FEATURES

Fully Programmable Reset Threshold

Fully Programmable Reset Period

Fully Programmable Watchdog Period

2% Accurate Reset Threshold

Input Voltage Down to 2 V

Input 18-μA Maximum Input Current

Reset Valid Down to 1 V

DESCRIPTION

The UCCx946 is designed to provide accurate

microprocessor supervision, including reset and

watchdog functions. During power up, the device

asserts a reset signal RES with VDD as low as 1 V.

The reset signal remains asserted until the VDD

voltage rises and remains above the reset

threshold for the reset period. Both reset threshold

and reset period are programmable by the user.

The UCCx946 is also resistant to glitches on the

VDD line. Once RES has been deasserted, any

drops below the threshold voltage need to be of

certain time duration and voltage magnitude to

generate a reset signal. These values are shown

in Figure 1. An I/O line of the microprocessor may

be tied to the watchdog input (WDI) for watchdog

functions. If the I/O line is not toggled within a set

watchdog period, programmable by the user,

WDO is asserted. The watchdog function is

disabled during reset conditions.

The UCCx946 is available in 8-pin SOIC(D), 8-pin

PDIP (N) and 8-pin TSSOP(PW) packages to

optimize board space.