Datasheet

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SBOS235E − MARCH 2002− REVISED MAY 2009
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12
RAIL-TO-RAIL OUTPUT
A class AB output stage with common-source transistors
is used to achieve rail-to-rail output. For high-impedance
loads (> 200Ω), the output voltage swing is typically
100mV from the supply rails. With 10Ω loads, a useful
output swing can be achieved while maintaining high
open-loop gain. See the typical characteristic curve Output
Voltage Swing vs Output Current.
OUTPUT DRIVE
The OPA357’s output stage can supply a continuous
output current of ±100mA and still provide approximately
2.7V of output swing on a 5V supply, as shown in Figure 2.
For maximum reliability, it is not recommended to run a
continuous DC current in excess of ±100mA. Refer to the
typical characteristic curve Output Voltage Swing vs
Output Current. For supplying continuous output currents
greater than ±100mA, the OPA357 may be operated in
parallel as shown in Figure 3.
The OPA357 will provide peak currents up to 200mA,
which corresponds to the typical short-circuit current.
Therefore, an on-chip thermal shutdown circuit is provided
to protect the OPA357 from dangerously high junction
temperatures. At 160°C, the protection circuit will shut
down the amplifier. Normal operation will resume when the
junction temperature cools to below 140°C.
V
IN
V
1
5V
R
SHUNT
Laser Diode
OPA357
C
1
50pF
R
1
10kΩ
R
3
10k
Ω
R
4
1kΩ
R
2
1kΩ
1µF
+
−
+
−
V+
V−
1V In = 100mA
Out, as Shown
Figure 2. Laser Diode Driver
R
SHUNT
1
Ω
Laser Diode
OPA2357
C
1
200pF
R
1
100k
Ω
R
3
100k
Ω
R
4
10k
Ω
R
2
10k
Ω
1
µ
F
+5V
+
−
OPA2357
2V In = 200mA
Out, as Shown
R
5
=1
Ω
R
6
=1
Ω
Figure 3. Parallel Operation
VIDEO
The OPA357 output stage is capable of driving standard
back-terminated 75Ω video cables, as shown in Figure 4.
By back-terminating a transmission line, it does not exhibit
a capacitive load to its driver. A properly back-terminated
75Ω cable does not appear as capacitance; it presents
only a 150Ω resistive load to the OPA357 output.
Video
In
Video
Output
+2.5V
+5V
+2.5V
604Ω
75
Ω
604Ω
75Ω
OPA357
To enable,
connect to V+
or drive with logic.
Figure 4. Single-Supply Video Line Driver