Guzik MR5-L Read/Write Headamplifier – Discontinued

The Guzik MR-5L read amplifier is designed to work with the high-impedance TMR heads. The impedance of such heads can be as high as 1000 Ohm, so it is impossible to achieve a high bandwidth with a high-impedance amplifier. This is the reason, why MR-5L is a current-sense low-impedance amplifier with voltage bias. The MR-5L also incorporates a heater driver and supports connection to a microactuator on a head suspension in order to perform the mechanical and electrical tests of the microactuator. The Guzik high-impedance injector (passive or active) is recommended for the calibration or the performance measurements of the MR-5L.

MR Amplifier 5L Specifications:

Read Amplifier

• Differential current sense low impedance amplifier
• Bandwidth: DC to 2GHz at –3 dB
• Flatness: ±0.5 dB, 0.3 MHz to 1 GHz
• Input noise: 0 (typical)
• TMR bias voltage: programmable ±400 mV in 0.1 mV steps
• TMR impedance measurements accuracy: 1% within the bias voltage range (20 mV to 400 mV)
• Common mode rejection ratio: 24 dB (typical) in full bandwidth (worst 18 dB at 700 MHz)
• Non linear distortion (1 GHz, 1 mV input level): less than 1%
• Amplification: 30 dB**
• Write to read recovery time: 100 nsec (typical) for both Bias On and Shut Down Bias modes***
• Input impedance: 80 Ohm differential (typical)
• Guzik MR5L head amplifier compatibility: with Universal Preamplifier UP8 only.

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*   US Patent 7,061,321 B1, Patent pending in Japan

**  Required amplification is provided by UP8

*** Measurements conditions: write current 50 mA, head inductance 20 nH, write data 1 Gbit/sec

Write Driver (General Specification)^*

• Write data speed: up to 2 Gbit/sec
• Rise/fall time of write current: (10-90%) 300 psec**
• Programmable overshoot: up to 100% of write current in 1% steps
• Output common mode voltage: less than ±0.1 V
• Write current: programmable 2 to 100 mA (zero to peak) in 0.02 mA steps***
• Read to write recovery time: less than 40 nsec
• Head voltage swing: more than 12 V peak to peak
• Output impedance: 100 Ohm differential

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* MR-5L comes with Guzik Write Driver Revision 5 (for more details see the bulletin “Guzik Read/Write Amplifier Revision 5”).

** Measurement conditions: write current 50 mA, 100% overshoot, and L=20 nH in series with R=20 Ohm; current probe Tektronix CT-6.

*** Maximum overshoot value in write current range 50-100 mA should be calculated according with formula I overshoot + I write = 100 mA.

Heater Features:

Single-ended or differential output configurable on the board upon customer request

Output heater voltage: from 0 to 9 V (typical, adjustable upon customer request)

Two types of heater voltage control:

• Internal: with separate control in the read and write modes by an internal DAC
• External (through MCX connector): input range from 0 to 4 V, amplification 2.5 (typical, adjustable upon customer request)

Heater impedance: not less than 50 Ohm.

Rise/Fall time: 100 nsec (defined by 4 MHz low pass filter)

Heater current and voltage measurements:

• Current measurement accuracy ±1.0 mA
• Voltage measurement accuracy ±5.0 mV

Maximum output current: 125 mA

MR-5L Frequency Response

Measurement Conditions: high-impedance injector,
MR-5L only (Left), MR-5L with Guzik Universal Preamplifier 8 (Right)

MR-5L Write-to-Read Recovery Time

Measurement Conditions:

• Write data 200 Mbit/sec

• Write current 50 mA

• High-impedance injector

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