Seagate Cheetah 15K.5 FC ST373455FC - Manual (Page 82)

72 Cheetah 15K.5 FC Product Manual, Rev. D
9.6.2 LED driver signals
Fault and Active LED signals are located in the FC-SCA connector (J1). See Table 30 for the output character-
istics of the LED drive signals.
9.6.3 FC Differential output
The serial output signal voltage characteristics are provided in Table 31. The outputs are not AC coupled in
order to deliver maximum signal without rise and fall time degradation. You must AC couple the receiver to iso-
late potentially different DC characteristics of the outputs and the receiver.
Figure 18 provides the data output valid eye diagram relative to the bit cell time.
Figure 18. Transmit eye diagram
9.6.4 FC Differential input
The serial input signal voltage characteristics are provided in Table 32.
Table 29: LED drive signal
State Current drive available Output voltage
LED off, high 0 < I
OH
< 100µA
LED on, low I
OL
< -30 mA 0 < V
OL
< 0.8V
Table 30: FC Differential output characteristics
Description Parameter Notes
Serial output voltage swing 600 < V
out
< 1300 mV Centered at 1.32V
Table 31: FC Differential input characteristics
Description Parameter Notes
Serial input voltage swing 200 < V
in
< 1.300 mV AC coupled
Bit Time
Vout (mv)
XMIT Eye