外付け部品不要、ヒステリシス及びμP監視回路付シングル/デュアルバッテリモニタ
Note to Editor: The MAX6439-MAX6442 integrate a battery monitor with internal hysteresis and an independent microprocessor reset. Single- or dual-level outputs are offered for signaling low and dead battery conditions. These low-power (3µA) devices are offered in a SOT23 package and require no external components.
SUNNYVALE, CA-October 3, 2002-Maxim Integrated Products
(NASDAQ: MXIM) introduces the MAX6439-MAX6442 battery monitors with hysteresis to eliminate low-battery chatter in battery-operated systems. In addition, these devices feature a µP supervisory reset circuit for monitoring system voltages from 1.8V to 3.3V. These small (SOT23), low-power (3µA) devices are perfect for portable, handheld applications.
In typical systems, when the battery voltage falls below its voltage threshold, the low-battery output (LBO) asserts and disconnects the load from the system. The battery voltage often recovers and reconnects the load, only to cause the LBO to reassert and cause chatter. The MAX6439-MAX6442 provide a hysteresis window to eliminate this problem.
Each device offers an LBO that asserts whenever the battery voltage falls below its preset low-voltage threshold, allowing the system to shut off. The MAX6441/MAX6442 offer a second LBO as an early warning indicator to allow the system to enter a low-power mode or back up critical data into memory. A third output is available as a power-good indicator. All low-battery outputs have active-low, open-drain configurations.
These battery monitors are offered with factory-trimmed thresholds that eliminate the need for external components. Factory-trimmed thresholds are available to monitor single Li+ cell applications as well as dual-cell Alkaline/NiCd/NiMH applications.
The MAX6439-MAX6442 also have an independent µP supervisory circuit that monitors system voltages from 1.8V to 3.3V. Seven factory-trimmed reset thresholds are available with two minimum reset timeout options of 150ms or 1200ms. The MAX6439/MAX6441 have an active-low, open-drain reset and the MAX6440/MAX6442 have an active-low, push-pull reset output.
All devices are available in a SOT23 package and are fully specified from -40°C to +85°C. Prices start at $1.63 (2500 or 10,000-up minimum, FOB USA).
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