Seagate ST3450856FC manual LED driver signals, FC Differential output, FC Differential input

9.6.2LED driver signals

Fault and Active LED signals are located in the FC-SCA connector (J1). See Table 33 for the output character- istics of the LED drive signals.

Table 33: LED drive signal

State	Current drive available	Output voltage
LED off, high	0 < IOH < 100µA
LED on, low	IOL < -30 mA	0 < VOL < 0.8V

9.6.3FC Differential output

The serial output signal voltage characteristics are provided in Table 34. 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.

Table 34:	FC Differential output characteristics
Description		Parameter	Notes
Serial output voltage swing		600 < Vout < 1300 mV	Centered at 1.32V

Figure 18 provides the data output valid eye diagram relative to the bit cell time.

Bit Time

Vout (mv)

XMIT Eye

Figure 18. Transmit eye diagram

9.6.4FC Differential input

The serial input signal voltage characteristics are provided in Table 35.

Table 35:	FC Differential input characteristics
Description		Parameter	Notes
Serial input voltage swing		200 < Vin < 1.300 mV	AC coupled

76 Cheetah 15K.6 FC Product Manual, Rev. D