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SMD Tuning Fork Crystal PSX1610 Features Ultra miniature SMD tuning fork crystal resonator A ceramic package with metal lid providing high precision and reliability. Metal lid connected to GND terminal to reduce EMI Suitable for mobile communications and consumer devices. Applications Mobile communications and consumer devices, etc. Smart card and Wearable devices More
SMD Tuning Fork Crystal PSX215 Features Ultra miniature SMD tuning fork crystal resonator A ceramic package with metal lid providing high precision and reliability. Metal lid connected to GND terminal to reduce EMI Suitable for mobile communications and consumer devices. Applications Mobile communications and consumer devices, etc. Smart card and Wearable devices More
3215mm with10ppm Features 3215 Size Miniature And Fork Crystal Resonator With A Low Profile Pf 0.75mm. A Ceramic Package Providing High Precision And Reliability. Metal Lid Connected To GND Terminal To Reduce EMI. Noise Resistance Application (Smart Meter Etc.) series resistance 50KΩ max available. AEC-Q200 Compliant Applications Mobile Communications, PDA, Wave Clock, Digital Appliance Auto Motive Applications Such As Multimedia Device More
SMD Tuning Fork Crystal PSX415 Features 4115 size miniature and fork crystal resonator with a low profile pf 0.75mm. a ceramic package providing high precision and reliability. metal lid connected to GND terminal to reduce EMI. Noise Resistance application (smart meter etc.) AEC-Q200 compliant Applications mobile Communications, PDA, wave clock, digital appliance auto motive applications such as multimedia device More
SMD Tuning Fork Crystal PMX145 Features Ultra Miniature SMD Tuning Fork Crystal Resonator Plastic molded SMD tuning fork crystal of heat-resistance Metal Lid Connected To GND Terminal To Reduce EMI Suitable For Mobile Communications And Consumer Devices. Applications Mobile Communications And Consumer Devices, Etc. Smart Card And Wearable Devices More
SMD Tuning Fork Crystal PMX206 Features Ultra Miniature SMD Tuning Fork Crystal Resonator Plastic molded SMD tuning fork crystal of heat-resistance Metal Lid Connected To GND Terminal To Reduce EMI Suitable For Mobile Communications And Consumer Devices. Applications Mobile Communications And Consumer Devices, Etc. Smart Card And Wearable Devices More
SMD Tuning Fork Crystal PMX405 Features Ultra Miniature SMD Tuning Fork Crystal Resonator Plastic molded SMD tuning fork crystal of heat-resistance Metal Lid Connected To GND Terminal To Reduce EMI Suitable For Mobile Communications And Consumer Devices. Applications Mobile Communications And Consumer Devices, Etc. Smart Card And Wearable Devices More
SMD Tuning Fork Crystal PMX406 Features Ultra Miniature SMD Tuning Fork Crystal Resonator Plastic molded SMD tuning fork crystal of heat-resistance Metal Lid Connected To GND Terminal To Reduce EMI Suitable For Mobile Communications And Consumer Devices. Applications Mobile Communications And Consumer Devices, Etc. Smart Card And Wearable Devices More
Mother of Timing 32.768kHz Clock Crystal
Clock Crystal Specification: FL:32.768kHz, CL:12.5pF,Tol.: +/-30ppm
Standard Pierce Oscillator from MICRO CRYSTAL WITZERLANO information:
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Oscillation Conditions
- Loop gain:
At steady state, the closed loop gain = 1.
. Phase shift:
At the oscillation's frequency, the closed loop phase shift = 2T
.Startup:
When initially energized,the noise component at the frequency which satisfies the phase condition for oscillation is propagated around the loop with increasing amplitude.Startup times around 1 second are normal values for such low frequency tuning fork crystals.
Amplitude:
The signal amplitude increases continually, until the amplifier gain is reduced either by nonlinearity of the active elements ("Self Limiting Pierce") or by some automatic level control (AGC circuitry, "Controlled Pierce").
Things to Check on an Oscillator
. Oscillation Allowance:
Negative resistance model, crystal constraints.
. Effective Load Capacitance:
Frequency accuracy.
. Overtone Mode Suppression:
Crystal's overtone mode ~6.ix the fundamental mode frequency..
. Drive Level:
Maximal power which could be dissipated by the crystal.
Layout Considerations
General Constraints
- Crystals oscillators are analog circuit and the PCB design must follow analog-board layout rules.
· Tuning Fork crystals drive level is extremely low(<1 uW).
. Long traces make crystals oscillators very sensitive to ESD,EMC and crosstalk.
For all these reasons, special attention should
be paid on the PCB layout!
Design Rules
. Traces between the micro controller pins, the crystal and the external load capacitors, should be as short as possible.
· External load capacitors layout have to be symmetrical and both ground connections should be as close as possible.
. ln order to avoid direct signal coupling，XIN and XOUT traces should be routed as far as possible from each other.
- Routing on inner layers and vias must be avoided.
.Digital signal lines should be kept as far as possible from the crystal.
. Digital signal lines should not be routed on inner layers under the crystal area.
. The crystal housing (Metal-can packages) should be connected to ground.
.A ground guard ring or an inner layer (or opposite side) ground plane is recommended.The guard ring or ground plane should be connected with a short trace to VSS of the micro controller, and should not be connected to any other ground signals.
Layout Example 1:
Layout Example 2
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