cxa1720q Sony Electronics, cxa1720q Datasheet - Page 15

• Manufacturer Part Number: cxa1720q
• Description: Read/write Amplifier With Built-in Filters For Fdds
• Manufacturer: Sony Electronics

(2) Write System
Furthermore, the Write current compensation I
26, and between Pin 27 and Pin 28.
(3) Erase System
(4) Power ON/OFF Detection System
Notes on Operation
Comparator
Time domain filter
Write data input through Pin 2 is frequency-divided by the T flip-flop and generates the head recording
current. The recording current can be switched by the setting of Pin 9.
The Write current Iw is set by the resistor R
V
Pins 30 and 31 are open collector outputs; the Erase current is set by the resistance between these pins
and the Erase head.
The power ON/OFF detection system detects a reduced voltage.
When V
the Write and Erase functions
• Select the voltage gain so that the pre-amplifier output amplitude is 1 Vp-p or less.
• Observe the following points when mounting this IC.
• Connect a V
• The ground should be as large as possible.
CC
The comparator detects the crosspoint of the filter differential output.
The time domain filter converts the comparator output to Read data.
This filter is equipped with two monostable multivibrators. Monostable multivibrator No. 1 eliminates
unnecessary pulses, and monostable multivibrator No. 2 determines the pulse width of Read data.
The monostable multivibrator No. 1 pulse width T
A.GND. T
The pulse width for monostable multivibrator No. 2 is fixed at 400 ns.
If the pre-amplifier output amplitude exceeds 1 Vp-p, the filter output waveform becomes distorted.
.
I
I
W
WC
HIGH DENSITY = “H”
HIGH DENSITY = “L”
= 11.6/R
= 10.8/R
CC
is below the stipulated voltage, the Write system and Erase system cease operation, disabling
A
can be switched as follows by the setting of Pin 9:
CC
W
WC
(mA)
decoupling capacitor of approximately 0.1 µF close to the IC.
(mA)
R
R
W
WC
T
T
(k )
A LOW
A HIGH
(k )
= 84R
= 42R
WC
W
A
A
connected between Pin 25 and V
is set by the resistor R
+ 180 (nS)
+ 110 (nS)
—15—
A
is determined by the resistor R
R
A
(k )
WC
connected between Pin 25 and Pin
CC
and between Pin 27 and
A
between Pin 12 and
CXA1720Q