AN1512 Philips, AN1512 Datasheet - Page 6

• Manufacturer Part Number: AN1512
• Description: All in one NE5230
• Manufacturer: Philips

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Philips Semiconductors
UPPER BAND FREQUENCY
The upper band lower frequencies were tailored using the same
filters. The upper band upper frequencies can be tailored by using
the bias adjust pin in the unconventional manner described earlier.
The lower end cutoff frequency was chosen to be about 3kHz and
the upper end band was selected to be about 26kHz.
PERFORMANCE
Clearly one other band could have been used to bolster the
response between the lowest and midband frequencies. See Figure
amplifier. The photograph shows the composite bandwidth of the
three circuits. The potentiometers are intended to serve as an
interfacing adjustment element and not as a gain adjustment.
However, some interaction was seen when adjusting these
potentiometers. Adjustment of one changes the relative attenuation
of the other bands. Because of this, it may be desirable to include a
buffer with gain for each band. Certainly more than three bands can
be designed using this technique. In this case, cascading would be
required to increase the slope of each band to provide better
separation.
BRIDGE-TIED LOAD
One of the concerns found when using low voltage op amps is
deliverable power to the load. Although the NE5230 has excellent
drive capability, the Bridge-Tied Load (BTL) configuration can be
used to increase the output power of the NE5230. Figure 9 shows
the outputs arranged in a push-pull configuration; output power can
thereby be doubled. This circuit finds applications in the audio field
where low distortion power is critical. A 0.1% THD was measured
with a 1k load at 10kHz at room temperature. The single NE5230
amplifier is specified to drive a 10k load. While a lighter load will
improve the distortion figures, the intention here is to demonstrate
the concept.
CONCLUSIONS
The NE5230 is a versatile precision, low voltage op amp. Its
rail-to-rail capabilities coupled with its low voltage operating range
and power supply current programmability make this op amp stand
out among the competition. While other op amps have individual
features which, on paper, seem to be better, the NE5230 shines on
its combined merits. Its unique combination of features makes it the
new leader in low voltage op amps.
REFERENCES:
Lancaster, Don, Active Filter Cook Book, 1985
Markus, John, Modern Electronic Circuits Reference Manual, 1980
Pelser, F. A., Car Radio Audio Power Amplifiers up to 24 Watts with
the TDA1015; Philips, Elcoma Applications Laboratory, Philips, The
Netherlands.
Sheingold, Daniel H., Transducer Interfacing Handbook, 1980
Raytheon Data Manual, 1984
1991 Dec
8. The outputs of each of the circuits were fed into a summing
All in one: NE5230
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V
IN
NE5230
Figure 8. Equalizer Bandwidth
Figure 9. Bridge-Tied Load
10k
R
PHOTO
A
1
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R
1k
1k
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L
2
2
R 3
R 2
,
10k
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R 1
3
NE5230
R 3 ,
AN1512
Application note
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R 3
R 2
SL00912
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