TDA5153

The 5.0 V pre-amplifier TDA5153 for HDD described here is designed for five terminals, dual stripe Magneto-Resistive (MR)-read/inductive-write heads. The disks of the disk drive are connected to ground. To avoid voltage break-through 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 TDA5153 incorporates read amplifiers, write amplifiers, serial interface, digital-to-analog converters, reference and control circuits which operate on a single supply voltage of 5 V ±10%. The output drivers have a separate supply voltage pin, TDA5153 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 TDA5153 has a 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 TDA5153 may be left biased during writing so as to reduce the duration of these transients even more. 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 TDA5153 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 TDA5153 serial interface is operational. Figure 1 shows the block diagram of the device.