MAX705

Figures 1-32 and 1-33 show a typical application circuit and pin configurations, respectively, for the MAX705-708. The ICs are similar to that described for Figs. t-J through 1-M, but with generally lower cost. The ICs have a 200-ms reset pulse width, 200-p, A quiescent current, and a 1.25-V threshold detector for power-fail warning, low-battery detection, or for monitoring a power supply other than +5 V.

The MAX705/MAX707 generate a reset pulse when the supply is below 4.65V. The MAX706/708 generate a reset below 4.4V. The MAX707/708 is the same as the MAX705/706, except an active-high reset is substituted for the watchdog timer.

The watchdog is activated when the WDI input has not been toggled within 1.6 s. MAXIM HIGH-RELIABILITY DATA Book, 1993, P. 5-31.

The MAX705-MAX708/MAX813L microprocessor (µP) supervisory circuits reduce the complexity and number of components required to monitor power-supply and battery functions in µP systems.  These devices signifi-cantly improve system reliability and accuracy com-pared to separate ICs or discrete components.

The MAX705/MAX706/MAX813L provide four functions:
1) A reset output during power-up, power-down, and brownout conditions.
2) An independent watchdog output that goes low if the watchdog input has not been toggled within 1.6 seconds.
3) A 1.25V threshold detector for power-fail warning,low-battery detection, or for monitoring a power sup-ply other than +5V.
4) An active-low manual-reset input.

The MAX707/MAX708 are the same as the MAX705/ MAX706, except an active-high reset is substituted for the watchdog timer.  The MAX813L is the same as the MAX705, except RESET is provided instead of RESET.

Two supply-voltage monitor levels are available:  The MAX705/MAX707/MAX813L generate a reset pulse when the supply voltage drops below 4.65V, while the MAX706/MAX708 generate a reset pulse below 4.40V. All four parts are available in 8-pin DIP, SO and µMAX packages.