Analog Devices, a global provider in high-performance semiconductors for signal processing applications and the market share leader in amplifiers, announced two high-speed FET input operational amplifiers, the first in a new family of low-cost, broad-use devices called FastFET^TM amplifiers.

Amplifiers are found in virtually every electronic circuit built today, and according to the Worldwide Semiconductor Trade Statistics (WSTS), the amplifier/comparator market totaled over two billion dollars in 2001. Up to this point, FET input amplifiers - desirable for their ease of use - have not been ubiquitous due to their high cost and low speed. Analog Devices' FastFET amplifiers were developed to have both high performance and low price so that they can be used in almost any application requiring a high-speed operational amplifier. These include amplification, signal level shifting, signal driving, and buffering in industrial, consumer and communications applications, including fiber optic applications as photodiode preamplifiers.

The first two FastFET amplifiers from Analog Devices, the AD8034 and AD8065, offer a well-balanced combination of specifications unavailable until now: wide supply voltage range, low input bias current and noise, low distortion, low voltage noise, low offset voltage and drift, and rail-to-rail output. In addition, both products come in very small packaging, for use on even the most space-constrained boards. These performance levels at low cost are possible using Analog Devices' proprietary high-speed complementary bipolar process, called XFCB (eXtra-Fast Complementary Bipolar).

The AD8065 is a very high performance single voltage-feedback amplifier with FET inputs, with a dual version in development. The AD8065 is noteworthy for its very low noise, at 6.5 nV/rt Hz and 5 fA/rt Hz, and very low distortion, -91 dB SFDR at 1 MHz. The device operates at 150 MHZ with a slew rate of 180 V/uS. The AD8065 also has superior dc performance, with an IB of 1 pA typical, a VOS of 6 uV typical, and a drift of less than 1 mV/ degrees C. The differential gain and phase errors are 0.01% and 0.02 degrees, with 0.1dB flatness out to 7 MHz, making the part ideal for video applications. The AD8065 consumes 6.5 mA supply current.

The AD8034 is a dual voltage feedback amplifier with FET inputs, with a single version in development. The AD8034 is a lower priced version of the AD8065 offering similarly high-performance while consuming only 3.3 mA supply current maximum per amplifier. With 80 MHz bandwidth, slew rate of 80 V/uS, and low dc errors of 6 mV VOS and 11 nV/rt Hz noise, the AD8034 offers significant performance improvements over other low-cost FET amplifiers. A wide operating supply voltage range of 5 V to 24 V with rail-to-rail output, add to the general usefulness of these amplifiers.

Analog Devices, Inc., 804 Woburn Street, Wilmington, MA 01887. Tel: 1/800-ANALOGD (262-5643); Fax: 781-937-1021; http://www.analog.com

The first thing that must be done is to position this product. ADI says a FastFET is a new class of amplifiers. It combines a FET input amp's high input impedance (which almost eliminates the need to consider the input bias current in designs) with the company's proprietary eXtra-Fast Complementary Bipolar technology (the low power consumption, low noise and distortions, and a wide supply voltage). ADI expects designers will use the FastFET in applications that are robust but they will feel comfortable that they can just drop it into the design and it won't have any strange properties, thus allowing the job to be done quickly.

The exciting thing about these products - for the past 8 years there really hasn't been much new in the world of FET input amps. In the past, FET amps have been on the order of 10 MHz and ADI with their eXtra-Fast Complementary Bipolar (XFCB) technology has been able to push this speed to an impressive 150 MHz. But there's more, the input bias current is a very low 1 pA, and the noise is 7 nV. So it is a low noise amp as well as being fast. Typical FET amps have input bias current, on the order of tens of pico amps. ADI attained the very low input bias as a result of their XFCB process. The process dielectrically isolates the devices with glass trenches, which eliminates a junction leakage path that can add to the FET input current.

ADI believes these will become very popular in a wide variety of applications because you don't have to worry about the input bias current when you're doing the design. There is also plenty of speed so you don't have to worry about bandwidth or slew rate as you would with the previous generation of products. And don't forget the rail-to-rail output, with its wide voltage range, makes these FETs useful in many applications. These devices will work from 5V to 26V so they can be used in single supply applications or instrumentation applications where you have a +/-12V supply. Finally, these FETs are available in really tiny packages. The AD8034 and AD8065 are sampling now and are available in very small SOIC-8, SOT23-5 and uSOIC packages. The AD8034 and AD8065 are both priced at $1.59 per unit in 1,000 piece quantities. More information about the products can be found at the following websites.

Data Sheets:
AD8034
AD8065