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K2L EVM DDR3 alternative

Other Parts Discussed in Thread: 66AK2L06

Hi,

In the EVM for 66AK2L06, DDR3 SDRAM used is MT41K256M16HA-125 .For our custom design based on the same processor, we require the industrial version of this part number and unfortunately it is found as obsolete in micron site. The recommended replacement part is with CL of 13 which is not supported by keystone device.

Also in " DDR3 Design Guide for KeyStone Devices" document it is noted as "DDR3L SDRAMs operating at 1.35V are not supported at this time. ". All the 512M x 16 versions of Micron DDR3 are of 1.35V .

Our memory requirement is 2GB. Please recommend me an alternative to MT41K256M16HA-125 and can be used with Keystone2 device.

Regards

Sreejaya

  • Hi Sreejaya,

    I've forwarded this to the hw team.

    Best Regards,
    Yordan
  • Hi Sreejaya,
    The specification for DDR3L requires that all DDR3L memories operate at both 1.35V and at 1.5V providing backwards compatibility for DDR3 systems. The Hardware Design Guide is correct in stating that we don't support using DDR3L devices with a 1.35V IO voltage. You can use these parts provided that the IO voltage is set to 1.5V.
    Regards,
    Bill

  • Hello Bill,
    Thank you for the input.

    So do you mean that we can use the DDR3L device at 1.5V (ie. Vdd=Vddq=1.5V)?

    Is there any specific documentation which should be considered when using the DDR3L device at 1.5V?

    Regards
    Sreejaya
  • Hi Sreejaya,

    That is correct. If you look in the data sheet for the DDR3L device, you will see something like the following language.

    • Backward-compatible to VDD = VDDQ = 1.5V ±0.075V

    There isn't any special documentation from TI on the subject but the data sheet for the memory device should have additional information on using the device in 1.5V compatibility mode. For example, one of the Micron data sheets for a DDR3L device includes the line above and the following statement. 

    The 1.35V DDR3L SDRAM device is a low-voltage version of the 1.5V DDR3 SDRAM device. Refer to the DDR3 (1.5V) SDRAM data sheet specifications when running in 1.5V compatible mode.

    Note that the timing information needed for the REGCALC spreadsheet should be taken from the 1.5V version of the data sheet and not the 1.35V version.

    Regards,

    Bill