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Detailed Description
The MAX9830 features industry-leading quiescent cur-
rent, low-power shutdown mode, comprehensive click-
and-pop suppression, and excellent RF immunity.
The MAX9830 offers Class AB audio performance with
Class D efficiency in a minimal board-space solution.
The Class D amplifier features spread-spectrum modu-
lation combined with edge rate and overshoot control
circuitry that offers significant improvements to switch-
mode amplifier radiated emissions.
The MAX9830 includes thermal overload and short-cir-
cuit protection.
Class D Speaker Amplifier
The MAX9830 filterless Class D amplifier offers much
higher efficiency than Class AB amplifiers. The high
efficiency of a Class D amplifier is due to the switching
operation of the output stage transistors. Any power
loss associated with the Class D output stage is mostly
due to the I2R loss of the MOSFET on-resistance and
quiescent current overhead.
Ultra-Low EMI Filterless Output Stage
Traditional Class D amplifiers require the use of exter-
nal LC filters, or shielding, to meet EN55022B electro-
magnetic-interference (EMI) regulation standards.
Maxim’s active emissions limiting edge-rate control cir-
cuitry and spread-spectrum modulation reduces EMI
emissions, while maintaining up to 85% efficiency.
Maxim’s spread-spectrum modulation mode flattens
wideband spectral components, while proprietary tech-
niques ensure that the cycle-to-cycle variation of the
switching period does not degrade audio reproduction
or efficiency. The MAX9830’s spread-spectrum
modulator
randomly
varies
the
switching
frequency by ±10kHz around the center frequency
(600kHz). Above 10MHz, the wideband spectrum looks
like noise for EMI purposes (Figure 1).
Speaker Current Limit
If the output current of the speaker amplifier exceeds
the current limit (1.8A typ), the MAX9830 disables the
outputs for approximately 400s. At the end of 400s,
the outputs are re-enabled. If the fault condition still
exists, the MAX9830 continues to disable and re-enable
the outputs until the fault condition is removed.
Shutdown
The MAX9830 features a low-power shutdown mode,
drawing 0.5A of supply current. Drive SHDN low to put
the MAX9830 into shutdown.
Click-and-Pop Suppression
The MAX9830 speaker amplifier features Maxim’s com-
prehensive click-and-pop suppression. During startup,
the click-and-pop suppression circuitry reduces any
audible transient sources internal to the device. When
entering shutdown, the differential speaker outputs
ramp down to PGND quickly and simultaneously.
MAX9830
Mono 2W Class D Amplifier
Pin Description
PIN
NAME
FUNCTION
1
IN+
Noninverting Audio Input
2
IN-
Inverting Audio Input
3
SHDN
Active-Low Shutdown Input. Drive
SHDN low to place the device in shutdown mode.
4
N.C.
No Connection. Leave unconnected.
5
PGND
Ground
6
OUT-
Negative Speaker Output
7
OUT+
Positive Speaker Output
8
PVDD
Power Supply. Bypass PVDD to PGND with a 0.1F capacitor.
—
EP
Exposed Pad. Connect exposed pad to a solid ground plane.
FREQUENCY (MHz)
AMPLITUDE
(dB
V/m)
40
30
20
10
0
-10
30
60
100
140
180
220
260
300
80
120
160
200
240
280
EN55022B LIMIT
Figure 1. EMI with 24in of Speaker Cable