New Battery Pack Monitor Protects Multi-Cell Li-ion Batteries

Intersil Corp. recently announced the ISL94203 3-to-8 cell battery pack monitor that supports lithium-ion (Li-ion) and other batteries. The ISL94203 can monitor, protect, and cell balance rechargeable battery packs to maximize battery life and ensure safe charging and system operation. It works as a stand-alone battery management system for rechargeable Li-ion battery packs.Intersil-ISL94203

The ISL94203’s internal state machine has five preprogrammed stages that accurately control each cell of a battery pack to extend operating life. In addition, it integrates high-side charge/discharge FET drive circuitry.

Notable features and specifications:

  • Highest level of integration
  • Eight cell voltage monitors support Li-ion CoO2, Li-ion Mn2O4, Li-ion phosphate and other battery chemistries
  • Can operate as a standalone solution or with a microcontroller
  • Integrated charge pump controls cutoff FETs used to charge/discharge battery pack
  • Multiple cell voltage protection options up to 4.8 V
  • Programmable detection/recovery times for over-voltage, under-voltage, over-current, and short circuit conditions
  • Open wire detection
  • EEPROM storage for device configuration
  • Power saving algorithm activated when battery pack is not in use

 

The ISL94203 battery pack monitor is available now through Intersil’s worldwide network of authorized distributors. The ISL94203 comes in a 6 mm × 6 mm, 48-lead TQFN package, and is priced at $2.19 in 1,000-piece quantities. The ISL94203EVKIT1Z evaluation kit ($328) includes an evaluation board, interface board with USB-to-I2C interface, and software GUI that supports stand-alone operation or an external microcontroller.

Source: Intersil Corp. 

High-Efficiency Buck-Boost Regulator for Mobile Devices

Intersil Corp. recently announced the availability of the ISL9120 buck-boost switching regulator, which enables efficient power management of system power supplies and peripherals such as Wi-Fi, Bluetooth, memory cards, or LCD modules. Its adaptive current limit PFM architecture delivers high efficiency up to 98% in addition to providing smooth transitions from buck-to-boost to prevent glitches in applications where light load efficiency and fast transient response are critical. The ISL9120’s small form factor make it well suited for Internet of Things (IoT) devices, such as wearables, smartphones, smart thermostats, and point-of-sale devices that run on single-cell Li-ion or Li-polymer batteries, or 2-cell alkaline, NiCd or NiMH batteries. Intersil ISL9120

The ISL9120 addresses a wider Vin range and providing boost to avoid low voltage glitches that can cause a battery brownout when the Vin droops below the output voltage. Requiring only a single inductor and available in a 1.41 mm × 1.41 mm package, you don’t have to compromise efficiency or form factor.

The ISL9120 offers you  the flexibility to cover a variety of design needs by operating from a Vin of 1.8 to 5.5 V and an adjustable output voltage from 1 to 5.2 V. Its adaptive PFM operation with forced bypass mode and 2-A switches support both low load and high load currents with high efficiency, ensuring longer battery life and less heat buildup. The regulator also provides 800-mA current with 2.5-V input and 3.3-V output.

Key features and specs:

  • Accepts a wide input voltage range from 1.8 to 5.5 V
  • Works with multiple battery topologies
  • Ultra high efficiency up to 98% reduces power drain and heat buildup
  • Adjustable output voltage range from 1 to 5.2 V for use with multiple power rails
  • Output current up to 800 mA (Vin = 2.5 V, Vout = 3.3 V)
  • 2-A switches supports both high and light load currents with high efficiency
  • Ultra-small footprint with 1.41 mm × 1.41 mm package saves board space, requires only a single inductor
  • Quiescent current of 41uA maximizes light load efficiency for low power consumption
  • Automatic and selectable forced bypass power saving mode reduces quiescent current to less than 0.5 µA
  • Full protection for under-voltage, short-circuit and over-temperature

The ISL9120 buck-boost regulator is available in 9-bump WLCSP and QFN packages and costs $0.72 USD in 1,000-piece quantities. Two ISL9120 evaluation boards enable you to evaluate device features and performance. The ISL9120IIN-EVZ (3.3 Vout) costs $74.45 and the ISL9120IIA-EVZ (adjustable Vout) costs $73.35.

Source: Intersil Corp.

Video Decoder with MIPI-CSI2 Output Interface Supports Next-Generation SoCs

Intersil Corp. recently introduced the TW9992 analog video decoder, which features an integrated MIPI-CSI2 output interface that provides compatibility with the newest SoC processors. The decoder’s MIPI-CSI2 interface simplifies design by making it easier to interface with SoCs, while also lowering the system’s EMI profile. The TW9992 decoder takes both single-ended and differential composite video inputs from a vehicle’s backup safety camera, and is the latest addition to Intersil’s video decoder product family for automotive applications.TW9992-intersil

Designed with built-in diagnostics and superior video quality, the TW9992 addresses the biggest challenges faced by automotive video systems. For example, the decoder’s Automatic Contrast Adjustment (ACA) image enhancement feature overcomes a major challenge for backup camera systems by adapting to rapidly changing lighting conditions. ACA is able to automatically boost up or reduce the brightness/contrast of an image for greater visibility and safety.

In addition, vehicle backup cameras typically employ differential twisted pair cables that require designers to use an operational amplifier (op amp) in front of the video decoder to convert the differential signal to single-ended. The TW9992 decoder eliminates the need for an external op amp by supporting direct differential CVBS inputs, thus reducing system cost and board space. The built-in short-to-battery and short-to-ground detection capability on each differential input channel further enhances video performance and automotive system reliability.

Features and specifications:

  • NTSC/PAL 10-bit ADC analog video decoder with 4H adaptive comb filter
  • MIPI-CSI2 output interface
  • Software selectable analog input control allows for combinations of single-ended or differential CVBS
  • Advanced image enhancement features: automatic contrast adjustment, and programmable hue, brightness, saturation, contrast and sharpness
  • Output voltage: 1.8 to 3.3 V with 3.3 V tolerance
  • Low-power consumption: 100-mW typical
  • Integrated short-to-battery and short-to-ground detection tests
  • AEC-Q100 qualified

The automotive-grade TW9992 analog video decoder is available in a 32-pin wettable flank QFN package. It costs $3 in 1,000-piece quantities.

Source: Intersil Corp.

Synchronous Buck Regulator with Output Tracking and Sequencing for FPGAs and Microprocessors

Intersil Corp. recently announced the availability of the ISL8002B synchronous buck (step-down) switching regulator, which delivers up to 2 A of continuous output current from a 2.7- to 5.5-V input supply. Its 2-MHz switching frequency provides superior transient response, and its key features—including programmable soft-start and output tracking and sequencing of FPGAs and microprocessors—increase system reliability for point-of load conversions in networking, factory automation, instrumentation, and medical equipment.Intersil ISL8002B

The ISL8002B enables greater system reliability through several innovative features. For example, the regulator’s output tracking and sequencing of FPGAs and MPUs ensures sensitive multi-rails properly start up and shutdown. In addition, its output rails are configurable for coincidental, ratio metric, or sequential settings, ensuring the FPGA or MPU’s internal ESD diodes are not biased or overstressed during rising or falling outputs. The ISL8002B’s undervoltage lockout and several other protection/stability features protect the system from damage from unwanted electrical fault events. And its unique negative current protection prevents switch failure.

The ISL8002B’s superior transient response and high level of integration enable a complete synchronous step-down DC/DC converter solution in less than a 0.10 in2 footprint. By integrating low RDS(ON) high-side PMOS and low-side NMOS MOSFETs, the buck regulator eliminates the need for a bootstrap capacitor and diode. Its high efficiency enables the use of small inductors to further reduce board space.

Features and specifications:

  • Dimensions: 2 mm × 2 mm
  • Output tracking and sequencing
  • Switching at high frequency, 2 MHz
  • High peak efficiency: up to 95%
  • Wide input voltage range: 2.7 to 5.5 V
  • Maximum output current: 2A
  • Under voltage lockout, overvoltage protection
  • Selectable PFM or PWM operation
  • Over current, short-circuit protection
  • Over temperature/thermal protection

The ISL8002B synchronous buck regulator is available in a 2 mm  × 2 mm, eight-pin TDFN package. It costs $1 in 1,000-piece quantities. The ISL8002B DEMO1Z demonstration board is available for $23.

Source: Intersil Corp.

 

 

Application Engineering: An Interview with Carmen Parisi

Carmen Parisi is an applications engineer who co-hosts an engineering podcast in his spare time. In this interview, he describes his work, shares some engineering tips, and  tells us about a fun prank he played on an unsuspecting designer.

CIRCUIT CELLAR: Where are you located?

CARMEN: Currently, I’m living and working in Raleigh-Durham, NC, around the Research Triangle Park area between the two cities with my wife and new dog Sadie. Kelly and I moved down about three years ago from Buffalo, NY, and really like it here. There’s a lot of tech companies and engineers around, tons of stuff to do, and great food and beer scenes. Plus, as a hearty Northerner, I get to laugh at the “cold” winters we experience. Come summer, though, I melt into a puddle on the pavement. Snow all the way for me, but Kelly disagrees.

Carmen Parisi

Carmen Parisi

CIRCUIT CELLAR: When did you decide to pursue electrical engineering and why?

CARMEN: Ever since I was a kid I had a fascination with tools and how things worked. I would always have a toy sword and various tools stuffed into my belt and would volunteer to help my dad around the house building a deck around the pool or fixing the fence.

Once I got into high school, I took a few basic engineering courses during which time I got bit by the engineering bug. The course that really “doomed” me to a life of electronics was a Robotics course taught by my favorite teacher C, as we called him. He put me through my paces learning how to solder, reading schematics, programming in BASIC, and robbing Fort Knox using a LEGO Mindstorms robot. C’s class solidified my choice to go to college for engineering, and shortly thereafter, I picked electrical over mechanical for my major.

CIRCUIT CELLAR: When was the first time you used a microcontroller in a project?

CARMEN: If we’re counting LEGO Mindstorms, then the Robotics class in tenth grade with C where we had to build a robot to lift a golden brick and run away with it (thus “robbing Fort Knox”). I met all the individual milestones with my group for the project, but we couldn’t get the whole thing working smoothly from beginning to end. I guess that was my first time learning how to successfully fail too which has turned out to be a very useful skill.

My first real microcontroller experience was the summer after sophomore year when I took a college course at a local community college offering a few classes to high school students interested in engineering. During that course I learned more basic circuit theory, got introduced briefly to SMT soldering, and built some robots using the Parallax BOE Bot. Looking back, I’d say this was the time my analog career kicked off as I slowly started to realize that I was more interested in the circuits themselves than the overall robot.

CIRCUIT CELLAR: Tell us about your university-level schooling.

CARMEN: I still consider myself a student in that I’m always looking to learn new things and grow as an engineer, but my formal schooling is over for the foreseeable future. In 2011, I completed a combined BS/MS degree in Electrical Engineering at the Rochester Institute of Technology in Rochester, NY. I initially started off interested in robotics but after working with a great analog designer on my first co-op at GE, I switched into the analog circuit and semiconductor track and never looked back.

CIRCUIT CELLAR: Can you tell us about your work in graduate school?

CARMEN: Sure thing. My graduate work was primarily with the Communications professor who needed a proof of concept built to test out a theory that looked plausible on paper. Prior to my joining the Comms Lab, my advisor and two past grad students had worked out a method of securing wireless channels using the randomness of the channel itself. There was an initial front end of sorts to test the idea out but I don’t think it was ever tested.

I looked over the circuit design, decided to scrap it and start fresh, and immediately realized I had a big job ahead of me. Cue the analog professor becoming my co-advisor. Mixing circuits, active filters, phase detectors, ADCs, and communication theory swam through my head as I slowly cajoled the circuit to life. Two PCB revisions later the circuit worked in that it took the RF input signal and spat out some bits at the other end, but after my advisor applied his algorithm to the data, we weren’t able to generate symmetric keys on different boards. Whether this was from an error in theory or with my board I never found out, as I ended the project there to focus on my full-time job leaving with a grad paper instead of a full thesis.

I still have all my old lab notebooks, schematics, and board layouts on my bookshelf at home. I think the files are sitting on a hard drive somewhere too. Looking at them now, I can spot a lot of little errors I’d like to fix due to my inexperience at the time and some maybe a few not so little errors too.

CIRCUIT CELLAR: What did you do after school?

CARMEN: After I left RIT, I moved down here to Raleigh-Durham to start my career as an Applications Engineer working on switching regulators with Intersil. Back in 2009 I had done a summer stint as an FAE at a small field office in Long Island with the company which got me interested in working in the semiconductor industry.

Life on the road as an FAE didn’t appeal to me after spending my college years constantly moving around for co-ops, so my former boss set me up with an interview here at the RTP design center. On the way down for the interview, I got stuck in Dulles for the night thanks to some bad weather in Rochester causing me to miss my connection. I wound up getting a bare 3 hours of sleep that night on an empty terminal bench. The next morning, groggy and sleep deprived, I suited up in the family restroom and flew out for six wonderful hours of technical interviews. I was absolutely wiped out by the end of the day but managed to survive the ordeal. The rest is history.

CIRCUIT CELLAR: Tell us about the work you are doing as an applications engineer for Intersil.

CARMEN: Well, for starters, being an apps engineer is exactly the rock n’ roll lifestyle I’m sure all your readers expect it to be. I roll into the office every morning and have the roadies warm up my iron for me!

In reality though, I work on buck regulators for computing applications like notebooks, tablets, ultrabooks, with maybe a bit of desktop work from time to time. Most of the parts I work on are for the primary core voltage on Intel processors. Sometimes, should the part integrate multiple regulators, I’ll work on a graphics rail or one of the other many voltage rails present on a motherboard. For each new processor tock (tick? I always confuse the two), Intel releases a laundry list of specs that have to be met in order to provide power to their CPUs and my parts are designed to those specs.

When I work apps on a brand spanking new chip, I’ll first work with the design engineers to run some feasibility studies and help define any new features for the IC. These tests range from tuning a similar part to the new Intel specs to see if the control scheme hits any corners or has stability issues to beating up some power FETs to determine if they can handle the new current requirements we have to meet. Once the chip tapes out, I’ll start work on preliminary documentation—a rough datasheet draft or early reference design based on feasibility testing and simulations—for the field to use when working with customers. During this time, I also design the evaluation board I’ll use to validate the part and send to customers for sampling.

The real meat and potatoes of my job is silicon validation. I’ve got an exhaustive spreadsheet of bench tests to do that functionally verify the IC over a wide range of corners. The first few weeks after silicon comes back I’m working full throttle, round the clock if need be, to make sure there are no show stopping bugs we need to address. I never see my office during validation. Instead I’m spending all my time in the lab hunched over the eval board or squinting at my scope.

Things calm down slightly after the initial validation, but the work is still nowhere near done. Now I’m working with design and test engineers to debug any issues that crept up during validation and implement fixes. Ideally, a board-level change is found because PCB or apps level schematic changes are much easier and cheaper than silicon spins. In conjunction with this work, I’ll also refine my reference designs and documentation as well as work with the field on initial customer designs by answering questions and checking over layouts and schematics to make sure everything’s optimal for their builds.

Up until the part releases, I’ll continue cycling through validation, debug, and customer support as needed, squeezing in documentation when I get a chance too. At any given time, I’m also supporting old parts still in production or, if I’m in a lull with my work, getting pulled onto other chips to help out other apps engineers in a jam.

The last part I released, and my first as the lead apps guy, was the ISL95813, a single phase regulator for Haswell and Broadwell systems. My next part is scheduled for release next year which I can’t talk too much about, but it’s really cool.

CIRCUIT CELLAR: During your time at Intersil, you must have learned some important lessons about professional engineering. Can you share one or two things you took from the experience?

CARMEN: Most importantly, good communication skills are key. A large chunk of my job is talking to other engineers and customers across the country and overseas. Their whole interaction with me is through the emails and reports I send out and I want to make sure they’re top notch. You don’t need to be a poet laureate by any means, but if you come across like a rock head, it will be much harder to get taken seriously and problems will drag out longer than necessary. Proofread your work; make sure you’re getting your point across clearly; and tailor your email, report, PowerPoint, whatever, to your audience’s level of technical expertise. Study up on how to make a slideshow that won’t bore your audience or read a technical writing guide. It can’t hurt.

Secondly, document, document, document—even if it’s only for your own reference. And keep it somewhat organized so you can find what you need again without too much hassle. Yes, it can help CYA, but also I’ve saved myself a ton of time not redoing the same derivations or looking back at a difficult test setup I had documented in my notebooks. It’s especially nice being able to pull up old data from past parts to see why the heck we did what we did years later.

CIRCUIT CELLAR: Tell us about your most recent electrical engineering project. What did you build and why?

CARMEN: Well, I can’t talk too much about work since all my projects at the moment are either customer related or under development, but suffice it to say I’m working on a lot of low power, multi-role chips.

Outside of work though for nearly two years now I’ve been co-hosting a podcast which keeps me plenty busy. The show’s called The Engineering Commons and it gets released every other week by myself and three other engineers scattered across the US. It was originally started by Chris Gammell and Jeff Shelton, but when Chris left the show for other projects back in 2013, I threw my hat into the ring when Jeff put the word out he was looking for new co-hosts. We discuss the engineering discipline as a whole rather than focus on any one field and some of our favorite topics include education, the value of co-ops, life in the workplace, and the stories of other engineers we bring on to interview.

The semiconductor field is pretty niche, and so through the show, I get exposed to all sorts of new ideas and philosophies, whether it’s from researching a topic when coming up with show notes or hearing the stories of engineers and professors from across the globe. Some of my favorite episodes are the ones while interviewing a guest I barely have to say anything and not just because I hate hearing my voice when I re-listen to an episode! Hearing someone get really into a story and talk about their passion I can’t help but get drawn in and become excited myself. All us engineers are alike; no matter the field once you get us going about that tricky bug we finally tracked down, the ridiculous meeting that happened the other day, or those ah-ha moments when a solution just clicks in your head we just can’t help but gush and it makes for great content. I’ve put out nearly 50 episodes with Jeff, Adam, and Brian, and I can’t wait to do the next 50!

CIRCUIT CELLAR: Tell our readers about the prank circuit gag you pulled on the designer you worked with. And can you share an image of the prank circuit?

CARMEN: A good way through the 813 development I found some problems that ended up being non-issues because I misinterpreted a spec, had a test setup issue, or made a silly component choice in my design. The designer started ribbing me a bit by immediately calling everything a board issue from that point on. This kind of back and forth goes on all the time between apps and design and it’s always good natured in tone. I didn’t take it personally and took strides to be more thorough before ringing alarm bells going forward but I couldn’t let him get way Scot-free.

Prank circuit

Prank circuit

With my boss’ permission I waited until a slow day came along and rigged up a little circuit to the bottom of the eval board that would overdrive the compensation node of our regulator, propagate through the control loop, and cause seemingly random spikes in the output voltage. I took some waveforms and sent them off to the designer explaining how I found an operational corner that affected regulation we needed to address. Since he was a thorough designer and liked to regularly pop into the apps lab I actually spent my morning running the tests he asked me to just to keep up the illusion something was wrong if he showed up.

I kept him digging through the schematics trying to find his mistake until mid-afternoon before I brought him in the lab and slowly flipped the board over while telling him I found the error was caused by a parasitic circuit. At this point a couple other engineers who were in on the gag had found reasons to be in the lab for the reveal and we all had a good laugh. The designer took it pretty well, and I even bought him a beer for being a good sport.

You can read the entire interview in Circuit Cellar 295 (February 2015).

Industry’s Smallest Dual 3A/Single 6A Step-Down Power Module

Intersil Corp. recently announced the ISL8203M, a dual 3A/single 6A step-down DC/DC power module that simplifies power supply design for FPGAs, ASICs, microprocessors, DSPs, and other point of load conversions in communications, test and measurement, and industrial systems. The module’s compact 9.0 mm × 6.5 mm × 1.83 mm footprint combined with industry-leading 95% efficiency provides power system designers with a high-performance, easy-to-use solution for low-power, low-voltage applications.INT0325_ISL8203M_Intersil_Power_Module The ISL8203M is a complete power system in an encapsulated module that includes a PWM controller, synchronous switching MOSFETs, inductors and passive components to build a power supply supporting an input voltage range of 2.85 to 6 V. With an adjustable output voltage between 0.8 and 5 V, you can use one device to build a single 6-A or dual output 3-A power supply.

Designed to maximize efficiency, the ISL8203M power module offers best-in-class 15° C/W thermal performance and delivers 6 A at 85°C without the need for heatsinks or a fan. The ISL8203M leverages Intersil’s patented technology and advanced packaging techniques to deliver high power density and the best thermal performance in the industry, allowing the ISL8203M to operate at full load over a wide temperature range. The power module also provides over-temperature, over-current and under-voltage lockout protection, further enhancing its robustness and reliability.

Features and specifications:
•       Dual 3-A or single 6-A switching power supply
•       High efficiency, up to 95°
•       Wide input voltage range: 2.85 to 6 V
•       Adjustable output range: 0.8 to 5 V
•       Internal digital soft-start: 1.5 ms
•       External synchronization up to 4 MHz
•       Overcurrent protection

The ISL8203M power module is available in a 9 mm × 6.5 mm, QFN package. It costs $5.97 in 1,000-piece quantities. The ISL8203MEVAL2Z evaluation costs $67.

Source: Intersil

A Shed Packed with Projects and EMF Test Equipment

David Bellerose, a retired electronic equipment repairman for the New York State Thruway, has had a variety of careers that have honed the DIY skills he employs in his Lady Lake, FL, workspace.

Bellerose has been a US Navy aviation electronics technician and a computer repairman. “I also ran my own computer/electronic and steel/metal welding fabrication businesses, so I have many talents under my belt,” he says.

Bellerose’s Protostation, purchased on eBay, is on top shelf (left). He designed the setup on the right, which includes a voltmeter, a power supply, and transistor-transistor logic (TTL) oscillators. A second protoboard unit is on the middle shelf (left). On the right are various Intersil ICM7216D frequency-counter units and DDS-based signal generator units from eBay. The bottom shelf is used for protoboard storage.

Bellerose’s Protostation, purchased on eBay, is on top shelf (left). He designed the setup on the right, which includes a voltmeter, a power supply, and transistor-transistor logic (TTL) oscillators. A second protoboard unit is on the middle shelf (left). On the right are various Intersil ICM7216D frequency-counter units and DDS-based signal generator units from eBay. The bottom shelf is used for protoboard storage.

Bellerose’s project interests include model rockets, video security, solar panels, and computer systems. “My present project involves Intersil ICM7216D-based frequency counter modules to companion with various frequency generator modules, which I am also designing for a frequency range of 1 Hz to 12 GHz,” he says.

His workspace is an 8′-by-15′ shed lined with shelves and foldable tables. He describes how he tries to make the best use of the space available:

“My main bench is a 4′-by-6’ table with a 2’-by-6’ table to hold my storage drawers. A center rack holds my prototype units—one bought on eBay and two others I designed and built myself. My Tektronix 200-MHz oscilloscope bought on eBay sits on the main rack on the left, along with a video monitor. On the right is my laptop, a Heathkit oscilloscope from eBay, a 2.4-GHz frequency counter and more storage units. All the units are labeled.

“I try to keep all projects on paper and computer with plenty of storage space. My network-attached storage (NAS) totals about 23 terabytes of space.

“I get almost all of my test equipment from eBay along with parts that I can’t get from my distributors, such as the ICM7216D chips, which are obsolete. I try to cover the full EMF spectrum with my test equipment, so I have photometers, EMF testers, lasers, etc.”

The main workbench has a 4′-by-6′ center rack and parts storage units on the left and right. The main bench includes an OWON 25-MHz oscilloscope, storage drawers for lithium-ion (Li-on) batteries (center), voltage converter modules, various project modules on right, a Dremel drill press, and a PC monitor.

The main workbench has a 4′-by-6′ center rack and parts storage units on the left and right. The main bench includes an OWON 25-MHz oscilloscope, storage drawers for lithium-ion (Li-on) batteries (center), voltage converter modules, various project modules on the right, a Dremel drill press, and a PC monitor.

Photo 3: This full-room view shows the main bench (center), storage racks (left), and an auxiliary folding bench to work on large repairs. The area on right includes network-attached storage (NAS) storage and two PCs with a range extender and 24-port network switch.

Photo 3: This full-room view shows the main bench (center), storage racks (left), and an auxiliary folding bench to work on large repairs. The area on right includes network-attached storage (NAS) and two PCs with a range extender and 24-port network switch.

Photo 4: Various versions of Bellerose’s present project are shown. The plug-in units are for eight-digit displays. They are based on the 28-pin Intersil ICM 7216D chip with a 10-MHz time base oscillator, a 74HC132 input buffer, and a 74HC390 prescaler to bring the range to 60 MHz. The units’ eight-digit displays vary from  1″ to 0.56″ and 0.36″.

Various versions of Bellerose’s present project are shown. The plug-in units are for eight-digit displays. They are based on the 28-pin Intersil ICM 7216D chip with a 10-MHz time base oscillator, a 74HC132 input buffer, and a 74HC390 prescaler to bring the range to 60 MHz. The units’ eight-digit displays vary from 1″ to 0.56″ and 0.36″.

Photo 5: This is a smaller version of Bellerose’s project with a 0.36″ display mounted over an ICM chip with 74hc132 and 74hc390 chips and 5-V regulators. Bellerose is still working on the final PCB layout. “With regulators, I can use a 9-V adapter,” he says.  “Otherwise, I use 5 V for increased sensitivity. I use monolithic microwave (MMIC) amplifiers (MSA-0486) for input.”

This is a smaller version of Bellerose’s project with a 0.36″ display mounted over an ICM chip with 74HC132 and 74HC390 chips and 5-V regulators. Bellerose is still working on the final PCB layout. “With regulators, I can use a 9-V adapter,” he says. “Otherwise, I use 5 V for increased sensitivity. I use monolithic microwave (MMIC) amplifiers (MSA-0486) for input.”