lm48310sd National Semiconductor Corporation, lm48310sd Datasheet - Page 15

• Manufacturer Part Number: lm48310sd
• Description: Ultra-low Emi, Filterless, 2.6w, Mono, Class D Audio Power Amplifier With E2s
• Manufacturer: National Semiconductor Corporation

PCB LAYOUT GUIDELINES
As output power increases, interconnect resistance (PCB
traces and wires) between the amplifier, load and power sup-
ply create a voltage drop. The voltage loss due to the traces
between the LM48310 and the load results in lower output
power and decreased efficiency. Higher trace resistance be-
tween the supply and the LM48310 has the same effect as a
poorly regulated supply, increasing ripple on the supply line,
and reducing peak output power. The effects of residual trace
resistance increases as output current increases due to high-
er output power, decreased load impedance or both. To main-
tain the highest output voltage swing and corresponding peak
output power, the PCB traces that connect the output pins to
the load and the supply pins to the power supply should be
as wide as possible to minimize trace resistance.
The use of power and ground planes will give the best THD
+N performance. In addition to reducing trace resistance, the
use of power planes creates parasitic capacitors that help to
filter the power supply line.
The inductive nature of the transducer load can also result in
overshoot on one of both edges, clamped by the parasitic
diodes to GND and V
point, this is an aggressive waveform that can radiate or
conduct to other components in the system and cause inter-
ference. In is essential to keep the power and output traces
short and well shielded if possible. Use of ground planes
beads and micros-strip layout techniques are all useful in pre-
venting unwanted interference.
DD
in each case. From an EMI stand-
15
As the distance from the LM48310 and the speaker increases,
the amount of EMI radiation increases due to the output wires
or traces acting as antennas become more efficient with
length. Ferrite chip inductors places close to the LM48310
outputs may be needed to reduce EMI radiation.
LM48310SDL
Designator Quantity
JP1 — JP2
C2, C3
C4, C5
C1
C6
R1
1
2
2
1
1
2
1
10μF ±10% 16V 500Ω Tantalum
Capacitor (B Case) AVX
TPSB106K016R0500
1μF ±10% 16V X7R Ceramic
Capacitor (603) Panasonic
ECJ-1VB1C105K
1μF ±10% 16V X7R Ceramic
Capacitor (1206) Panasonic
ECJ-3YB1C105K
Not Installed Ceramic Capacitor
(603)
0Ω ±1% resistor (603)
3 Pin Headers
LM48310SD (10-pin LLP)
Description
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