SMALLEST AND LOWEST NOISE FLEXIBLE NEGATIVE SUPPLY FOR SERVERS, TELECOM, AND NETWORKS
SUNNYVALE, CA-September 18, 2001-Maxim Integrated Products introduces the very small MAX1846/MAX1847 inverting power supply controller ICs, which eliminate isolated power supplies ("brick" supplies) for the negative voltage rails in central office xDSL, telecom, and networking equipment. Their wide input range, adjustable operating frequency, and compatibility with a variety of capacitor types offer the flexibility to use a common part for a wide variety of applications. Constant-frequency pulse-width-modulated (PWM) operation and optional external synchronization reduce switching noise.
The MAX1846/MAX1847 are the smallest negative supplies for several reasons: their µMAX package is 50% smaller than their competitor’s 8-pin SO package; they operate at up to 500kHz (vs. 100kHz for competitors) which reduces LC filter values by 80%; they are compatible with smaller and cheaper ceramic or electrolytic capacitors; and a shutdown feature is built into the MAX1847, eliminating four external components.
The MAX1846/MAX1847 offer >90% power conversion efficiency, 3V to 16.5V input range, and an output range down to -200V. Both devices drive an external P-channel MOSFET.
For noise-sensitive applications, current-mode PWM provides quiet design. Switching frequency can be adjusted from 100kHz to 500kHz or synchronized to an external clock. Fixed-frequency operation permits easier noise filtering, and current-mode control provides good transient responses.
Packaged in an ultra-compact 10-pin µMAX, the MAX1846 addresses space-critical applications. The MAX1847, packaged in a small 16-pin QSOP, offers additional flexibility with its shutdown and synchronization functions.
The MAX1846EUB starts at $1.90 (1000-up, FOB USA). The MAX1847EEE starts at $2.05 (1000-up, FOB USA). These devices are specified for the extended-industrial temperature range (-40°C to +85°C). The MAX1846 and the MAX1847 evaluation kits are available to speed designs.
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