Mating Connectors - Seagate ST3146854LC - Cheetah 146.8 GB Hard Drive User Manual

• propagation delay (see T10/1365D Sections 6.3.6 and 6.3.7)
• stub length (see T10/1365D Section 6.9)
• device spacing (see T10/1365D Section 6.9)
To minimize discontinuances and signal reflections, cables of different impedances should not be used in the
same bus. Implementations may require trade-offs in shielding effectiveness, cable length, number of loads
and spacing, transfer rates, and cost to achieve satisfactory system operation. If shielded and unshielded
cables are mixed within the same SCSI bus, the effect of impedance mismatch must be carefully considered.
Proper impedance matching is especially important in order to maintain adequate margin at FAST-20, FAST-
40, FAST-80, and FAST-160 SCSI transfer rates.
Note. For LVD operation, twisted pair cables are recommended. For LVD Fast-40 operation, twisted pair
cables are strongly recommended. For Fast-80 and Fast-160 operation, twisted pair cables are
required.
LC Models
The 80-pin connector option provided on LC models is intended for use on drives that plug directly into back-
plane connector in the host equipment. In such installations, all backplane wiring segments are subject to the
electromagnetic concepts presented in Standard T10/1365D, Rev. 3, Section 6. For LC model drives, installa-
tions with connectors on cables are not recommended.
9.6.4

Mating connectors

Part numbers for the different type connectors that mate with the various Cheetah 15K.4 SCSI I/O connectors
are given in the sections following.
9.6.4.1 Mating connectors for LW model drives
The nonshielded cable connector shall be a 68 conductor connector consisting of two rows of 34 male contacts
with adjacent contacts 0.050 inch (1.27 mm) apart.
Recommended mating flat cable connector part numbers are:
Amp Model 786096-7
Amp Model 786090-7
Amp Model 749925-5
Amp Model 88-5870-294-5 W/O Strain Relief (25 mil conductor centers, 30 AWG wire).
Amp Model 1-480420-0
Berg 69307-012
[1] See Figure 24.
The drive device connector is a nonshielded 68 conductor connector consisting of two rows of 34 female pins
with adjacent pins 50 mils apart. The connector is keyed by means of its shape (see Figure 25).
68
Female, 68-pin, panel mount
Female, 68-pin, cable mount
(50 mil conductor centers, 28 or 30 AWG wire)
Use two, 34 conductor, 50 mil center flat cable with this connector.
This type connector can only be used on cable ends. [1]
Use either on cable ends or in cable middle section for daisy-chain
installations [1].
Power connector 4 circuit housing
12-position, 2 x 6, 2 mm receptacle housing
Cheetah 15K.4 SCSI Product Manual, Rev. D