Texas Instruments’ PGA20 x series

One, Two, Gain!

Test equipment and sensors both profit from amplifiers which change their gain on the fly. One of Texas Instruments evergreens recently saw quite a bit of additional attention.

From a technical point of view, the part is extremely simple. As shown in the figure, the part – in essence – is an operational amplifier which subtracts the two inputs and emits the result after multiplying it with a specified gain factor. The really interesting aspect is the set of digital inputs which allow users to pick the wanted voltage level comfortably.

PGA20 x parts are easy to use

Texas Instruments provides two different part families, which differ by the gain levels implemented. Figure two shows the available amplifier levels – simply order the one ideally suited to your application.

Texas Instruments provide two amplification classes

Texas Instruments provide two amplification classes

While the parts power supply demands – it can work from a dual 6V supply but works best with +/-15V – are handle-able, be aware that the PGA family’s full gain bandwidth is limited to a few ten Kilohertz at best. This, clearly, is not a part intended to handle high-speed signals.

A question of performance

Being a development by Burr Brown, the PGA20 x family comes with a group of nifty tweaks not found in other opamp families. For example, output sensing is not done inside of the chip – instead, a dedicated pin lets you “slide in” amplifiers as shown in figure three.

The power booster’s gain error is eliminated via the feedback circuit

The power booster’s gain error is eliminated via the feedback circuit

The part can even be cascaded in a “family group”. If one PGA20 2 and one PGA20 3 are ganged up, the amount of selectable amplification levels increases greatly.

Conclusion

While the PGA20 2 / PGA20 3 family definitely is not the newest part on the market, it is a well-proven design which saw use in more than one piece of high-value test equipment. If your circuit can live with the relatively moderate speed and the large DIP housing, definitely to give the part a chance!

Recent Articles
STSPIN32F0 – Series
Extremely integrated STM32-based system-in-package solution for driving three-phase BLDC motors We would like to introduce you to ST’s growing portfolio of STSPIN32F0 devices. Embedding a 32-bit ARM... Read Article
Enter for your chance to win a Digilent Dev Board worth over $500
To celebrate our 10 Year Anniversary this month and to thank everyone for their support over the last decade, we’ve partnered with Digilent to give away 2x Digilent development boards... Read Article
Efficient High-Power Gallium Nitride FETs from Nexperia
Whether designing a motor drive/controller for the next generation of battery-electric vehicles, or a power supply for the latest 5G telecommunication networks, Nexperia’s GaN FETs will be key... Read Article
Debug your embedded systems from the home office
Use USB Logic Analyzer and Pattern Generator to debug, visualize, and simulate signals in digital systems The quarantines are forcing an increasing number of engineers and... Read Article
Learn more about Optocoupler Design for EMI Immunity by Broadcom & EBV
Join the IEEE Webinar on 26th May, 4pm CET – Optocoupler Design for EMI Immunity Also available on demand This webinar takes a close look into... Read Article
6 use cases for adaptable technology and its impact on automotive trends
Overcome technological complexity in automotive design with Xilinx and Avnet Silica The automotive industry is a highly competitive space. In the blink of an eye, a... Read Article