HA12220F Datasheet, PDF (6/20 Pages) Hitachi Semiconductor – CD-ROM Drive Head Amplifier IC

HA12220F
Operation
Control by Serial Data
The IC’s internal switches can be operated by sending control data from the HD49250.
The signal timing is shown in figure 1, and the control commands are listed in table 1 and 2.
Pin 15 DATA
Pin 14 CLK
Pin 16 XLT
0123456 7
T1
T2
T3
T4
Item
Symbol Min Typ
Clock frequency f_CLK
—
—
Clock pulse width T1, T2 0.96 —
Delay time
T3
1
—
Latch pulse width T4
2
—
Max Unit
520 kHz
— µs
—
µs
— µs
Figure 1 Timing Diagram for Serial Data Control
Signals from the HD49250 are input at pins 14 to 16. Pin13 is connected to the microcomputer.
A low input at the XRST pin resets the IC. Normally this pin should be kept high.
The serial data from the HD49250 switches the following settings.
1. Tracking error EF balance
2. Focus offset
3. Tracking gain, Focus gain
4. FOK Vth
5. Mirror circuit, defect circuit normal speed / 4× speed / 8× speed mode
6. Tracking error cut-off frequency
7. APC amplifier ON/OFF
8. RF equalizer
9. Stand-by mode (cleared by setting XRST on)
Rev.1, Apr. 1997, page 6 of 20