ATMEGA406-1AAU Atmel, ATMEGA406-1AAU Datasheet - Page 122

• Manufacturer Part Number: ATMEGA406-1AAU
• Description: IC AVR MCU 40K 1MHZ 48LQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA406-1AAU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 1MHz
• Connectivity: I²C
• Peripherals: POR, WDT
• Number Of I /o: 18
• Program Memory Size: 40KB (20K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 25 V
• Data Converters: A/D 10x12b
• Oscillator Type: Internal
• Operating Temperature: -30°C ~ 85°C
• Package / Case: 48-LQFP
• Processor Series: ATMEGA48x
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: 2-Wire
• Maximum Clock Frequency: 1 MHz
• Number Of Programmable I/os: 18
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVRDRAGON, ATSTK500, ATSTK600, ATAVRISP2, ATAVRONEKIT
• Minimum Operating Temperature: - 30 C
• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 1MHz
• Total Internal Ram Size: 2KB
• # I/os (max): 18
• Number Of Timers - General Purpose: 2
• Operating Supply Voltage (typ): 5/9/12/15/18/24V
• Operating Supply Voltage (max): 25V
• Operating Supply Voltage (min): 4V
• On-chip Adc: 10-chx12-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -30C to 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 48
• Package Type: LQFP
• Controller Family/series: AVR MEGA
• No. Of I/o's: 18
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 2KB
• Cpu Speed: 1MHz
• Rohs Compliant: Yes
• For Use With: 770-1007 - ISP 4PORT ATMEL AVR MCU SPI/JTAG770-1005 - ISP 4PORT FOR ATMEL AVR MCU JTAG770-1004 - ISP 4PORT FOR ATMEL AVR MCU SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

21.2
122
Writing to Bandgap Calibration Registers
ATmega406
Figure 21-1. Reference Circuitry
When the calibration registers are changed it will affect both the Voltage Regulator output and
BOD-level. The BOD will react quickly to new detection levels, while the regulator will adjust the
voltage more slowly, depending on the size of the external decoupling capacitor. To avoid that a
BOD-reset is issued when calibration is done, it is recommended to change the values of the
BGCC and BGCR bits stepwise, with a step size of 1, and with a hold-off time between each
step.
The hold-off time depends on the size of the voltage regulators external decoupling capacitor.
For details, see
Table 21-1.
Regulator Cap
BG Reference
10 µF
1 µF
2 µF
3 µF
4 µF
5 µF
6 µF
7 µF
8 µF
9 µF
Hold-off Times depending on CREG.
Table
21-1.
1.1V
VPTAT
Hold-off Time BGCCR
10.8 µs
12.0 µs
1.2 µs
2.4 µs
3.6 µs
4.8 µs
6.0 µs
7.2 µs
8.4 µs
9.6 µs
VREF_P
VREF_N
0.22V
VREF_GND
VREF
Hold-off Time BGCRR
12.0 µs
15.0 µs
18.0 µs
21.0 µs
24.0 µs
27.0 µs
30.0 µs
3.0 µs
6.0 µs
9.0 µs
CREF
2548E–AVR–07/06