Seagate ST39102LC Product Manual - Page 70

Cheetah 9LP Product Manual, Rev. C, Input characteristics

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60 Cheetah 9LP Product Manual, Rev. C 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 17. 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 = < 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. (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. Single Ended Circuitry VCCA LVD Signal Drivers LVD Receiver VCCB Single Ended Receiver Single Ended Negation Driver Single Ended Ground Driver LVD Signal Drivers Ground Single Ended: GND LVD: +Signal -Signal -Signal Figure 18. Typical SE-LVD alternative transmitter receiver circuits Single Ended Assertion Driver

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60
Cheetah 9LP Product Manual, Rev. C
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 17.
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
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.
Input characteristics shall additionally conform to EIA RS-485-983.
Figure 18.
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