Texas Instruments TI-35

The TI-35 was the next calculator following the TI-50 in the slimline epoche. Differences in functionality were small, in appearance great. Compared to the design of the TI-50 or TI-53 with their metal housing and molded keys this one looks really cheap. TI corrected this "failure" later with a stylistic enhanced TI-35. Compare it for your own.

Simply by comparing the designation of the integrated circuits of the calculators you'll get the first members of the slimline family:

Don't miss the rare Business Card, probably the missing calculator using one of the TP032x chips.

If you dig deeper into the early slimline calculators you'll notice two different designs of the keys itself. The cheap looking black keys like the ones on the left (1979) or the engraved keys started in the year 1978 with the TI-50. Some calculators used both keyboard:

A similar calculator was introduced with the TI-38. In Brazil a similiar calculator was advertised as TI-35B.

In the year 1978 Texas Instruments introduced the first C-MOS calculator chips based on the TMS1000 Microcomputer family. The TP0320 architecture is similar to the TMC0980 chips introduced two years earlier for the TI-30 calculator. Main disadvantage of this family was the limited capacity with just 2k*9 bits ROM and 64*13 bits RAM resulting in simplified and sometimes inaccurate calculating algorithm.

The next generation of enhanced C-MOS calculator chips was introduced in 1981 with the TP0455 resp. TP0456 family. The third edition of the TI-35 received during its production time an upgrade to the CD4557 chip and the accuracy of e.g. the Calculator forensics test increased slightly:

Recently an early TI-35 with a Calculator forensics test result of 9.177087103 was reported. We noticed two minor differences: The calculator chips reads TP0324-4N instead the common TP0324-4NL designation and the finish of the keyboard plate looks different. 

In 1984 the era of the slimline calculators was over and Texas Instruments introduced a family of three calculators manufactured in Taiwan:

If you are interested in the calculating accuracy of scientific calculators don't miss the Calculator forensics.

The US based company Jeppesen Sanderson developed a very interesting navigation computer called avstar based on this TI-35.

If you have additions to the above article please email: joerg@datamath.org.

© Joerg Woerner, December 5, 2001. No reprints without written permission.