ( tm4c1233h6pm). I use the NX-16MHZ from NDK, in the datasheet, the recommend cap charge for the crystal are 2 cap of 10 pF for a 16 Mhz crystal. My question is ...
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1answer
100 views

Atmega328P 32.768KHz Crystal Issue

I am having an issue with 32.768khz crystal connected to an Atmega328P (which I am using as an external source to timer2 in asynchronous mode to wake up the Atmega from sleep every second). On a ...
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1answer
84 views

Can I use a series crystal in an parallel crystal optimized oscillator?

Based on this application note from Maxim Integrated in section "Resonance Mode": "Crystals have two modes of resonance, parallel and series, and all crystals exhibit both resonance modes. The ...
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3answers
68 views

Capacitor rated for 100vdc on 5vdc board

As the title says, I have capacitors rated 100VDC 18pF. Can I use these on a board that uses 5V Max ? I can't really find any direct answer to that question. What I want to do is to put a crystal to ...
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1answer
113 views

Crystal PCB track

This is my current PCB crystal set up. The crystal run at 16 Mhz. Any thoughts/comment? Links: MCU - Datasheet TI PCB guideline Tiva C - Here
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2answers
130 views

NEED HELP: Oscillator Error and PIC24F stopped working

I have a 30MHz Crystal Oscillator to clock a PIC24FJ128GC010 Controller. I am programming in MPLAB X. My idea is to generate a pulse on one of the I/O pin toggling. But unfortunately, I cannot do so. ...
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1answer
137 views

Crystal oscillator frequency Vs size?

What is the relationship between crystal oscillator frequency Vs Die size? Why it is smaller Die size over the high frequency ranges and bigger Die size in lower frequency ranges?
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5answers
7k views

Why do we use 32.768 kHz crystals in most circuits?

Why do we use 32.768 kHz crystals in most circuits, for example in RTC circuits? What will happen if I use a 35 or 25 kHz crystal? I assume because the IC internal Xin, Xout pin circuitry should be ...
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3answers
689 views

SMD Crystal solder(?) problem and any recommended test procedure

I use a 32.768 kHz SMD crystal (datasheet) for a MCU. Here is the layout part of the crystal. Here is a view from an actual PCB I mounted the components by hand-soldering, and produced about 30 ...
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41 views

Load resistor placement for clock section

I am placing a crystal, associated capacitors, damping resistor and load resistor to a clock section of a MCU. My question is, should the load resistor be placed close to the MCU or close to the ...
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1answer
88 views

Crystal Footprint Placement

Pretty simple question, please point me in the right direction if this has already been asked. I am designing a board around freescale's IMX23 microprocessor which runs from an external crystal at ...
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2answers
68 views

MEMS oscillator how to wire them and can they replace crystals?

My question is: Can a MEMS oscillator replace a crystal oscillator? If answer is yes, how I can wire them to XIN and XOUT? How should I select capacitor? And since they don't have crystal capacitance ...
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1answer
179 views

stm32f4 HSE crystal

I'm trying to set up an HSE for my STM32f4, using this crystal. but there are 2 pins : OSC_IN and OSC_OUT, but my crystal only has one output. So what do I link OSC_IN and OUT to ?
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2answers
55 views

Correctly choose Crystals and Cext

I've a problem to choose correctly which Crystal to use with an ARM Cortex M4. In particular, I can't understand relationship between datasheet specifics and a Crystal used in an ARM Cortex M4 EVB. ...
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3answers
423 views

external crystal not working but internal clock worked normaly in PIC18F45K22

I have designed a PCB based on the PIC18F45K22 microcontroller. I want to use an external crystal (4Mhz crystal with two 22pF capacitors). I can successfully program the code but the PIC won't run. ...
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1answer
167 views

Problems with using 20Mhz crystal withPIC18f2420

I am using PIC18f2420 to generate PWM. I am using Timer 2 with 4MHZ crystal, which works perfectly by giving me PWM. I need to get 100KHZ of frequency for PWM, for which, 4MHZ crystal is not enough as ...
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1answer
532 views

When we need external crystal for atmega?

I created microcontroller circuit, refers to most of circuit in internet. Which is it is using external crystal. As i know now, that atmega16 has internal oscillator by default 1MHz. So, ...
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1answer
166 views

How do I deal with different XTAL pin capacitance when selecting XTAL and load capacitors

I'm trying to select a 32kHz crystal and appropriate load capacitors for Atmega48A MCU. Atmega48A specifies different capacitances for Xtal1 and Xtal2 pins: 18pF for Xtal1 8pF for Xtal2 The ...