Texas Instruments TI-2500 / Minimath Prototype

The famous TI-2500 Datamath calculator was first announced in April 1972 with a suggested retail price (SRP) of $149.95. Beginning June 1972 first customers in selected areas got their calculators before the formally introduction on September 21, 1972.

The SRP was reduced to $119.95 by the date of introduction. Together with the TI-2500 Texas Instruments introduced the two desktop models TI-3000 and TI-3500. Find a reprint of the Press Release about the introduction here.

The Minimath calculator represent Texas Instruments effort in the LCD (Liquid-Crystal-Display) technology. One limitation of the early Datamath calculator was the short operation time although it uses 6 of the expensive NiCd-cells. A short analysis of the overall power consumption demonstrates easily that the light-emitting-diodes in conjunction with the necessary display drivers are the power hungry parts in the calculator design.

The TMS0100 "Calculator-on-a-Chip" itself was designed in a low-power PMOS-process. Engineers at Texas Instruments started the design of a LCD for the Datamath and named the calculator "Minimath". The Minimath uses a transmissive LCD instead of todays reflective LCD's and added a light-path to illuminate the display with the ambient light from the back. Because of the short life expectancy of the LCD's at that time, Minimath was never put into production.

The Minimath uses the TMS0111 variation of the TMS0100 design.

The Datamath Calculator Museum received in the meantime a Minimath calculator that seems to precede the pictured model from the Smithsonian.

Courtesy of Nance L. Briscoe, Specialist
History of Integrated Circuit Technology
National Museum of American History
http://smithsonianchips.si.edu
A Continuing Work-in-Progress Digital Research Paper

Datamath™ is a trademark of Texas Instruments.

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

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