STLC2150

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Crystal oscillator

An on-chip crystal oscillator provides a 13MHz master clock. The external crystal must be connected to the pads

XTAL13I and XTAL13O.

The frequency specification of ±20 ppm can be achieved by 2 different ways:

1.

by external components choice (default);

2.

by internal tuning (with internal capacitors as defined by the control word stored in the registers.

The control word allows modifying the value of the capacitor connected to the oscillator pads. The total capac-

itance (including the parasitic capacitors) must be about 16 pF.

The variable capacitor is implemented as a capacitor array of about 255 x 90 fF.

External crystal example

Low power clock

The STLC2150 can provide 3.2 or 32 KHz, low power clock for baseband chip operation in Hold, Snif and Park

modes.

External reference frequency

The STLC2150 can take a digital clock from external source 13 MHz on the CLK13MHZ pin.

The IC also can use an analogue (sine wave, from 0.2 up to 1 Vpp) clock from external 13 MHz source on the

XTAL13I pin.

Registers description

To provide operational control, configuration flexibility (e.g. clock configuration, XTAL trimming) and to set max-

imum performance the STLC2150 has a bank of registers. Detailed description is available in “STLC2150: In-

terface and Programming Guide”.

Parameter

Value

Unit

tolerance

Comment

Frequency

13.000000

MHz

± 10 ppm

At 25 °C ± 3 °C

Mode

Fundamental

Drive level

100

µW± 20

Temp drift

±10

ppm

Referred to value at 25°C over temperature

Aging

±1

Ppm/year

max

Cload

16.0

pF

± 1 %

Rseries

40

Ω

max

C0

1.7

pF

± 20 %

Shunt capacitance

C1

6.5

pF

± 24 %

Motional capacitance

Rins

500

M

Ω

min

Insulation resistance

Pull_sens

10

Ppm

± 20 %

(16 pF)

Activity Dips

± 0.5

Ppm / °C

max