Datasheet

392
7593L–AVR–09/12
AT90USB64/128
7. As specified on the USB Electrical chapter of USB Specifications 2.0, the D+/D- pads can withstand voltages down to -1V
applied through a 39Ω resistor
8. USB Peripheral consumes up to 50mA from the regulator or UV
CC
pin when USB is used at full-load
31.3 External clock drive waveforms
Figure 31-1. External clock drive waveforms.
31.4 External clock drive
Note: All DC characteristics contained in this datasheet are based on simulation and characterization of
other AVR microcontrollers manufactured in the same process technology. These values are pre-
liminary values representing design targets, and will be updated after characterization of actual
silicon.
31.5 Maximum speed vs. V
CC
Maximum frequency is depending on V
CC.
As shown in Figure 31-2 on page 393, the maximum
frequency vs. V
CC
curve is linear between 2.7V < V
CC
< 5.5V.
V
IL1
V
IH1
Table 31-1. External clock drive.
Symbol Parameter
V
CC
=1.8-5.5V V
CC
=2.7-5.5V V
CC
=4.5-5.5V
UnitsMin. Max. Min. Max. Min. Max.
1/t
CLCL
Oscillator
Frequency
0208016MHz
t
CLCL
Clock Period 500 125 62.5
nst
CHCX
High Time 200 50 25
t
CLCX
Low Time 200 50 25
t
CLCH
Rise Time 2.0 1.6 0.5
μs
t
CHCL
Fall Time 2.0 1.6 0.5
Δt
CLCL
Change in period
from one clock
cycle to the next
22 2%