TC1278 Datasheet, PDF (5/12 Pages) Microchip Technology – 3-Pin Reset Monitors for 5V Systems

3.2 V_CC Transient Rejection
The TC1278/TC1279 provides accurate V_CC monitor-
ing and reset timing during power-up, power-down,
and brownout/sag conditions, and rejects negative-
going transients (glitches) on the power supply line.
Figure 3-5 shows the maximum transient duration vs.
maximum negative excursion (overdrive) for glitch
rejection. Any combination of duration and overdrive
that lays under the curve will not generate a reset
signal. Combinations above the curve are detected as
a brownout or power-down. Transient immunity can be
improved by adding a capacitor in close proximity to the
V_CC pin of the TC1278/TC1279.
TC1278/TC1279
FIGURE 3-5:
V_CC
MAXIMUM TRANSIENT
DURATION VS.
OVERDRIVE FOR GLITCH
REJECTION AT 25°C
V_CCTP
Overdrive
5
T_A
4
Duration
°C
3
2
1
TC1278/9
0
1
5
100
1000
RESET COMPARATOR OVERDRIVE,
[V_CCTP - V_CC] (mV)
© 2002 Microchip Technology Inc.
DS21384B-page 5