Texas Instruments TI-450

This rare TI-450 was introduced in the year 1973 soon after the TI-3500. The main limitation in daily use of the TI-3500 was the lack of a memory. The TI-450 used instead the of the then modern "calculator-on-a-chip" invented already in the year 1971 a two-chip solution. The TMS0200 Chipset for 12-digit desktop calculators incorporate both enhanced driving capabilities for 12-digit displays and enhanced memory for program and data. 

Related calculators using this chipset are the SR-20 and SR-22. The first usage of the chip set was the TI-4000 and the Canon 121F.

A similar housing was used with the PM550-301 Programmer.

Dismantling the featured TI-450 manufactured in March 1974 by Texas Instruments reveals a rather complex design using multiple printed circuit boards (PCBs).

The Main-PCB is centered around the above mentioned TMS0200 Building Blocks for Desktop Calculators and complemented by various discrete components to drive the Panaplex II style display and generating the two-phase clock for the TMS0200.

The TI-450 uses the TMS0200 Data Chip marked with TMS0203 and a TMS0300 ROM Chip marked with TMC0322, indicating a switch with TI's nomenclature from TMS for Texas Instruments MOS (Metal-Oxide-Semiconductor) Standard to TMC for Texas Instruments MOS Custom.

Texas Instruments started in 1973 manufacturing Panaplex II style displays for their expanding line of 12-digit calculators.

Don't miss the rare TI-500, the first printing calculator introduced by Texas Instruments and the related TI-620.

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

© Joerg Woerner and Roger Gravel, May 5, 2002. No reprints without written permission.