1999 June 10

25

Philips Semiconductors

Preliminary specification

5 V spindle & VCM driver combo

TDA5345HT

Spindle brake after retract sequence :

In case of power down, an emergency procedure is initiated by the PorN signal : the spindle back-EMF is synchronously

rectified to supply the VCM ramp unload function. At the end of the full power step, a spindle short-circuit brake is

activated (SpinMotA, SpinMotB & SpinMotC are together short-circuited to ground). It is supplied by an external reservoir

capacitor connected to pin BrakePower (60).

Shock sensor amplifier:

A complete circuitry is included on-chip to control an external shock sensor.

Figure 14 shows a typical application diagram:

Fig.17 The states for the VCM retract

VCM+

VCM-

BRAKE

SOFT RETRACT

FULL POWER

BRAKE DELAY

SOFT RISING

FCK135