Analog Devices Releases New Low-Power Difference Amplifiers

The AD827x high-performance difference amplifiers reduce board space for power-efficient, robust process- and motor-control applications

Analog Devices has released three new low-power difference amplifiers as small as 4.9 mm x 3 mm and featuring slew rates up to 10 times faster than competing products. Designed for high-performance, power-critical applications, the AD8276, AD8277 and AD8278 difference amplifiers are half the size of competing devices and much smaller than discrete alternatives consisting of resistor arrays and operational amplifiers.

The amplifiers also eliminate the added expense and design overhead associated with complex peripheral protection circuitry.

The slew rate of 1.1 V/µs (volts per microsecond) combined with an input range of two times the power supply make the AD827x products well suited for robust voltage and current sensing in process-control, motor-control, and power-management applications. In addition, the low price is unprecedented with versions available at under $1 USD each.

The AD827x low-power difference amplifiers combine the benefits of a wide supply range of 2.5 V to 36 V and low power with a 550-kHz bandwidth that is two times faster than other low-power difference amplifiers. In addition, these difference amplifiers feature 220-µA maximum quiescent current with an 86-dB CMRR (common-mode rejection ratio) that is 10-dB greater than competing devices. AD827x difference amplifiers reject external interferences in low-power systems without increasing system power dissipation. Response time includes a 1.1-V/µS slew rate and 15-µS settling time to 0.01 percent. The settling time is more than five times faster than other amplifiers in their class and ensures shorter propagation delays in control loops. On-chip resistors are laser-trimmed for accurate gain, low gain drift, and high common-mode rejection.

The AD827x difference amplifiers work well with other low-power components, such as ADI's ADCs (analog-to-digital converters) including the AD7450 12-bit SAR ADC and AD7982 18-bit PulSAR ADC, as well as low-power operational amplifiers, including the AD8500 precision CMOS op amp, AD8538 auto-zero op amp, and AD8603 rail-to-rail input-output op amp.

Using the AD8276 Difference Amp as a Low-cost Current Source
Current sources using the low-power AD8276 difference amplifier and the AD8603 op amp are affordable, flexible, and small in size. Performance characteristics, such as initial error, temperature drift, and power dissipation, are excellent. Engineers can quickly and with confidence design this circuit by accessing circuit note CN-0099 from ADI's Circuits from the Lab collection. Circuits from the Lab is a design assistance resource that provides design engineers with tested circuit solutions for many common applications. Each circuit has been verified by ADI test engineers and can be easily integrated into designs, resulting in reduced design risk and faster time-to-market. Close to 100 circuit notes are available, featuring some of ADI’s most popular products and how they address common design challenges.

Features of the AD8278 Difference Amplifiers

More information on the AD8278 Difference Amplifiers, can be found on the Analog Devices website at Analog Devices AD8278 product page

The Analog Devices website address is www.analog.com
[Reprinted with kind permission from Analog Devices]