ATMEGA128RFA1-ZU Atmel, ATMEGA128RFA1-ZU Datasheet - Page 81

• Manufacturer Part Number: ATMEGA128RFA1-ZU
• Description: IC AVR MCU 2.4GHZ XCEIVER 64QFN
• Manufacturer: Atmel
• Series: ATMEGAr

Specifications of ATMEGA128RFA1-ZU

• Frequency: 2.4GHz
• Data Rate - Maximum: 2Mbps
• Modulation Or Protocol: 802.15.4 Zigbee
• Applications: General Purpose
• Power - Output: 3.5dBm
• Sensitivity: -100dBm
• Voltage - Supply: 1.8 V ~ 3.6 V
• Current - Receiving: 12.5mA
• Current - Transmitting: 14.5mA
• Data Interface: PCB, Surface Mount
• Memory Size: 128kB Flash, 4kB EEPROM, 16kB RAM
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VFQFN, Exposed Pad
• Rf Ic Case Style: QFN
• No. Of Pins: 64
• Supply Voltage Range: 1.8V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Svhc: No SVHC (15-Dec-2010)
• Rohs Compliant: Yes
• Processor Series: ATMEGA128x
• Core: AVR8
• Data Bus Width: 8 bit
• Program Memory Type: Flash
• Program Memory Size: 128 KB
• Data Ram Size: 16 KB
• Interface Type: JTAG
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 38
• Number Of Timers: 6
• Operating Supply Voltage: 1.8 V to 3.6 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWAVR, EWAVR-BL
• Development Tools By Supplier: ATAVR128RFA1-EK1
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

9.6.5.3 External Reference Frequency Setup
8266A-MCU Wireless-12/09
The following figure shows all parasitic capacitances, such as PCB stray capacitances
and the pin input capacitance summarized to C
Figure 9-25. Simplified XOSC Schematic with External Components
Additional internal trimming capacitors C
0 pF to 4.5 pF with a 0.3 pF resolution is selectable using XTAL_TRIM of register
XOSC_CTRL. To calculate the total load capacitance, the following formula can be
used
The trimming capacitors provide the possibility to reduce frequency deviations caused
by variations of the production process or by tolerances of external components. Note
that the oscillation frequency can only be reduced by increasing the trimming
capacitance. The frequency deviation caused by one step of C
increasing values of the crystal load capacitor.
An amplitude control circuit is included to ensure stable operation under different
operating conditions and for different crystal types. Enabling the crystal oscillator after
leaving SLEEP state causes a slightly higher current during the amplitude build-up
phase to guarantee a short start-up time. The current is reduced to the amount
necessary for a robust oscillation during stable operation. This also keeps the drive
level of the crystal low.
Crystals with a higher load capacitance are generally less sensitive to parasitic pulling
effects caused by variations of external components or board and circuit parasitics. On
the other hand a larger crystal load capacitance results in a longer start-up time and a
higher steady state current consumption.
When using an external reference frequency, the signal must be connected to
pin XTAL1 as indicated in
XOSC_CTRL need to be set to the external oscillator mode. The oscillation peak-to-
peak amplitude shall between 100 mV and 500 mV, the optimum range is between
400 mV and 500 mV. Pin XTAL2 should not be wired
EVDD
XTAL_TRIM[3:0]
V
C
EVDD
L
= 0.5 • (CX + C
C
TRIM
XTAL1
C
PAR
TRIM
Figure 9-26 on
CX
EVDD
+ C
16MHz
PAR
).
TRIM
page 82 and the bits XTAL_MODE of register
are available. Any value in the range from
XTAL2
CX
XTAL_TRIM[3:0]
PAR
.
C
IC internal
ATmega128RFA1
TRIM
C
PAR
PCB
TRIM
decreases with
81