Seagate ST318418N Product Manual - Page 80
See ANSI Standard T10/1302D SPI-3 for detailed electrical specifications.
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70 Barracuda 36ES2 Product Manual, Rev. B 9.7.1.1 Single-ended drivers/receivers for N models For "N" models which use single-ended drivers and receivers, typical circuits are shown in Figure 24. Terminator circuits (see Note [1]) are to be enabled only when the disc drive is first or last in the daisy-chain. Transmitter characteristics Single-ended drives use an ANSI SCSI compatible open collector single-ended driver. This driver is capable of sinking a current of 48 mA with a low level output voltage of 0.4 volt. Receiver characteristics Single-ended drives use an ANSI SCSI single-ended receiver with hysteresis gate or equivalent as a line receiver. Line Driver Line Receiver Transmitter (or transceiver) [4] TP [1] 110 Ohm Flat Cable Pair [4]TP [1] 110 Ohm Receiver [5] [3] [2] [2] Figure 24. Single-ended transmitters and receivers on N models Notes. [1] Part of active terminator circuits. Non-removable LSI terminators, enabled in the drive (model N only) with jumper plug TE when it is first of last in the daisy-chain. [2] ANSI SCSI compatible circuits. [3] Total interface cable length should not exceed that specified in ANSI Standard T10/1302D. [4] Source of drive terminator power is an active circuit which has an input source voltage selected by jumper plug TP. See Figure 14. Applies to N models. [5] Interface signal levels and logical sense at the drive I/O connector for N models are defined as follows: Vil (low-level input voltage) = 1.0 V maximum (signal true); minimum = Vss - 0.5 V. Vih (high-level input voltage) = 1.9 V minimum (signal false); maximum = Vdd +0.5V. Vihys (Input Hysteresis) = 425 mV minimum See ANSI Standard T10/1302D (SPI-3) for detailed electrical specifications. 9.7.1.2 Single-ended drivers/receivers for LW models The maximum total cable length allowed with drives using single-ended I/O driver and receiver circuits depends on several factors. Table 16 lists the maximum lengths allowed for different configurations of drive usage. These values are from the SPI-3 document. All device I/O lines must have equal to or less than 25 pf capacitance to ground, measured at the beginning of the stub.