Kent Lundberg
@doctoranalog.com
Analog-circuit and control-systems engineer, oscilloscope collector, synthesizer geek, amateur historian, unrepentant bibliophile. He/him.
Happy birthday to Robert J. Widlar, who would have been 88 today (Nov. 30).
December 1, 2025 at 12:57 AM
Happy birthday to Robert J. Widlar, who would have been 88 today (Nov. 30).
To solve the temperature variation problem, Widlar invented the band-gap reference (Fig. 2), now used in voltage references everywhere, and National Semiconductor produced the 5V LM109 (Fig. 5), which is the grandfather of all three-terminal voltage regulators.
December 1, 2025 at 12:56 AM
To solve the temperature variation problem, Widlar invented the band-gap reference (Fig. 2), now used in voltage references everywhere, and National Semiconductor produced the 5V LM109 (Fig. 5), which is the grandfather of all three-terminal voltage regulators.
A year later, in 1970, he unveiled the solution in an ISSCC talk and a JSSC paper: a 3-terminal regular using a band-gap voltage reference. Widlar wrote, "The author has previously advanced arguments against including the pass transistor in an integrated-circuit regulator."
![A useful on-card regulator must include everything within one package, including the series-pass transistor. The author has previously advanced arguments against including the pass trasistor in an integrated-circuit regulator [1]. First, there are no standard multilead power packages. Second, integrated circuits necessarily have a lower maximum operating temperature because they contain low-level circuitry. This means that an IC regulator needs a more massive heat sink. Third, the gross variations in chip temperature due to dissipation in the pass transistor worsen load and line regulation. However, these problem can be largely overcome using the new techniques, especially for the kind of regulator required by digital systems.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:ynia5stn2qgmkwbwfrq7j4ai/bafkreiara46hsbygyjgjq63an4utnn6b4zfqevzzvaq22np3hb7xjuptvq@jpeg)
December 1, 2025 at 12:55 AM
A year later, in 1970, he unveiled the solution in an ISSCC talk and a JSSC paper: a 3-terminal regular using a band-gap voltage reference. Widlar wrote, "The author has previously advanced arguments against including the pass transistor in an integrated-circuit regulator."
Widlar piled on more arguments... circuit interactions with the temperature gradient, leakage, and cost, are all bad.
December 1, 2025 at 12:54 AM
Widlar piled on more arguments... circuit interactions with the temperature gradient, leakage, and cost, are all bad.
In 1969, Bob Widlar wrote an article for EEE, "Designing Positive Voltage Regulators", arguing that fully integrated voltage regulators were impossible. The reasoning: the pass transistor kills you: it gets too hot, varying the chip temperature, and there are no standard IC power packages.
December 1, 2025 at 12:53 AM
In 1969, Bob Widlar wrote an article for EEE, "Designing Positive Voltage Regulators", arguing that fully integrated voltage regulators were impossible. The reasoning: the pass transistor kills you: it gets too hot, varying the chip temperature, and there are no standard IC power packages.
I shall try some of your burned replicated bird meat.
November 27, 2025 at 12:29 PM
I shall try some of your burned replicated bird meat.
Happy 5.25 floppy disk day.
May 25, 2025 at 2:50 PM
Happy 5.25 floppy disk day.
Happy 318th birthday, Leonhard Euler.
April 15, 2025 at 8:41 PM
Happy 318th birthday, Leonhard Euler.
March 5: Happy 3.5-inch floppy disk day!
March 5, 2025 at 2:55 PM
March 5: Happy 3.5-inch floppy disk day!
Don't you just love it when your insufferable boss comes to the photo op, insists on sitting at the lab bench, and pretends he helped? John Bardeen (left), Walter Brattain (right), and William Shockley (seated). These three men won the 1956 Nobel Prize in Physics for the invention of the transistor.
February 13, 2025 at 1:32 PM
Don't you just love it when your insufferable boss comes to the photo op, insists on sitting at the lab bench, and pretends he helped? John Bardeen (left), Walter Brattain (right), and William Shockley (seated). These three men won the 1956 Nobel Prize in Physics for the invention of the transistor.
If a polar plot of the frequency response of the loop transfer function of a feedback system encircles the -1 point, the closed-loop system will be unstable.
February 7, 2025 at 2:11 PM
If a polar plot of the frequency response of the loop transfer function of a feedback system encircles the -1 point, the closed-loop system will be unstable.
TIL 2025 is not only a square, but it's a square of a triangular number, so it is also a sum of cubes.
January 1, 2025 at 12:38 AM
TIL 2025 is not only a square, but it's a square of a triangular number, so it is also a sum of cubes.
Nope. That is not a valid date, unless you're talking about something that happened 2000 years ago. I will die on this hill.
December 3, 2024 at 4:17 PM
Nope. That is not a valid date, unless you're talking about something that happened 2000 years ago. I will die on this hill.
I shall try some of your burned replicated bird meat.
November 28, 2024 at 3:28 PM
I shall try some of your burned replicated bird meat.
Happy Max Headroom Day to all who celebrate
November 22, 2024 at 12:52 PM
Happy Max Headroom Day to all who celebrate
Do you remember
The 21st night of September?
Love was changin' the minds of pretenders
While chasin' the clouds away
The 21st night of September?
Love was changin' the minds of pretenders
While chasin' the clouds away
September 21, 2024 at 10:58 AM
Do you remember
The 21st night of September?
Love was changin' the minds of pretenders
While chasin' the clouds away
The 21st night of September?
Love was changin' the minds of pretenders
While chasin' the clouds away
