SM320C40: Memory Retention for SM320C40GFS60

Alex,

This device does not have non-volatile memory. 

The ROM bootloader code is mask programmed, so it is permanent.

Absolute Max junction temp is 150c.    Unfortunately, this old device is not specified correctly for the absolute max temp.   It shows Tc for abs max of 125.  This should be Tj of 150.  

Recommended operating condition max for M version is Tcase of 125c.

Reflow profiles are dependent on numerous factors including, but not limited to, solder type, flux, package type, number of components, board layers, board size, reflow oven type and accuracy as well as pre and post cleaning processes.  Because of the number of variables it is not possible to provide a single reflow profile that is representative of every board using a specific package type. Typically manufacturing houses have reflow profiles in place and modify them for specific hardware.

We suggest using the flux manufacturer’s recommended profile as a starting point.  In general ceramic parts are compatible with ramp-rates of less than or equal to 5°C/second with a maximum temperature of 265°C.  Variations of course need to be comprehended based on time required to volatize the flux prior to the solder reaching liquidus.  

Note that though-hole hermetic devices are specifying a maximum temperature for soldering as a lead-temperature of 300°C for 10 seconds.  This is not a reflow temperature.   Metal lid packages use a tin-gold solder preform to attach the lid.  Tin-gold solder will begin to soften at 270°C and has a eutectic point of 280°C.   Do not allow package body temperature to exceed 265°C at any time or permanent damage may result.

TI recommends pre-tinning parts with gold-plated leads (gold thickness is 60 microinches minimum to 240 microinches maximum) to prevent gold-embrittlement of the leads.

Customers needing to use a high-temperature solder in excess of 265°C should hand-solder the leads.

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Regards,
Wade