acquisitionZONE Products for the week of April 17, 2006
Analog Devices Inc., a global leader in high-performance semiconductors for signal processing applications and market leader in amplifier ICs, today is introducing the industry's first dual-channel in-amp available in a tiny 16-lead 4 mm x 4 mm chip scale package and the first to provide complete performance specifications for differential operation. For space-constrained industrial and instrumentation applications that demand precise measurement and high channel densities, the AD8222 offers designers twice the number of output channels and 40 dB higher common mode rejection ratio (CMRR) than competitive dual-channel in-amps, all in a package that is 50% smaller. The AD8222's combination of higher channel count, smaller size and superior noise rejection enables manufacturers of factory automation systems, medical monitoring devices and other industrial and instrumentation equipment to significantly boost the precision, accuracy, channel density and response time of their products without increasing component count or board size.
The flexible AD8222 can also be configured as a differential output instrumentation amplifier. This differential output capability, coupled with the AD8222's outstanding noise performance (8 nV/root-Hz input noise) allows designers to use smaller supply rails without sacrificing signal-to-noise performance. The unique ability of the new in-amp to drive differentially also allows systems designers to pair the AD8222 with high-performance differential-input analog-to-digital converters (ADCs) and affords them the flexibility of operating their products with a single supply or with signal conditioning blocks to further improve noise immunity. Additionally, while competing multi-chip in-amp solutions are unable to specify differential performance, the AD8222's single-chip differential operation is specified for all key performance parameters.
"Higher channel count and the ability to reject common mode noise
are key attributes that enable today's high-performance industrial and medical
instrumentation equipment to improve resolution and decrease space,"
said Steve Sockolov, product line director, Precision Linear Products, at
Analog Devices. "The AD8222 in-amp more than satisfies these requirements
while adding differential output capability and complete performance specifications,
something no other supplier can lay claim to."
analogZONE Says . . .
The most important thing about the AD8222 is not what ADI is pushing. The expanded range of CMRR is nice for some applications, but it could also be an enormous pain for others. However, the ability to use both channels of the part together to form a differential output is what makes the part both important and competition, at last, for TI's INA2128 and INA2141.
The ADI and TI numbers are uncommonly similar, even down to noise performance and quiescent, with the real differential being the discounted price that ADI is offering.
The data sheet for the AD8222 -- the front page of which reads more like an advertisement than a data sheet -- only provides numbers for a split rail operation of ±15 V although it is said that it will operate from ±2.3 V to ±18 V, so it is anyone's guess what the lower voltage performance is like. This is, clearly, a dual version of the AD8221 but even now -- nearly two-and-a-half years after its release -- the data sheet for the AD8221 only offers specifications at ±15 V.
Because of the pricing the AD8222 is a must-look-at part as a possible replacement for the TI parts, particularly for differentially driving ADCs. Whether, six years on, ADI can bridge the gap will be interesting to see. The package could either be very attractive, or muttered about, depending on the application. The production date is ridiculous for what amounts to yet another premature announcement from the company. Customers will probably call for a MSOP-16 version.
The AD8222 is sampling in LFCSP-16 with production scheduled for Q3 of 2006. It will be priced at $3.59 in 1000-piece lots.