S29JL064J

MiLe_2706411 · ‎Feb 03, 2020

I am using the S29JL064J and are seeing intermittent write behavior. We have three devices, two have undershoot on the WE and OE pins around -1.2V for ~ 20ns. For these two we see about a 90% and 10% write success. The third device does not have the undershoot and we see 100% write success.

My question is: Does the -2.0V undershoot for <20ns in the datasheet indicate that anything less the device will still function properly, or could our -1.2V undershoot be the cause of our write issues?

AlbertB_56 · ‎Feb 07, 2020

Hello,

Thank you for contacting Cypress Semiconductor.

There may the possibility that the -1.2V undershoot may cause WRITE issues for the S29JL064J.

Undershoot or overshoot in excess over 2.0V may cause irreversible damage to the FLASH memory

device

Please confirm that a decoupling capacitor (0.1uF) exists between VCC and GND, but placed

as close to the VCC pin, as possible.

Although the S29JL064J is a Simultaneous READ/WRITE device, lets first concentrate on successfully

writing to the S29JL064J : Is there any AC termination or Parallel termination that exists on the WE#

and/or OE# input signal pin(s)? If no, an AC termination or Parallel termination may eliminate or reduce

the presence of undershoot/overshoot on the WE# and OE# input signal pins.

Please verify and confirm at your earliest convenience.

Best regards,
Albert

Cypress Semiconductor

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