Philips TDA5360 - Manual (Page 14)

1998 July 30
Philips Semiconductors Objective Specification, Revision 2.2
Pre-Amplifier for Hard Disk Drive with
MR-Read / Inductive Write Heads
TDA5360
14
The following are valid READ fault conditions which set FLT=LOW
•
Rext pin open or shorted to GND or Vcc
•
Thermal Asperity detected
•
Read Head open
• Power supplies too low (VCC and/or VEE)
•
Write current present in read mode
•
Illegal head address ( i.e. head 12, 13, 14 or 15)
In this case, besides asserting the fault flag, the MR bias current is diverted to the dummy head.
The following are valid WRITE fault conditions which set FLT=HIGH. An action can eventually be taken :
FAULT ACTION
•
No write current in write mode Disable write current
• Rext pin open or shorted to GND or Vcc Disable write current
•
Open write head or shorted to GND Do not disable write current
•
Write data frequency too low Do not disable write current
• Power supplies too low Disable write current
• lllegal head address (i.e. HD 12, 13, 14, 15) Disable write current
If the write current is disabled, the writer is powered down. The only way to restart a write sequence is to switch R/W
high and then to switch R/W low again.
Trying to go in Write mode from a sleep or standby mode condition will disable the write current.
If two fault conditions occurs nearly at the same time, the first to occur will be loaded in Reg. 07.