AD815-EB Analog Devices, AD815-EB Datasheet - Page 14

• Manufacturer Part Number: AD815-EB
• Description: High Output Current Differential Driver
• Manufacturer: Analog Devices

AD815
If a resistor (R
+ input of Amp 1, negative feedback is provided which closes
the loop. An input resistor (R
conventional inverting op amp configuration with differential
outputs. The inverting input to this dual output op amp becomes
Pin 4, the positive input of Amp 1.
The gain of this circuit from input to either output will be
R
The differential outputs can be applied to the primary of a
transformer. If each output can swing 10 V, the effective swing
on the transformer primary is 40 V p-p. The optional capacitor
can be added to prevent any dc current in the transformer due
to dc offsets at the output of the AD815.
(OPTIONAL)
I
. Or the single-ended-to-differential gain will be 2 R
V
B2
B1
B3
IN
(50 )
Figure 53. Single-Ended-to-Differential Driver
250
J1
J3
499
R
I
AMP1
AMP2
F
J2
) is connected from the output of Amp 2 to the
+15V
–15V
1
2
3
10
11
4
5
1/2
AD815
1/2
AD815
R9
R2
499
499
+15V
–15V
R
R
8
A
A
7
V
TP4 TP3
CC
V
R5
R12
CC
R10
R1
6
9
~
499
I
R4
0.1 F
) will make the circuit look like a
20pF
R
R
499
R
499
F
0.1 F
B
B
R18
R21
R19
C13
10 F
10 F
11
10
4
5
+15V
AD815
AD815
–15V
Figure 55. AD815 Evaluation Board Schematic
1/2
1/2
R16
R6
TP2
TP1
8
7
50
C1
U1
50
U1
0.1 F
(OPTIONAL)
10 F
6
10 F
0.1 F
9
C11
C2
C3
C10
R15
R3
F
/R
R17
R11
R7
100
I.
R
F
/
R13
–14–
Twelve Channel Video Distribution Amplifier
The high current of the AD815 enables it to drive up to twelve
standard 75
schematic of such an application.
The input video signal is terminated in 75
noninverting inputs of both amplifiers of the AD815. Each
amplifier is configured for a gain of two to compensate for the
divide-by-two feature of each cable termination. Six separate
75
back termination. In this manner, all cables are relatively
independent of each other and small disturbances on any cable
will not have an effect on the other cables.
When driving six video cables in this fashion, the load seen by
each amplifier output is resistive and is equal to 150 /6 or
25 . The differential gain is 0.05% and the differential phase
is 0.45 .
C6
Figure 54. AD815 Video Distribution Amp Driving
12 Video Cables
C9
VIDEO IN
resistors for each amplifier output are used for the cable
R8
R14
75
J7
reverse terminated video loads. Figure 54 is a
499
1
2
3
499
100
100
499
499
R22
10
11
5
4
AD815
10
+15V
–15V
2
1
9
11
8
7
JP1
T1
6
9
0.1 F
0.1 F
8
12
12
5
6
4
7
10 F
10 F
J5
J6
and applied to the
75
R20
12
VIDEO OUT
TO 75
CABLES
J4
REV. B
1
2
3