SA58672 Datasheet, PDF (15/27 Pages) NXP Semiconductors – 3.0 W mono class-D audio amplifier

NXP Semiconductors
SA58672
3.0 W mono class-D audio amplifier
SV1
GND
SD
PVDD
GND
1
2
3
PVDD
GND
R4
C3
1 µF
INM
INP
C2
R3 ^{1 µF}
C7
10 µF
GND
R2
R1
GND
GND9 GND6 GND
SA58672
C6
1 µF
1 _SD
2 _AVDD
3 _INM
4 _INP
5
AGND
OUTP ¹⁰
PVDD ⁹
PGND ⁸
OUTM ⁷
6
n.c.
HVSON10
(3 mm × 3 mm)
GND
FB1
2 A - 220 Ω
C4
1 nF
C1 1 µF
GND
FB2
2 A - 220 Ω
C5
1 nF
GND
OUTP
OUTP
OUTM
OUTM
GND
EXT_AVDD
C8
10 µF
1
PVDD ^GND
2
AVDD
3
EXT_AVDD
SV2
002aad872
R3 and R4 are not populated for differential input drive. For single-ended input drive, either R3 or R4 are shorted to ground
using a 0 Ω resistor (i.e., one input is AC grounded and the other is driven with the input signal).
Fig 14. SA58672 evaluation demo board schematic
11.6 Filter-free operation and ferrite bead filters
A ferrite bead low-pass filter can be used to reduce radio frequency emissions in
applications that have circuits sensitive to greater than 1 MHz. A ferrite bead low-pass
filter functions well for amplifiers that must pass FCC unintentional radiation requirements
at greater than 30 MHz. Choose a bead with high-impedance at high frequencies and very
low-impedance at low frequencies. In order to prevent distortion of the output signal,
select a ferrite bead with adequate current rating.
Ferrite bead sources are:
• TDK MPZ1608S221A: 220 Ω at 100 MHz; 3 A peak max current;
0.04 Ω DC resistance.
• KOA CZP2AFTTD221P: 220 Ω at 100 MHz; 2 A peak max current;
0.05 Ω DC resistance.
• Murata BLM21PG221SN1: 220 Ω at 100 MHz; 2 A peak max current;
0.05 Ω DC resistance.
The DC resistance should be as low as possible and the maximum current must exceed at
least 1 A. Impedance of 220 Ω at 100 MHz is common spec, but 600 Ω and 1 kΩ ferrite
beads may be used. Generally, the current rating decreases with increasing impedance at
100 MHz. However, larger impedance at 100 MHz allows for a smaller, shunt capacitor
that will reduce the quiescent load current; this is important for battery operated
applications.
SA58672_4
Product data sheet
Rev. 04 — 8 June 2009
© NXP B.V. 2009. All rights reserved.
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