AM9858

Optical Disc ICs

http://www.amtek-semi.com

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Specifications subject to change without notice

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1) Wiring for RSP

Considering the wiring resistance, connect each detecting resistor as close as possible to

the current detection terminals for the spindle drive RSP (pin 25, 26) of the IC.

2) Reverse-rotation braking

In the case of reverse-rotation braking from high speed rotation, pay good attention to

reverse electromotive force. Furthermore, fully check the voltage to be applied to the output

terminal and consider the revolutions applied to the reverse-rotation brake.

3) Bypass capacitor

Please connect a bypass capacitor (0.1uF) across the supply voltage lines close to the IC

pins.

Supply fault, ground fault, and short-circuit between output terminals.

Do not short-circuit between any output pin and supply pin (supply fault) or ground (ground

fault), or between any output pins (load short-circuit). When mounting the IC on the circuit

board, be extremely cautions about the orientation of the IC. If the orientation is mistaken,

the IC may break down, and produce smoke in some cases.

4) Heat dissipation fins

Heat dissipation fins are attached to the GND on the inside of the package. Make sure to

connect them to the external GND.

5) Brake mode select

This IC has two brake mode, PWM Reverse-rotation braking mode and Short-circuit braking

mode.

It is possible to select brake mode when MU2(pin6) terminal are set “H” or “L”.

In this IC recommendation, Short-circuit braking mode is superior to PWM Reverse-rotation

braking to reducing the power dissipation and to avoid breaking down of this IC.

We suggest to take Short-circuit braking mode over 3000rpm and PWM Reverse-rotation

braking mode below 3000rpm.

6) MU1 H→L setting

Before MU1(pin5) terminal set are from “H” to “L”, please low down pin10(SPIN)

voltage to ensure the spindle motor speed lower than 3000RPM.

7) The capacitor between RSP-GND

The capacitor between RSP-GND absorbs change of steep voltage and current on

account PWM drive, and suppresses disorder of VM voltage. However, if a capacitor

becomes far from IC, the effect will fall under the influence of wiring impedance etc.

Please arrange the capacitor between RSP-GND near the IC.