Datasheet

STM32F051x Electrical characteristics
Doc ID 022265 Rev 3 73/105
Output driving current
The GPIOs (general purpose input/outputs) can sink or source up to +/-8 mA, and sink or
source up to +/- 20 mA (with a relaxed V
OL/
V
OH
).
In the user application, the number of I/O pins which can drive current must be limited to
respect the absolute maximum rating specified in Section 6.2:
● The sum of the currents sourced by all the I/Os on V
DD,
plus the maximum Run
consumption of the MCU sourced on V
DD,
cannot exceed the absolute maximum rating
I
VDD
(see Ta ble 1 8 ).
● The sum of the currents sunk by all the I/Os on V
SS
plus the maximum Run
consumption of the MCU sunk on V
SS
cannot exceed the absolute maximum rating
I
VSS
(see Ta bl e 1 8 ).
Output voltage levels
Unless otherwise specified, the parameters given in Ta bl e 5 1 are derived from tests
performed under ambient temperature and V
DD
supply voltage conditions summarized in
Table 2 0 . All I/Os are CMOS and TTL compliant (FT, TTa or TC unless otherwise specified).
Table 51. Output voltage characteristics
Symbol Parameter Conditions Min Max Unit
V
OL
(1)
1. The I
IO
current sunk by the device must always respect the absolute maximum rating specified in Table 18
and the sum of I
IO
(I/O ports and control pins) must not exceed I
VSS
.
Output low level voltage for an I/O pin
when 8 pins are sunk at same time
CMOS port
(2)
I
IO
= +8 mA
2.7 V < V
DD
< 3.6 V
2. TTL and CMOS outputs are compatible with JEDEC standards JESD36 and JESD52.
-0.4
V
V
OH
(3)
3. The I
IO
current sourced by the device must always respect the absolute maximum rating specified in
Table 18 and the sum of I
IO
(I/O ports and control pins) must not exceed I
VDD
.
Output high level voltage for an I/O pin
when 8 pins are sourced at same time
V
DD
–0.4 -
V
OL
(1)
Output low level voltage for an I/O pin
when 8 pins are sunk at same time
TTL port
(2)
I
IO
=+ 8mA
2.7 V < V
DD
< 3.6 V
-0.4
V
V
OH
(3)
Output high level voltage for an I/O pin
when 8 pins are sourced at same time
2.4 -
V
OL
(1)(4)
4. Data based on characterization results, not tested in production.
Output low level voltage for an I/O pin
when 5 pins are sunk at same time
I
IO
= +20 mA
2.7 V < V
DD
< 3.6 V
-1.3
V
V
OH
(3)(4)
Output high level voltage for an I/O pin
when 5 pins are sourced at same time
V
DD
–1.3 -
V
OL
(1)(4)
Output low level voltage for an I/O pin
when 8 pins are sunk at same time
I
IO
= +6 mA
2 V < V
DD
< 2.7 V
-0.4
V
V
OH
(3)(4)
Output high level voltage for an I/O pin
when 8 pins are sourced at same time
V
DD
–0.4 -
V
OLFM+
Output low level voltage for an FTf I/O
pin in FM+ mode
I
IO
= +20 mA
2.7 V < V
DD
< 3.6 V
-0.4V