DUAL-VOLTAGE µP SUPERVISORY ICs WITH SEQUENCED RESET OUTPUTS
Note to Editors : The MAX6391/MAX6392 are the first dual-voltage microprocessor (µP) circuits with sequenced reset outputs designed to provide reset logic sequencing for multiprocessor systems.
SUNNYVALE, CA-November 29, 2001-Maxim Integrated Products introduces the MAX6391/MAX6392 microprocessor (µP) supervisory circuits with sequenced reset outputs designed to provide reset logic sequencing for multi-component or dual-voltage systems. Each device can monitor two supply voltages and time sequence two reset outputs to control the order in which system components are turned on and off. The MAX6391/MAX6392 increase system reliability and reduce circuit complexity and cost compared to separate ICs or discrete components.
The MAX6391/MAX6392 monitor VCC as the master supply. Whenever VCC falls below the factory-fixed reset threshold, both reset outputs assert and remain asserted for at least 140ms after VCC exceeds the reset threshold. The MAX6391/MAX6392 have nine preset reset thresholds to monitor +1.8V to +5V primary VCC supplies.
An adjustable secondary voltage can be monitored using a resistive divider network at the reset input (RESET IN2). Whenever RESET IN2 or VCC falls below its reset threshold, RESET2 asserts and remains asserted for the reset timeout period until both VCC and RESET IN2 exceed their respective reset thresholds. The timeout period for RESET2 is either 140ms (fixed) or externally adjustable with a capacitor. RESET2 always deasserts after RESET1 during system power-up and is always asserted before RESET1 during power-down.
For easier logic interfacing, the MAX6391 also includes two internal pullup resistors for both reset outputs. The MAX6392 includes an active-low, manual reset input that asserts both reset outputs.
These devices operate from -40°C to +85°C and are available in an 8-pin SOT23 package. Prices start at $1.50 (2,500-up minimum, FOB USA).
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