Electrical characteristics
STM32F105xx, STM32F107xx
Figure 17. I/O AC characteristics definition
90%
10 %
50%
50%
90%
10%
t
EXTERNAL
OUTPUT
ON 50pF
t
r(IO)out
r(IO)out
T
Maximum frequency is achieved if (t + t ) ~"2/3)T and if the duty cycle is (45-55%)"
r
f
when loaded by 50pF
ai14131
5.3.13
NRST pin characteristics
The NRST pin input driver uses CMOS technology. It is connected to a permanent pull-up
resistor, R (see Table 35).
PU
Unless otherwise specified, the parameters given in Table 38 are derived from tests
performed under the ambient temperature and V supply voltage conditions summarized
in Table 9.
DD
Table 38. NRST pin characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
(1)
VIL(NRST)
NRST Input low level voltage
NRST Input high level voltage
–0.5
2
0.8
V
(1)
VIH(NRST)
Vhys(NRST)
RPU
VDD+0.5
NRST Schmitt trigger voltage
hysteresis
200
40
mV
Weak pull-up equivalent resistor(2)
NRST Input filtered pulse
VIN ?"VSS
30
50
kY
ns
ns
(1)
VF(NRST)
100
(1)
VNF(NRST)
NRST Input not filtered pulse
VDD > 2.7 V
300
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).
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STMICROELECTRONICS [ ST ]
