CC2420 Datasheet, PDF (50/87 Pages) List of Unclassifed Manufacturers – 2.4 GHz IEEE 802.15.4 / ZigBee-ready RF Transceiver

SmartRF ^® CC2420
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.
Output Power Programming
The RF output power of the device is
programmable and is controlled by the
TXCTRL.PA_LEVEL register. Table 9
shows the output power for different
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_CALIBRATE and
TX_ACK_CALIBRATE control states in
Figure 24 on page 43.
settings, including the complete
programming of the TXCTRL control
register. The typical current consumption
is also shown.
PA_LEVEL
TXCTRL register
Output Power [dBm]
Current Consumption [mA]
31
0xA0FF
0
17.4
27
0xA0FB
-1
16.5
23
0xA0F7
-3
15.2
19
0xA0F3
-5
13.9
15
0xA0EF
-7
12.5
11
0xA0EB
-10
11.2
7
0xA0E7
-15
9.9
3
0xA0E3
-25
8.5
Table 9. Output power settings and typical current consumption @ 2.45 GHz
Voltage Regulator
CC2420 includes a low drop-out voltage
regulator. This is used to provide a 1.8 V
power supply to the CC2420 power
supplies. The voltage regulator should not
be used to provide power to other circuits
because of limited power sourcing
capability and noise considerations.
The voltage regulator input pin VREG_IN
is connected to the unregulated 2.1 to 3.6
V power supply. The voltage regulator is
enabled / disabled using the active high
voltage regulator enable pin VREG_EN.
The regulated 1.8 V voltage output is
available on the VREG_OUT pin. A
simplified schematic of the voltage
regulator is shown in Figure 27.
The voltage regulator requires external
components as described in the
Application Circuit section on page 18.
When disabling the voltage regulator, note
that register and RAM programming will
be lost as leakage current reduces the
output voltage on the VREG_OUT pin below
Chipcon AS SmartRF^® CC2420 Preliminary Datasheet (rev 1.2), 2004-06-09
Page 50 of 87