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ISL43485 Datasheet, PDF (6/11 Pages) Intersil Corporation – 3.3V, Low Power, 30Mbps, RS-485/RS-422
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ISL43485
Test Circuits and Waveforms (Continued)
DE
3V
DI
SIGNAL
GENERATOR
Z
D
Y
CL = 15pF
RDIFF = 60Ω
CL = 15pF
FIGURE 2A. DIFFERENTIAL TEST CIRCUIT
3V DE
DI
SIGNAL
GENERATOR
Z
D
Y
OUT
RL = 27Ω
VOM
CL = 15pF
VOH + VOL
VOM =
2
≈ 1.5V
tr, tf = 4.5ns
DI
1.5V
3V
1.5V
0V
OUT (Y)
tPLH
50%
tPHL
50%
VOH
VOL
OUT (Z)
tPHL
50%
tPLH
50%
VOH
VOL
tDD
DIFF OUT (Y - Z)
50%
10%
tR
90%
SKEW = |tPLH (Y or Z) - tPHL (Z OR Y)|
tDD
90%
50%
10%
tF
+VOD
-VOD
FIGURE 2C. SINGLE ENDED TEST CIRCUIT
FIGURE 2B. MEASUREMENT POINTS
FIGURE 2. DRIVER DATA RATE, PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES
DE
DI
SIGNAL
GENERATOR
Z
D
Y
110Ω
SW
CL = 50pF
VCC
GND
PARAMETER OUTPUT
RE
DI
tHZ
Y/Z
tLZ
Y/Z
tZH
Y/Z
tZL
Y/Z
tZH(SHDN)
Y/Z
tZL(SHDN)
Y/Z
X
1/0
X
0/1
0 (Note 5) 1/0
0 (Note 5) 0/1
1 (Note 8) 1/0
1 (Note 8) 0/1
SW
GND
VCC
GND
VCC
GND
VCC
DE
NOTE 7
tZH, tZH(SHDN)
NOTE 7
OUT (Y, Z)
tZL, tZL(SHDN)
NOTE 7
OUT (Y, Z)
1.5V
3V
1.5V
0V
tHZ
OUTPUT HIGH
50%
VOH - 0.25V VOH
0V
tLZ
50%
OUTPUT LOW
VCC
VOL + 0.25V VOL
FIGURE 3A. TEST CIRCUIT
FIGURE 3B. MEASUREMENT POINTS
FIGURE 3. DRIVER ENABLE AND DISABLE TIMES
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