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Quartz Crystals

Quartz crystals - terms / properties PDF Symbol klein (41kB)

terms and definitions commonly used in oscillating quartz crystals

Oscillator circuits with transistors PDF Symbol klein

layout suggestions for discrete transistors with oscillator circuits, a.o. NF-oscillator from 800 kHz, Pierce and Colpitts oscillator tone, Pierce-overtone oscillator to 200 MHz

Oscillator circuits with inverter IC PDF Symbol klein

Quartz oscillator circuits for standard microprocessor Crystals in AT section 3-25 MHz using integrated, unbuffered inverters

Pierce oscillator circuit for tuning fork Crystals 10 - 600 kHzPDF Symbol klein

tips to circuit design with tuning fork quartz crystals of the series V by the manufacturer Statek - these tips also apply in general to all tuning fork Crystals in Pierce oscillators

explanatory notes on the order code:
e.g.: Quartz 32,000000 MHz1) HC-49/US-2,42) 50/100/20/303) GT 4) BT 5) taped 6)

1) frequency with max. 6 decimals in MHz
2) case: 4,1 = height h = 4,1 mm (standard); optional h = 3,1 or 2,7 mm!
3) here are – separated with slashes – the following values defined: frequency tolerance (ppm or 10-6), max. allowed tolerance over operating temperature range, the operating temperature range and the load capacitance
30 ... ±30 ppm @ +25°C
100 ... ±100 ppm over operating temperature range
10 ... -10...+60°C; only lower temperature limit is mentioned, temperature tolerance is symmetric around +25°C or, in special cases, the lower and upper limit e.g. /-40+85/
30 ... load capacitance CL = 30 pF; S means series resistance (CL = ∞)
4) GT ... fundamental (default up to 30 MHz, fundamental is standard!) 3.OT ... means 3rd overtone
5) AT ... AT-cut (default under 30 MHz, AT is standard) BT ... BT-cut
6) option: e.g. gegurtet = tape on reel

Recommendation on quartz crystals in ceramic packages with 4 solder pads:

Quartz crystals in ceramic cases are available in sizes 3,2x5, 3,5x6 and 5x7mm with 2 and 4 solder pads. For new developments, we recommend that you use the versions with 4 solder pads: 2 pads of which are connected to the metallic lid and the quartz thus has an improved EMI performance.
While there is no product discontinuation for 2 pad housing but the availability of the 4 pad package is better, and we will focus on expanding our warehouse towards the 4 pad model.

Recommended Quartz specification for the RFID IC from TI TRF7960 and TRF7961:

frequency: 13.560000 MHz
fundamental mode, AT-cut, parallel resonance
frequency tolerance ±20 ppm max.
aging < 5 ppm/year
operating temperature range -40°C to 85°C
resonance resistance max. 50 Ohm

Informations come from data sheet SLOU186E August 2006 revised July 2008

Selection criteria of load capacity:

These clock crystals are offered with load capacities ranging from 6 - 12,5pF, the IC manufacturers generally write these values prior to the operation of the circuit guarantee. The following properties result from:
Settling with small CL small, with large CL high (0,5...3 seconds)
Stability at high CL better than at low.
Load (power consumption) increases with the CL value.

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