OPA2541 Datasheet, PDF (6/13 Pages) Burr-Brown (TI) – Dual High Power OPERATIONAL AMPLIFIER

The internal current limit will not provide short-circuit
protection in most applications. When the amplifier output is
shorted to ground, the full power supply voltage is im-
pressed across the conducting output transistor. For in-
stance, with V_S = ±35V, a short circuit to ground would
impress 35V across the conducting power transistor. The
maximum safe output current at this voltage is 1.8A, so the
internal current limit would not protect the amplifier. The
unit-to-unit variation and temperature dependence of the
internal current limit suggest that it be used to handle
abnormal conditions and not activated in commonly encoun-
tered circuit operation.
SAFE OPERATING AREA
10
T_C = +25°C
T_C = +85°C
*
T_C = +125°C
1.0
*Depending on temperature, maximum output may
be restricted by internal current limit. See output
0.1 ^{current specifications and typical curves.}
1
10
100
|V_S – V_OUT| (V)
FIGURE 1. Safe Operating Area.
Reactive, or EMF generating loads such as DC motors can
present demanding SOA requirements. With a purely reac-
tive load, output voltage current occurs when the output
voltage is zero and the voltage across the conducting transis-
tor is equal to the full power supply voltage. See Burr-
Brown Application Note AN-123 for further information on
evaluating SOA.
Applications with inductive or EMF-generating loads which
can produce “kick back” voltage surges to the amplifiers
should include clamp diodes from the output terminals to the
power supplies. These diodes should be chosen to limit the
peak amplifier output voltage surges to less than 2V beyond
the power supply rail voltage. Common 1A rated rectifier
diodes will suffice in most applications.
APPLICATIONS CIRCUITS
+V_S
10µF
+
0.1µF
0.1µF
D₁
Inductive-
L ^{or EMF-}
D₂
Generating
Load
10µF
+
–V_S
D₁ – D₂: IN4003
FIGURE 2. Clamping Output for EMF-Generating Loads.
+35V
0.1µF
R₂
10kΩ
V_IN
R₁
2.5kΩ
30pF
0.1µF
V_O
0.5Ω
A_V = 1 + R₂/R₁ = 5
–35V
FIGURE 3. Isolating Capacitive Loads.
R₁
10kΩ
V_IN
20pF
R₂
100kΩ
A
Master
0.1Ω
10kΩ
A_V = –R₂/R₁ = –10
L
20pF
B
Slave
0.1Ω
FIGURE 4. Paralleled Operation, Extended SOA.
®
OPA2541
6