Seagate 4.55GB PATA ST34520LW Manual De Usuario

Each signal (V

s

) 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 = <  V

s

 = < –1.55 V (signal negation/logic 0)

Steady state High level output voltage* =  –.95 V = <  V

s

 = < 1.55 V (signal assertion/logic 1)

Differential voltage = +0.6 V minimum with common-mode voltage ranges 0.700 V = < V

cm

 = < 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.

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

Steady state Low level output voltage* =  0.030 V = <  V

s

 = < 3.6 V (signal negation/logic 0)

Steady state High level output voltage* =  –3.6 V = <  V

s

 = < –0.030 V (signal assertion/logic 1)

Differential voltage = +0.30 V minimum with common-mode voltage ranges 0.700 V = < V

cm

 = < 1.800 V.

(X3T10/1142D revision 13, p. 152)

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

This requirement shall be met with the input voltage varying between 0.700 V and 1.8 V, with power on or off,
and with the hysteresis equaling TBD mV, minimum.

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

Signal +

Signal –

LVD Differential

Driver

1.55V

V

0

 = True / Logic 1 / Assertion

–15ma

.95V

+15ma

Signal +

Signal –

LVD Differential

Driver

.95V

V

0

 = False / Logic 0 / Negation

|V

0

| = .6V

+15ma

1.55V

–15ma