Texas Instruments IC - Integrated Circuits

Texas Instruments invented the Integrated Circuit (IC) in the year 1958. The first calculators with integrated circuits used DTL (Diode Transistor Logic), RTL (Resistor Transistor Logic) or TTL (Transistor Transistor Logic) elements. These ICs are small building blocks with typical 4 logic gates or 2 flip-flops in a 14 to 16 pin plastic housing. To get a working calculator you need more than 50 of them. The Cal-Tech project demonstrated in 1967 a calculator using only 3 LSI circuits (Large Scale Integration) with more than 1,000 transistors per circuit and some additional shift registers. From that starting point the calculator race created every year new integrated circuits with higher complexity following the Law of Moore. Working at another supplier of integrated circuits, the well known company Intel, Moore stated: Every two to three years the complexity of ICs will double. The law is proved, within 30 years the complexity reached more than a million of transistors per device and in 2024 we stand at 100 billion transistors on a ingle chip.

In the meantime Texas Instruments stopped the production of integrated circuits for calculators. Most modern TI products use chips from Toshiba. View the calculator chips manufactured by Toshiba here.

It's difficult to get information about the calculator circuits manufactured by Texas Instruments. The following table gives an overview of the known circuits, a brief description and the calculators using them.

First TI chipset produced for Canon Inc.

This set of 3 Integrated Circuits was streamlined to the Pocketronic with its thermal printer.
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline Ceramic or Plastic (DIC/DIP) packages with 40 pins and 28 pins.

Second TI chipset produced for Canon Inc.

The second chipset supported displays instead the thermal printer of the Pocketronic. Two different Data Chips are known, the Arithmetic Chip was later replaced.
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline Ceramic or Plastic (DIC/DIP) cases with 40 pins and 28 pins.

Third TI chipset produced for Canon Inc.

This chipset consists of 6 Integrated Circuits, one of them was later replaced.
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline-Plastic (DIP) cases with 40 pins.

First TI chipset produced for Smith Corona Marchant

This set of 3 Integrated Circuits was manufactured for the Smith Corona Marchant Model 1 calculator introduced in October 1970 as a replacement for the chipset provided by American Microsystems, Inc (AMI).
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Single-Inline Ceramic (CIP) packages with 40 pins.

Forth TI chipset produced for Canon Inc.

The development of this chipset for Canon was cancelled in favor of the TMS0200 Building Blocks for Desktop Calculators.
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline Plastic (DIP) cases with 40 pins.

Fifth TI chipset produced for Canon Inc.

Compared with the previous chipsets the trend goes toward single-chip solutions. Both chips contain together 512*13-bit Read-Only program Memory (ROM), a 19*16-bit Serial-Access Memory (SAM) and support calculators with up to 14 digits display width.
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline Plastic (DIP) cases with 40 pins.

First TI chipset produced for Sumlock-Compucorp

This large chipset was developed by the engineers of Compucorp and produced by AMI. Later TI qualified as a second source to AMI. The chipset forms one of the first programmable calculators, the Compucorp 324G Scientist.

First TI chipset produced for Olivetti

This rare chipset was found in October 2010 by fellow collector Miguel from Argentina in an Olivetti Logos 270 desktop printing calculator. The keyboard of the calculator sports unusual [*=] [/=] [Q], [P], [R] keys and [S] and [T] memories.
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline Plastic (DIP) cases with 28 pins (TMC1829) and 16 pins (TMC1827, TMC1828).

Second TI chipset produced for Olivetti

This rare chipset was found recently in an Olivetti 55 desktop printing calculator from the Logos 50/60 series. The keyboard of the calculator sports additional [00][000] keys, unusual [*=] [/=] keys and a memory.
These chips are manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline Plastic (DIP) cases with 28 pins (TMC1876) and 16 pins (TMC1828, TMC1877).

First commercial available single-chip calculator circuit

The first commercial available "calculator-on-a-chip" was an MOS integrated circuit announced by TI in September 17, 1971. Find the original press release here. The chip contains 3520-bit Read-Only program Memory (ROM), a 182-bit Serial-Access Memory (SAM) and a decimal arithmetic logic unit as well as control, timing, and output decoders but no drivers for the display. This results in an overall complexity of roughly 5,000 transistors. The typical supply voltage of this chip is ƒA7.2 V at roughly 15 mA power consumption.
These chips were originally manufactured in a "state of the art" 10-micron 1-metal PMOS process and using Dual-Inline Plastic (DIP) cases with 28 pins. Around July 1973 the first TMS0100 designs were ported to an 8-micron process and internally renamed to TMS0700.
It took about a year till the first copy of the original design appeared. US based company MOSTEK introduced the MK5020P December, 1972.

First commercial available single-chip scientific calculator circuit

The original TMS1802 single-chip calculator circuit was limited to basic calculators with 8 digits or 10 digits calculations. The SR-10 "Slide Rule" calculator is based on the TMS0120 using the TMS0100 in a novel approach to add to the 8-digit Mantissa in scientific notation a 2-digit Exponent and repurposing the unused Segment H for the minus sign of the Exponent.

Chipset for 12-digit calculators

One limitation of the 28-pin packages of the TMS01xx was the maximum number of 10 or 8+2 digits for the results. For desktop calculators Texas Instruments developed with the TMS0200 Building Blocks a chipsets with 40-pin packages for the integrated circuits.

Chipset for scientific calculators

With the TMS0500 Building Blocks Texas Instruments created a novel architecture for scalable scientific calculators. The architecture used minimum a 2-chip design with the Arithmetic chip and the SCOM (Scanning Read-Only Memory) but was expandable to a maximum of 8 SCOMs, additional RAM as program memory for programmable calculators, additional RAM for general purpose registers and even a chip driving a printer borrowed from the TMS0200 family. Most scientific and programmable calculators manufactured by Texas Instruments between the years 1974 and 1982 (SR-50..TI-59) are based on these chips.

Abbreviations:

? ARITH Arithmetic Chip with 5*16 Digits registers, segment scanning and driving
? SCOM Scanning and Read Only Memory Chipwith 1k*13 Bits instruction memory and 16*16 Digits constants
? DSCOM SCOM Scip with doubled memory capacity of 2.5k*13 Bits instruction memory and 16*16 Digits constants
? QSCOM SCOM Chip with fourfold memory capacity
? BROM Bare Read Only Memory Chip with 1k*13 Bits instruction memory
? DRAM External Random Access Memory Chip for user data (memory registers)
? PRAM External Random Access Memory Chip for user programs (keycodes) with 1,920 Bits of read/write memory
? CROM External Customer Only Memory Chip for user programs (keycodes)
? PCHIP Printer Chip

Texas Instruments used the leading designation TMS (Texas MOS Standard) or TMC (Texas MOS Custom) for most chips. The following table uses only the (more common) TMC designations.

The TI-58/59 architecture introduced the Solid State Software Modules? with up to 5000 program steps. On the backside of the TI-58/59 you'll note a small lid with a place for the 8-pin module, view it here.

Enhanced First generation single-chip calculator circuits

Enabled by a combination of smaller transistors due to a process shrink in the manufacturing process of Integrated Circuits and a higher yield in production, Texas Instruments launched with the TMS0600, TMS0700 and TMS0800 single-chip calculator circuits about two years after the introduction of the original TMS0100 family a three-tier approach: The TMS0600 increasing Read-Only program Memory (ROM) for additional functionality while keeping the need for external segment- and digit-drivers, the TMS0700 keeping the specifications of the TMS0100 for a cost-reduction of the chips and the TMS0800 reducing the calculating capabilities but integrating both a clock driver and segment drivers to simplify the electronics of the calculators and consequently reducing their manufacturing costs.

The TMS0640 Printer Chip is acting as a peripheral device for the TMS0100 single-chip calculator circuits and supports serial dot-matrix thermal printer heads like the ones used with the original Canon Pocketronic calculator.

The TMS0100 Product Family of single-chip calculator circuits went through multiple design changes and was around July 1973 internally renamed to TMS0700 but still marked on the outside of the package with TMS01XX. Only the chips (and usually the bottom of the chip package) carry the TMS07XX designation and we have difficulties to define the exact cut-off date of the "original" TMS0100 chips. We are not sure which TMS0100 chips were ported to a smaller manufacturing process and include most TMS0100 members in the TMS0700 overview.

Some calculators, e.g. the Exactra 20, used only digit drivers, the segment outputs of the chip were connected directly to the display.

The TMS0800 Product Family adds segment-drivers for LED-Displays with up to 9 digits to the TMS0100 series.

The TMS0830 Product Family are TMS0800 devices specified for low-voltage power supply of 9 Volts.

The TMS0850 Product Family adds segment- and digit-drivers for low-voltage VF-Displays with up to 9 digits to the TMS0800 series.

Third generation single chip calculator circuits

With the TMS1001 Texas Instruments introduced the first member of the famous TMS1000 Microcomputer Family. The chip contains a microcomputer complete with a Read-Only program Memory (ROM) having 1,024 8-bit Words; a temporary storage Random-Access Memory (RAM); input (from keypad); output (to control keypad scan and LED display); and an oscillator (clock). The TMS1000 chip was designed to span a range of hand-held calculator products (from four-function up through simple memory calculators). Since the chip had to be customized with the ROM program appropriate to a product, other programmable features were included to improve the chip's flexibility. Today we know 13 different chips used in TI calculators. These chips vary in implementation technology, number of I/O lines, display drive, amount of ROM (up to 26.6k Bits) and amount of RAM (up to 1,280 Bits). Calculator applications range from simple four-function calculators to the 50-step programmable TI-57. As of mid 1979, over 35 million TMS1000 chips were deployed in both calculator and non-calculator applications, establishing the TMS1000 as the computer architecture with the largest installed base. The internal clock rate varies from 200 to 450 kHz, depending on technology. Die photos courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

With the TI-1200 and TI-1250 calculators Texas Instruments introduced in March 1975 the first calculators using a real single chip design. The 8 digit LED-display and 8*4 matrix keyboard are connected directly to the integrated circuit and the whole system is powered by a single 9V battery. While the original design of the TMS0950 series is very similar to the TMS1000 with added display drivers for 7-segment LEDs, reduced the TMS0970 design the chip size dramatically while maintaining its specifications. Texas Instruments changed its nomenclature in 1977 from TMS0970 to TMC0970/TMC0900. The chip design of the TMC0970 is very similar to the more capable TMC0980.

In the year 1976, with the SR-40 and TI-30 the first scientific calculators using a real single chip design were introduced. These calculators used a 8 digit LED-display, too. In 1977 the display size was expanded to 8+2 digits with the introduction of the TMC1500 design. The TMC1980 family replaced the drivers for LED from the TMC0980 with drivers for VFD. Find more details in the description of the TMS1000 Microcomputer family. Die photo courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

Shortly before the introduction of the CMOS technology in the year 1978 a final chip-size optimized architecture for four-function calculators was introduced with the TMC1990. Find more details in the description of the TMS1000 Microcomputer family.

Simplified single chip calculator circuits

During the peak of the calculator war (around 1976 to 1978) a lot of customized chip architectures appeared even from Texas Instruments. Instead using the TMS1000 device with the large ROM and RAM count, some "area optimized" architectures appeared. Don’t forget that in the early days of IC-Technology the yield of designs with some thousands of transistors was poor! The TMC0920 introduced in June 1977 uses a serial architecture with five 40-bit registers instead the 16*4-bit data registers of the TMS1000 family, just 511*9 Bits ROM and a one-bit serial adder. Only few calculators make use of the TMC0920 devices.

In 1977 the display size of the single chip scientific calculators was expanded to 8+2 digits. Together with a larger memory these chips have transistor counts of roughly 30,000 elements. Like the TMC0920 series utilizes the TMC1500 a serial architecture but changed its specifications significantly featuring twenty 64-bit registers, 2,048*13 Bits ROM, one-bit serial adder and drivers for a 12-digit LED display. Die photo courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

Texas Instruments introduced with the redesigned TI-5040 in 1978 a desktop calculator with integrated thermal printer and VF-Display based on the TMC0260.

In the year 1978 Texas Instruments invented the synthesizer technology to reproduce human speech with tuned voices stored in ROM's (integrated circuits) and created the Speak & Spell. Find more information about the synthesizer chips and their Speech-ROMs here. The first products used specialized calculator chips of the TMS1000 family to manage keyboard and display of the product. From a technical point of view these devices are very similar to the TMS0980 family but optimized for 14-segment VF-Displays instead of 7-segment LED-displays.

The derivatives were either numbered like TMC0271, TMC0272... or got a CD (Custom Design) number, e.g. CD2702.

First generation CMOS single chip calculator circuits

In 1978 Texas Instruments introduced the first CMOS 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. The main difference ? beside the manufacturing process ? is the permanent connection of the internal memory (12*64 Bits RAM + 64 Bits Display RAM) to the supply voltage. This feature allowed the „Constant Memory? found on the calculators based on the TP0320 family like the TI-50 or TI-53. Even after you turn off the calculator its user memory is stored inside the chip. The supply current is low enough to buffer the memory more than a year from two small button cells. The program memory with 2k*9 Bits ROM allowed the conversion of most calculating features known from Majestic calculators (Scientific, Statistical and Financial calculator or even Flight computers). Die photo courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

Remember that the first LCD-calculators sold by Texas Instruments used foreign calculator chips manufactured by Toshiba. Find more information about them here.

Together with the CMOS process the employees of Texas Instruments changed the nomenclature of the chips. Instead of the leading characters TMS (Texas MOS Standard) or TMC (Texas MOS Custom) the abbreviation TP appeared for the new device families. These Microcomputers got both ROM programmability and Gate programmability (e.g. segment decoder). The derivatives were either numbered like TP0320, TP0321... or got a CD (Custom Design) number, e.g. CD3202.

Simplified CMOS single chip calculator circuits

During the calculator war (about 1976 to 1978) a lot of customized chip architectures appeared even from Texas Instruments. Instead using the TMS1000 device with the large ROM and RAM count, some "area optimized" architectures appeared. Don’t forget that in the early days of IC-Technology the yield of designs with some thousands of transistors was poor! The TP0310 introduced in the year 1978 based on the serial architecture of the TMS0920 optimized for the TMS1050 calculator. This was the most compact design with only 511*9 Bits ROM and 40*5 Bits RAM using a one-bit serial adder. Only few calculators make use of the TP0310 devices. Die photo courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

Enhanced CMOS calculator chips

The TP0320 architecture with only 28-pin housings, 2k*9 Bits ROM and (12+1)*64 Bits RAM limited calculator designs to simple Scientific (TI-50), Statistical (TI-35) and Financial (Business Analyst II) calculators driving displays with only 8 digits (or 5 digits + 2 exponents) resolution. The "programmable" TI-53 stored as much as 32 key entries in the memory, that’s it!

Texas Instruments introduced with the TP0455 architecture a new design to overcome these limitations. It is related to the TMS1000 architecture but added time-keeping capabilities, a more flexible display driver and a different RAM architecture with 128*4 Bits capacity. The TP0455 is still gate-programmable. The first use of the TP0455 was the CD4501 design found in the Time Card introduced end of the year 1981. The TI-55 II demonstrated the flexibility of the TP0455 architecture, two chips formed a powerful Primary-Secondary architecture. The Primary device uses a 40-pin housing and scans the keyboard, drives a huge display with 8+2 digits and performs the math capabilities. The Secondary device in the well known 28-pin housing doubles the memory capacity of the calculator. This allows e.g. 56 program steps compared to the 32 steps of the TI-53.

The TP0455 design was soon replaced with the TP0456 and most designs were converted. The CD numbers were incremented 50 units to distinguish the difference between TP0455 (e.g. CD4515) and TP0456 e.g. CD4565). The TP0456 seems to be upward compatible to the TP0320, we know with the TI-30 LCD and TI-30-II calculators using either the CD3202 or CD4565 design. Die photo courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

We assume that the CD46xx nomenclature was used for original TP0456 designs, they were discovered mainly in educational toys. Die photo courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

The next step in the enhanced CMOS architectures could be found in the TP0458 architecture. These chips with the CD48xx nameplate use always a 40-pin housing and hold 50% more ROM and RAM cells compared to the TP0456 for an impressive 3k*9 Bits ROM and 192*4 Bits RAM capacity. In conjunction with the Primary-Secondary architecture some powerful calculators like the TI-62 Galaxy or TI-65 appeared with as much as 112 programming steps or 16 data memories and even timer functions. Single-chip designs were discovered in "display intensive? products like the TI-30 Galaxy or the rare BA-III. Die photo courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

With the introduction of the TP0458 we could almost (save LCD III Family) close the history of calculator chips manufactured by Texas Instruments. The years between 1967 and 1982 brought us a lot of exciting calculator architectures driven by

? Technology (early steps with multi-chip designs)
? Flexibility (TMS1000 architecture)
? Cost Price (serial architectures)
? Development Costs (TP0456 architecture)

Later calculator developments based mostly on Toshiba calculator chips, Texas Instruments dropped their own business with the TMS1000 and concentrated on DSP (Digital Signal Processing) chips. Once again TI is a leading supplier in commercial products, most mobile phones use their DSP-architecture nowadays.

LCD III Family CMOS single chip calculator circuits

If you dig deep into the calculator related patents filed by Texas Instruments and know about the mystery TI-88 calculator, you’ll discover additional devices:

? TP0470/TP0475 4-bit microcontroller with CD2901, CD2902 and CD2903
? TP0480 4-bit microcontroller with LCD Driver
? TP0485 4-bit microcontroller with CD2901 and CD2902
? TP0530 Serial cascadable driver for alphanumeric LC-Display
? TP0531 and TP0532 4-bit Memories with CD5402 and CD5403

Unfortunately we don’t know much about the LCD III calculator chip family. The patent application is centered around a „Data processing system integrated circuit having modular memory add-on capacity? and describes a TMS1000 chip with different slice-lines to produce area-optimized chips with adoptable memory size. According to the patent the ROM-size varies between 1k Words and 4k Words, the RAM-size seems to be between 56 and 224 Bytes. Based on information from the estate of CB Wilson located by Jon Guidry and made available on his website www.hexbus.com we understand the naming convention of the TP0470 - TP0485 devices:

? TP0470 3k Bytes ROM, 128 Bytes Fast ROM, 22*16*4 Bits RAM, no Timekeeping, no LCD Driver
? TP0475 3k Bytes ROM, 128 Bytes Fast ROM, 22*16*4 Bits RAM, Timekeeping, no LCD Driver
? TP0480 3k Bytes ROM, 128 Bytes Fast ROM, 22*16*4 Bits RAM, no Timekeeping, LCD Driver
? TP0485 3k Bytes ROM, 128 Bytes Fast ROM, 22*16*4 Bits RAM, Timekeeping, LCD Driver

The inside view of a TI-88 gives you some chip numbers but without destroying the calculator we aren’t able to reverse engineer them.

UPDATE January 2021: We sacrificed a working TI Programmable 88 and decapped its chips to reveal amazing technology! Die photos courtesy of Sean Riddle. RAM-size determination courtesy of Ken Shirriff.

It’s a pity that the TI-88 never got the final approval for mass production...

Display Driver Chips

Before the real single-chip calculators were introduced in the mid of the Seventies, the LED displays were connected to digit drivers and on the first designs to additional segment drivers.

Clock Generation Chips and Clock Buffer Chips

Some earlier calculators are using Integrated Circuits instead of discrete electronics to generate the single-phase or dual-phase clock signals of the calculator chips. Die photos courtesy of Sean Riddle.

DC/DC Converter Chips

Some earlier calculators are using DC/DC converters to generate the supply voltages of the calculator chips. Die photos courtesy of Sean Riddle.

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

ƒD Juergen Dobrinski, Sean Riddle, Mikhail Svarichevsky, and Joerg Woerner, 2001 - 2022. No reprints without written permission.