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STM32F405xx, STM32F407xx Electrical characteristics
5.3.23 Embedded reference voltage
The parameters given in Table 72 are derived from tests performed under ambient
temperature and V
DD
supply voltage conditions summarized in Table 14.
5.3.24 DAC electrical characteristics
Table 72. Embedded internal reference voltage
Symbol Parameter Conditions Min Typ Max Unit
V
REFINT
Internal reference voltage –40 °C < T
A
< +105 °C 1.18 1.21 1.24 V
T
S_vrefint
(1)
ADC sampling time when reading the
internal reference voltage
10 - - µs
V
RERINT_s
(2)
Internal reference voltage spread over the
temperature range
V
DD
= 3 V - 3 5 mV
T
Coeff
(2)
Temperature coefficient - 30 50 ppm/°C
t
START
(2)
Startup time - 6 10 µs
1. Shortest sampling time can be determined in the application by multiple iterations.
2. Guaranteed by design, not tested in production.
Table 73. Internal reference voltage calibration values
Symbol Parameter Memory address
V
REFIN_CAL
Raw data acquired at temperature of 30 °C, V
DDA
=3.3 V 0x1FFF 7A2A - 0x1FFF 7A2B
Table 74. DAC characteristics
Symbol Parameter Min Typ Max Unit Comments
V
DDA
Analog supply voltage 1.8
(1)
-3.6 V
V
REF+
Reference supply voltage 1.8
(1)
-3.6VV
REF+
≤ V
DDA
V
SSA
Ground 0 - 0 V
R
LOAD
(2)
Resistive load with buffer
ON
5- - kΩ
R
O
(2)
Impedance output with
buffer OFF
-- 15 kΩ
When the buffer is OFF, the
Minimum resistive load between
DAC_OUT and V
SS
to have a 1%
accuracy is 1.5 MΩ
C
LOAD
(2)
Capacitive load - - 50 pF
Maximum capacitive load at
DAC_OUT pin (when the buffer is
ON).
DAC_OUT
min
(2)
Lower DAC_OUT voltage
with buffer ON
0.2 - - V
It gives the maximum output
excursion of the DAC.
It corresponds to 12-bit input code
(0x0E0) to (0xF1C) at V
REF+
=
3.6 V and (0x1C7) to (0xE38) at
V
REF+
= 1.8 V
DAC_OUT
max
(2)
Higher DAC_OUT voltage
with buffer ON
--V
DDA
– 0.2 V