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Nor Flash

MiLe_2706411
New Contributor

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?

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1 Solution
AlbertB_56
Employee

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

View solution in original post

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4 Replies
AlbertB_56
Employee

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

0 Likes
AlbertB_56
Employee

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

View solution in original post

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MiLe_2706411
New Contributor

Hello sorry for the delay.

I am asking on behalve of one of our customer so I do not have access to the board itself.  I passed on your information and appreciate the reply. 

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AlbertB_56
Employee

Hello,

Thank you for the status update.

Please do keep me informed, once you have received the response from your end customer.

Cypress awaits for your end customer's response...

Best regards,

Albert

Cypress Semiconductor

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