AD8278 Datasheet, PDF (1/24 Pages) Analog Devices – Low Power, Wide Supply Range, Low Cost Difference Amplifier, G = ½, 2

Low Power, Wide Supply Range,
Low Cost Difference Amplifier, G = ½, 2
AD8278
FEATURES
Wide input range beyond supplies
Rugged input overvoltage protection
Low supply current: 200 μA maximum
Low power dissipation: 0.5 mW at VS = 2.5 V
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
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.
FUNCTIONAL BLOCK DIAGRAM
+VS
40kΩ
–IN 2
7
AD8278
20kΩ
5 SENSE
6 OUT
40kΩ
+IN ³
20kΩ
1 _REF
4
–VS
Figure 1.
Table 1. Difference Amplifiers by Category
Low
Distortion
AD8270
AD8271
AD8273
AD8274
AMP03
High
Voltage
AD628
AD629
Current
Sensing¹
AD8202 (U)
AD8203 (U)
AD8205 (B)
AD8206 (B)
AD8216 (B)
Low Power
AD8276
AD8277
1 _{U = unidirectional, B = bidirectional.}
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.
Rev. 0
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