Supervisory Circuits

Linear Technology’s power supply voltage monitors and microprocessor supervisors monitor positive and negative power supplies, with integration of up to eight supply monitors in a tiny package. These devices generate a RESET signal if any power supply goes above or below the user-defined threshold. Reset times are usually fixed at 200ms or are adjustable with just a single capacitor. Aside from power supply monitoring, CPUs and ASICs can also be supervised by an integrated watchdog timer. Portable applications will appreciate the nano-current supervisors, LTC2934 and LTC2935, or the high voltage LTC2960 which can directly monitor voltages up to 36V. These supervisor circuits make up the heart of a complete system monitor and control application.

Linear Technology supervisory circuits offer many benefits that help simplify design, such as high accuracy, adjustable thresholds and tolerances, and a guaranteed RESET signal down to a low supply voltage. Most Linear Technology supervisors exhibit ±1.5% threshold accuracy (±1% for programmable LTC2933) around the nominal threshold voltage, minimizing the required system voltage margin and probability of system malfunction. Voltage supervisors with pin or I2C/SMBus adjustable thresholds and tolerances provide users with maximum flexibility, allowing a single part to be used across multiple designs. Some applications require a valid reset signal at low supply voltages in order to prevent low voltage components from generating erroneous data or malfunction as a system powers up or down. Linear Technology supervisors guarantee a valid reset signal to an industry leading low of 0.5V to help preserve system integrity.

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