Analog Devices Inc., has released a low-voltage instrumentation amplifier
(in-amp) to offer high precision at voltages as low as 1.8 V, claiming it to be
the first of its kind to work at such a low voltage. The release said previous
generations of in-amps operated only as low as 2.7 V, many ultra low-voltage
applications, such as medical monitoring devices, could not benefit from the
combination of precision performance, low-noise operation and reduced pricing
offered by in-amps. For applications where precision is crucial, in-amps magnify
small signals while rejecting large amounts of noise that can interfere with the
accuracy of measurements. The instrumentation amplifier is optimized for a broad
range of industrial, communications and medical applications that require
low-voltage operation.
“The growing at-home medical monitoring market is driving the demand for
high precision, portable products that operate at voltages as low as 1.8 V,”
said Steve Sockolov, product line director for precision amplifiers at Analog
Devices. “With the introduction of the AD8553, ADI is extending the company’s
proven expertise in developing highly accurate, low-noise in-amps to +1.8 V
applications. Prior to the AD8553, lower voltage systems could only achieve high
levels of precision performance by using discrete solutions that required
additional trimming, consumed more board space, and were extremely costly and
difficult to implement.”
The AD8553 provides superior performance to a variety of low-voltage medical,
industrial and communications applications. A power-saving shutdown mode that
extends battery life combined with low-noise operation at 1.8 V targets portable
medical devices, particularly those intended for at-home, non-invasive patient
use such as blood pressure and glucose monitors. High-performance hospital
equipment such as defibrillators and electrocardiogram monitor, and industrial
applications such as strain gages, weigh scales, and pressure sensors benefit
from the high precision and high CMRR (common mode rejection ratio). The AD8553’s
high dc accuracy is also of benefit to low-side current sensing and other
monitoring functions in communications base station control systems.
About the AD8553:The AD8553 precision in-amp features very high CMRR even at
low gains, low offset and low offset drift for the highest dc accuracy,
low-noise operation and low-voltage operation from +1.8 V to +5.5 V. In shutdown
mode, the total supply current is reduced to less than 4 microamps.
With low offset voltage of 25 microvolts max, offset voltage drift of 0.1
microvolts/degrees C max and voltage noise of only 0.7 microvolts p-p (0.1 Hz to
10 Hz), the AD8553 is ideal for applications where error sources cannot be
tolerated. Unlike many in-amps, parasitic resistance in series with the Vref pin
does not degrade performance, allowing the AD8553 to attain very high CMRR
performance of 120 dB min at G=100 without using a buffer amplifier to drive the
Vref pin. The rail-to-rail output of the AD8553 makes it ideal for driving and
buffering converters, such as ADI’s AD7466, AD7687 and AD7942.
Pricing and Availability
The AD8553 is sampling now with production quantities available in September
2005. The device is packaged in 10-lead MSOP and is priced at $1.30 per unit in
1,000-piece quantities.
Contact Information:
Charlotte.betterley@analog.com
