Beware! There are dangerously fake LY68L6400SLIT’s exist on AliExpress.
Bought some for electronic tags/badges project just to found that their pins (to be precise 5-6 and 7-8) are short-circuited!
Why dangerously? Because 8 is Vcc and 7 must be tied to ground in SPI mode, so using this fake chips leads to device-wide power short-circuit.
UPD. Cracked one “chip” casing – there is no crystal inside at all!