acquisitionZONE Products for the week of January 8, 2007

Intersil Corporation, a world leader in the design and manufacture of high-performance analog semiconductors, introduced the ISL21009 voltage reference. This reference delivers initial accuracy, along with the industry's lowest supply current consumption for low-noise references, making it the ideal choice for industrial and medical instrumentation applications where power is a concern.

Intersil's ISL21009 offers the most power savings of any low-noise voltage reference on the market. With less than 3ppm/degrees C of temperature drift, this device provides very precise performance, allowing for accurate measurements even in noisy environments with great temperature variations.

"This combination of precision and low power consumption provides a new benchmark for precision voltage references," said Lisa Wong, marketing manager for Intersil's Precision Analog products group. "The ISL21009 provides new levels of power efficiency for precision instrumentation and data acquisition equipment."

EN-Genius Says . . .

The first Intersil-numbered FGA reference, the ISL60002 (reviewed here and an EN-Genius Product of the Year award winner in 2004) was the result of the work done at the acquired Xicor. Unlike conventional silicon junction based references, these references store a charge on a floating gate cell that is protected, almost completely, from external elements. This results in very stable operation against changes in time, temperature and supply voltage with low quiescent current.

The only real negative going for the initial parts was noise -- at about 30 µVp-p over the frequency range of 0.1 Hz to 10 Hz -- not comparing very favorably with some other high-end references. With this new part that noise number has been sliced to 4 µVp-p for the same frequency band, putting it right up there with the leading low noise reference. It looks like the cost of the better noise is a higher quiescent current at a typical 95 µA, which should hardly be a deal breaker in the majority of applications.

The first parts being released are 2.500 V references and 1.250 V parts will follow soon. Because they are not based on a junction's behavior, however, any voltage could be offered. The original C and D grades for the references now have a third grade as well (B). The differences are in the initial accuracy and Tempco, with B offering ±0.5 mV and 3 ppm/°C; C with ±1.0 mV and 5 ppm/°C; D with ±2.0 mV and 10 ppm/°C. Presumably Intersil sees the possibility of improving the devices even more by leaving the "A" designation unfilled.

No reference output current numbers are in the data sheet but the typical short-circuit is 10 mA and we can deduce from the load regulation of 20 µV/mA sinking -7 mA, and 10 µV/mA sourcing 7 mA that 7 mA is it. The input voltage is a massive 3.5 V to 16.5 V and the line regulation below 5.5 V supply is a typical 50 µV/V. PSRR is flat at about -60 dB out to about 1 kHz and then falls -- depending on the load capacitance.

Intersil has improved their product quite dramatically...and we thought it was good already! The low noise of the new parts invites them to share the real estate of very high resolution ADCs and DACs, and they will. The company will continue to expand its presence in test, medical and communications equipment and in such rather mundane applications as battery management. It keeps looking like the purchase of Xicor really was a good call. The price premiums sought after with the new parts will be paid. The choice of package has been reduced to a single option.

The ISL21009 is in production in SOIC-8 priced at $4.04 for the B grade, $3.74 for the C, and $2.65 for the D grade, all in 1000-piece lots. Pb-free is available.

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