Monitor, Control and Protection Supervisory Circuits

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 and LTC2936) 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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