ZSM561

The ZSM561 is a three terminal under vol tage monitor circuit for use in microprocessor systems. The threshold voltage of the device has been set to 4.6 volts making it ideal for 5 volt circuits.

Included in the device is a precise voltage   reference and a comparator with built in  hysteresis to prevent erratic operation. The ZSM561 features an open collector output capable of sinking at least l0mA which only requires a single external resistor to interface to following circuits.

Operation of the device is guaranteed from one volt upwards, from this level to the device threshold voltage the output is held low providing a power on reset function. Should the supply voltage, once established, at any time drop below the threshold level then the output again will pull low. Also included is a 6 volt zener diode connected between Vcc and Gnd. With just the addition of a low cost external NPN transistor and resistor, this zener allows the ZSM561 to provide both regulator and supply monitor functions

The ZSM561 device is available in a TO92 package for through hole applications as well as SO8 and SOT223 for surface mount requirements.