What does LM (Linear Monolithic) mean? - Page 1
Forum section: electronics / beginners

author: fubar.gr
author_rank: Unknown
timestamp: September 12, 2014, 10:28:11 am
content: If I'm not mistaken, Monolithic means that the entire ic is on the same die. Why the distinction? Did they used to make ICs in separate, interconnected dice back in the day?How about Linear? AFAIC there are two definitions of linear, one that the circuit's output changes linearly with the input, and the other that the output frequency is the same as the input.But most LM ICs don't fit either definition. So why linear?

author: Richard Crowley
author_rank: Super Contributor
timestamp: September 12, 2014, 11:04:40 am
content: Linear ("analog", continuous) as distinguished from digital ("binary", two-state). Some people have used otherwise binary/digital ICs (notably inverters) as linear/analog amplifiers for circuit applications where distortion and noise is not important. Of course all integrated circuits are linear/analog INSIDE. But "digital" chips are designed and optimized for operation at the "rails" where a binary zero is represented by a lower voltage and binary one is represented by a higher voltage. And there are some integrated circuits that are BOTH linear and digital, like comparators and analog-to-digital converters, and digital-to-analog converters.Monolithic as in "one-piece". Before the development of the monolithic integrated circuit, Jack Kilby (Texas Instruments) had devised "integrated circuit" technology with separate little bits of substrate for different components, and wire-bonded together. In the case of Kilby, he was working in Germanium at TI, and meanwhile, out in California, Bob Noyce (Fairchild then Intel) was doing parallel development in Silicon.

author: wiss
author_rank: Frequent Contributor
timestamp: September 12, 2014, 11:10:11 am
content: Quote from: fubar.gr on September 12, 2014, 10:28:11 amLinear (Electronics) translates to Continuous (Mathematics), sort of.Linear (Mathematics) is quite different from Linear (Electronics)and "LM" is more of a brand-name.

author: fubar.gr
author_rank: Unknown
timestamp: September 12, 2014, 11:34:06 am
content: So basically "linear" in the LM naming context is another word for analog. Thanks!

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 12, 2014, 11:45:04 am
content: Quote from: fubar.gr on September 12, 2014, 10:28:11 amThe "monolithic" distinction would be in comparison to discrete solutions (build it on the PCB) or "thick film" / "hybrid" modules (metallized ceramic substrate, with better thermal performance, and finer scale laser etching, than PCBs can offer, usually assembled from resistive track, ceramic chip components and bare dies).A very popular example might be comparing the Tektronix 465 scope (discrete) to the 475 (hybrids and ICs). As far as I've heard, the circuits are nearly identical, but the bandwidth doubled in the process. Later model scopes had even more integration (monolithic), and even better performance.A related example of monolithic technology might be those three-channel CRT cathode drivers, occasionally found in high resolution CRTs (megapixels on up). Though Trinitrons (some of the highest res CRTs) often resorted to discrete or hybrid methods, anyway."LM" of course is National's (now TI's) traditional prefix; other companies had similar nomenclature, for example RCA's CD (rCa Digital?) and CA (rCa Analog?) series ICs.Tim

author: amyk
author_rank: Super Contributor
timestamp: September 12, 2014, 12:22:14 pm
content: Quote from: T3sl4co1l on September 12, 2014, 11:45:04 amI think the C was for CMOS.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 13, 2014, 01:15:32 am
content: Including CA series? There are plenty of bipolar, CMOS and BiCMOS in that range (not to mention arrays from diodes to transistors), that wouldn't seem to fit. AFAIK, CD was all CMOS though, even the analog-ey bits (at worst, the CD4046 might have a reference in it?).Tim