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TCAN4550-Q1: No oscillating signal on the crystal

Part Number: TCAN4550-Q1
Other Parts Discussed in Thread: TCAN4550

There is no oscillation signal on the crystal, the design circuit is as shown in the figure, VCCout has 5V signal, Vio=3.3V, does EP suspension have any effect? Replace TCAN4500, crystal, and C27, C30 (10p, 12p,15p,18p,20p) have no oscillation signal,when R58=680K C27=C30=12pf , there is an oscillation signal, but the frequency is 71KHz or so, also incorrect.

  • 您好,

    已经收到了您的案例,调查需要些时间,感谢您的耐心等待。

  • What is the VSUP supply voltage?  You state VIO=3.3V but you don't state what the VSUP voltage is and the schematic only shows "VS".

    You said

    does EP suspension have any effect?
    I can't confirm whether there is any direct effect from not soldering the thermal pad because I don't have a board that excludes the thermal pad connection to GND, but this is a violation of the datasheet and the the thermal pad needs to be soldered to GND.

    Note that the device has an internal 500k resistor between OSC1 and OSC2 pins so the R58 resistor is not required.

    Can you clarify what the scope plot is showing and specifically where in the schematic the scope probe was connected when it was captured?  This is nothing like I've seen before and any oscillation waveform from the crystal should appear as a sine wave.  The scope says "U4_PIN3" but the schematic has reference designators for the TCAN4550 as U5 and the crystal is XC2

  • Long time no reply, this post is closed.
    If there are still issues, please repost