Datasheet

ATmega48PA/88PA/168PA [DATASHEET]
9223F–AVR–04/14
272
29.5 System and Reset Characteristics
Table 29-5. Power on Reset Specifications
(1)
Parameter Symbol Min. Typ Max Unit
Power-on reset threshold voltage (rising) V
POT
1.4 V
Power-on reset threshold voltage (falling)
(2)
V
POT
0.6 1.3 1.6 V
VCC maximum start voltage to ensure internal
power-on reset signal
Vpormax 0.4 V
VCC Min. start voltage to ensure internal power-on reset signal Vpormin –0.1 V
VCC rise rate to ensure power-on reset V
CCRR
0.01 V/ms
RESET pin threshold voltage V
RST
0.2Vcc 0.9Vcc V
Minimum pulse width on RESET pin t
RST
2.5 µs
Bandgap reference voltage V
BG
1.0 1.1 1.2 V
Bandgap reference start-up time t
BG
40 70 µs
Brown-out detector hysteresis V
HYST
80 mV
Notes: 1. Values are guidelines only.
2. Before rising, the supply has to be between VPORMIN and VPORMAX to ensure a reset.
Table 29-6. BODLEVEL Fuse Coding
(1)
BODLEVEL 2:0 Fuses Min. V
BOT
Typ V
BOT
Max V
BOT
Unit
111 BOD disabled
110 1.6 1.8 2.0
V
101 2.5 2.7 2.9
100 3.9 4.3 4.6
011 2.3
(2)
010 2.2
(2)
000 2.0
(2)
001 1.9
(2)
Notes: 1. V
BOT
may be below nominal minimum operating voltage for some devices. For devices where this is the case, the device
is tested down to V
CC
= V
BOT
during the production test. This guarantees that a brown-out reset will occur before V
CC
drops to a voltage where correct operation of the microcontroller is no longer guaranteed. The test is performed using
BODLEVEL = 110, 101 and 100.
2. Not tested in production