1037
SAM4CP [DATASHEET]
43051E–ATPL–08/14
45.5.15 Programmable Voltage Reference Characteristics
SAM4CP embeds a programmable voltage reference designed to drive the 10-bit ADC ADVREF input.
Table 45-39
shows the electrical characteristics of this internal voltage reference. In case of need, this voltage reference can be
bypassed with some level of configurability: the user can either choose to feed the ADVREF input with an external
voltage source or with the VDDIO internal power rail. See programming details in the ADC Analog Control Register
(ADC_ACR) in the ADC Controller section.
Notes: 1.
T
C
= (max (V
ADVREF
) - min (V
ADVREF
)) / ((T
MAX
- T
MIN
) * V
ADVREF
(25oC)).
Does not include the current consumed by the ADC′s ADVREF input if ADC is ON.
2.
Notes: 1.
Voltage Reference values are configurable in the ADC_ACR register (the IRVS field).
Table 45-39. Programmable Voltage Reference Characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
V
VDDIN
Voltage Reference Supply Range
—
2.5
—
3.6
V
V
ADVREF
Programmable Output Range
See
Table 45-40
V
VDDIN
> V
ADVREF
+ 100mV
1.6
—
3.4
V
ACC
Reference Voltage Accuracy
With respect to the programmed value
V
VDDIN
= 3.3V; T
J
= 25oC
Box method
(1)
-3
—
3
%
T
C
Temperature coefficient
—
—
250
ppm/oC
t
ON
Startup Time
V
VDDIN
= 2.5V
V
VDDIN
= 3.0V
V
VDDIN
= 3.6V
—
—
100
70
40
μ
s
Z
LOAD
Load Impedance
Resistive
4
—
—
k
Ω
Capacitive
0.1
—
1
μ
F
I
VDDIN
Current Consumption on VDDIN
(2)
ADC is OFF
—
20
30
μ
A
Table 45-40. Programmable Voltage Reference Selection values
Sel. Value
(1)
ADVREF
Notes
0
2.40
Default value
1
2.28
—
2
2.16
—
3
2.04
—
4
1.92
—
5
1.80
—
6
1.68
—
7
1.55
Min value
8
3.38
Max value
9
3.25
—
A
3.13
—
B
3.01
—
C
2.89
—
D
2.77
—
E
2.65
—
F
2.53
—