PCA2000USLASHAB datasheet(13/28 Pages) NXP

13 / 28 page

PCA2000_2001_5

Product data sheet

Rev. 05 — 11 November 2008

13 of 28

NXP Semiconductors

PCA2000; PCA2001

32 kHz watch circuit with programmable adaptive motor pulse

7.10 Frequency tuning of assembled watch

Figure 9 shows the test set-up for frequency tuning the assembled watch.

7.11 Measurement of oscillator frequency and inhibition time

The output of the two measuring states can either be monitored directly at pad RESET or

as a modulation of the supply voltage (a modulating resistor of 30 k

Ω is connected

between VDD and VSS when the signal at pad RESET is at HIGH-level).

The supply voltage modulation must be followed as shown in Figure 10 in order to

guarantee the correct start-up of the circuit during production and testing.

Measuring states:

• State 1: quartz crystal oscillator frequency divided by 1024; state 1 starts with a pulse

to Vp and ends with a second pulse to Vp

Fig 9.

Frequency tuning at assembled watch

mgw568

FREQUENCY

COUNTER

PROGRAMMABLE

DC POWER SUPPLY

PC INTERFACE

motor

32 kHz

PCA200x

battery

Fig 10. Supply voltage at start-up during production and testing

VDD

VP(prog)(stop)

td(start) > 500 ms

VSS

VDD(nom)

001aac503

tp(stop)

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