ATMEGA8U2_14 Datasheet, PDF (266/310 Pages) ATMEL Corporation – 125 Powerful Instructions – Most Single Clock Cycle Execution

ATmega8U2/16U2/32U2
5. All DC Characteristics contained in this datasheet are based on simulation and characterization of other AVR microcon-
trollers manufactured in the same process technology. These values are preliminary values representing design targets, and
will be updated after characterization of actual silicon
6. Values with “PRR1 – Power Reduction Register 1” disabled (0x00).
7. As specified in the USB Electrical chapter, the D+/D- pads can withstand voltages down to -1V applied through a 39 resis-
tor (in series with the external 39 resistor).
8. All IOs Except XTAL1 and Reset pins
26.3 Speed Grades
Maximum frequency is depending on V_CC. As shown in Figure 26-1, the Maximum Frequency vs.
V_CC curve is linear between 2.7V < V_CC < 4.5V.
Figure 26-1. Maximum Frequency vs. V_CC, ATmega8U2/16U2/32U2
16 MHz
8 MHz
Safe Operating Area
2.7V
4.5V
5.5V
26.4 Clock Characteristics
26.4.1 Calibrated Internal RC Oscillator Accuracy
Table 26-1. Calibration Accuracy of Internal RC Oscillator
Factory
Calibration
Frequency
V_CC
8.0 MHz
3V
User
Calibration
7.3 - 8.1 MHz
2.7V - 5.5V
26.4.2 External Clock Drive Waveforms
Figure 26-2. External Clock Drive Waveforms
Temperature
25C
-40C - 85C
Calibration Accuracy
±10%
±1%
V_IH1
V_IL1
7799D–AVR–11/10
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