EM2420-STR Ember, EM2420-STR Datasheet - Page 57

• 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: -

The length of the λ/4-monopole antenna is
given by:
where f is in MHz, giving the length in cm.
An antenna for 2450 MHz should be 2.9
cm.
Non-resonant monopole antennas shorter
than λ/4 can also be used, but at the
expense of range. In size and cost critical
applications, such an antenna may be
integrated into the PCB.
Enclosing the antenna in high dielectric
constant material reduces the overall size
of the antenna. Many vendors offer such
antennas intended for PCB mounting.
Ember Part Number: 120-0049-000D
L = 7125 / f
EM2420 Datasheet
Helical antennas can be thought of as a
combination of a monopole and a loop
antenna. They are a good compromise in
size critical applications. Helical antennas
tend to be more difficult to optimize than
the simple monopole.
Loop antennas are easy to integrate into
the PCB, but are less effective due to
difficult impedance matching because of
their very low radiation resistance.
The differential antenna is recommended
for low-power applications. It has the best
range and is simple.
The antenna should be connected as
close as possible to the IC. If the antenna
is located away from the RF pins, the
antenna should be matched to the feeding
transmission line (50 Ω).
EM2420
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