SH3000EK SEMTECH [Semtech Corporation], SH3000EK Datasheet - Page 6

• Manufacturer Part Number: SH3000EK
• Description: Reset Management and Clock Management Support IC for Microcontrollers
• Manufacturer: SEMTECH [Semtech Corporation]

the reset interval, when V
some time, energy savings are realized and the startup
of the whole system is made easier. The commonly
used reset approach forces the processor to turn the
oscillator on and to run at full speed (thus consuming full
power) during the critical time when the (possibly
depleted) battery is trying to raise V
level. In contrast, the SH3002 allows the power source
to charge the bypass capacitors and raise the level of
V
stabilized is the target micro permitted to start expending
energy.
continues to provide the clock to the target processor,
but at a reduced frequency between 500 kHz and
1.0 MHz. After a delay of 2 ms this clock is stopped,
automatically lowering the energy consumption of the
whole system, see Figure 2.
activations from noise and small power glitches on the
V
V
durations of the negative-going spikes.
to activate within 5 µs from the time V
Copyright ©2002-2005 Semtech Corporation
SYSTEM MANAGEMENT
DD
DD
DD
Since the clock is only active for the last 1 or 2 ms of
When a brownout event occurs, the SH3002
A Noise Filter (see Figure 1) prevents reset
When V
with little additional load. Only when power has
line. A typical behavior is shown in Figure 3 for the
level just above V
DD
is falling, both reset lines are guaranteed
BO
DD
and various amplitudes and
has already been valid for
DD
BO
to an acceptable
is crossed over.
6
V
RST
N
CLK
RST
Figure 2. Operations of low V
DD
OUT
V
Figure 3. Response to negative voltage spikes
BO
1V
10
5
0
V
0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5
BO
+ V
Undefined
HYST
Normal
F
1 ms
Guaranteed NO reset
OUT
3-5ms
SH3002 MicroBuddy™
Am plitude, V
V1.20
DD
2 ms
Reduced F
Guaranteed reset
0.5-1.0 MHz
12ms minimum
/ Brownout Detector
Duration
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OUT
2 ms
6ms