Figure 21. Lvd Output Signals; Figure 22. Typical Se-Lvd Alternative Transmitter Receiver Circuits - Seagate ST173404LW Product Manual

Cheetah 73 Product Manual, Rev. D
Steady state Low level output voltage* = –.95 V = < V
Steady state High level output voltage* = –.95 V = < V
Differential voltage = +0.6 V minimum with common-mode voltage ranges 0.700 V = < 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.
LVD Differential
Driver
Signal +
Signal –
LVD Differential
Driver
Signal +
Signal –
|V | = .6V
0
Figure 21. LVD output signals
Input characteristics
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
Steady state High level output voltage* = –3.6 V = < V
Differential voltage = +0.30 V minimum with common-mode voltage ranges 0.700 V = < V
(X3T10/1142D revision 13, p. 152)
*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.
Figure 22. Typical SE-LVD alternative transmitter receiver circuits
1.55V –15ma
.95V +15ma
.95V +15ma
1.55V –15ma
VCCA
LVD Signal Drivers
Single
Ended
Circuitry
Receiver
Single
Ended
Ground
Driver
LVD Signal Drivers
Ground
Single Ended: GND
LVD: +Signal
= < –1.55 V (signal negation/logic 0)
s
= < 1.55 V (signal assertion/logic 1)
s
V = True / Logic 1 / Assertion
0
V = False / Logic 0 / Negation
0
= < 3.6 V (signal negation/logic 0)
s
= < –0.030 V (signal assertion/logic 1)
s
VCCB
Single
Ended
Receiver
LVD
–Signal
–Signal
= < 1.800 V.
cm
= < 1.800 V.
cm
Single
Ended
Negation
Driver
Single
Ended
Assertion
Driver
63