Seagate ST3400755SS manual Transmitter signal characteristics, Signal characteristica Units Gbps

9.5.2.2Transmitter signal characteristics

Table 14 specifies the signal requirements at the transmitter end of a TxRx connection as measured into the zero-length test load. All specifications are based on differential measurements.

The OOB sequence is performed at signal voltage levels corresponding to the lowest supported transfer rate. Table 14 specifies the signal characteristics.

Table 14: Transmitter signal characteristics

Signal characteristica	Units	1.5 Gbps	3.0 Gbps
Skewb	ps	20	15
Tx Off Voltagec	mV(P-P)	< 50	< 50
Maximum rise/fall timed	ps	273	137
Minimum rise/fall timed	ps	67	67
Maximum transmitter output imbalancee	%	10	10
OOB offset deltaf	mV	± 25	± 25
OOB common mode deltag	mV	± 50	± 50

aAll tests in this table shall be performed with zero-length test load shown in figure 34.

bThe skew measurement shall be made at the midpoint of the transition with a repeating 0101b pattern on the physical link. The same stable trigger, coherent to the data stream, shall be used for both the Tx+ and Tx- signals. Skew is defined as the time difference between the means of the midpoint crossing times of the Tx+ signal and the Tx- signal.

cThe transmitter off voltage is the maximum A.C. voltage measured at compliance points when the transmitter is unpowered or transmitting D.C. idle (e.g., during idle time of an OOB signal).

dRise/fall times are measured from 20 % to 80 % of the transition with a repeating 0101b pattern on the physical link.

eThe maximum difference between the V+ and V- A.C. RMS transmitter amplitudes measured on a CJTPAT test pattern (see 9.5.2.3.3) into the test load shown in figure 34, as a percentage of the average of the V+ and V- A.C. RMS amplitudes.

fThe maximum difference in the average differential voltage (D.C. offset) component between the burst times and the idle times of an OOB signal.

gThe maximum difference in the average of the common mode voltage between the burst times and the idle times of an OOB signal.

Cheetah NS SAS Product Manual, Rev. B 59