TDA5345HT Datasheet, PDF (31/44 Pages) NXP Semiconductors – 5 V spindle & VCM driver combo

Philips Semiconductors
5 V spindle & VCM driver combo
CLOCK
Programmable ^{500 kHz}
divider
Switch
manager
Vdd5
PumpNeg3V
(35)
3 bits
RegNegClk[2,0]
Band Gap
1.23V
Preliminary specification
TDA5345HT
Neg3V
(36)
Load
Fig.26 -3V switched cap. regulator
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 :
CLOCK
10 MHz
12.5 MHz
15 MHz
16.5 MHz
20 MHz
25 MHz
30 MHz
33 MHz
REGNEGCLK[2:0]
000
001
010
011
100
101
110
111
DIVISION FACTOR
20
22
30
32
40
50
60
66
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.
1999 June 10
31