7 Replies Latest reply on Apr 2, 2018 2:10 AM by user_78878863

The relationship between Output High Voltage and Current of FRAM

morimoto-n_1534561 Mar 5, 2018 6:41 PM

Hello,

My customer is comparing the Voh level between FRAM and the host CPU.

Voh_min of FRAM is Vdd - 0.8 = 2.5V (at Vdd = 3.3V).

On the other hand, the Vih_min of the CPU is Vcc x 0.8 = 2.64V.

There is a possibility that Voh of FRAM is lower than Vih of CPU.

However, since the test condition of FRAM is as strict as 2 mA,

so we think that it can be cleared by changing the conditions.

Please provide information on the relationship between FRAM current value and Voh.

Best Regards,

Naoaki Morimoto

1. Re: The relationship between Output High Voltage and Current of FRAM

morimoto-n_1534561 Mar 5, 2018 6:49 PM (in response to morimoto-n_1534561)

Sorry, MPN is FM25L16B.

Customers are requesting information like the attached graph.
Like Show 0 Likes(0)

Actions
2. Re: The relationship between Output High Voltage and Current of FRAM

morimoto-n_1534561 Mar 14, 2018 10:28 PM (in response to morimoto-n_1534561)

Hello Cypress,

Do you have any update on this?
I need to answer the customer by tomorrow.

Best Regards,
Naoaki Morimoto
Like Show 0 Likes(0)

Actions
3. Re: The relationship between Output High Voltage and Current of FRAM

ndma Mar 14, 2018 11:35 PM (in response to morimoto-n_1534561)

Hi Morimoto-san,

I have checked internally regarding your request but unfortunately we do not have the data you requested.

Thanks,
Nada
Like Show 0 Likes(0)

Actions
4. Re: The relationship between Output High Voltage and Current of FRAM

morimoto-n_1534561 Mar 27, 2018 1:43 AM (in response to ndma)

Hello Nada-san,

Is it possible to consider if the condition of the current value at the output high is limited to a certain value?

Best Regards,
Naoaki Morimoto
Like Show 0 Likes(0)

Actions
5. Re: The relationship between Output High Voltage and Current of FRAM

user_78878863 Mar 27, 2018 12:37 PM (in response to morimoto-n_1534561)

Out of curiosity: which CPU are you using? The usual threshold for CMOS inputs is Vlow=0.3xVdd and Vhi=0.7xVdd.
Like Show 0 Likes(0)

Actions
6. Re: The relationship between Output High Voltage and Current of FRAM

morimoto-n_1534561 Apr 2, 2018 1:26 AM (in response to user_78878863)

Hello,

Customer use Renesas RX 631.
The Min value of Vih of the connection destination MCU is specified as Vcc x 0.8,
Therefore, it becomes 2.64 V when Vcc = 3.3V.

Best Regards,
Naoaki Morimoto
Like Show 0 Likes(0)

Actions
7. Re: The relationship between Output High Voltage and Current of FRAM

user_78878863 Apr 2, 2018 2:10 AM (in response to morimoto-n_1534561)

Which pins are you using for the FRAM connection? the input threshold voltages differ by pin
If you want to have more detailed information about the FRAM output voltages, you should create a support case (top right menu, 'my cases'). I think you should be safe since the input currents of the MCU should be much lower than the 2mA where the FRAM output voltages are specified. If you want to be 100% sure, you need a buffer inbetween.
Like Show 0 Likes(0)

Actions

Go to original post