AX8052F143

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9

Table 6. LOGIC

Symbol

Description

Condition

Min

Typ

Max

Units

Digital Inputs

Schmitt trigger low to high threshold point

VDD_IO = 3.3 V

1.55

V

Schmitt trigger high to low threshold point

1.25

V

Input voltage, low

0.8

V

Input voltage, high

2.0

V

Input voltage range, Port A

−0.5

VDD_IO

V

Input voltage range, Ports B, C

−0.5

5.5

V

Input leakage current

−10

10

mA

Programmable Pull−Up Resistance

65

kW

Digital Outputs

Output Current, high

Ports PA, PB and PC

8

mA

Output Current, low

Ports PA, PB and PC

8

mA

Output Current, high

Pin SYSCLK

4

mA

Output Current, low

Pin SYSCLK

4

mA

Tri−state output leakage current

−10

10

mA

AC Characteristics

Table 7. CRYSTAL OSCILLATOR (RF REFERENCE OSCILLATOR)

Symbol

Description

Condition

Min

Typ

Max

Units

Crystal or frequency

Note 1, 2, 3

10

16

50

MHz

Oscillator transconductance range

Self−regulated see note 4

0.2

20

mS

Programmable tuning capacitors at pins

CLK16N and CLK16P

AX5043_XTALCAP = 0x00

default

3

pF

AX5043_XTALCAP = 0x01

8.5

pF

AX5043_XTALCAP = 0xFF

40

pF

Programmable tuning capacitors,

increment per LSB of AX5043_XTALCAP

AX5043_XTALCAP = 0x01

– 0xFF

0.5

pF

External clock input (TCXO)

Note 2, 3, 5

10

16

50

MHz

Input DC impedance

10

kW

1. Tolerances and start−up times depend on the crystal used. Depending on the RF frequency and channel spacing the IC must be calibrated

to the exact crystal frequency using the readings of the register AX5043_TRKFREQ.

2. The choice of crystal oscillator or TCXO frequency depends on the targeted regulatory regime for TX, see separate documentation on

meeting regulatory requirements.

3. To avoid spurious emission, the crystal or TCXO reference frequency should be chosen so that the RF carrier frequency is not an integer

multiple of the crystal or TCXO frequency.

4. The oscillator transconductance is regulated for fastest start−up time during start−up and for lowest power curing steady state oscillation.

This means that values depend on the crystal used.

5. If an external clock or TCXO is used, it should be input via an AC coupling at pin CLK16P with the oscillator powered up and

AX5043_XTALCAP = 000000. For detailed TCXO network recommendations depending on the TCXO output swing refer to the AX5043

Application Note: Use with a TCXO Reference Clock.