Seagate Cheetah 100516225, Product Manual

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C
HEETAH
15K.7 FC P
RODUCT
M
ANUAL
, R
EV
. E 59
11.5.5 FC-AL transmitters and receivers
A typical FC-AL differential copper transmitter and receiver pair is shown in Figure 15. The receiver is required to provide the
AC coupling to eliminate ground shift noise.
Figure 15. FC-AL transmitters and receivers
11.5.6 Power
Power is supplied through the FC-SCA with support for +5 volts and +12 volts. All of the voltage pins in the drive connector
are the same length.
Four 12 volt pins p12 volt power to the drive. 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. The maximum
current typically occurs while the drive motor is starting.
Three 5 volt pins provide logic power to the drive. The current return for the +5 volt power supply is through the common
ground pins. Distribute supply and return current as evenly as possible among the voltage and ground pins.
The mating connector pins use shorter contacts to achieve power surge reductions and to aid in “hot plugging” the drives.
There are longer voltage contacts in the connector to enable the drive filter capacitors to charge. Current to the drive through
the long charge pins is limited by the system in which the drive operates. Three of the +12 volt pins are shorter to allow
capacitive pre-charging through the 12 volt charge pin. Two of the +5 volt pins are shorter to allow capacitive
precharging through the 5 volt charge pin.
11.5.7 Fault LED Out
The Fault LED Out signal is driven by the drive when:
• the drive detects failure of both ports
• the drive detects an internal failure
• the drive receives the appropriate fault LED command from the host
The Fault LED Out signal is designed to pull down the cathode of an LED. The anode is attached to the 5 volt supply
through an appropriate current-limiting resistor. The LED and the current-limiting resistor are external to the drive.
TY
.01
Differential
Transfer Medium
.01
Transmitter
TX
RY
Receiver
RX
100 100