Electronic Design

Power-Management ICs Target Multiple Supplies And USB OTG

The SMM665 power-supply controller from Summit Microelectronics monitors, margins, and sequences up to six voltage supplies at 0.3 to 5.5 V. This chip performs both on and off sequencing of supplies, such as those generated by bricks and other dc-dc converters, without external load switches. However, it doesn't track voltages. Also, the IC's active dc output control (ADOC) adjusts a dc-dc converter's trim pin to achieve voltage accuracy as high as ±0.2% with an external reference. For more details, go to www.summitmicro.com.

Other recently introduced ICs provide dc-dc conversion and additional circuitry required by the USB On-The-Go (OTG) specification.

Advanced Analogic Technologies' AAT3125 supplies power and port protection in accordance with USB OTG. The chip's 1-MHz charge pump steps up a battery voltage to generate the regulated 5-V VBUS at currents of 8 to 100 mA. Also, the chip performs voltage monitoring of the VBUS to support USB OTG session request protocol. Two on-chip PowerOK detectors confirm the bus is in regulation while session-detect and session-ready detectors manage the communications protocol. Packaging consists of a 4- by 4-mm QFN. The AAT3125 costs $2.42 each per 1000. For details, see www.analogictech.com or contact [email protected]

Maxim Integrated Products has also introduced USB OTG-compliant devices, the MAX3353E/3355E USB-On-The-Go Power Plus Support ICs. These chips contain a charge pump that generates the VBUS output and comparators that detect VBUS voltage levels used for Host Negotiation Protocol and Session Request Protocol. Other features include ID monitoring, pull-up and pull-down resistors, ±15-kV electrostatic-discharge protection, an I2C interface, and chip-scale or TSSOP packaging. Pricing starts at $1.21 each per 1000. For details, see www.maxim-ic.com or call (800) 998-8800.

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