Seagate ST3400071FC, ST3500071FC LED driver signals, LED drive signal, Differential Pecl output

9.6.2LED driver signals

Fault and Active LED signals are located in the FC-SCA connector (J1). See Table 35 for the output character- istics of the LED drive signals.

Table 35:	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

9.6.3Differential PECL output

The serial PECL output signal voltage characteristics are provided in Table 36. 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 isolate potentially different DC characteristics of the outputs and the receiver.

Table 36: Differential PECL output characteristics

Description	Parameter
Serial output voltage swing	600 < Vout < 1300 mV

Figure 12 provides the data output valid eye diagram relative to the bit cell time. Table 38 lists the data values.

Bit Time

Vout (mv)

XMIT Eye

Figure 12. Transmit eye diagram

9.6.4Differential PECL input

The serial PECL input signal voltage characteristics are provided in Table 37.

Table 37: Differential PECL input characteristics

Description	Parameter	Notes
Serial input voltage swing	400 < Vin < 2.000 mV	AC coupled

68 NL35 Series FC Product Manual, Rev. D