SR1730ABA +5/-5V 4/8-CHANNEL MR READ/WRITE DEVICE May, 2000 DESCRIPTION FEATURES The TI SR1730ABA is a BiCMOS monolithic integrated circuit designed for use with four-terminal Magneto-Resistive recording heads. The reader architecture is MR current bias/voltage sense and will support a user data rate of up to 500 Mbits/sec. A read/write capable serial port is provided to enable the implementation of on-chip MR bias and Write current DACs. The device provides a write driver, low-noise read amplifier, serial port controlled head selection, write current, MR read bias current and read and write fault detection circuitry for up to eight channels. The device requires +5V and -5V and comes in die form or in a 48-pin TQFP package. * +5V 10%, -5V 10% supplies * Designed for four-terminal MR heads with minimum external components * DC blocking capacitors integrated on chip * Truly differential current bias/voltage sense MR read Amp * MR head bias current range = 2.1 - 9.6 mA (5-bit) * MR read gain = 93 V/V and 137 V/V @ 45 * MR read input noise = .70 nV/ Hz @ 45 * Read bandwidth = 300 MHz * Differential PECL write data input, 3V logic compatible * Head voltage swing = 12 Vp-p * Write current range = 15.8 - 63 mA (5-bit) * Write current rise/fall time = 0.8 ns (Lh = 80 nH, Rh = 11 , 50% boost) * Servo bank write capability * Read and write unsafe detection * Thermal asperity detection and fast recovery * Power supply fault protection * Serial port controls head selection, write current, MR read bias current 5/18/00 1 SR1730ABA +5/-5V 4/8-CHANNEL MR READ/WRITE DEVICE BLOCK DIAGRAM VCC VEE GND HR0X HR0Y HW0X HW0Y MR BIAS AMP 5 SCLK SDATA 5-BIT DAC READ CURRENT SERIAL PORT SDEN READ PREAMPS/ MR BIAS & WRITE DRIVERS 5 IMRON 5-BIT DAC WRITE CURRENT MODE CONTROL R/W VREF RDX RDY READ AMP HR7X VOLTAGE FAULT DETECTOR WDX WDY WRITE UNSAFE DETECTOR FLT 2 BHV MONITOR HR7Y HW7X HW7Y