
TLS24308, TLS24310, TLS24318, TLS24320
8- AND 10-CHANNEL MAGNETORESISTIVE/THIN-FILM
READ/WRITE PREAMPLIFIERS
SQHS009 – JANUARY 1996
24
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
PRINCIPLES OF OPERATION
All the normal and fault modes and the possible states are illustrated in Figure 5.
Head Short to GND
Low Frequency
Head Open
No Write Current
WRITE FLT
R/W = L
IBON = L
CS = L
FLT = L
lI(BIAS) = Hi Z
lI(W) = Hi Z
WRITE FLT
R/W = L
IBON = L
CS = L
FLT = L
lI(BIAS) = ON
lI(W) = ON
WRITE FLT
R/W = L
IBON = H
CS = L
FLT = L
lI(BIAS) = Hi Z
lI(W) = ON
WRITE FLT
R/W = L
IBON = H
CS = L
FLT = L
lI(BIAS) = Hi Z
lI(W) = Hi Z
WRITE FLT
R/W = L
IBON = H
CS = L
FLT = L
lI(BIAS) = Hi Z
lI(W) = P.D.
READ FLT
R/W = H
CS = H
FLT = L
lI(BIAS) = Hi Z
lI(W) = P.D.
READ MODE
R/W = H
CS = L
FLT = H
lI(BIAS) = ON
lI(W) = P.D.
WRITE MODE
R/W = L
IBON = H
CS = L
FLT = H
lI(BIAS) = Hi Z
lI(W) = ON
READ FLT
R/W = H
CS = L
FLT = L
lI(BIAS) = ON
lI(W) = P.D.
READ FLT Latch
R/W = H
CS = L
FLT = L
lI(BIAS) = Hi Z
lI(W) = P.D.
IDLE FLT
CS = H
R/W = L
R/W = H
FLT = L
lI(BIAS) = Hi Z
lI(W) = P.D.
IDLE MODE
CS = H
FLT = H
lI(BIAS) = Hi Z
lI(W) = P.D.
R/W = L
R/W = H
WRITE (W/IBON)
R/W = L
IBON = L
CS = L
FLT = H
lI(BIAS) = ON
lI(W) = ON
SERVO WRITE MODE
R/W = L
IBON = H
CS = L
FLT = SE
lI(BIAS) = Hi Z
lI(W) = ON
H/S
H/S
H/S
Low VCC
Low VCC
CS
CS
CS = H
MR Head Short (Metal Option)
MR Head Open
HS Change
R/W
IBON
VCC+ 1.2 V
R/W
Low VCC
Thermal Asperity
(Metal Option)
Low Frequency
No Write Current
15
14
5
4
12
11
10
6
1
7
3
2
8
9
WRITE FLT
R/W = L
IBON = L
CS = L
FLT = L
lI(BIAS) = Hi Z
lI(W) = P.D.
13
Head Short
to GND
Low VCC
Low VCC
P.D. = Pulled down
Figure 5. All-States Diagram (Normal Mode and Fault Mode)