A Dual Read/Write Preamplifier for Disk Drive Head Interfaces

A 2 channel Read/Write Preamplifier for disk drive head interfaces implemented in a high speed complementary bipolar process will be described. The read circuit features bandwidth set by on-chip capacitors and gains of up to 250V/V. The write circuit provides up to 100mA peak-to-peak current to the head with delays of less than 18ns. Fault detection circuitry is also provided. The complementary bipolar process employed allows fast switching times between modes of operation, low noise, low input capacitance over the entire bandwidth, and reduced power operation.