Connector Requirements - Seagate ST15150N - Barracuda 4.3 GB Hard Drive Product Manual

70
11.7.1.2.3
11.7.2
ST15150N/ND/W/WD/WC/DC Product Manual, Rev. D
General cable characteristics
In general, cables having the characteristic impedances given in Sections
11.7.1.2.1 and 11.7.1.2.2 are not available; however, impedances that are
somewhat lower are satisfactory. A characteristic impedance of 100 ohm
10% is recommended for non-shielded flat or twisted-pair ribbon cable.
However, most available cables have a somewhat lower characteristic
impedance. To minimize discontinuities and signal reflections, cables of
different impedances should not be used in the same bus. Your specific setup
may require tradeoffs in shielding effectiveness, cable length, the number of
loads, transfer rates, and cost to achieve satisfactory system operation. If
shielded and non-shielded cables are mixed within the same SCSI bus, the
effect of impedance mismatch must be carefully considered. Proper imped-
ance matching is especially important to maintain adequate margin at fast
SCSI transfer rates.
Only non-shielded cable connectors are applicable for N and ND drives. A
50-conductor flat cable or 25 twisted-pair cable is used. A minimum conduc-
tor size of 28 AWG should be used to minimize noise effects. Suggested non-
shielded flat cable part numbers are:
Flat cable, 35M-3365-50
Twisted pair, Spectra Twist in flat 455-248-50
Equivalent parts may be used.

Connector requirements

ST15150N/ND drives
The non-shielded cable connector is a 50-conductor connector consisting of
two rows of 25 female contacts with adjacent contents 100 mils apart.
Recommended mating flat cable connectors part numbers:
Closed end 3M-3425-7000 without strain relief, no center key
(for cable ends) 3M-3425-7050 with strain relief, no center key
Berg-66900-290 with strain relief, with center key
Open end 3M-3425-6000 without strain relief, no center key
(in daisy chain) 3M-3425-6050 with strain relief, no center key
Berg-66900-250 with strain relief, with center key
The drive device connector is a non-shielded 50-conductor connector
consisting of two rows of 25 male pins with adjacent pins 100 mils apart. The
connector is keyed (see Figure 33).
Mating panel mount connector 3M-CHE-2050-J01A10-KLE
ST15150W/WD drives
Recommended mating wide cable connectors part numbers:
AMP 786096-7, female 68-pin
AMP 786090-7, male 68-pin