Taking a “family-first” approach to op amp design

qwqwqw2088

Taking a “family-first” approach to op amp design [Copy link]

By: Hayden Hast – Systems Engineer

When I first visited a Texas barbecue restaurant, I was so surprised by the variety of meats on the menu that I had no idea which one to choose. Luckily, the restaurant offered a platter of three meats so I could try the flavors of the different meats.

In fact, similar to the experience of the barbecue restaurant, engineers also face many choices when choosing operational amplifiers (op amps). In addition, as today's production cycles continue to shorten, engineers often need to make decisions quickly. Carelessly choosing an inappropriate operational amplifier will delay the R&D cycle and consume unnecessary R&D funds.

This article will introduce TI's full range of op amp products, the TLV90xx series, which offers up to 48 different product combinations (including the latest products TLV9001 , TLV9052 and TLV9064 ). We will provide up to 16 different package options, including the industry's smallest single-channel and quad-channel packages. In this technical article, you will learn how this new operational amplifier series can meet various project needs, saving printed circuit board (PCB) space, and providing multiple bandwidth options to provide more gain for your signal chain.

Thanks to the rich and comprehensive product portfolio, engineers will have more flexibility when choosing the number of channels, speed and size of op amps.

Diversity of product performance

Figure 1 shows the full TLV90xx family, with common parameters for the family shown above the table. The three sub-families are interchangeable under certain conditions because they use the same supply voltage, input and output voltage ranges, and offset voltage. In addition, the family has a low resistive output impedance to minimize stability issues.

查看详情

Figure 1 : Amplifier Series Comparison

However, each sub-family offers unique performance advantages. For example, if you initially use the TLV9002 in a single-supply, low-side, unidirectional current sensing solution with an output swing-to-GND circuit for motor current sensing , but later determine that higher gain and faster slew rates are required to handle larger motor transient currents, you can easily switch to the higher-bandwidth, pin-to-pin compatible TLV9052 without redesigning. This is possible because each sub-family has the same 16 package options covering single-channel, dual-channel, and quad-channel channel configurations.

Packaging flexibility

Figure 2 shows the various package options in detail. The “Industrial Standard” column identifies whether the package is common in the industry and available from other suppliers as a second supply option. The “Shutdown” column shows packages that have a shutdown feature, which can help engineers further reduce system power consumption.

While most of the small package options in the table are quad flat no-lead (QFN) packages, we want to highlight the small leaded package type SOT23-THIN. The dual-channel, small-outline transistor (SOT)-23-thin package (SOT23-THIN) is similar to the familiar single-channel SOT-23 package body, but it has 8 pins instead of the traditional 5 or 6 pins. Compared with larger leaded packages such as small-outline integrated circuits (SOIC), thin small-outline packages (TSSOP), and very thin small-outline packages (VSSOP), SOT23-THIN has the advantages of pin-out and smaller size, making it a better package choice. To achieve compatible design of SOT23-THIN and traditional leaded packages on the same PCB board, you can also use dual layout techniques. For more details, read the Analog Design Journal article, " Second Package Compatibility Design for Small Package Op Amps ." Of course, if you want to save the most PCB space, we recommend the QFN package option.

查看详情

Figure 2 : Amplifier family packaging options

Size breakthrough

These three amplifier sub-families are available in the industry's smallest single- and quad-channel packages. TI's single-channel 0.8mm x 0.8mm ultra-small leadless (X2SON) package is 13% smaller than similar small-footprint devices currently available on the market, and the quad-channel 2.0mm x 2.0mm ultra-small QFN (X2QFN) package is 7% smaller. These packages, along with the dual-channel 1.0mm x 1.5mm X2QFN package, provide engineers with more packaging options to further reduce PCB area. The right side of Figure 3 shows you the three smallest packages.

查看详情

Figure 3 : Progressive smaller packages

Due to the small pitch of the ultra-small QFN package, the factory's production process level may limit the application of this package. To meet this challenge, TI can also provide a variety of small package options with different pitches. The application note " Design and Manufacturing Using TI X2SON Package " provides layout and routing guidelines for these packages.

Summarize

Some say too many choices can be overwhelming. But we believe that whether you're deciding what barbecue to eat in Texas or an R&D engineer choosing an amplifier, the more choices the better. The next time you design a product, choose TI's TLV90xx family of op amps: three performance options to choose from; 16 different package options; and the industry's smallest single- and quad-channel packages when you need to save PCB space.