Digital pots eliminate instability

A family of volatile, 32-tap digitally-controlled potentiometers (DCPs) from Intersil Corp. were designed to address the need for space-constrained applications that require ultra-low power, such as LCD contrast and backlight brightness control in cell phones, PDAs and GPS receivers.

With options ranging from a 100-kiloohms SOT-23 package down to the smallest 10-kiloohm SC-70 package, Intersil's DCPs feature three potentiometer configurations, a two-pin up/down (U/D) interface, low power dissipation and a supply voltage range of 2.7V to 5.5V.

"The ISL90460/61/62 are digitally adjustable, electronic potentiometers that eliminate the stability issues caused by vibration or shock when using mechanical potentiometers," said Andy Jenkins, marketing director of Intersil's analog signal processing group. "Because these parts employ a volatile memory to control the DCP wiper setting, they are significantly more cost-effective than devices using non-volatile electrically erasable programmable read only memory (EEPROM). Consequently, these DCPs are very attractive as replacements for mechanical potentiometers."

Intersil's ISL90460/61/62 are low-noise DCPs used for adjustment, trimming, and calibration applications in industrial, medical, automotive, and consumer markets. The devices can be used for industrial automotive control, parameter and bias adjustments, and laser diode driver biasing.

The ISL90460 (a variable resistor with one end grounded) is available in a 5-pin SOT-23 or SC-70 Pb-free package and is priced at 64 cents each. The ISL90461 (a floating variable resistor) and ISL90462 (a potentiometer with one end terminal grounded) are available in a 6-pin SOT-23 or SC-70 lead-free package and are priced at 57 cents each, all in 1,000-piece quantities.

- Bettyann Liotta

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