About C. J. Abate

C. J. Abate is Circuit Cellar's Editor in Chief. You can reach him at cabate@circuitcellar.com and @editor_cc.

16-Bit, 1.5-Msps Per Channel Octal Simultaneous Sampling SAR ADC

Linear Technology Corp. recently introduced the LTC2320-16 16-bit, 1.5-Msps per channel, no-latency successive approximation register (SAR) ADC. Featuring eight simultaneously sampling channels supporting a rail-to-rail input common mode range, the LTC2320-16 offers a flexible analog front end that accepts fully differential, unipolar or bipolar analog input signals. It also accepts arbitrary input signals and maintains an 82-dB signal-to-noise ratio (SNR) and high common mode rejection ratio (CMRR) of 102 dB when sampling input signals up to the Nyquist frequency. Linear LTC2320-16


The LTC2320-16’s specs, features, and benefits:

  • Wide input bandwidth enables the digitization of input signals up to the Nyquist frequency of 750 kHz
  • 1.5 Msps per channel throughput rate
  • Eight simultaneous sampling channels
  • ±2 LSB INL (typ)
  • Guaranteed 16-bit, no missing codes
  • 8.192 VPP true differential inputs with rail-to-rail common mode
  • 82-dB SNR (typ) at fIN = 500 kHz
  • –90-dB THD (Typ) at fIN = 500kHz
  • Guaranteed operation to 125°C
  • Single 3.3- or 5-V supply
  • Low drift (20 ppm/°C max) 2.048- or 4.096-V internal reference
  • 1.8-to-2.5-V I/O voltages
  • CMOS or LVDS SPI-Compatible Serial I/O
  • Power dissipation 20 mW/Ch (typ, 5-V operation)
  • 52-pin 7 mm × 8 mm QFN package

The LTC2320-16 is available in commercial, industrial, and automotive (–40° to 125°C) temperature grades. Pricing begins at $16.50 each in 1,000-piece quantities. The DC2395A evaluation board for the LTC2320 SAR ADC family is available at www.linear.com/demo.

Source: Linear Technology

Infineon Digitizes power for Energy-Efficient LEDs

Infineon Technologies recently announced that it developed a digital platform for power supply with which LED lighting systems can be controlled intelligently, thus making maximum energy savings possible. According to Infineon, with .dp digital power 2.0, development time can be reduced by up to 70%. The ICL8105 and ILD2111 controllers are the two new members of the platform. Infineon-ICL8105

The ICL8105 is a digitally configurable flyback controller with Power Factor Correction (PFC) for constant power LED drivers from 10 to 80 W. Since only a few external components are required, a cost reduction of up to 10% is possible. The controller has powerful algorithms and supports multiple operating modes. Advantages are a high efficiency and power factor correction plus low distortion. This produces a high quality of light with no flickering. The controller has an input for 0 to 10 V dimming; there is no need for an oscillator including power supply. An active burst mode significantly extends the dimming range, while preventing undesirable effects such as flickering or shimmering. To protect the LED driver in case of overtemperature, the ICL8105 automatically reduces the output current in case of overload.

The ILD2111 is a digitally configurable buck controller that’s designed as a constant current source with output current control (backlash) for LED drivers in the range from 10 to 150 W. Thus, the regulator addresses diverse commercial LED applications. Like the ICL8105, the ILD2111 requires only a few external components. The output current can be set easily and accurately by a resistor, and is also compatible with the LEDset interface. The IC provides flicker-free PWM dimming down to 1%. The component automatically selects an operating window in order to optimally regulate different loads, depending on the switching frequency and the ripple of the output current. The output voltage is specified with 15 to 55 VDC. User-configurable features protect the component at undervoltage and overvoltage, short circuits, overcurrent or high temperatures.

Both the ICL8105 and the ILD2111 are available as samples and can be ordered in high volume. Development boards, the .dp Interface Board and the .dp Vision GUI software are offered for both controllers.

Source: Infineon Technologies




Electrical Engineering Crossword (Issue 301)

The answers to Circuit Cellar’s August 2015 electrical engineering crossword puzzle are now available.301 crosswordgrid


  2. NODE—Point of minimum amplitude
  3. AVOGADRO—6.0221415×1023 atoms/mole?
  4. DECODE—Covert a digital signal back to an analog signal
  5. ROGERS—Founded MIT in 186
  6. STATOR—Non-rotating part of an electric motor
  7. NIBBLE—A half-byte
  9. TETRODE—Vacuum tube with four elements
  10. FILTERSLOPE—The steepness or severity of a filter’s attenuation [two words]
  11. OMNIDIRECTIONAL—Uniform propagation of energy in all directions


  1. BITERROR—The loss of a single bit in a digital word [two words]
  2. KLUDGE—Poor solution
  3. BIDIRECTIONAL—A figure-eight polar pattern
  4. HANDSHAKE—Signal exchange to start or finish a function
  5. TRACE—A line of conductive material on a PCB
  6. JFET—FET in which the gate consists of a p-n junction
  7. YOTTA—1,000,000,000,000,000,000,000,000
  8. NINE—Nonet
  9. NTSC—Analog television system
  10. DELIMIT—Set limits
  11. IRON—Fe

Issue 296: EQ Answers

Answer 1—The frequency generated at the QB output of the counter is 16.000 MHz × 3 / 13 = 3.6923 MHz. The ratio between this and 3.6864 MHz is 1.0016, so the error expressed as a percentage is +0.16%. This is well within the tolerance required for asynchronous serial communications.

Answer 2—The circuit generates rising edges (also falling edges) at intervals of 4 clocks, 4 clocks and 5 clocks, but the ideal spacing would be 4.3333 clocks. Therefore two of the intervals are short by 1/3 clock and one of them is long by 2/3 clock.

Therefore, the cycle-to-cycle peak-to-peak jitter is 1/3 + 2/3 = 1 full input clock period, or 62.5 ns. But taking an average over a complete group of 13 clocks, no edge is displaced from its “ideal” location by more than 1/3 clock, or 20.8 ns.

Answer 3—The following table shows the divider ratios required for various standard baud rates.297 eq answers

As you can see, a modern UART can generate the clocks for baud rates up to 38400 with the exact same error as the 3/13 counter scheme — note that 26 and 52 are multiples of 13. But above that, the frequency error increases. This is why microcontrollers with built-in UARTs often run at “oddball” frequencies such as 11.0592 MHz or 12.288 MHz — these freqeuncies can be easily divided down to produce precisely correct baud rates.

Answer 4—A UART receiver waits for the leading edge of the start bit, and then samples the next 10 bits in the center of each bit “cell”. If by the time it gets to the 10th cell, the sampling point at the receiver has moved beyond the edge of the 10th bit (the stop bit) defined by the transmitter, the transmission will fail. This means that the timing error must be no more than ± 1/2 bit over a 9.5-bit span, or a total error between transmitter and receiver of ±5.26%. If the error is split evenly, this means that each baud rate generator must be accurate to within ±2.63%.

However, in reality, the receiver cannot determine the location of the leading edge precisely. Since it is using a 16× clock to do the sampling, there could be as much as 1/16 of a bit delay before the receiver actually recognizes the start bit, and all of its sampling points for the subsequent bits will be delayed by that amount. This means that the timing error must be no more than ± 7/16 of a bit by the time we get to the last bit, which means that the maximum total error is ±4.60%, or ±2.30% for each baud rate generator.



APEI Builds First Multiphysics Simulation App with the Application Builder

Application Builder was released in October 2014 and is now available with COMSOL Multiphysics software version 5.0. The Application Builder allows COMSOL software users to build an intuitive interface to run any COMSOL model. COMSOL Multiphysics users are already building applications and exploring the benefits of sharing their models with colleagues and customers worldwide.

Image made using COMSOL Multiphysics and is provided courtesy of COMSOL

Image made using COMSOL Multiphysics and is provided courtesy of COMSOL

One such company is Arkansas Power Electronics Intl. (APEI), a manufacturer of high-power density and high performance power electronics products. APEI has found that the Application Builder can provide enormous benefits throughout the organization.

“I’m building applications to help us expedite our design processes,” says Brice McPherson, a Senior Staff Engineer at APEI. “Our engineers often spend time running analyses for the sales or manufacturing departments to find model results based on diverse conditions and requirements. The Application Builder will be hugely important for accelerating our work in this respect; any colleague outside of the engineering team will now be able to confidently run these studies by themselves, with no learning curve.”

The first application built by APEI looks at fusing current and ampacity of wire bonds—very small wires used to interconnect semiconductor devices with their packages.

The team at APEI envisions using the Application Builder for a variety of other projects, including applications to automate and streamline the calculation of wire bond inductance, package thermal performance, and more.

Source: COMSOL

Electrical Engineering Crossword (Issue 291)

The answers to Circuit Cellar’s October electronics engineering crossword puzzle are now available.291crossword (key)


4.     PARAMETRON—Phase-locked oscillator

8.     UNBALANCED—Single-ended

9.     STRAY—Unwanted capacitance

10.   LEYDENJAR—Early capacitor [two words]

12.   ELECTROLYTE—Conducting fluid

14.   CROSSTALK—Caused when one circuit’s signal creates an unwanted effect on another

16.   ANECHOIC—Absorbs sound or electromagnetic wave reflections

17.   BIFILAR—Used in bipolar power-supply transformers to improve output voltage symmetry

18.   CRYSTALRECTIFIER—Semiconductor diode [two words]

19.   DOPPLEREFFECT—Frequency change that occurs when emitter and receiver move in unison [two words]


1.     BLEEDER—A resistor that draws the critical amount of load current

2.     GAUSSMETER—Detects magnetic anomalies

3.     HETERODYNE—Two frequencies combine to produce new ones

5.     SURFACEMOUNT—Place components directly on PCBs [two words]

6.     HASH—Garbage or gibberish

7.     GALVANOMETER—Measures small voltages

11.   RECTIFIER—Passes current in only one direction

13.   CATWHISKER—Sharp, flexible wire that connects to a semiconductor crystal’s surface [two words]

15.   ANOTRON—Cold-cathode-glow discharge diode


Electrical Engineering Crossword (Issue 290)

The answers to Circuit Cellar’s September electronics engineering crossword puzzle are now available.CrosswordEmptyGrid (key)


2.     THREE—Trivalent valence

3.     PHYSICS—Kilby’s Noble Prize in 2000

5.     INVERTER—Converts DC to AC

8.     BATCH—BAT file

9.     MAXIM—Founded ARRL in 1914

10.   KEYBOARD—If you are AFK, what are you away from?

11.   UPENN—University that housed the ENIAC in a 30’ × 40’ room

12.   HERTZ—1 cycle per second

14.   NIBBLE—4 bits

17.   EXPLAINER—Asimov was the great what?


1.     TRACK—PCB path

3.     PATCH—Quick fix

4.     SNIFFER—Used to monitor network traffic

6.     MAXWELL—A Gauss is one of these per square centimeter

7.     IBM—”Big Blue”

8.     BOOLE—“An Investigation of the Laws of Thought” (1854)

13.   TOGGLE—Move from setting A to B

15.   BLUE—Screen of death

16.   NINE—A nonet is a group of what?

17.   EW—Exawatt

Electrical Engineering Crossword (Issue 289)

The answers to Circuit Cellar’s August electronics engineering crossword puzzle are now available.289PuzzleGrid (key)


1.     FAST—Ethernet at 100 Mbps

3.     FAB—IC factory

6.     XOR—Logic gate

7.     VERILOG—HDL created in the early 1980s by Goel and Moorby

9.     MIL—0.001 inches = 25.4 what?

10.   AMPHOUR—Current flow over time [two words]

13.   SANTOS—Greek national soccer team manager with a degree in electrical engineering

14.   NOLEAD—Quad, flat, … [two words]

16.   BUCK—Step-down

17.   FEMTO—0.000000000000001

18.   GND—Ground pin

19.   NULL—Zero


2.     SLICE—Wafer or substrate

3.     FILO—Antonym for FIFO

4.     QUINARY—Base-5

5.     CODERDECODER—CODEC [two words]

7.     VERSORIUM—Gilbert’s static-detection device

8.     DISSIPATION—Release heat

11.   HAPTIC—Relates to touch

12.   JOULE—1 watt second

15.   DOPING—Process of purposely adding impurities

Electrical Engineering Crossword (Issue 288)

The answers to Circuit Cellar’s July electronics engineering crossword puzzle are now available.288Crossword (key)


2.     QUIESCE—Inactive but still available

4.     GLUELOGIC—Used for circuitry interfacing [two words]

7.     AMAYA—Open-source web tool developed by members of the World Wide Web Consortium (W3C)

8.     ROUNDROBIN—A continuous sequence [two words]

9.     FATCLIENT—A tower PC, for example [two words]

11.   LOGICBOMB—Explosive code [two words]

15.   HEISENBUG—A software glitch that changes its conduct when analyzed

16.   STROBOSCOPE—Makes things appear to move slowly or not at all

17.   STATAMPERE—Approximately 0.333 nanoampere

18.   KORNSHELL—Unix command-line interpreter developed by and named after a Bell Labs employee [two words]

19.   VOXEL—Defines a point in 3-D


1.     BEAMFORMING—Signal processing for sensor arrays

3.     SPIBUS—Works in double-duplex mode [two words]

4.     GREP—UNIX-based command-line utility

5.     SUPERHETERODYNE—Used to convert to intermediate frequencies

6.     ENDIAN—Creates data words

10.   PHOTOVOLTAICS—Uses solar power to create energy

12.   BITTORRENT—File sharing protocol

13.   BINARYPREFIX—E.g., gibi [two words]

14.   AUSTRUMI—Linux distribution based on Slackware


Linear LT3999 DC/DC Transformer Driver

Linear Technology recently launched the LT3999 monolithic push-pull isolated DC/DC transformer driver with two 1-A current limited power switches. It operates over an input voltage of 2.7 to 36 V and is targeted for power levels up to 15 W, making it a good option for a variety of industrial applications.

Source: Linear Technology

Source: Linear Technology

The LT3999’s features include:

  • Wide VIN range: 2.7 to 36 V
  • Dual 1-A switches
  • Programmable switching frequency: 50 kHz to 1 MHz
  • Synchronizable to an external clock up to 1 MHz
  • Duty cycle control for output voltage regulation
  • Low noise topology
  • Programmable input over- and under-voltage lockout
  • Cross-conduction prevention circuitry
  • Extended and industrial grades: –40° to 125°C operating junction temperature
  • Automotive temperature grade: –40° to 150°C operating junction temperature
  • Military temperature grade: –55° to 150°C operating junction temperature

The LT3999’s 1,000-piece price starts at $2.75 each for the E-grade.

Source: Linear Technology


New 8-Bit PICs for Sensor Applications

Microchip Technology recently expanded it’s PIC12/16LF155X 8-bit microcontroller family with the PIC16LF1554 and PIC16LF1559 (PIC16LF1554/9), which are targeted toward a variety of sensor applications. The PIC16LF1554/9 features two independent 10-bit, 100,000 samples per second ADCs with hardware Capacitive Voltage Divider (CVD) support for capacitive touch sensing.

Source: Microchip Techno

Source: Microchip Techno

Watch a short video:

The PIC16LF1554 MCUs are available now for sampling and production in 14-pin PDIP, TSSOP, SOIC, and 16-pin QFN (4 x 4 x .9 mm) packages. The PIC16LF1559 MCUs are available for sampling and production in 20-pin PDIP, SSOP, and QFN (4 x 4 x .9 mm) packages. Pricing starts at $0.63 each, in 10,000-unit quantities.

Source: Microchip Technology

EIM Bootcamp: Circuit Cellar Today & Tomorrow


Elektor bootcamp discussion

Want a behind-the-scenes look at the Elektor and Circuit Cellar teams?  You can link to a short, free report on my recent visit to our company headquarters in Limbricht, Netherlands, where EIM staffers from around the globe met up for a corporate “bootcamp.” The purpose of the meeting was to assess the company’s current offerings (magazines, books, kits, etc.), discuss the needs of members, and plan for the future.


Embedded Security (EE Tip #139)

Embedded security is one of the most important topics in our industry. You could build an amazing microcontroller-based design, but if it is vulnerable to attack, it could become useless or even a liability.  EmbeddSecurity

Virginia Tech professor Patrick Schaumont explains, “perfect embedded security cannot exist. Attackers have a wide variety of techniques at their disposal, ranging from analysis to reverse engineering. When attackers get their hands on your embedded system, it is only a matter of time and sufficient eyeballs before someone finds a flaw and exploits it.”

So, what can you do? In CC25, Patrick Schaumont provided some tips:

As design engineers, we should understand what can and what cannot be done. If we understand the risks, we can create designs that give the best possible protection at a given level of complexity. Think about the following four observations before you start designing an embedded security implementation.

First, you have to understand the threats that you are facing. If you don’t have a threat model, it makes no sense to design a protection—there’s no threat! A threat model for an embedded system will specify what can attacker can and cannot do. Can she probe components? Control the power supply? Control the inputs of the design? The more precisely you specify the threats, the more robust your defenses will be. Realize that perfect security does not exist, so it doesn’t make sense to try to achieve it. Instead, focus on the threats you are willing to deal with.

Second, make a distinction between what you trust and what you cannot trust. In terms of building protections, you only need to worry about what you don’t trust. The boundary between what you trust and what you don’t trust is suitably called the trust boundary. While trust boundaries were originally logical boundaries in software systems, they also have a physical meaning in embedded context. For example, let’s say that you define the trust boundary to be at the chip package level of a microcontroller.

This implies that you’re assuming an attacker will get as close to the chip as the package pins, but not closer. With such a trust boundary, your defenses should focus on off-chip communication. If there’s nothing or no one to trust, then you’re in trouble. It’s not possible to build a secure solution without trust.

Third, security has a cost. You cannot get it for free. Security has a cost in resources and energy. In a resource-limited embedded system, this means that security will always be in competition with other system features in terms of resources. And because security is typically designed to prevent bad things from happening rather than to enable good things, it may be a difficult trade-off. In feature-rich consumer devices, security may not be a feature for which a customer is willing to pay extra. The fourth observation, and maybe the most important one, is to realize is that you’re not alone. There are many things to learn from conferences, books, and magazines. Don’t invent your own security. Adapt standards and proven techniques. Learn about the experiences of other designers. The following examples are good starting points for learning about current concerns and issues in embedded security.

Security is a complex field with many different dimensions. I find it very helpful to have several reference works close by to help me navigate the steps of building any type of security service.

Schaumont suggested the following useful resources:

3400-F Ultracapacitor

Maxwell Technologies has announced the addition of a 2.85-V, 3400-F cell to its K2 family of ultracapacitors. It is the most powerful cell available in the industry-standard, 60-mm cylindrical form factor. Incorporating Maxwell’s DuraBlue Advanced Shock and Vibration technology, it is a rugged cell that’s suitable for high-energy storage in demanding environments (e.g., in public transit vehicles).maxwell

The electrostatic charge can be cycled over a million times without performance degradation. The cells can also provide extended power and energy for long periods of propulsion in automotive subsystems and give fast response in UPS/Backup Power and grid applications to ensure critical information is not lost during dips, sags, and outages in the main power source. In addition, they can relieve batteries of burst power functions, thereby reducing costs and maximizing space and energy efficiency.

The K2 family of cells work in tandem with batteries for applications that require both a constant power discharge for continual function and a pulse power for peak loads. In these applications, the ultracapacitor relieves batteries of peak power functions resulting in an extension of battery life and a reduction of overall battery size and cost. The cells are available with threaded terminals or with compact, weldable terminals.

[via Elektor]

Dutch Designer’s “Comfort Zone”

Check out this amusing workspace submission from Henk Stegeman who lives and works in The Netherlands (which is widely referred to as the land of Elektor). We especially like his Dutch-orange power strips, which stand out in relation to the muted grey, white, and black colors of his IT equipment and furniture. StegemanWorkspace

Some might call the space busy. Others might say it’s cramped. Stegeman referred to it his “comfort zone.” He must move and shift a lot of objects before he starts to design. But, hey, whatever works, right?


Attached you picture of my workspace.
Where ? (you might ask.)
I just move the keyboard aside.
To where ?
Euuh… (good question)


The Netherlands

Visit Circuit Cellar‘s Workspace page for more write-ups and photos of engineering workbenches and tools from around the world!

Want to share your space? Email our editorial team pics and info about your spaces!