STM32F103xx
Electrical characteristics
47/67
Figure 16.
I/O AC characteristics definition
5.3.13 NRST
pin
characteristics
The NRST pin input driver uses CMOS technology. It is connected to a permanent pull-up
resistor, R
PU
(see
Unless otherwise specified, the parameters given in
are derived from tests
performed under ambient temperature and V
DD
supply voltage conditions summarized in
ai14131
10%
90%
50%
tr(IO)out
OUTPUT
EXT ERNAL
ON 50pF
Maximum fr equency is achieved if (tr + tf)
£
2/3) T and if the duty cycle is (45-55%)
10%
50%
90%
when loaded by 50pF
T
tr(IO)out
Table 32.
NRST pin characteristics
(1)
1.
TBD stands for to be determined.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
V
IL(NRST)
NRST Input low level voltage
–0.5
0.8
V
V
IH(NRST)
NRST Input high level voltage
2
V
DD
+0.5
V
hys(NRST)
NRST Schmitt trigger voltage
hysteresis
200
R
PU
Weak pull-up equivalent resistor
(2)
2.
The pull-up is designed with a true resistance in series with a switchable PMOS. This PMOS contribution
to the series resistance must be minimum
(~10% order)
.
V
IN
=
V
SS
30
40
50
k
Ω
V
F(NRST)
NRST Input filtered pulse
(3)
3.
Values guaranteed by design, not tested in production.
100
ns
V
NF(NRST)
NRST Input not filtered pulse
(3)
300
µs