ssm2311 Analog Devices, Inc., ssm2311 Datasheet - Page 16

• Manufacturer Part Number: ssm2311
• Description: Filterless High Efficiency Mono 3 W Class-d Audio Amplifier
• Manufacturer: Analog Devices, Inc.

SSM2311
INPUT CAPACITOR SELECTION
The SSM2311 does not require input coupling capacitors if the
input signal is biased from 1.0 V to V
are required if the input signal is not biased within this recom­
mended input dc common-mode voltage range, if high-pass
filtering is needed (Figure 43), or if using a single-ended source
(Figure 44). If high-pass filtering is needed at the input, the input
capacitor along with the input resistor of the SSM2311 forms a
high-pass filter whose corner frequency is determined by the
following equation:
The input capacitor can significantly affect the performance of
the circuit. Not using input capacitors degrades both the output
offset of the amplifier and the PSRR performance.
f
C
= 1/(2π × R
IN
× C
IN
)
DD
− 1.0 V. Input capacitors
Rev. PrA | Page 16 of 20
PROPER POWER SUPPLY DECOUPLING
To ensure high efficiency, low THD, and high PSRR, proper power
supply decoupling is necessary. Noise transients on the power
supply lines are short-duration voltage spikes. Although the actual
switching frequency can range from 10 kHz to 100 kHz, these
spikes can contain frequency components that extend into the
hundreds of megahertz. The power supply input needs to be
decoupled with a good quality low ESL, low ESR capacitor—usually
of around 4.7 μF. This capacitor bypasses low frequency noises
to the ground plane. For high frequency transients noises, use a
0.1 μF capacitor as close as possible to the VDD pin of the device.
Placing the decoupling capacitor as close as possible to the SSM2311
helps maintain efficiency performance.
Preliminary Technical Data