Due to numerous manufacturers and thousands of products, it is difficult to accurately calculate the specific quantity. This does not include variants derived from the base model that differ only slightly in electrical parameters, temperature ratings, or package form.
These basic, simple and versatile analog components play a key role in signal processing simulation front-end (AFE), filters and sensor interfaces. Circuits already have many functions to implement, but the emergence of edge artificial intelligence (AI), intelligent controllers, and a myriad of other applications that need to interact with the real world further lengthens the list of functional requirements.
Given the full range of operational amplifiers available in the market, ranging from mid-end sufficient to high-end precision, it is easy to assume that new products are no longer needed. However, recent releases of new products have again shown how naive this assumption is.
Latest operational amplifier innovations for ultra-low drift
Over the past year, mainstream and mid-tier suppliers have launched dozens of new operational amplifiers. Some of these are highly specialized products, such as high voltage operational amplifiers or electrically isolated operational amplifiers, but most are still common architectures, only significantly optimized in some specifications.
The following three recently released operational amplifiers have ultra-low drift characteristics:
Analog Devices MAX74810ARMZ-RL: A chopper stable, low power consumption, dual channel, zero drift operational amplifier with low noise, ground induction input and rail-to-rail output to maintain high overall accuracy over time, temperature and voltage variations
STMicroelectronics TSZ901IYLT: an operational amplifier certified by AEC-Q100, belonging to the company's TSZ series, with near-zero drift and ultra-low offset voltage, both of which are key attributes for signal conditioning of high-performance sensors
Texas Instruments' TLV488PWR: A 36 V, 14 MHz Chopper Stable, Zero Drift, 4 Channel, Multiplexer Friendly CMOS Precision Operational Amplifier
Common dilemmas between suppliers and designers
For this kind of highly popular device, both the supplier and the user have a complex and contradictory attitude to the traditional operational amplifier. Suppliers want to continue to produce these legacy devices because they are profitable and their manufacturing and testing processes are predictable; Users need them because they understand their performance and nuances. At the same time, both sides hope to obtain the potential benefits of new products: long-term market binding for suppliers and better system performance for users.
Although operational amplifiers are simple basic modules in function, they contain a large number of important and often very subtle performance parameters. Although the required tests and subsequent data analysis are highly automated, the time and effort required to initiate, complete, and document these efforts is still significant.- g.
One of the key and difficult parameters to fully test is the variation characteristics of input bias current (IB) with temperature, as shown in MAX74810ARMZ-RL (Fig. 1).
Figure 1: IB curve of MAX74810ARMZ RL with temperature; These curves are critical to precise AFE designers. Picture Source: Analog Devices)
Operational amplifier specifications typically provide input skew voltage (VIO) distribution statistics for thousands of devices under test. These plots (e.g. Figure 2 for TSZ901IYLT) provide the user with confidence that the supplier's production process is stable and manageable, thereby significantly improving simulation reliability and design confidence.
Figure 2: The VIO distribution diagram of TSZ901IYLT makes the designers believe that the production process is strictly controlled. Picture Source: STMicroelectronics)
The supplier must also indicate the maximum (or minimum) values for some parameters as the typical values are only for preliminary estimation and do not meet the requirements for a complete system analysis by tools such as Spice. Operational amplifier parameter tables, such as Figure 3 for TLV488PWR, give typical and maximum values over the full temperature range to support rigorous engineering evaluations. These parameters are usually presented in tabular form, including typical values of parameters such as offset voltage and input bias current.
Figure 3: Typical and maximum values are required for rigorous design evaluation of devices such as TLV488PWR; The operational amplifier supplier will provide in tabular form as required. Picture source: Texas Instruments)
What are the benefits of a supplier launching a new product?
Is such huge R&D investment and cost worthwhile for suppliers? Overall, the answer is yes. A successful simulator is often able to consistently contribute stable and profitable revenues over many years. If the supplier can achieve an accurate combination of functions, characteristics, and performance specifications, and match the customer's successful product, the operational amplifier is likely to be used in the current and next generation designs. Eventually an alternative to the traditional preferred model is achieved.
It is not easy to replace a mature device. Unlike processors, a reliable operational amplifier, once adopted, is usually used for a long time rather than being easily replaced. Why, then, are designers unwilling to replace old, relatively poor operational amplifiers with new models?
The reason is that analog devices are more susceptible to subtle features and individual differences in design, layout, and production processes than digital devices. Experienced analog circuit designers are unwilling to easily replace new devices and bear learning and verification costs unless there are sufficient reasons; Designers who tend to be digital are reluctant to go deep into simulation details. Their general idea is: "As long as it is sufficient, keep it unchanged and keep moving forward with the project."
For suppliers and designers, there are other long-term benefits to the new product:
Mature manufacturing and testing processes significantly reduce production and supply risks.
Manufacturing technology improvements and higher yield can lead to higher margins for suppliers.
Parts have been listed on many OEM designers' approved vendors and component lists so the company has no concerns when adding them to the Product Bill of Material (BOM).
A typical example of this "not easy to replace" design concept is Burr Brown INA133 instrument amplifiers, a special operational amplifier topology. The device was introduced around 1998 and is still offering a variety of packages and grades, such as Texas Instruments' INA133UA/2K5 (acquired when Burr-Brown was acquired in 2000).
Of course, facing a large number of new and old operational amplifier products, how to select the most appropriate model for specific applications has become a major challenge. Some designers start with a small number of trusted suppliers, while others rely on industry experience. AI may be able to help here by entering the minimum/maximum values of required parameters, expected parameters and other parameters, which returns a list of suitable operational amplifiers sorted by priority.
This is a good entry point, but there is no better way to narrow the selection and really understand the nuances of these devices than to look up documentation and communicate one-to-one with vendor contacts.