Datasheet

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STM32F051x4 STM32F051x6 STM32F051x8 Electrical characteristics
90
Figure 23. I/O AC characteristics definition
6.3.15 NRST pin characteristics
The NRST pin input driver uses the CMOS technology. It is connected to a permanent pull-
up resistor, R
PU
.
Unless otherwise specified, the p
arameters given in the table below are derived from tests
performed under the ambient temperature and supply voltage conditions summarized in
Table 20: General operating conditions.
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Table 51. NRST pin characteristics
Symbol Parameter Conditions Min Typ Max Unit
V
IL(NRST)
NRST input low level voltage - - - 0.3 V
DD
+0.07
(1)
V
V
IH(NRST)
NRST input high level voltage - 0.445 V
DD
+0.398
(1)
--
V
hys(NRST)
NRST Schmitt trigger voltage
hysteresis
--200-mV
R
PU
Weak pull-up equivalent
resistor
(2)
V
IN
= V
SS
25 40 55 kΩ
V
F(NRST)
NRST input filtered pulse - - - 100
(1)
ns
V
NF(NRST)
NRST input not filtered pulse
2.7 < V
DD
< 3.6 300
(3)
--
ns
2.0 < V
DD
< 3.6 500
(3)
--
1. Data based on design simulation only. Not tested in production.
2. The pull-up is designed with a true resistance in series with a switchable PMOS. This PMOS contribution to the series
resistance is minimal (~10% order).
3. Data based on design simulation only. Not tested in production.
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