Seagate ST336705LW/LC, ST318405LW/LC, ST39205LW/LC Output characteristics, Input characteristics

70 Cheetah 36XL Product Manual, Rev. E

Output characteristics

Each signal (Vs) driven by LVD interface drivers shall have the following output characteristics when measured at the disc drive connector:

Steady state Low level output voltage* = –.95 V = < Vs = < –1.55 V (signal negation/logic 0) Steady state High level output voltage* = –.95 V = < Vs = < 1.55 V (signal assertion/logic 1) Differential voltage = +0.6 V minimum with common-mode voltage ranges 0.700 V = < Vcm = < 1.800 V.

*These voltages shall be measured between the output terminal and the SCSI device’s logic ground reference.

The output characteristics shall additionally conform to EIA RS-485.

STEADY STATE	–SIGNAL	100Ω
		V1
LOGIC INPUT
(1 OR 0)
D	Vs	75Ω
		100Ω
	+SIGNAL	V2

MEASURED

PARAMETER

DEVICE CONNECTOR

Figure 24. LVD output signals

Input characteristics

Each signal (Vs) received by LVD interface receiver circuits shall have the following input characteristics when measured at the disk drive connector:

Steady state Low level output voltage* = 0.030 V = < Vs = < 3.6 V (signal negation/logic 0) Steady state High level output voltage* = –3.6 V = < Vs = < –0.030 V (signal assertion/logic 1)

Differential voltage = +0.30 V minimum with common-mode voltage ranges 0.700 V = < Vcm = < 1.800 V. (X3T10/1302D)

*These voltages shall be measured between the output terminal and the SCSI device’s logic ground reference.

Input characteristics shall additionally conform to EIA RS-485-983.

	VCCA		VCCB
Single	LVD Signal Drivers	Single	Single
Ended		Ended	Ended
Circuitry		Receiver	Negation
	LVD		Driver
	Receiver
Single			Single
Ended			Ended
Ground			Assertion
Driver			Driver
	LVD Signal Drivers
Ground

Single Ended:	GND	–Signal
LVD:	+Signal	–Signal

Figure 25. Typical SE-LVD alternative transmitter receiver circuits