Datasheet

916
32142D–06/2013
ATUC64/128/256L3/4U
35.9.6 Analog to Digital Converter Characteristics
Note: These values are based on simulation and characterization of other AVR microcontrollers manufactured in the same process
technology. These values are not covered by test limits in production.
35.9.6.1 Inputs and Sample and Hold Acquisition Times
Note: 1. These values are based on simulation and characterization of other AVR microcontrollers manufactured in the same pro-
cess technology. These values are not covered by test limits in production.
The analog voltage source must be able to charge the sample and hold (S/H) capacitor in the
ADC in order to achieve maximum accuracy. Seen externally the ADC input consists of a resis-
tor ( ) and a capacitor ( ). In addition, the resistance ( ) and capacitance
Table 35-29. ADC Characteristics
Symbol Parameter Conditions Min Typ Max Units
f
ADC
ADC clock frequency
12-bit resolution mode 6
MHz10-bit resolution mode 6
8-bit resolution mode 6
t
STARTUP
Startup time Return from Idle Mode 15 µs
t
CONV
Conversion time (latency) f
ADC
= 6MHz 11 26 cycles
Throughput rate
V
VDD
> 3.0V, f
ADC
= 6MHz,
12-bit resolution mode,
low impedance source
28
kSPS
V
VDD
> 3.0V, f
ADC
= 6MHz,
10-bit resolution mode,
low impedance source
460
V
VDD
> 3.0V, f
ADC
= 6MHz,
8-bit resolution mode,
low impedance source
460
V
ADVREFP
Reference voltage range V
ADVREFP
= V
VDDANA
1.62 1.98 V
I
ADC
Current consumption on V
VDDANA
ADC Clock = 6MHz 350
µA
I
ADVREFP
Current consumption on ADVREFP
pin
f
ADC
= 6MHz 150
Table 35-30. Analog Inputs
Symbol Parameter Conditions Min Typ Max Units
V
ADn
Input Voltage Range
12-bit mode
0V
ADVREFP
V10-bit mode
8-bit mode
C
ONCHIP
Internal Capacitance
(1)
22.5 pF
R
ONCHIP
Internal Resistance
(1)
V
VDDIO
= 3.0V to 3.6V,
V
VDDCORE
= 1.8V
3.15
kOhm
V
VDDIO
= V
VDDCORE
= 1.62V to 1.98V 55.9
R
ONCHIP
C
ONCHIP
R
SOURCE