tda5155 NXP Semiconductors, tda5155 Datasheet - Page 3

• Manufacturer Part Number: tda5155
• Description: Pre-amplifier For Hard Disk Drive Hdd With Mr-read/inductive Write Heads
• Manufacturer: NXP Semiconductors

Philips Semiconductors
1
2
4
1997 Apr 08
TDA5155X
NUMBER
Designed for 10 dual-stripe MR-read/inductive write
heads
Current bias-current sense architecture
Single supply voltage (5.0 V 10%); a separate write
drivers supply pin can be biased from V
MR elements connected to ground (GND)
Equal bias currents in the two MR stripes of each head
On-chip AC couplings eliminate MR head DC offset
3-wire serial interface for programming
Programmable voltage/current mode write data input
Programmable high frequency zero-pole gain boost
Programmable write driver compensation capacitance
Programmable MR bias currents and write currents
1-bit programmable read gain
Sleep, standby, active and test modes available
Measurement of head resistances in test mode
In test mode, one MR bias current may be forced to a
minimum current
Short write current rise and fall times with near
rail-to-rail voltage swing
Head unsafe pin for signalling of abnormal conditions
and behaviour
Low supply voltage write current inhibit (active or
inactive)
Support servo writing
Provide temperature monitor
Thermal asperity detection with programmable
threshold level
Requires only one external resistor.
Hard Disk Drive (HDD).
Pre-amplifier for Hard Disk Drive (HDD)
with MR-read/inductive write heads
TYPE
FEATURES
APPLICATIONS
ORDERING INFORMATION
NAME
naked die
CC
to 8 V +10%
DESCRIPTION
3
PACKAGE
3
The 5.0 V pre-amplifier for HDD applications has been
designed for five terminal, dual-stripe
Magneto-Resistive (MR)-read/inductive write heads.
The disks of the disk drive are connected to ground.
To avoid voltage breakthrough between the heads and the
disk, the MR elements of the heads are also connected to
ground. The symmetry of the dual-stripe head-amplifier
combination automatically distinguishes between the
differential signals such as signals and the common-mode
effects like interference. The latter are rejected by the
amplifier.
The device incorporates read amplifiers, write amplifiers, a
serial interface, digital-to-analog converters, reference and
control circuits which all operate on a single supply voltage
of 5 V 10%. The output drivers have a separate supply
voltage pin which can be connected to a higher supply
voltage of up to 8 V +10%. The complementary output
stages of the write amplifier allow writing with near
rail-to-rail peak voltages across the inductive write head.
The read amplifier has low input impedance. The DC offset
between the two stripes of the MR head is eliminated using
on-chip AC coupling. Fast settling features are used to
keep the transients short. As an option, the read amplifier
may be left biased during writing so as to reduce the
duration of these transients even further. Series
inductance in the leads between the amplifier and
MR heads influences the bandwidth which can be
compensated by using a programmable high frequency
gain boost (HF zero). HF noise and bandwidth can be
attenuated using a programmable high frequency gain
attenuator (HF pole).
On-chip digital-to-analog converters for MR bias currents
and write currents are programmed via a 3-wire serial
interface. Head selection, mode control, testing and servo
writing can also be programmed using the serial interface.
In sleep mode the CMOS serial interface is operational.
Fig.1 shows the block diagram of the device.
GENERAL DESCRIPTION
Preliminary specification
TDA5155
VERSION