Active Led Status; Fluid Dynamic Bearings (Fdb); Staggered Spinup And Activity Indication (Sata Power Pin 11); Staggered Spinup - Western Digital Blue WD20SPZX Technical Reference Manual

contributes to both data availability and serviceability without any associated
downtime, making it a critical feature for extending SATA into enterprise applications.
WD SATA drives support hot plugging only in systems where a SATA hard drive
storage backplane is used.
The Serial ATA revision 2.5 specification requires staggered pins for both the hard
drive and drive receptacles. Staggered pins mate the power signals in the
appropriate sequences required for powering up the hot plugged device. These pins
are also specified to handle in excess of the maximum allowed inrush current that
occurs during drive insertion. SATA-compliant devices thus need no further
modification to be hot pluggable and provide the necessary building blocks for a
robust hot plug solution, which typically includes:
Device detection even with power downed receptacles (typical of server

applications).
Pre-charging resistors to passively limit inrush current during drive insertion.

Hot plug controllers to actively limit inrush current during drive insertion.

3.8

Active LED Status

The drive supports external LED requirements. It provides an activity LED output
which is ON during command execution and OFF otherwise.
The drive strength of this open drain drive active signal is that it can sink 12mA to 0.4V
Max. It is 5V tolerant, meaning that the external LED may be driven from +5V or +3.3V
so long as the Host system provides a series resistor to limit the LED current to the
lower of 12mA or the rated operating current of the LED. As an example with +5V and
a 2 volt forward drop across a 10mA LED, a 300 Ohm 5% 1/16W resistor would be
suitable. In the case of a 3.3V supply for the same LED, the resistor would be 130 Ohm
5% 1/16W.
The pin corresponding to P11 shall be used for Active LED.
3.9

Fluid Dynamic Bearings (FDB)

A bearing design that allows ultra-low rotational drag while providing high lateral
stiffness to steadily hold the spinning center of the diskpack for high-accuracy of
reading and writing of data. FDB provide increased shock robustness and enhanced
reliability while reducing power consumption and acoustics.
3.10 Staggered Spinup and Activity Indication (SATA Power Pin
11)
SATA device power connector pin 11 is defined as a means by the host to DISABLE
staggered spinup and it may also be used by the device to provide the host with an
activity indication. According to the SATA II specs, "Staggered Spin-up Disable and
Activity Signal shall not be enabled at the same time."
3.10.1

Staggered Spinup

When multiple disks are installed in an enclosure, it is desirable to provide a simple
mechanism by which a subsystem controller can sequence hard drive initialization to
minimize the current load presented during power up. Staggered spinup provides
Product Features
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