DHT

MicroPhysics DHT-2

MicroPhysics Disk Head Tester (DHT-2)

MicroPhysics DHT has been designed “from a clean slate” to realize a tester capable of measuring ultra-high track pitch heads. For active track following, the DHT uses an embedded servo, sectored and in quadrature. The track following is accomplished using a voice-coil rotary actuator with an independent 2.5 Angstrom (0.01 u”) resolution. While others have added piezo actuators to legacy systems to accomplish micropositioning, MicroPhysics has introduced a new concept in spinstands, directly addressing the needs of higher track pitch testing. MicroPhysics DHT has been proven to measure real heads at well over 6 KTPmm (150 KTPI).

For 2005, the DHT-2 has been updated with capability for 165 servo sectors, a completely digital parametrics measurement, and lower cost, with the entire electronics system packaged onto 3 PCI cards.

Product Features:

Open Architecture:
New MicroPhysics DHT preamp boards can be engineered and manufactured by MicroPhysics, or by the end user. With its open configuration, customers have been able to integrate preamps into MicroPhysics system more quickly than on other systems.

Full Quad Servo:
The DHT-2 utilizes a true quadrature closed-loop servo for track position during write/read and off-track measurements. The system has been designed to allow high servo bandwidth sufficient to reduce once-around variations allowing greater capability for very narrow track width heads.

Spinstand Specifications:

	Kinematics closely resemble drive
	Tooling designed to be extremely light and stiff to allow fast servo actuation.
	Integrated with electronics to provide very sophisticated track following servo motion.
	Typical NRRO --- Better than 2 nm (0.08 m”) rms measured at head gap for applications well above 6KTPmm (150KTPI) – includes spindle NRRO and all other mechanical motions

System specifications are subject to change.

MicroPhysics DHT-2 Complete Electronics Set is 3 PCI Cards

Designed for High TPI and Cost Effectiveness

The MicroPhysics DHT electronics package is 3 PCI cards. This architecture allows low initial cost and major upgrade capabilities.

Electronics Specifications:

	PRML Chip Integration: Data Rates limited only by currently available channel chips
	Integrated Digitizer: 2 Gsample/second, with faster upgrade option available
	Programmable Pattern Generator: Data rate limited only by currently available channel chips
	Amplitude Measurements: Full digital analysis, no attack/decay settings
	PW50 Detector: Full digital analysis, excellent correlation and accuracy.