stm1001t STMicroelectronics, stm1001t Datasheet - Page 4

• Manufacturer Part Number: stm1001t
• Description: Reset Circuit
• Manufacturer: STMicroelectronics

STM1001
OPERATION
Reset Output
The STM1001 MICROPROCESSOR RESET
CIRCUIT asserts a reset signal to the MCU when-
ever V
RST is guaranteed valid down to V
70°C).
During power-up, once V
threshold an internal timer keeps RST low for the
reset time-out period, t
returns high.
If V
low. Each time RST is asserted, it stays low for at
least the reset time-out period. Any time V
below the reset threshold, the internal timer clears.
The reset timer starts when V
reset threshold. The active-low reset (RST) is an
open drain output.
4/14
CC
CC
drops below the reset threshold, RST goes
goes below the reset threshold (V
rec
. After this interval, RST
CC
CC
exceeds the reset
returns above the
CC
= 1V (0° to
CC
RST
goes
).
Negative-Going V
The STM1001 is relatively immune to negative-go-
ing V
shows typical transient duration versus reset com-
parator overdrive (for which the STM1001 will
NOT generate a reset pulse). The graph was gen-
erated using a negative pulse applied to V
starting at 0.5V above the actual reset threshold
and ending below it by the magnitude indicated
(comparator overdrive). The graph indicates the
maximum pulse width a negative V
can have without causing a reset pulse. As the
magnitude of the transient increases (further be-
low the threshold), the maximum allowable pulse
width decreases. Any combination of duration and
overdrive which lies under the curve will NOT gen-
erate a reset signal. Typically, a V
goes 100mV below the reset threshold and lasts
20µs or less will not cause a reset pulse. A 0.1µF
bypass capacitor mounted as close as possible to
the V
CC
CC
pin provides additional transient immunity.
transients (glitches).
CC
Transients
Figure 11., page 7
CC
transient that
CC
transient
CC
,