TSOP 48 Type 1 - Different dimension

[ultrasmurf]

Hi All,

I was replacing SRAM on an old controller. Was ordering the TSOP48 package without paying too much attention on the body/pin to pin dimension as I thought TSOP48 type I has only 1 standard size. After removing the old component I was struck with horror as I tried to positioned the new SRAM and could not fit it within the pads. Pitch was ok, body width was ok, and the issue is on the body length. The old SRAM has body length of 16mm with 18mm pin to pin. The new TSOP48 has 18mm body length and 20mm pin to pin.

Browsing around the only thing I can find is clip on adapter that has a mention of these 2 different size, but I cant figure out what standard is the 16mm body is following.

Refer to here http://www.edcon-components.com/Webside/LIE/500637/PDFE/tsop-typei-pinchcontact.pdf

I am trying to source for a new SRAM with the correct dimension, and started to pull my hair as checking the specsheet 1 by 1 shows that all of the one I have checked from mouser and element14 has the 20mm pin to pin. Would like to be able to quickly shortlist the possible replacement by putting standard name on google. So if anyone could help me out by letting me know what standard is the TSOP48 with 18mm pin to pin length called ? (i.e. JEDEC xxxx, ISO xxx, etc)

Thanks....