SA58631 Datasheet, PDF (8/21 Pages) NXP Semiconductors – 3 W BTL audio amplifier

NXP Semiconductors
SA58631
3 W BTL audio amplifier
6.0
P_o
(W)
4.0
2.0
R_L = 8 Ω
16 Ω
002aac008
5.0
P
(3)
(W)
(2)
4.0
3.0
2.0
(1)
1.0
002aac009
0
0
5.0
10.0
15.0
20.0
V_CC (V)
Fig 4. Output power versus supply voltage @
THD+N = 10 %; 32 cm² (5 in²) heat spreader
0
0
50
100
150
T_amb (°C)
(1) No heat spreader.
(2) Top only heat spreader (9.7 cm² (1.5 in²), 35 µm
(1 ounce) copper).
(3) Both top and bottom heat spreader (approximately
32 cm² (5 in²), 35 µm (1 ounce) copper).
Fig 5. Power dissipation versus ambient temperature
14.2 BTL application
T_amb = 25 °C, V_CC = 9 V, f = 1 kHz, R_L = 8 Ω, G_v = 20 dB, audio band-pass 20 Hz to
20 kHz. The BTL diagram is shown in Figure 3.
The quiescent current has been measured without any load impedance. The total
harmonic distortion + noise (THD+N) as a function of frequency was measured with a
low-pass filter of 80 kHz. The value of capacitor C2 influences the behavior of PSRR at
low frequencies; increasing the value of C2 increases the performance of PSRR. Figure 6
shows three areas: operating, mute and standby. It shows that the DC switching levels of
the mute and standby respectively depends on the supply voltage level.
The following characterization curves show the room temperature performance for
SA58631 using the demo PCB shown in Figure 21. The 8 curves for power dissipation
versus output power (Figure 10 through Figure 17) as a function of supply voltage, heat
spreader area, load resistance and voltage gain show that there is very little difference in
performance with voltage gain; however, there are significant differences with supply
voltage and load resistance.
The curves for THD+N versus output power (Figure 18) show that the SA58631 yields the
best power output using an 8 Ω load at 9 V supply. Under these conditions the part
delivers typically 3 W output power for THD+N = 10 %.
SA58631_2
Product data sheet
Rev. 02 — 12 October 2007
© NXP B.V. 2007. All rights reserved.
8 of 21