1999 June 10

31

Philips Semiconductors

Preliminary specification

5 V spindle & VCM driver combo

TDA5345HT

Depending on the external CLOCK value, the programmable CLOCK divider has to be programmed according to the

following table :

Table 17 Division factor to program in order to get 500 kHz for the -3 V switched cap. regulator :

Adjustable bandgap :

An internal regulated voltage source (called BandGap) delivers a very accurate voltage to many different circuitry inside

the IC. This voltage (1.23 V) is almost independant of power supply, temperature and process spread. However, there

is still a +/- 3% spread on this voltage. To come to about +/- 0.5%, it is possible to adjust this voltage from an external

micro controller with a very accurate voltage source and an ADC. The following table gives the voltage added or

substracted to the BandGap voltage according to the code written in register 2, bit 4 to 6.

CLOCK

REGNEGCLK[2:0]

DIVISION FACTOR

10 MHz

000

20

12.5 MHz

001

22

15 MHz

010

30

16.5 MHz

011

32

20 MHz

100

40

25 MHz

101

50

30 MHz

110

60

33 MHz

111

66

Fig.26 -3V switched cap. regulator

Vdd5

Load

Switch

Band Gap

1.23V

manager

500 kHz

Programmable

divider

CLOCK

RegNegClk[2,0]

3 bits

Neg3V

PumpNeg3V

(35)

(36)