- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
14
3.4. Reset Circuit
3.4.1. Outline
This circuit performs system reset to enable stable operation when the CXD3172AR and peripheral ICs start
up after power is supplied.
However, problems may also be caused by a transient power supply. For a reliable way to avoid such
problems, add a circuit that meets the following conditions.
3.4.2. Example Circuit and Timing Chart
The sample reset circuit is shown in "
Example Reset Circuit," and the timing chart is shown in
If the 3.3V voltage supply surges to exceed 2.7V after power is supplied or other events, set the CXD3172AR
XRST terminal to Low (at least 500ns) and be sure to reset it. Additionally, if the 3.3V power supply falls under
2.7V, set the XRST terminal to Low and be sure to reset it.
* The guaranteed voltage for DSP operation is 3.0 to 3.6V. For details refer to the product specifications.
Fig 3.4-1
Example Reset Circuit
CXD3172AR
XRST
RESET SW
100pF
4
VOUT
PST9127N
3
1
5
2
GND
SUB
NC
VCC
RESET IC
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+3.3V