EM2420-STR Ember, EM2420-STR Datasheet - Page 54

• Manufacturer Part Number: EM2420-STR
• Description: IC RF TXRX ZIGBEE 2.4GHZ 48-QLP
• Manufacturer: Ember

Specifications of EM2420-STR

• Mfg Application Notes: EM2420
• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: 802.15.4
• Applications: ZigBee™
• Power - Output: -3dBm
• Sensitivity: -94dBm
• Voltage - Supply: 2.1 V ~ 3.6 V
• Current - Receiving: 19.7mA
• Current - Transmitting: 17.4mA
• Data Interface: PCB, Surface Mount
• Antenna Connector: PCB, Surface Mount
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-QLP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Memory Size: -

System Considerations and Guidelines
SRD regulations
International regulations and national laws
regulate the use of radio receivers and
transmitters. SRDs (Short Range Devices)
for license free operation are allowed to
operate in the 2.4 GHz band worldwide.
The most important regulations are ETSI
EN 300 328 and EN 300 440 (Europe),
FCC CFR-47 part 15.247 and 15.249
(USA), and ARIB STD-T66 (Japan).
Frequency hopping and multi-channel
systems
The 2.4 GHz band is shared by many
systems both in industrial, office and home
environments. The
sequence spread spectrum (DSSS) as
defined by [1] to spread the output power,
thereby making the communication link
more robust even in a noisy environment.
With the
combine both DSSS and FHSS (frequency
hopping spread spectrum) in a proprietary
non-IEEE
achieved by reprogramming the operating
frequency
Channel Programming section on page
47) before enabling RX or TX. A frequency
synchronization scheme must then be
implemented within the proprietary MAC
layer to make the transmitter and receiver
operate on the same RF channel.
Data burst transmissions
The data buffering in the
user have a lower data rate link between
the microcontroller and the RF device than
the RF bit rate of 250 kbps. This allows
the microcontroller to buffer data at its own
speed, reducing the workload and timing
requirements.
The relatively high data rate of the
also
consumption compared to the 868 / 915
MHz bands defined by [1], where only 20 /
40 kbps are available. The
powered up a smaller portion of the time,
so that the average power consumption is
reduced for a given amount of data to be
transferred.
Ember Part Number: 120-0049-000D
reduces
EM2420
802.15.4
(see
the
the
it is also possible to
EM2420
system.
average
Frequency
EM2420
EM2420
uses direct
This
lets the
may be
EM2420
power
and
EM2420 Datasheet
is
Crystal accuracy and drift
A crystal accuracy of ±40 ppm is required
for compliance with IEEE 802.15.4 [1].
This accuracy must also take aging and
temperature drift into consideration.
A crystal with low temperature drift and
low aging could be used without further
compensation. A trimmer capacitor in the
crystal oscillator circuit (in parallel with C7)
could be used to set the initial frequency
accurately.
For non-IEEE 802.15.4 systems, the
robust demodulator in the
up to 120 ppm total frequency offset
between the transmitter and receiver. As
an example, this could relax the accuracy
requirement to 60 ppm for each of the
devices.
Optionally in a star network topology, the
FFD could be equipped with a more
accurate crystal, thereby relaxing the
requirement on the RFD. This can make
sense in systems where the RFDs ship in
higher volumes than the FFDs.
Communication robustness
The
alternate and co-channel rejection, image
frequency
properties. The
significantly better than the requirements
imposed by [1]. These are highly important
parameters for reliable operation in the 2.4
GHz band, since an increasing number of
devices/systems are using this license-
free frequency band.
Communication security
The
authentication operations in the
enable secure communication, which is
required for many applications. Security
operations
processing, which is costly in a 8-bit
microcontroller system. The hardware
support within the
level of security, even with a low-cost 8 bit
controller.
EM2420
hardware
provides very good adjacent,
suppression
require
EM2420
EM2420
encryption
a
EM2420
performance is
enables a high
and
lot
EM2420
Page 54 of 84
of
blocking
EM2420
allows
data
and