OPA547F500 BURR-BROWN [Burr-Brown Corporation], OPA547F500 Datasheet - Page 8

• Manufacturer Part Number: OPA547F500
• Description: High-Voltage, High-Current OPERATIONAL AMPLIFIER
• Manufacturer: BURR-BROWN [Burr-Brown Corporation]

APPLICATIONS INFORMATION
Figure 1 shows the OPA547 connected as a basic non-
inverting amplifier. The OPA547 can be used in virtually
any op amp configuration.
Power supply terminals should be bypassed with low series
impedance capacitors. The technique shown, using a ce-
ramic and tantalum type in parallel is recommended. Power
supply wiring should have low series impedance.
FIGURE 1. Basic Circuit Connections.
POWER SUPPLIES
The OPA547 operates from single (+8V to +60V) or dual
( 4V to 30V) supplies with excellent performance. Most
behavior remains unchanged throughout the full operating
voltage range. Parameters which vary significantly with
operating voltage are shown in the typical characteristics
curves.
Some applications do not require equal positive and negative
output voltage swing. Power supply voltages do not need to
be equal. The OPA547 can operate with as little as 8V
between the supplies and with up to 60V between the
supplies. For example, the positive supply could be set to
55V with the negative supply at –5V, or vice-versa.
ADJUSTABLE CURRENT LIMIT
The OPA547 features an accurate, user-selected current
limit. Current limit is set from 0 to 750mA by controlling the
input to the I
resistor in series with the output current path, the OPA547
senses the load indirectly. This allows the current limit to be
set with a 0 to 150 A control signal. In contrast, other
designs require a limiting resistor to handle the full output
current (750mA in this case).
8
V
NOTE: (1) I
limit, 750mA (peak). (2) Connect 0.1µF capacitors directly
to package power supply pins.
IN
LIM
R
pin. Unlike other designs which use a power
LIM
1
connected to V– gives the maximum current
0.1µF
10µF
2
1
+
(2)
OPA547
5
V+
V–
0.1µF
10µF
3
7
R
I
G = 1+
LIM
+
2
(2)
6
(1)
E/S
R
R
2
1
Z
L
V
O
www.ti.com
FIGURE 2. Safe Operating Area.
With the OPA547, the simplest method for adjusting the
current limit uses a resistor or potentiometer connected
between the I
The low level control signal (0 to 150 A) also allows the
current limit to be digitally controlled with a current-out or
voltage-out DAC reference to V– according to the equations
given in Figure 3.
Figure 3 shows a simplified schematic of the internal cir-
cuitry used to set the current limit. Leaving the I
programs the output current to zero, while connecting I
directly to V– programs the maximum output current limit,
typically 750mA.
SAFE OPERATING AREA
Stress on the output transistors is determined both by the
output current and by the output voltage across the conduct-
ing output transistor, V
output transistor is equal to the product of the output current
and the voltage across the conducting transistor, V
The Safe Operating Area (SOA curve, Figure 2) shows the
permissible range of voltage and current.
The safe output current decreases as V
put short-circuits are a very demanding case for SOA. A
short-circuit to ground forces the full power supply voltage
(V+ or V–) across the conducting transistor. With T
the maximum output current of 500mA can be achieved
under most conditions. Increasing the case temperature re-
duces the safe output current that can be tolerated without
activating the thermal shutdown circuit of the OPA547. For
further insight on SOA, consult Application Bulletin
AB-039.
POWER DISSIPATION
Power dissipation depends on power supply, signal and load
conditions. For dc signals, power dissipation is equal to the
product of output current times the voltage across the con-
100
10
1k
1
Output current may
be limited to less
than 500mA—see text.
LIM
R
Pulse Operation Only (<50% Duty-Cycle)
2
CL
pin and V– according to the equation:
(5000)(4. 75)
SAFE OPERATING AREA
Current-Limited
S
– V
5
I
LIM
V
O
S
. The power dissipated by the
T
– V
C
10
= 25°C
O
(V)
– 31.6k
T
T
C
S
C
20
= 85°C
= 125°C
– V
O
increases. Out-
LIM
50
OPA547
SBOS056A
C
pin open
S
= 25 C
– V
100
LIM
O
.