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USB Low-Full-High Speed Peripherals

MSSa_1300736
New Contributor II

Hi Community,

I am using Fx2LP CY7C68013A.

According to AN15456_Guide_to_a_Successful_EZ-USB_FX2LP_Hardware_Design  :

Resonator Requirements

The FX2LP crystal requirements are as follows:

▪ 24 MHz

▪ Parallel resonant

▪ Fundamental mode

▪ 500-μW drive level

▪ 12-pF (5 percent tolerance) load capacitor

Cypress specifies resonator frequency tolerance as ±100 ppm to take into account other circuit factors that can add to the USB ±500-ppm tolerance budget such as circuit board layout, temperature, load capacitors, and crystal aging. One resonator manufacturer, Murata, offers CERALOCK® series resonators with initial accuracies of 70 ppm and 100 ppm. For FX2LP, a Murata part number may be encoded according to Table 2.

I have tried to find crystal for all the above listed requirements but there is no available parts which can satisfy ALL the above specifications .

So can anyone suggest crystal oscillator os some specs that can be overlooked?

Also I have gone through  : Re: Finding an appropriate crystal for CY7C68013A (FX2LP)

according to that part  ECS-240-20-4 can be used but its also obsolete.

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1 Solution
YatheeshD_36
Moderator
Moderator

Hello,

The XRCHA24M000f0A13R0 crystal cant be used.

Power dissipation of the crystal i.e.

pastedImage_0.png

should be within the maximum drive level of the crystal.

For XRCHA24M000f0A13R0  power dissipation (calculated to be 633uW) exceeds the max drive level of the crystal (600uW).

Please refer to this link   ECS-240-20-4 ECS Inc. | Crystals, Oscillators, Resonators | DigiKey where ECS-240-20-4 is available.

Best Regards,

Yatheesh

View solution in original post

3 Replies
MSSa_1300736
New Contributor II

one of the option is : XRCHA24M000f0A13R0

Its 24MHz at 100PPM but load capacitor is 8PF and 600uW drive level. Can it be appropriate to use?

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MSSa_1300736
New Contributor II

Hi,

Can anyone please help with this?

600uW drive level and 8pF shunt load will be ok?

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YatheeshD_36
Moderator
Moderator

Hello,

The XRCHA24M000f0A13R0 crystal cant be used.

Power dissipation of the crystal i.e.

pastedImage_0.png

should be within the maximum drive level of the crystal.

For XRCHA24M000f0A13R0  power dissipation (calculated to be 633uW) exceeds the max drive level of the crystal (600uW).

Please refer to this link   ECS-240-20-4 ECS Inc. | Crystals, Oscillators, Resonators | DigiKey where ECS-240-20-4 is available.

Best Regards,

Yatheesh

View solution in original post