83CXXX

Preliminary

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

5 of 6

www.unisonic.com.tw

QW-R502-353.a

APPLICATION INFORMATION

circuit. Therefore, high-impedance CMOS logic input connected to RESET can drift to undetermined voltages. This

is under 1V. In figure 1, however, in applications where RESET must be valid down to 0V. In order to causes any

stray leakage currents to flow to ground, adding a pull-down resistor to RESET , that holding RESET low. (R1’s

value is not critical and the value 100kΩ is large enough not to load RESET and small enough to pull RESET to

ground).

2. Benefits of Highly Accurate Reset Threshold

Most microprocessor supervisor ICs has reset threshold voltages between 5% and 10% below the value of

nominal supply voltages. If using ICs rated at only the nominal supply ±5%, this leaves an uncertainty zone where

the supply is between 5% and 10% low and where the reset may or may not be asserted.

The UTC 83C308 with high accuracy ensure that the reset is asserted closely to 5% limit and long before the

supply has declined to 10% below nominal.