Philips TDA5360 - Manual (Page 31)

1998 July 30
Philips Semiconductors Objective Specification, Revision 2.2
Pre-Amplifier for Hard Disk Drive with
MR-Read / Inductive Write Heads
TDA5360
31
5. The noise figure is defined as :
NF[dB] = 10xlog[(Vnout/Av) 2 / (4kTxR
MR
)]
where Av is the gain and Vnout is the noise voltage at the output of the amplifier
6. See Section 11 for Serial Interface timing diagrams
7. This tWR is defined for a specific load on RDP,RDN reader outputs :
tWR is the time between R/Wn going HIGH and the time when :
90% of the signal envelop is present at RDPch-RDNch
AND the differential DC decaying at RDPch-RDNch is below 10mV :
Changing the load of the preamp will change tWR according to the new RC time constant.
8. When changing MR bias current, from SEN to 90% of I
MR
bias current.
270pF
270pF
330 Ohm R
MR
A
v
RDP
RDN
RDPch
RDNch
10mV
RDPch-RDNch
tWR
R/Wn