Currently, the carrier frequency of infrared remote controllers is generally 38kHz, although there are also 36kHz and 40kHz options.
This is because the typical crystal oscillator frequency is 455kHz, and in order to send a signal, it needs to be divided.
The usual method is to divide it into 12 equal parts, resulting in a frequency of approximately 37.9kHz, which is rounded to 38kHz.
3*8mm 38kHz cylinder crystal datasheet:
|Frequency Tolerance (at 25℃)||±20ppm|
|Resonance resistance(ESR)||30k ohms|
|Drive level||0.1 uW Max|
|Aging @25 ℃1st year (Max)||±3ppm,5ppm/year|
|Storage Temperature Range||-40~85℃|
|Shunt Capacitance||3pF Max|
|Insulation Resistance||Min 500MΩ @DC 100 Volt|
Not recommended reflow furnace welding,If it is to be used, the maximum temperature shall not exceed 230℃.
Mounting method to PCB
When the crystal products need to be lay down please fix to PCB securely
If the crystal is used with mechanical vibration location, please put cushion in between PCB or fix with
elasticity glue (Silicon etc) as shown in below figure. Please don’t gluing hermetic seal grass.
When the crystal products need to be mounted vertically, gap between crystal units and PCB more than 3mm for 3×8 type
more than 2mm for 2×6 type is recommended.