Cheetah T10 SAS Product Manual, Rev. A
61
9.4.6
SAS transmitters and receivers
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.
Figure 19.
SAS transmitters and receivers
9.4.7
Power
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.
9.5
Signal characteristics
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.
9.5.1
Ready LED Out
The Ready LED Out signal is driven by the drive as indicated in Table 16.
Table 16:
Ready LED Out conditions
Normal command activity
LED status
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
Summary of Contents for Cheetah T10 SAS ST3146755SS
Page 1: ...Cheetah T10 SAS ST3300555SS ST3146755SS ST373355SS ...
Page 6: ...2 Cheetah T10 SAS Product Manual Rev A ...
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Page 32: ...26 Cheetah T10 SAS Product Manual Rev A Figure 2 Typical ST3300555SS drive current profiles ...
Page 33: ...Cheetah T10 SAS Product Manual Rev A 27 Figure 3 Typical ST3146755SS drive current profiles ...
Page 34: ...28 Cheetah T10 SAS Product Manual Rev A Figure 4 Typical ST373355SS drive current profiles ...
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