Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate
Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate
Barracuda 18LP Family: ST39175LW/LC ST318275LW ... - Seagate
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66 <strong>Barracuda</strong> <strong>18LP</strong> Product Manual, Rev. E<br />
LVD Differential<br />
Driver<br />
Signal +<br />
Signal –<br />
1.55V<br />
–15ma<br />
.95V +15ma<br />
V 0 = True / Logic 1 / Assertion<br />
LVD Differential<br />
Driver<br />
Signal +<br />
Signal –<br />
.95V<br />
+15ma<br />
1.55V –15ma<br />
V 0 = False / Logic 0 / Negation<br />
|V 0 | = .6V<br />
Figure 12.<br />
LVD output signals<br />
Input characteristics<br />
Each signal (Vs) received by LVD interface receiver circuits shall have the following input characteristics when<br />
measured at the disk drive connector:<br />
Steady state Low level output voltage* = 0.030 V = < V s = < 3.6 V (signal negation/logic 0)<br />
Steady state High level output voltage* = –3.6 V = < V s = < –0.030 V (signal assertion/logic 1)<br />
Differential voltage = +0.30 V minimum with common-mode voltage ranges 0.700 V = < V cm = < 1.800 V. (T10/<br />
1302D, SPI-3)<br />
*These voltages shall be measured between the output terminal and the SCSI device’s logic ground reference.<br />
Input characteristics shall additionally conform to EIA RS-485-983.<br />
VCCA<br />
VCCB<br />
Single<br />
Ended<br />
Circuitry<br />
LVD Signal Drivers<br />
LVD<br />
Receiver<br />
Single<br />
Ended<br />
Receiver<br />
Single<br />
Ended<br />
Negation<br />
Driver<br />
Single<br />
Ended<br />
Ground<br />
Driver<br />
LVD Signal Drivers<br />
Single<br />
Ended<br />
Assertion<br />
Driver<br />
Ground<br />
Single Ended:<br />
LVD:<br />
GND<br />
+Signal<br />
–Signal<br />
–Signal<br />
Figure 13.<br />
Typical SE-LVD alternative transmitter receiver circuits
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