NE5230, SA5230, SE5230
http://onsemi.com
8
THERMAL CONSIDERATIONS
When using the NE5230, the internal power dissipation
capabilities of each package should be considered.
ON Semiconductor does not recommend operation at die
temperatures above 110°C in the SO package because of its
inherently smaller package mass. Die temperatures of
150°C can be tolerated in all the other packages. With this
in mind, the following equation can be used to estimate the
die temperature:
T
j
+ T
amb
) (P
D
q
JA
)
(eq. 1)
Where
T
amb
= Ambient Temperature
T
j
= Die Temperature
P
D
= Power Dissipation
= (I
CC
x V
CC
)
q
JA
= Package Thermal Resistance
= 270°C/W for SO−8 in PC Board Mounting
See the packaging section for information regarding other
methods of mounting.
q
JA
− 100°C/W for the plastic DIP.
The maximum supply voltage for the part is 15 V and the
typical supply current is 1.1 mA (1.6 mA max). For
operation at supply voltages other than the maximum, see
the data sheet for I
CC
versus V
CC
curves. The supply current
is somewhat proportional to temperature and varies no more
than 100 mA between 25°C and either temperature extreme.
Operation at higher junction temperatures than that
recommended is possible but will result in lower Mean Time
Between Failures (MTBF). This should be considered
before operating beyond recommended die temperature
because of the overall reliability degradation.
DESIGN TECHNIQUES AND APPLICATIONS
The NE5230 is a very user−friendly amplifier for an
engineer to design into any type of system. The supply
current adjust pin (Pin 5) can be left open or tied through a
pot or fixed resistor to the most negative supply (i.e., ground
for single supply or to the negative supply for split supplies).
The minimum supply current is achieved by leaving this pin
open. In this state it will also decrease the bandwidth and
slew rate. When tied directly to the most negative supply, the
device has full bandwidth, slew rate and I
CC
. The
programming of the current−control pin depends on the
trade−offs which can be made in the designer’s application.
The graphs in Figures 3 and 4 will help by showing
bandwidth versus I
CC
. As can be seen, the supply current can
be varied anywhere over the range of 100 mA to 600 mA for
a supply voltage of 1.8 V. An external resistor can be
inserted between the current control pin and the most
negative supply. The resistor can be selected between 1.0 W
to 100 kW to provide any required supply current over the
indicated range. In addition, a small varying voltage on the
bias current control pin could be used for such exotic things
as changing the gain−bandwidth for voltage controlled low
pass filters or amplitude modulation. Furthermore, control
over the slew rate and the rise time of the amplifier can be
obtained in the same manner. This control over the slew rate
also changes the settling time and overshoot in pulse
response applications. The settling time to 0.1% changes
from 5.0 ms at low bias to 2.0 ms at high bias. The supply
current control can also be utilized for wave−shaping
applications such as for pulse or triangular waveforms. The
gain−bandwidth can be varied from between 250 kHz at low
bias to 600 kHz at high bias current. The slew rate range is
0.08 V/ms at low bias and 0.25 V/ms at high bias.
Figure 3. Unity Gain Bandwidth vs. Power Supply
Current for V
CC
= ±0.9 V
Figure 4. I
CC
Current vs. Bias Current Adjusting
Resistor for Several Supply Voltages
800
700
600
500
400
300
200
100
100 200 300 400 500 600700
UNITY GAIN BANDWIDTH (kHz)
T
A
− 25°CV
CC
− 15V
V
CC
− 12V
V
CC
− 9V
V
CC
− 6V
V
CC
− 3V
V
CC
− 2V
V
CC
− 1.8V
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
10
0
10
1
10
2
10
3
10
4
10
5
R
ADJ
(W)
POWER SUPPLY CURRENT (mA)
I
CC
CURRENT (mA)
