All about Op Amp stability app note from Linear Technology.
Well, it shouldn’t. We analog designers take great pains to make our amplifiers stable when we design them, but there are many situations that cause them to oscillate in the real world. Various types of loads can make them sing. Improperly designed feedback networks can cause instability. Insufficient supply bypassing can offend. Finally, inputs and outputs can oscillate by themselves as one-port systems. This article will address common causes of oscillation and their remedies.
App note: Does your op amp oscillate? - [Link]
Two new low-cost, op amps with close to zero drift operation and low operating quiescent current have been introduced by On Semiconductor. Typical applications include front-end amplifier circuits and power management designs. The NCS325 and NCS333 provide rail-to-rail input and output performance and are optimized for low voltage operation of 1.8 V to 5.5 V. the op amps feature a quiescent operating current of 21 µA and 17 µA respectively at 3.3 V. The devices operate with a gain bandwidth of 350 kHz with ultra-low peak to peak noise down to 1.1 µV from 0.1 Hz to 10 Hz.
New zero-drift Op Amps - [Link]
Kerry Wong writes:
Hysteresis can be added to a comparator circuit to improve its stability, especially when the input signal is noisy. In this post, we will examine the hysteresis characteristics of some common comparator and Op Amps using an oscilloscope.
Perhaps the most intuitive way to visualize the hysteresis in a circuit is to plot the input signal (x axis) against the output signal (y axis). So, if we sweep the input voltage we should be able to see the characteristics of the transitioning of the output voltage due to hysteresis.
Visualizing comparator and Op Amp hysteresis - [Link]
by Barry Harvey @ edn.com:
We analog designers take great pains to make our amplifiers stable when we design them, but there are many situations that cause them to oscillate in the real world. Various types of loads can make them sing. Improperly designed feedback networks can cause instability. Insufficient supply bypassing can offend. Finally, inputs and outputs can oscillate by themselves as one-port systems. This article will address common causes of oscillation and their remedies.
Does your op amp oscillate? - [Link]
An app note on Gamma-photon radiation detector (PDF) by Maxim:
A PIN photodiode, four low-noise op amps and a comparator are used to detect individual photons of gamma radiation. The schematic, design considerations and component selection are discussed.
Gamma-photon radiation detector - [Link]
by w2aew @ yoututbe.com
Op amp gain-BW product and slew rate limiting are defined, discussed and demonstrated on the bench. This discussion applies to the majority of general purpose op amps on the market – as most op amps are internally compensated with a single dominant pole. High speed op amps, unconditionally stable op amps, non-unity gain stable op amps, high power opamps, etc. may not follow these characteristics because they are often compensated differently in their design. An LM358N is used for the example circuit. Other popular op amps like the LM741, etc. will behave in a similar way. Sometimes the slew rate limit of a device will be the dominant factor in determining the bandwidth, and other times the gain-bandwidth product will determine the resulting frequency response. The video demonstrates why this happens.
Basics of Op Amp Gain Bandwidth Product and Slew Rate Limit - [Link]
Open Analog is an organization dedicated to exciting makers about analog hardware. We make popular ICs into transistor level kits!
The first Open Source analog IC kit from Open Analog has been created, assembled, and verified. We call it the SevenFortyFun and it is a transistor level op amp kit. You can finally get the chance to understand whats going on inside those ICs! Now we need your help to proto the next revision (I gotta eat somehow!). This Kickstarter campaign is to raise money in order to print the first batch of PCBs and order parts for production volume.
741 Op-Amp Kit - [Link]
Warren Young of Tangentsoft writes:
Experienced audio DIYers are familiar with monolithic linear regulators like the 78xx series and the LM317. Here’s a simplified block diagram of a standard linear regulator, from National Semiconductor’s Application Note 1148
Let’s see… We have an op-amp, a couple of transistors, a voltage reference, and a few resistors. Can we build a linear regulator from these individual components? Yes, we can!
Op-Amp based linear regulators - [Link]
An application note from Texas Instruments, A single-supply Op-Amp circuit collection (PDF!):
There have been many excellent collections of op-amp circuits in the past, but all of them focus exclusively on split-supply circuits. Many times, the designer who has to operate a circuit from a single supply does not know how to do the conversion.
Single-supply operation requires a little more care than split-supply circuits. The designer should read and understand this introductory material.
A single-supply Op-Amp circuit collection - [Link]
by Roy McCammon:
The traditional three op-amp differential amplifier’s signal to noise ratio can be improved by 6dB by adding a resistor and slightly changing the connections. There is a trade-off though: The traditional topology has a high input impedance, whereas the low-noise version has a lower input impedance.
Differential amp has 6dB lower noise, twice the bandwidth - [Link]