Seagate ST3146755SS ユーザーズマニュアル

Cheetah T10 SAS Product Manual, Rev. A

61

A typical SAS differential copper transmitter and receiver pair is shown in Figure 19. The receiver is  AC cou-
pling to eliminate ground shift noise. 

The drive receives power (+5 volts and +12 volts) through the SAS device connector. 

Three +12 volt pins provide power to the drive, 2 short and 1 long. The current return for the +12 volt power 
supply is through the common ground pins. The supply current and return current must be distributed as 
evenly as possible among the pins. 

Three +5 volt pins provide power to the drive, 2 short and 1 long. The current return for the +5 volt power sup-
ply is through the common ground pins. The supply current and return current must be distributed as evenly as 
possible among the pins. 

Current to the drive through the long power pins may be limited by the system to reduce inrush current to the 
drive during hot plugging. 

This section describes the electrical signal characteristics of the drive’s input and output signals. See Table 15
for signal type and signal name information.

The Ready LED Out signal is driven by the drive as indicated in Table 16.

Ready LED Meaning bit mode page 19h

0

1

Spun down and no activity

Off

Off

Spun down and activity  (command executing)

On

On

Spun up and no activity

On

Off

Spun up and activity  (command executing)

Off

On

Spinning up or down

Blinks steadily

(50% on and 50% off, 0.5 seconds on and off for 0.5 seconds)

Format in progress, each cylinder change

Toggles on/off

TY

.01

Differential

Transfer Medium

.01

Transmitter

TX

RY

Receiver

RX

100

100