Monolithic difference amplifiers are integrated circuits that incorporate an operational amplifier (op amp) and four or more precision resistors in the same package. They are incredibly useful building blocks for analog designers who need to convert a differential signal to a single-ended one while rejecting common-mode signals. For example, the INA134, shown in Figure 1, is intended…
Here’s a frustrating situation: You finally get your analog-to-digital converter (ADC) up and running, but things are just a little bit off. You put in a voltage, but your ADC reports something different.
What’s wrong?
It looks like everything’s set up right. It might be a communication problem, or it could be that your ADC isn’t measuring your analog inputs correctly.
The best tools for debugging…
In parts 1 and 2 of this series, my colleague Matthew Sauceda described how to successfully bias radio frequency (RF) power amplifiers (PAs). A monitoring and control) solution is required to overcome the temperature-dependent nonlinearity of a RF PA. Automated monitoring and control (AMC) solutions overcome the nonlinearity by dynamically controlling the PA’s gate voltage to maintain a desired drain current (I
…Consider the following scenario.
You’ve just opened the box with your brand-new evaluation module (EVM) inside, and you’re eager to start taking data. You think, “I’ll start off nice and slow with a single-ended measurement at a gain of 1V/V using the internal 2.5V reference.” Simple and quick, right? What could go wrong?
You hook up your supplies, program…
The publication Planet Analog picked up one of my blog posts for publication to their readers. I invite you to go to their site for the full post.
To complement the 2-wire and 3-wire sensor transmitter blogs that Kevin Duke and I have already published on Precision Hub, my next few blog topics will be on 4-wire sensor transmitters. The blogs will explain 4-wire transmitter basics, the circuit structure of 4-wire output…
High-precision current sensing is key to improve efficiency of closed-loop control systems, i.e. motor drives. In this blog, I summarize the pros and cons of different approaches to isolated current sensing and list some typical applications in which they’re used.
Shunt resistors are used in wide range of industrial applications and offer relatively high accuracy at low temperature drift. However, their use is limited…
OK so power supplies are important – what more can I do?
My previous post explained the impact that power supply variation and noise can have on analog-to-digital converter (ADC) performance. Thankfully, your data acquisition systems are not doomed. Here are four steps that you can take to ensure that your ADC is less susceptible to variation and noise…
My colleague Collin Wells recently completed a blog series about 2-wire 4-20mA transmitters and their associated design challenges. The series concluded with a look at isolation schemes for 2-wire transmitters as defined by the American National Standards Institute (ANSI)/International Society of Automation (ISA)-50.1-1982 specification. After reading that post, I thought it would…
This technical article was updated on July 23, 2020.
My previous post discussed the requirements for a high-throughput data-acquisition (DAQ) system and how to select the right precision op amp to drive the SAR ADC. In this post, I’ll discuss the circuit configuration required to drive the SAR ADC, how that circuit configuration affects operational amplifier (op amp) stability, and the measured data of the OPA6…
When it comes to the analog signal chain, everyone understands the importance of the input signal path. We design our systems to capture and preserve the integrity of signals of interest, while doing our best to block out or reduce interference. We pay careful attention to the selection of every component placed along the way…and then we just power it.
I once heard someone describe power supplies as “the shoelaces…
In my previous post in this series on understanding voltage references, I talked about the ways to build a shunt reference with a precision of series voltage reference. In this blog I will discuss how to design a new precision voltage reference by level-shifting existing references.
Due to circuit topology limitations, some of the highest-precision series voltage references…
In part three of our Understanding Voltage References series, my colleague Marek Lis talked about how to achieve shunt reference flexibility with series reference precision. In this blog, you’ll see how to use an adjustable shunt reference as a comparator.
Figure 1: TLV431 as a comparator
In a typical adjustable shunt reference application, the output is fed through a resistor divider to the feedback pin, such that…
This technical article was updated on July 23, 2020.
Designing high-performance multiplexed data-acquisition (DAQ) systems with high throughputs can be difficult. That’s because the entire system, shown in Figure 1, only has up to the maximum time between conversions of the analog-to-digital converter (ADC) to settle within one-half of a least significant bit (LSB). For example, if the ADC is operating at a 1-MSPS…
In part two of our Understanding Voltage References series, my colleague Christopher Dean talked about ultra-low dropout and how it is not just for the series reference. Today I’ll address how to achieve shunt reference flexibility with series reference precision.
A series voltage reference is a three-terminal device: VIN, VOUT and GND. It is similar in concept to a linear voltage regulator (LDO) but designed for a…
The AMC1304 reinforced isolated modulator family is designed specifically for systems, such as motor controllers and solar power inverters, where the presence of high voltage demands the use of an isolation barrier in order to protect both the end user and sensitive components. Because of this isolation barrier requirement, you’ll need two power supplies: one for the analog input…
In the first post in our Understanding Voltage References series, we discussed the differences between a series and shunt voltage reference. Today I’ll address ultra-low dropout and how it is not just for the series reference.
Have you ever needed a voltage reference that has to tolerate wide-input voltage ranges yet is still capable of low-dropout operation? For example, most series references with low dropout…
There are two types of voltage references, shunt references and series references. Each type has its own usage conditions and the process of selecting between the two can be intimidating. Comparison tables do exist, but they typically provide little insight on how to choose one reference topology over the other for specific applications. This blog series will discuss the applications of both shunt and series references…
In my previous blog post, I talked about power amplifiers (PAs) and their use in wireless base stations. The main takeaway was how quiescent current, or the DC current through the PA, plays a large role in overall system performance and efficiency. This quiescent current, IDSQ, is chosen to optimize power dissipation and signal (radio frequency [RF]) gain.
Now that you understand this concept, let’s say you immediately…
In part 5 of this blog series, I discussed the construction of an input-isolated 2-wire sensor transmitter. Input-isolated 2-wire transmitters require isolating the sensor power and data signals from the 2-wire loop supply and 2-wire loop return (RTN). The main challenge when creating input-isolated or other complex 2-wire sensor transmitters is keeping the total current consumption from the loop to less than 4mA, a requirement…
In last month’s post, I talked about the relationship between an external reference on the output stage of the DRV411 and the common-mode output of the H-bridge compensation-coil drive stage. This month, I’ll take a look at motor drives and industrial controllers where the current sensor needs to be powered from a bipolar supply rail. Closed-loop current sensors provide a highly accurate representation of either…
Bad communication is a common problem engineers face with their analog-to-digital converters (ADCs). While this isn’t strictly a data converter issue, it does come up regularly and can be hard to debug. In this post I’ll talk about how to debug digital communication problems, along with some things you might see when communications go wrong.
A picture is worth a thousand words
If you can’t communicate with…
Warning: This construction article uses dihydrogen monoxide. Make sure you have researched and understood the dangers associated with this substance before proceeding.
When your home’s deep freezer, full of food, experiences an AC power failure while you are out for an extended time, its contents can thaw out. If the AC power is then restored before you return home, the contents can re-freeze and you may never know that…
Over the years I have sifted through a lot of technical literature, been to many seminars and viewed many online video trainings to gain a better understanding of analog electronics. While there are mountains of excellent material out there, I have noticed...
We use radio frequency (RF) communication in our everyday activities, whether calling a relative, texting a friend or even reading this blog post from a mobile device. There are many signals zipping through the air, but where do most of these signals...
