EM2420 ETC [List of Unclassifed Manufacturers], EM2420 Datasheet - Page 51

• Manufacturer Part Number: EM2420
• Description: 2.4 GHz IEEE 802.15.4 / ZigBee RF Transceiver
• Manufacturer: ETC [List of Unclassifed Manufacturers]

Frequency and Channel Programming
The
programming the 10 bit frequency word
located
operating frequency F
F
In receive mode the actual LO frequency
is F
Direct conversion is used for transmission,
so here the LO frequency equals F
2 MHz IF is automatically set by the
EM2420, so the frequency programming is
equal for RX and TX.
VCO and PLL Self-Calibration
VCO
The VCO is completely integrated and
operates at 4800 – 4966 MHz. The VCO
frequency is divided by 2 to generate
frequencies in the desired band (2400-
2483.5 MHz).
PLL self-calibration
The VCO's characteristics will vary with
temperature, changes in supply voltages,
and the desired operating frequency.
Ember Part Number: 120-0049-000C
C
= 2048 + FSCTRL.FREQ[9:0] MHz
C
– 2 MHz, since a 2 MHz IF is used.
operating
in
FSCTRL.FREQ[9:0].
frequency
C
in MHz is given by:
is
set
C
. The
The
EM2420 Datasheet
by
IEEE 802.15.4 specifies 16 channels
within the 2.4 GHz band, numbered 11
through 26. The RF frequency of channel
k is given by [1]:
F
For
FSCTRL.FREQ register should therefore
be set to:
FSCTRL.FREQ = 357 + 5 (k-11)
In order to ensure reliable operation the
VCO’s bias current and tuning range are
automatically calibrated every time the RX
mode or TX mode is enabled, i.e. in the
RX_CALIBRATE,
TX_ACK_CALIBRATE control states in
Figure 23 on page 43.
C
= 2405 + 5 (k-11) MHz, k=11, 12, ..., 26
operation
in
TX_CALIBRATE and
channel
EM2420
Page 51 of 89
k,
the