Information

Electrical characteristics STM32F405xx, STM32F407xx
130/185 DocID022152 Rev 4
Equation 1: R
AIN
max formula
The formula above (Equation 1) is used to determine the maximum external impedance
allowed for an error below 1/4 of LSB. N = 12 (from 12-bit resolution) and k is the number of
sampling periods defined in the ADC_SMPR1 register.
t
CONV
(4)
Total conversion time (including
sampling time)
f
ADC
= 30 MHz
12-bit resolution
0.50 - 16.40 µs
f
ADC
= 30 MHz
10-bit resolution
0.43 - 16.34 µs
f
ADC
= 30 MHz
8-bit resolution
0.37 - 16.27 µs
f
ADC
= 30 MHz
6-bit resolution
0.30 - 16.20 µs
9 to 492 (t
S
for sampling +n-bit resolution for successive
approximation)
1/f
ADC
f
S
(4)
Sampling rate
(f
ADC
= 30 MHz, and
t
S
= 3 ADC cycles)
12-bit resolution
Single ADC
- - 2 Msps
12-bit resolution
Interleave Dual ADC
mode
- - 3.75 Msps
12-bit resolution
Interleave Triple ADC
mode
- - 6 Msps
I
VREF+
(4)
ADC V
REF
DC current
consumption in conversion
mode
-300500µA
I
VDDA
(4)
ADC V
DDA
DC current
consumption in conversion
mode
-1.61.8mA
1. V
DD
/V
DDA
minimum value of 1.7 V is obtained when the device operates in reduced temperature range, and with the use of
an external power supply supervisor (refer to Section : Internal reset OFF).
2. It is recommended to maintain the voltage difference between V
REF+
and V
DDA
below 1.8 V.
3. V
DDA
-V
REF+
< 1.2 V.
4. Based on characterization, not tested in production.
5. V
REF+
is internally connected to V
DDA
and V
REF-
is internally connected to V
SSA
.
6. R
ADC
maximum value is given for V
DD
=1.8 V, and minimum value for V
DD
=3.3 V.
7. For external triggers, a delay of 1/f
PCLK2
must be added to the latency specified in Table 67.
Table 67. ADC characteristics (continued)
Symbol Parameter Conditions Min Typ Max Unit
R
AIN
k0.5–()
f
ADC
C
ADC
2
N 2+
()ln××
-------------------------------------------------------------- R
ADC
–=