Page Comparison

LYONTEK - LY62W10248ML-55LLI - SRAM, 8M, 1MX8, 2.7-5.5V, 44TSOPII

This memory chip is a 'drop-in' replacement for the BSI chip (see below).

TESTED FAILS when loading a file in PipeDream.

Manufacture response:-

We have read the information on web-site provided from customer. Just as customer said, yes, the circuit diagram is pretty straightforward. We can not  find an problem from that. Just we know, the major differences between our parts and BSI's are the design on ESD protection devices, shown as below. We use type 2 on our parts, but BSI uses type 1 without using P-diode,Dp. We wondered  if this could be the issue. Maybe, we need to make some tests on customer's AP board to learn the real situations.

My response :-

Sorry about the delay in replying but I have been comparing the specs between both these chips and running more tests.

Where do we go from here?

I just can’t believe it is a timing issue because the Z80 is running at 3.2768 Mhz. A read or write command takes 3 clock cycles. This gives 915.52734375 nS and the device only needs 55.

How can we test and see what is happening? Have you got any suitable test equipment?

Manufacture response:-

Lyontek really wants to realize what happened. We will do our best to find out the issues as Vic would offer his supports, providing measurement results on application boards.

After reading Vic's information and thinking over, I supposed that the major differences I reported, design on ESD protection diodes, could be the issue. The protection diode may limit the trigger voltage in the input nodes to be less than Vcc+0.6V. Hence, I try to check if there exists any input voltage for Flash Memory which is quite over Vcc. The following comes from datasheet of AM29F080B-90ED, in the page 10. I guess that it could  be an issue on Lyontek's parts as the function of Auto-select Mode is executed because the trigger voltage on A9 is limited by ESD protection diode, less than Vcc+5.6V.

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