From: "Zhong Pan"
Subject: Re: Help: Why 1.5V output in Samsung SRAM K6R1016C1C(KM6161002C) ?
Date: Thu, 26 Dec 2002 17:06:08 -0800
Organization: University of California, Davis
NNTP-Posting-Date: Fri, 27 Dec 2002 01:06:15 +0000 (UTC)
X-Newsreader: Microsoft Outlook Express 6.00.2800.1106
Thanks John. That would be my guess too (no power or chip blown up) if I
hadn't seen correct data being written into and read out of the chip. Yes, I
can write into the chip and read out of the chip correctly, according to the
measurement done by an Agilent Infiniium DCA. But the voltage is low, and I
suspect that it is the reason that causes some glitches in my next stage,
which is a DAC. This still puzzles me.
One thought: could it be that I am not measuring the right voltage at all?
My measurement at the SMA connectors driven by a BERT shows a HI voltage of
2.5V, and power source current does not change. But while measuring the SRAM
chip, the power source current will increase for around dozens of mA. Is the
oscilliscope seen by the SRAM chip as a big load?
"John Devereux" wrote in message
> "Zhong Pan" wrote:
> >I am using a Samsung K6R1016C1C (KM6161002C is the new part#). It's a
> >CMOS memory that has TTL-compatible inputs and outputs. Datasheets
> >that the input (address and data) HI voltage must be at least 2.2V, and
> >output (data) HI voltage will be at least 2.4V. However, I found that for
> >the several pull-up resistor and current-limiting resistor values I use,
> >HI for outputs of the memory are always around 1.5V, which is too low for
> >the next stage. What surprises me more is that, the input voltage is also
> >"pulled down" by the chip from the initial 2.5V (from previous stage) to
> >1.5V! The chip is still reading correct data out, but the next stage
> >to have trouble with this low output.
> >Anybody has any idea what is going on?
> >Samsung has information about this chip at:
> >Thanks in advance, and Merry Christmas, Happy New Year!
> Sounds like you have blown it up, or perhaps got the power
> supply connected wrongly (or not at all).
> John Devereux