ADM1485
Test Circuits
VOD
R
R
VOC
Test Circuit 1. Driver Voltage Measurement
375⍀
VOD3
60⍀
375⍀
VTST
Test Circuit 2. Driver Voltage Measurement
A
CL1
RLDIFF
B
CL2
Test Circuit 3. Driver Propagation Delay
Switching Characteristics
3V
1.5V
1.5V
0V
tPLH
B
1/2VO
VO
A
VO
0V
–VO
90% POINT
10% POINT
tR
tSKEW = ͦtPLH – tPHLͦ
tPHL
90% POINT
10% POINT
tF
Figure 1. Driver Propagation Delay, Rise/Fall Timing
0V OR 3V
VCC
A
RL
S1
S2
DE
B
CL VOUT
DE IN
Test Circuit 4. Driver Enable/Disable
A
B
RE
VOUT
CL
Test Circuit 5. Receiver Propagation Delay
+1.5V
S1
–1.5V
RL
RE
CL VOUT
VCC
S2
RE IN
Test Circuit 6. Receiver Enable/Disable
A, B
0V
0V
tPLH
tPHL
VOH
RO
1.5V
tSKEW = ͦtPLH – tPHLͦ
1.5V
VOL
Figure 3. Receiver Propagation Delay
DE
1.5V
tZL
3V
1.5V
0V
tLZ
A, B
A, B
2.3V
tZH
2.3V
VOL + 0.5V
tHZ
VOH – 0.5V
VOL
VOH
0V
Figure 2. Driver Enable/Disable Timing
1.5V
RE
tZL
3V
1.5V
0V
tLZ
–4–
1.5V
R
O/P LOW
VOL + 0.5V
VOL
tZH
tHZ
O/P HIGH
VOH
R
1.5V
VOH – 0.5V
0V
Figure 4. Receiver Enable/Disable Timing
REV. '