Suitable for keyless entry system of on-board equipment, crystal oscillator FA-238A for automotive use

The FA-238A crystal oscillator for automobiles is a high-temperature resistant crystal oscillator suitable for keyless entry systems of in vehicle devices. The FA-238A crystal oscillator for automobiles is a MHz surface mount crystal unit launched by Epson, which has good pre rate performance and complies with the AEC-0200 standard. Its packaging size is only 3.2x2.5x0.7mm, and the working temperature range is between -40 ℃ to+125 ℃. It is a high-temperature resistant crystal oscillator. Combined with the advantages of high stability and low power consumption, it has become an ideal choice for high-precision clocks in on-board equipment. With the continuous upgrading of automotive manufacturing technology, mid to high end cars are equipped with a Keyless Entry (PKE) system. Through wireless radio frequency technology and vehicle identification code recognition technology, combined with remote control lock technology, it can provide users with a more comfortable user experience and ensure the safety of the car by preventing theft. Compared with traditional mechanical keys, the keyless entry system for cars is more convenient, and can remotely avoid tedious operations such as finding the keyhole and inserting and removing keys. At the same time, it can also remotely avoid embarrassing situations such as key loss or falling into the car. The circuit of the car keyless entry system includes a signal transmitter and a signal receiver. Both the transmitting and receiving circuits require microcontrollers (MCUs) and clock oscillation circuits, which can be used to generate the clock signal required for normal MCU operation. Meanwhile, due to the low gain feature of the clock oscillation circuit, it is beneficial to reduce system power consumption. However, in order to avoid errors in MCU operation caused by noise in low gain circuits, when designing clock oscillation circuits, consideration should be given to using automotive crystal oscillators (crystal oscillators) with low load capacitance CL to avoid such situations. So why can the automotive crystal oscillator FA-238A be used in the clock oscillation circuit of the keyless entry system?

The FA-238A crystal oscillator used in automobiles is very suitable for designing clock oscillation circuits in keyless entry systems. The load capacitance of FA-238A is as low as 7pF, which is beneficial for avoiding incorrect operation of MCU. Meanwhile, the rated frequency range of the FA-238A crystal oscillator used in automobiles is as wide as 12MHz~62.4MHz, with a frequency tolerance range of+15x10-6~± 50x10-6 (25 ° C), and an excitation power of up to 200 μ W (Official recommendation to control within 1) μ Within the range of W~100uW. In addition, it has a small size (3.2mm x 2.5mm x 0.7mm), saving system space, and a wide working temperature range of -40 ° C to+125 ° C, making it a high-temperature resistant crystal oscillator. Strong environmental adaptability makes it a great choice for automotive grade applications. In addition, the frequency aging rate is as low as+5x10-6/year, with a long service life. The two commonly used frequency points for automotive crystal oscillator FA-238A are: FA-238A, 20MHz, 12PF, 15PPM, X1E0003410031. The other one is FA-238A, 22.5792MHz, 12PF, 15PPM, X1E0003410028. Of course, in addition to the high-temperature resistant crystal oscillator FA-238A, Epson's FA2016AA, NS-21R, NS32R, FS-335, FS-555, FS-585, FF-555, and FF-32N are also suitable for the design of keyless entry systems in cars.