Datasheet

Electrical characteristics STM8AF52/62xx, STM8AF51/61xx
82/110 Doc ID 14395 Rev 9
10.3.11 10-bit ADC characteristics
Subject to general operating conditions for V
DDA
, f
MASTER
and T
A
unless otherwise
specified.
Figure 42. Typical application with ADC
1. Legend: R
AIN
= external resistance, C
AIN
= capacitors, C
samp
= internal sample and hold capacitor.
Table 45. ADC characteristics
Symbol Parameter Conditions Min Typ Max Unit
f
ADC
ADC clock frequency — 111 kHz — 4 MHz kHz/MHz
V
DDA
Analog supply — 3 — 5.5
V
V
REF+
Positive reference voltage — 2.75 — V
DDA
V
REF-
Negative reference voltage — V
SSA
—0.5
V
AIN
Conversion voltage range
(1)
1. During the sample time, the sampling capacitance, C
samp
(3 pF typ), can be charged/discharged by the
external source. The internal resistance of the analog source must allow the capacitance to reach its final
voltage level within t
S.
After the end of the sample time t
S
, changes of the analog input voltage have no
effect on the conversion result.
—V
SSA
—V
DDA
Devices with
external V
REF+
/
V
REF-
pins
V
REF-
—V
REF+
C
samp
Internal sample and hold capacitor — — — 3 pF
t
S
(1)
Sampling time
(3 x 1/f
ADC
)
f
ADC
= 2 MHz — 1.5 —
µs
f
ADC
= 4 MHz — 0.75 —
t
STAB
Wakeup time from standby
f
ADC
= 2 MHz — 7 —
f
ADC
= 4 MHz 3.5
t
CONV
Total conversion time including
sampling time
(14 x 1/f
ADC
)
f
ADC
= 2 MHz — 7 —
f
ADC
= 4 MHz — 3.5 —
R
switch
Equivalent switch resistance — — — 30 kΩ
AINx
STM8A
V
DD
I
L
V
T
0.6V
V
T
0.6V
V
AIN
R
AIN
10-bit A/D
conversion
C
AIN
T
s
C
samp
Rswitch