Low Power, Wide Supply Range,

Low Cost Difference Amplifier, G = ½, 2

AD8278

Rev. 0

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FEATURES

Wide input range beyond supplies

Rugged input overvoltage protection

Low supply current: 200 μA maximum

Bandwidth: 1 MHz (G = ½)

CMRR: 80 dB minimum, dc to 20 kHz (G = ½)

Low offset voltage drift: ±2 μV/°C maximum (B Grade)

Low gain drift: 1 ppm/°C maximum (B Grade)

Enhanced slew rate: 1.4 V/μs

Wide power supply range:

Single supply: 2 V to 36 V

Dual supplies: ±2 V to ±18 V

8-lead SOIC and MSOP packages

APPLICATIONS

Voltage measurement and monitoring

Current measurement and monitoring

Instrumentation amplifier building block

Portable, battery-powered equipment

Test and measurement

FUNCTIONAL BLOCK DIAGRAM

2

5

3

1

6

7

4

40kΩ

20kΩ

40kΩ

–VS

+VS

–IN

+IN

SENSE

OUT

REF

20kΩ

AD8278

Figure 1.

Table 1. Difference Amplifiers by Category

Low

Distortion

High

Voltage

Current

Sensing1

Low Power

AD8270

AD628

AD8202 (U)

AD8276

AD8271

AD629

AD8203 (U)

AD8277

AD8273

AD8205 (B)

AD8274

AD8206 (B)

AMP03

AD8216 (B)

GENERAL DESCRIPTION

The AD8278 is a general-purpose difference amplifier intended

for precision signal conditioning in power critical applications

that require both high performance and low power. The AD8278

provides exceptional common-mode rejection ratio (80 dB) and

high bandwidth while amplifying signals well beyond the supply

rails. The on-chip resistors are laser-trimmed for excellent gain

accuracy and high CMRR. They also have extremely low gain

drift vs. temperature.

The common-mode range of the amplifier extends to almost

triple the supply voltage (for G = ½), making it ideal for single-

supply applications that require a high common-mode voltage

range. The internal resistors and ESD circuitry at the inputs also

provide overvoltage protection to the op amp.

The AD8278 can be used as a difference amplifier with G = ½

or G = 2. It can also be connected in a high precision, single-

ended configuration for non-inverting and inverting gains of

−½, −2, +3, +2, +1½, +1, or +½. The AD8278 provides an

integrated precision solution that has a smaller size, lower cost,

and better performance than a discrete alternative.

The AD8278 operates on single supplies (2.0 V to 36 V) or dual

supplies (±2 V to ±18 V). The maximum quiescent supply current

is 200 μA, which makes it ideal for battery-operated and portable

systems.

The AD8278 is available in the space-saving 8-lead MSOP

and SOIC packages. It is specified for performance over the

industrial temperature range of −40°C to +85°C and is fully

RoHS compliant.