Seagate ST39204LC Product Manual - Page 78

Cheetah 18XL Product Manual, Rev. G, Input characteristics

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68 Cheetah 18XL Product Manual, Rev. G The output characteristics shall additionally conform to EIA RS-485. STEADY STATE LOGIC INPUT (1 OR 0) D -SIGNAL 100Ω V1 Vs 75Ω +SIGNAL 100Ω V2 Figure 24. LVD output signals MEASURED PARAMETER DEVICE CONNECTOR 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. (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. 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 25. Typical SE-LVD alternative transmitter receiver circuits Single Ended Assertion Driver

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68
Cheetah 18XL Product Manual, Rev. G
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.
(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
V1
–SIGNAL
100
V2
+SIGNAL
MEASURED
PARAMETER
STEADY STATE
LOGIC INPUT
(1 OR 0)
DEVICE CONNECTOR
100
75
V
s
D
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