The AD8638/AD8639 are single and dual wide bandwidth, auto-zero amplifiers featuring rail-to-rail output swing and low noise. These amplifiers have very low offset, drift, and bias current. Operation is fully specified from 5 V to 16 V single supply (±2.5 V to ±8 V dual supply).

The AD8638/AD8639 provide benefits previously found only in expensive zero-drift or chopper-stabilized amplifiers. Using the Analog Devices, Inc., topology, these auto-zero amplifiers combine low cost with high accuracy and low noise. No external capacitors are required. In addition, the AD8638/AD8639 greatly reduce the digital switching noise found in most chopper- stabilized amplifiers.

With a typical offset voltage of only 3 μV, drift of 0.01 μV/°C, and noise of 1.2 μV p-p (0.1 Hz to 10 Hz), the AD8638/AD8639 are suited for applications in which error sources cannot be tolerated. Position and pressure sensors, medical equipment, and strain gage amplifiers benefit greatly from nearly zero drift over their operating temperature ranges. Many systems can take advantage of the rail-to-rail output swing provided by the AD8638/AD8639 to maximize signal-to-noise ratio (SNR).

The AD8638/AD8639 are specified for the extended industrial temperature range (−40°C to +125°C). The single AD8638 is available in tiny 5-lead SOT-23 and 8-lead SOIC packages. The dual AD8639 is available in 8-lead MSOP, 8-lead SOIC, and 8-lead LFCSP packages.

The AD8638/AD8639 are members of a growing series of auto- zero op amps offered by Analog Devices (see Table 1 in the data sheet).

Applications

Pressure and position sensors

Strain gage amplifiers Medical instrumentation

Thermocouple amplifiers Automotive sensors

Precision references

Precision current sensing

Part#	Small Signal Bandwidth	Vos	Ib	V Noise Density	Amplifiers Per Package	Widest Temp Range (°C)
AD8551	1.5MHz	1µV	10pA	42nV/rtHz	1	-40 to +125
AD8571	1.5MHz	1µV	10pA	51nV/rtHz	1	-40 to +125
AD8638	1.5MHz	3µV	20pA	59nV/rtHz	1	-40 to +125
AD8552	1.5MHz	1µV	10pA	42nV/rtHz	2	-40 to +125
AD8572	1.5MHz	1µV	10pA	51nV/rtHz	2	-40 to +125
AD8628	2.5MHz	1µV	30pA	22nV/rtHz	1	-40 to +125
AD8538	430KHz	5µV	15pA	50nV/rtHz	1	-40 to +125
AD8603	400KHz	12µV	200fA	22nV/rtHz	1	-40 to +125
AD8663	540KHz	30µV	300fA	21nV/rtHz	1	-40 to +125
AD8641	3.5MHz	50µV	250fA	27.5nV/rtHz	1	-40 to +125
AD8661	4MHz	30µV	300fA	12nV/rtHz	1	-40 to +125

The model number is a specific version of a generic that can be purchased or sampled.

Status indicates the current lifecycle of the product. This can be one of 4 stages:

• Pre-Release: The model has not been released to general production, but samples may be available.
• Production: The model is currently being produced, and generally available for purchase and sampling.
• Last Time Buy: The model has been scheduled for obsolescence, but may still be purchased for a limited time.
• Obsolete: The specific part is obsolete and no longer available. Other models listed in the table may still be available (if they have a status that is not obsolete).

The package for this IC (i.e. DIP, SOIC, BGA). An Evaluation Board is a board engineered to show the performance of the model, the part is included on the board.

For detailed drawings and chemical composition please consult our  Package Site

Pin Count is the number of pins, balls, or pads on the device. Pin-out diagrams & pin function descriptions may be found in the datasheet.

This is the acceptable operating range of the device. The various ranges specified are as follows:

• Commercial: 0 to +70 degrees Celsius
• Military : -55 to +125 degrees Celsius
• Industrial: Temperature ranges may vary by model. Please consult the datasheet for more information.
• Automotive: -40 to +125 degrees Celsius

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