© Cypress Semiconductor Corporation, 2005. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use
of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be
used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its
products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress
products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
The workaround is to have a low value of external pullup resistor for the DOFF pin (recommended value is
<500
). When DOFF pins from multiple QDR devices are connected through the same pull-up resistors on
the board, it is recommended that this DOFF pin be directly connected to Vdd due to the lower effective
resistance since the "leakers" are in parallel.
Figure 2 shows the proposed workaround and the fix planned.
•FIX STATUS
Fix involved removing the internal pull-down resistor on the DOFF pin. The fix has been implemented on the
new revision and is now available. The new revision is an increment of the existing revision. The following
table lists the devices affected, current revision and the new revision after the fix.
Table 3. List of Affected Devices and the new revison
2.Output Buffer Issue
Figure 2. Proposed workaround with the 500
external pullup
Current Revision
New Revision after the Fix
CY7C129*DV18
CY7C129*EV18
CY7C131*BV18
CY7C131*CV18
CY7C132*BV18
CY7C132*CV18
CY7C139*BV18
CY7C139*CV18
CY7C191*BV18
CY7C191*CV18
CY7C141*AV18
CY7C141*BV18
CY7C142*AV18
CY7C142*BV18
CY7C151*V18
CY7C151*AV18
CY7C152*V18
CY7C152*AV18
Ω
Ω
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