Seagate ST373405LW Product Manual - Page 74

Cheetah 73LP Product Manual, Rev. C, Output characteristics, Input characteristics

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64 Cheetah 73LP Product Manual, Rev. C 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. LVD Differential Driver Signal + Signal - 1.55V .95V -15ma +15ma V0 = True / Logic 1 / Assertion LVD Differential Driver Signal + Signal - .95V 1.55V +15ma -15ma V0 = False / Logic 0 / Negation |V0| = .6V 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. (T10/ 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 Ended Circuitry LVD Signal Drivers LVD Receiver Single Ended Receiver Single Ended Negation Driver Single Ended Ground Driver LVD Signal Drivers Ground Single Ended: GND LVD: +Signal -Signal -Signal Figure 25. Typical SE-LVD alternative transmitter receiver circuits Single Ended Assertion Driver

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64
Cheetah 73LP Product Manual, Rev. C
Output characteristics
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.
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
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. (T10/
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
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
VCCA
VCCB
Single
Ended
Circuitry
Single
Ended
Receiver
Single
Ended
Negation
Driver
Single
Ended
Assertion
Driver
Single
Ended
Ground
Driver
Single Ended:
LVD:
LVD Signal Drivers
LVD Signal Drivers
LVD
Receiver
Ground
GND
+Signal
–Signal
–Signal