Datasheet

Electrical characteristics STM32F303xB STM32F303xC
92/133 DocID023353 Rev 7
Figure 22. I/O AC characteristics definition
6.3.15 NRST pin characteristics
The NRST pin input driver uses CMOS technology. It is connected to a permanent pull-up
resistor, R
PU
(see Table 52).
Unless otherwise specified, the parameters given in Table 55 are derived from tests
performed under ambient temperature and V
DD
supply voltage conditions summarized in
Table 22.
ai14131c
10%
90%
50%
t
r(IO)out
OUTPUT
EXTERNAL
ON 50pF
Maximum frequency is achieved if (t
r
+ t
f
) ≤ 2/3)T and if the duty cycle is (45-55%)
10%
50%
90%
when loaded by 50pF
T
t
f(IO)out
Table 55. NRST pin characteristics
Symbol Parameter Conditions Min Typ Max Unit
V
IL(NRST)
(1)
NRST Input low level voltage - -
0.3V
DD
+
0.07
(1)
V
V
IH(NRST)
(1)
NRST Input high level voltage
0.445V
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 k
V
F(NRST)
(1)
NRST Input filtered pulse - - 100
(1)
ns
V
NF(NRST)
(1)
NRST Input not filtered pulse 500
(1)
--ns
1. Guaranteed by design, 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 must be minimum
(~10% order).