Company: Precision Monolithics, Inc. (PMI)
Based: Santa Clara, CA. Founder: Marv Rudin & co-founder Garth Wilson Founded: 1969 (bought out by Analog Devices in 1990) Specialty: Developed and produced mixed signal and linear semiconductors. First company to make two-chip and single chip D/A converters. |
 Analog Devices DAC-08 Chip (1975) |
PMI DAC-76 First COMDAC Companding Digital to Analog Converter Chip (1975)
Item #466
This Lucite paperweight features an actual PMI DAC-76 chip. This DAC chip is in a 16-pin white ceramic carrier with gold cavity and legs. The DAC-76's gold lid was not solder onto this particular unit so this allows for viewing of the PMI's integrated circuit inside as well as the carrier's gold wire bond pads inside the cavity.
This "mixed-signal" integrated circuit was manufactured by PMI using Bipolar process technology. Both the digital and the analog sections of it's circuitry are contained on one single chip of silicon.
The 8-bit PMI DAC-76 in DIP packaging was the first DAC (Digital to Analog Converting) chip that was capable of converting a digital input signal to an analog output signal using "Companding" (compressing or expanding to improve the dynamic range of an analog electronic signal).
In the 1970s many semiconductor manufacturers, including Analog Devices, AMD, Harris, Intersil, Motorola, National Semiconductor, Precision Monolithics (PMI), TI, and TRW, were all competing to develop fully integrated Digital to Analog chips. PMI was the first to introduce a two-chip and also a single chip DAC converter chip and put them into DIP packaging.
Using diffused resistors Dan Dooley of PMI designed the 6-bit DAC01 in 1969. The first monolithic (single chip) converter, the MonoDac01, was developed and marketed by PMI in 1971. The MonoDAC01 was the first fully integrated DAC.
In 1972 PMI introduced their hugely successful 10 bit D/A converter on a single chip, the monoDac02. Motorola (MC1408) and PMI (DAC08) followed with 8-bit devices in 1975.
In 1976 Peter Holloway of Analog Devices laser trimmed thin-film resistors on wafers to achieve the required precision for the first single-chip 10-bit DAC (AD561).
Many of PMI's converters & linear IC's continue to be manufactured and marketed by Analog Devices to the tune of over two billion dollars a year of market share in the Linear IC market.
 Close-up of the PMI DAC-76 COMDAC Chip |
 PMI DAC-76 D/A IC Pinout |
PMI Lead Frame Integrated Circuit Package (1980s)
Item #906
This Lucite keychain from PMI features an example of a metal Lead Frame that would have been used in one of their Quad Flat Package (QFP) surface-mounted integrated circuits.
An integrated circuit chip die would have been bonded to the center of the lead frame package and then fine gold or aluminum wires bonded from the chip's die pads to the package leads.
Next, the lead frame would be moulded in a hermetically sealed plastic or ceramic case and then the outside edges of the lead frame would have been removed which would separate all the leads.
Lead Frame is marked PMI at the bottom.
An integrated circuit chip die would have been bonded to the center of the lead frame package and then fine gold or aluminum wires bonded from the chip's die pads to the package leads.
Next, the lead frame would be moulded in a hermetically sealed plastic or ceramic case and then the outside edges of the lead frame would have been removed which would separate all the leads.
Lead Frame is marked PMI at the bottom.
PMI / Analog Devices
Dolby Pro-Logic Surround Decoder - Processor Chip (1990)
Item #742
This enamel pin contains an actual Dolby Pro-Logic Surround decoder/processor chip produced by PMI after it became a division of Analog Devices in 1990. The chip is marked "PMI 55032" and has the initials of it's designers.
Dolby Pro-Logic, introduced in 1987, used matrix technology to extract extra channels from stereo-encoded audio for use in 4-channel surround sound systems.
(#844 similar)
Dolby Pro-Logic, introduced in 1987, used matrix technology to extract extra channels from stereo-encoded audio for use in 4-channel surround sound systems.
(#844 similar)
Close-up of the Dolby Pro-Logic Surround Decoder/Processor chip
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The Dolby Pro-Logic 4-channel Surround System
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