Figure 24. Lvd Output Signals; Figure 25. Typical Se-Lvd Alternative Transmitter Receiver Circuits - Seagate ST39204LC - Cheetah 9.2 GB Hard Drive Product Manual

68
The output characteristics shall additionally conform to EIA RS-485.
STEADY STATE
LOGIC INPUT
(1 OR 0)
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 = < 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
(X3T10/1302D)
*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.
Figure 25. Typical SE-LVD alternative transmitter receiver circuits
D
VCCA
LVD Signal Drivers
Single
Ended
Circuitry
Receiver
Single
Ended
Ground
Driver
LVD Signal Drivers
Ground
Single Ended:
GND
LVD:
+Signal
Cheetah 18XL Product Manual, Rev. G
100Ω
–SIGNAL
V s
75Ω
100Ω
+SIGNAL
MEASURED
PARAMETER
DEVICE CONNECTOR
= < 3.6 V (signal negation/logic 0)
s
= < –0.030 V (signal assertion/logic 1)
s
VCCB
Single
Ended
Receiver
LVD
–Signal
–Signal
V1
V2
= < 1.800 V.
cm
Single
Ended
Negation
Driver
Single
Ended
Assertion
Driver