Hello
Would you please let us know the VTT supply Current for DLPC200 and DDR2 ( MT47H32M16HR-3)?
In the oteher word, the Light Commander has two VTT current source (TPS51100), but would you please let us know
the supply current for each VTT_B2 and VTT_B3_B4?
( it is too hard to measure it by ourselves.)
DDR# TPS51116 on LCB2:DDR_D[15:0] U8 U501B3:DDR_D[39:16] U7, U6 U503 B4:DDR_D[63:40] U6、U5 U503
The reason why is customer start the desgin, but there are no description about this value.
With my best regards
Shibitani-san,
Thank you for your inquiry. The DLPC200 Chipset was designed by TI, but the LightCommander Controller Board was designed by Logic PD. An inquiry has been submitted to Logic PD regarding the current on these two supplies. This will be updated when we receive their response. Thank you for your patience.
Fizix
Dear Fizix san
Thank you for your reply.
I had tried to measure VTT current on Lightcommander by myself, however TPS51100 VTT output pattern tied to DDR directly, so it was really very hard .
Cusomter know TPS51100 can handle 3A peak sink/source current, and also they will use TPS51100&TPS51116 in their design,
but want to know the actual (average) VTT current for DLPC200& DDR2 in order to estimate the heat/relaiability.
Anyway,I found following desciprtion on NS website.
According to this document, In DDR case, VTT current should be 200mA range, and there are no concern for customer's design.
Cusomter think 200mA average current is acceptable , however, VTT current on VTT_B3_B4 on Lightcommander exceeds 1A average?
http://www.national.com/assets/en/appnotes/AppBrief113.pdf
Would you please give me your comment/opinion?
Best Regards
Hello Shibatani-san,
You wrote:
VTT current on VTT_B3_B4 on Lightcommander exceeds 1A average?
Is this "1A" a measured value?
Best Regards,