More precision from JFET op amps

Analog Devices has a new range of precision JFET op amps with performance for demanding applications such as optical networking, wireless basestations, medical CT scanners and ATE.

Analog Devices has a new range of precision JFET (junction field effect transistor) op amps with performance for demanding applications such as optical networking, wireless basestations, medical CT scanners and automatic test equipment.

JFET amplifiers are generally known for their speed and flexibility, and for the first time these new amplifiers from ADI add unprecedented precision, low noise and load drive performance previously not available from a JFET.

This novel combination of features makes these new amplifiers ideal as diode amplifiers, filter amplifiers and precision signal/reference level buffers.

These applications typically require lower input bias current, higher slew rates and higher bandwidth than slower bipolar amplifiers.

The AD8610 has the lowest offset and highest accuracy of any JFET amplifier on the market, with only 100uV maximum offset voltage and noise of only 6nV/Hz.

The AD8620, a dual version of the AD8610 with slightly adjusted specifications, is currently in development.

Analog Devices achieved the breakthrough performance levels of the AD8610/20 using its proprietary extra-fast complementary bipolar (XFCB) process, which offers power efficiency and high-speed performance.

The AD8510, AD8512 and AD8513 have excellent performance for more cost-sensitive applications; these devices have faster settling time, half the noise, smaller packaging and nearly two times the bandwidth of their predecessors, the AD711x family.

These new precision amplifiers help designers meet the increasing demand for higher bandwidth in fibre-optic applications, supporting higher optical channel density per fibre.

In all applications, these amplifiers support higher density packaging and consume less power to allow more devices on a board.

"The AD8610 and AD8510/2/3 family are the fruit of years of accumulated amplifier experience at Analog Devices", said Steve Sockolov, director, Precision Analog Products Group, Analog Devices.

"Our experience has been put to the test to design these devices.

These parts are the only JFET amplifiers that address the challenge to increase board or optical-line density while maintaining high signal integrity in high-performance applications".

In addition to ultralow offset voltage and drift, the AD8610 features very low input voltage and current noise, as well as very low input bias current and wide bandwidth.

In the device, input bias current is maximum 10pA, and outputs settle to 0.01% accuracy in less than 600 ns.

In the AD8610, outputs slew at 50V/us in either inverting or non-inverting gain configurations, and output swings to within 1.2V of supplies even with a 1kohm load, maximising dynamic range with limited supply voltages.

Unlike many JFET amplifiers, the AD8610 input bias current is low over the entire operating temperature range.

Low voltage and low current noise achieve maximum signal resolution regardless of source impedance; low voltage combined with low drift means that the system has high DC accuracy, with no trimming or system level auto-zeroing required.

The AD8610 is available in an MSOP for high board and system density, in addition to industry-standard SOIC packaging.

The AD8510, AD8512 and AD8513 are single, dual and quad precision JFET amplifiers for used for high-impedance sensor amplification and precise current measurements using shunts.

Unlike many JFET amplifiers, these devices do not suffer from output phase reversal when input voltages exceed the common mode voltage range.

The devices feature offset voltage of 400uV maximum; very low input bias current and low 8nV/Hz noise levels.

The AD851x family settles to 0.01% accuracy in 600ns.

Offset voltage temperature drift is typically 2uV/degC.

In addition to industry-standard SOIC packaging, the devices are available in MSOP for the single and dual, and TSSOP for the quad.

The AD8610B is available in 8-lead SOIC packaging for $8.85 in 1,000-piece quantities.

The AD8610A is available in 8-lead SOIC or MSOP for $3.37 in 1000-piece quantities.

The AD8510 is available in 8-lead SOIC or MSOP for $1.13 in 1000-piece quantities.

The AD8512 is available in 8-lead SOIC or MSOP for $1.88 in 1000-piece quantities.

The AD8513 is available in 14-lead SOIC or TSSOP for $3.67 in 1000-piece quantities.

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