CC2420-RTR1 datasheet(51/92 Pages) TI

51 / 92 page

CC2420

SWRS041B

Page 51 of 89

27 VCO and PLL Self-Calibration

27.1

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).

27.2

PLL self-calibration

The VCO's characteristics will vary with

temperature, changes in supply voltages,

and the desired operating frequency.

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 25 on page 44.

28 Output Power Programming

The RF output power of the device is

programmable and is controlled by the

TXCTRL.PA_LEVEL

shows the output power for different

settings,

including

the

complete

programming of the TXCTRL control

is also shown.

PA_LEVEL

TXCTRL

Output Power [dBm]

Current Consumption [mA]

0xA0FF

17.4

0xA0FB

-1

16.5

0xA0F7

-3

15.2

0xA0F3

-5

13.9

0xA0EF

-7

12.5

0xA0EB

-10

11.2

0xA0E7

-15

9.9

0xA0E3

-25

8.5

Table 9. Output power settings and typical current consumption @ 2.45 GHz

29 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

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

the

voltage

regulator is shown in Figure 28.

The voltage regulator requires external

components

described

the

Application Circuit section on page 19.

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

1.6 V.

CC2420 should then be reset before

the voltage regulator is disabled.

CC2420-RTR1 数据表(PDF) 51 Page - Texas Instruments

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