TYPICAL CHARACTERISTICS
T
A
= +25°C, V
S
=
±15V,
unless otherwise noted.
(Cont.)
POWER DISSIPATION vs SUPPLY VOLTAGE
0.5
Total Power Dissipation (W)
1.4
MAXIMUM POWER DISSIPATION vs TEMPERATURE
0.45
Power Dissipation (W)
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
6
8
10
12
Typical high-level
music R
L
= 600Ω
Worst case sine
wave R
L
= 600Ω
1.2
1.0
0.8
0.6
0.4
0.2
0
Maximum
Specified Operating
Temperature
85°C
θ
J-A
= 90°C/W
Soldered to
Circuit Board
(see text)
No signal
or no load
14
16
18
20
22
24
0
25
50
75
100
125
150
Supply Voltage, ±V
S
(V)
Ambient Temperature (°C)
APPLICATIONS INFORMATION
OFFSET VOLTAGE ADJUSTMENT
The OPA604 offset voltage is laser-trimmed and will require
no further trim for most applications. As with most amplifiers,
externally trimming the remaining offset can change drift
performance by about 0.3µV/°C for each 100µV of adjusted
offset. The OPA604 can replace many other amplifiers by
leaving the external null circuit unconnected.
The OPA604 is unity-gain stable, making it easy to use in a
wide range of circuitry. Applications with noisy or high imped-
ance power supply lines may require decoupling capacitors
close to the device pins. In most cases, a 1µF tantalum
capacitor at each power supply pin is adequate.
Op amp distortion can be considered an internal error source
which can be referred to the input. Figure 2 shows a circuit
which causes the op amp distortion to be 101 times greater
than normally produced by the op amp. The addition of R
3
to
the otherwise standard noninverting amplifier configuration
alters the feedback factor or noise gain of the circuit. The
closed-loop gain is unchanged, but the feedback available
for error correction is reduced by a factor of 101. This
extends the measurement limit, including the effects of the
signal-source purity, by a factor of 101. Note that the input
signal and load applied to the op amp are the same as with
conventional feedback without R
3
.
Validity of this technique can be verified by duplicating
measurements at high gain and/or high frequency where the
distortion is within the measurement capability of the test
equipment. Measurements for this data sheet were made
with the Audio Precision System One, which greatly simpli-
fies such repetitive measurements. The measurement tech-
nique can, however, be performed with manual distortion
measurement instruments.
+V
CC
7
2
3
4
(1)
OPA604
5
6
1
±50mV
Typical
Trim Range
CAPACITIVE LOADS
The dynamic characteristics of the OPA604 have been
optimized for commonly encountered gains, loads and oper-
ating conditions. The combination of low closed-loop gain
and capacitive load will decrease the phase margin and may
lead to gain peaking or oscillations. Load capacitance reacts
with the op amp’s open-loop output resistance to form an
additional pole in the feedback loop. Figure 3 shows various
circuits which preserve phase margin with capacitive load.
For details of analysis techniques and applications circuits,
refer to application bulletin AB-028 (SBOA015) located at
www.ti.com.
–V
CC
NOTE: (1) 50kΩ to 1MΩ
Trim Potentiometer
(100kΩ Recommended)
FIGURE 1. Offset Voltage Trim.
DISTORTION MEASUREMENTS
The distortion produced by the OPA604 is below the mea-
surement limit of virtually all commercially available equip-
ment. A special test circuit, however, can be used to extend
the measurement capabilities.
OPA604
SBOS019A
www.ti.com
7
TI [ TEXAS INSTRUMENTS ]
