Datasheet

Electrical characteristics STM32F105xx, STM32F107xx
62/108 DocID15274 Rev 10
Figure 22. I/O AC characteristics definition
5.3.14 NRST pin characteristics
The NRST pin input driver uses CMOS technology. It is connected to a permanent pull-up
resistor, R
PU
(see Table 36).
Unless otherwise specified, the parameters given in Table 39 are derived from tests
performed under the ambient temperature and V
DD
supply voltage conditions summarized
in Table 9.
ai14131
t
r(IO)out
50%
90%
T
t
f(IO)out
Maximum frequency is achieved if (t + t ) < (2/3)T and if the duty cycle is (45-55%)
when loaded by 50 pF
r
f
EXTERNAL
OUTPUT
ON 50 pF
10%
50%
90%
10%
Table 39. NRST pin characteristics
Symbol Parameter Conditions Min Typ Max Unit
V
IL(NRST)
(1)
1. Guaranteed by design, not tested in production.
NRST Input low level voltage - –0.5 - 0.8
V
V
IH(NRST)
(1)
NRST Input high level voltage - 2 - V
DD
+0.5
V
hys(NRST)
NRST Schmitt trigger voltage
hysteresis
- - 200 - mV
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 kΩ
V
F(NRST)
(1)
NRST Input filtered pulse - - - 100 ns
V
NF(NRST)
(1)
NRST Input not filtered pulse V
DD
> 2.7 V 300 - - ns
Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.Downloaded from Arrow.com.