MAX9830 데이터 시트보기 (PDF) - Maxim Integrated

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MAX9830

Mono 2W Class D Amplifier

Maxim Integrated 

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 0.1µF capacitor.

—

EP

Exposed Pad. Connect exposed pad to a solid ground plane.

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 patented active emissions limiting edge-rate

control circuitry and spread-spectrum modulation

reduces EMI emissions, while maintaining up to 85%

efficiency.

Maxim’s patented spread-spectrum modulation mode

flattens wideband spectral components, while propri-

etary techniques ensure that the cycle-to-cycle varia-

tion of the switching period does not degrade audio

reproduction or efficiency. The MAX9830’s spread-

spectrum modulator randomly varies the switching

40

30

20

10

0

-10

30

EN55022B LIMIT

60 80 100 120 140 160 180 200 220 240 260 280 300

FREQUENCY (MHz)

Figure 1. EMI with 24in of Speaker Cable

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 400µs. At the end of 400µs,

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 0.5µA 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.

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