Ajacci, Ltd. Co.

High-Performance Mixed-Signal Circuits

Who we are

Ajacci, Ltd. Co. is an early-stage semiconductor startup in Austin, Texas, U.S.A., focused on producing high-performance mixed-signal circuits. Ajacci was founded in 2021, and is currently developing wideband, precision Delta-Sigma A/D converters (ADCs) and bandgap references.

Open-source GitHub Repo

Check out our open-source GitHub page (published April 2024) for a few peripheral circuits designed by us. These circuits were designed as part of the Chipalooza Challenge of efabless.com, and were all designed and laid out in 60 days. Currently the circuits support the 130nm 1.8V/5.0V SKY130 process from SkyWater Technology, and taped-out on a April 2024 MPW shuttle but not yet tested in silicon (01/02/2025 update: all three circuits are functional in silicon). All circuits are designed to operate from -40 to +85C:

Over-voltage detector - Detects a 4-bit programmable supply voltage from 3.3V-5.5V and triggers a chip/system-wide warning within 50us of an over-voltage event. Features hysteresis and filtering of glitches, internal biasing, 5uA typical power-consumption, and silicon area of 0.038mm sq.

Power-on-Reset - Provides a chip/system-wide reset signal during power-up, where the power-supply trip voltage is digitally programmable from 2.4V to 3.0V. Features a minimum reset active signal of 30ms, hysteresis and filtering of supply glitches to prevent false triggers, 5uA typical power-consumption, and silicon area under 0.06mm sq.

Brown-out detector - Provides a chip/system-wide alarm signal during a brown-out event (supply voltage drops below a certain level), where the brown-out trip voltage is digitally programmable from 2.4V to 3.0V. Features a minimum alarm signal of 50ms, hysteresis and filtering of supply glitches to prevent false triggers, 5uA typical power-consumption, and silicon area under 0.06mm sq.

Our technology

Ajacci, Ltd. Co. believes that great mixed-signal circuits, regardless of application or performance level, must first and foremost be easy to use. We believe that customers often get frustrated not being able to reproduce a datasheet spec when the part is placed in their own application circuit. More often than not, the higher the performance, the greater the frustration. At Ajacci, we make the commitment that all products are designed with ease-of-use in mind right from the get go. We won't make circuits that only work when all the stars align, and we won't make circuits that place unnecessary burden on surrounding circuits. By combining this easy-to-use mantra with great mixed-signal design, we hope our products will help our customers shorten their product cycle, and empower them to deliver truly differentiated products to their customers.

Why high-performance?

Many in the industry have a misconception that high-performance data conversion is a niche within a vast semiconductor market, and only applications that challenge the state-of-the-art will need such chips. Yes, it is true that some of these chips are used in state-of-the-art applications, but in practice, a significant portion of these chips are used in more mundane applications to simplify a design or to make a product more flexible. Below, we go over two basic examples to explain.

PREFACE

Raw Analog Input Signal

Let's assume that our application requires the above signal to have 16-bit resolution after digitization. Further assume that we will be using a 5-volt ADC with 16-bit resolution to digitize the signal. Because the raw analog input signal only spans about 1/16th of the input range of the ADC, in order to get a meaningful 16-bit output, the analog input signal has to be amplified by 16X.

Amplified Analog Input

After amplification by 16X, the signal is fed to the input of the ADC. Because the analog input now spans the entire input range of the ADC, it maximizes the dynamic range of the converter, delivering a true 16-bit output for our application.

EXAMPLE 1

Offset

Let's assume that the analog input signal comes with a large offset voltage, either introduced by the system, or directly from the transducer output where this analog signal is taken from. Our desired signal now sits on top of this offset, but the offset is in the way and we cannot amplify the signal by 16X like we did before, otherwise the signal will 'rail out' at the top. The traditional way to solve this problem is to cancel or remove the offset using analog circuits. But, there is another way...

ADC with more bits

Instead of the 16-bit ADC, let's say we used a 20-bit ADC, with everything else being equal. In this situation, because the 20-bit ADC has 16X more quantization levels, even without amplification, the 20-bit ADC can deliver the same meaningful representation of the analog input signal as the above 16-bit ADC example without offset. This 20-bit ADC 'swallows' the offset so to speak, where later it can be removed digitally.

EXAMPLE 2

Blocker signal

Now let's say that instead of the offset, the input now has a large unrelated sinewave interfering with our desired signal as shown above. This type of signal is typically called a 'blocker' because it desensitizes (or compresses) analog circuits in a way that causes such circuits to stop responding to smaller signals, effectively blocking the desired signal from getting through. In this case, the blocker almost spans the entire input range of the ADC, and no amplification is possible without first removing the blocker. The traditional way is to use an analog filter to remove this blocker, then amplify the residual output of the filter, which is our desired signal, then digitize it with the 16-bit ADC discussed above. But there's another way...

ADC with more bits

Instead of trying to filter out the blocker using analog circuitry, we can digitize with a 20-bit ADC. The ADC 'swallows' the blocker, where later can be filtered out digitally, leaving us with the desired 16-bit output that is a meaningful representation of the desired input, thus meeting our application requirement.

Why Austin?

Are you an engineer on the lookout for an exciting and rewarding career in the mixed-signal space? At the moment we are still trying to get off the ground and not looking for new hires. But as we grow, we need smart engineers like you to help us expand our product line, handle production test, and interface with customers. Please keep us in mind! Here are a few reasons why people love Austin ...

Live Music Capital of the World

Austin is home to some of the best live music on the planet. The mainstays are SXSW and Austin City Limits Festival.

Photo courtesy of ACL Festival, credit Taylor Regulski.

Lake Austin @ the Pennybacker Bridge

Austin is a paradise for watersports. 20-mile-long, constant-level body of water starting near downtown.

Photo credit Allen Boguslavsky.

The Texas Longhorns

Home of The University of Texas at Austin

Go to grad school here or send your kids here. Catch a live NCAA football or basketball game.

Hook'em Horns!

Photo courtesy of Pixabay.

Barton Springs Pool

Spring-fed pool open year-round in downtown. A gem of Austin for many.

Photo courtesy of The City of Austin

Paddle Board and Kayaking

Lady Bird Lake runs through downtown with run & bike trails on both sides. This whole area is known as Town Lake.

Photo courtesy of Daydreamer Creative Studios

Silicon Hills

Home to many high-tech companies, Austin is know as the "Silicon Hills", with a long history of outstanding mixed-signal design. Storied startups like Crystal Semiconductor (now part of Cirrus Logic), and Silicon Labs, were founded locally in the 1980's and 1990's, respectively.

Photo courtesy of Silicon Maps

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