Maxim MAX9778 用户手册

The MAX9777/MAX9778 combine a stereo 3W bridge-
tied load (BTL) audio power amplifier, stereo single-
ended (SE) headphone amplifier, headphone sensing,
and a 2:1 input multiplexer all in a tiny 28-pin thin QFN
package. These devices operate from a single 4.5V to
5.5V supply and feature an industry-leading 100dB
PSRR, allowing these devices to operate from noisy
supplies without the addition of a linear regulator. An
ultra-low 0.002% THD+N ensures clean, low-distortion
amplification of the audio signal. Click-and-pop sup-
pression minimizes audible transients on power and
shutdown cycles. Power-saving features include low
4mV V

OS

(minimizes DC current drain through the

speakers), low 13mA supply current, and a 10µA shut-
down mode. A MUTE function allows the outputs to be
quickly enabled or disabled. 

A headphone sense input detects the presence of a
headphone jack and automatically configures the
amplifiers for either speaker or headphone mode. In
speaker mode, the amplifiers can deliver up to 3W of
continuous average power into a 3Ω load. In head-
phone mode, the amplifier can deliver up to 200mW of
continuous average power into a 16Ω load. The gain of
the amplifiers is externally set, allowing maximum flexi-
bility in optimizing output levels for a given load. The
amplifiers also feature a 2:1 input multiplexer, allowing
multiple audio sources to be selected. The multiplexer
can also be used to compensate for limitations in the
frequency response of the loud speakers by selecting
an external equalizer network. The various functions are
controlled by either an I

2

C-compatible (MAX9777) or

simple parallel control interface (MAX9778).

The MAX9777/MAX9778 are available in a thermally
efficient 28-pin thin QFN package (5mm x 5mm x
0.8mm). These devices have thermal-overload protec-
tion (OVP) and are specified over the extended -40°C
to +85°C temperature range.

♦ Industry-Leading, Ultra-High 100dB PSRR
♦ 3W BTL Stereo Speaker Amplifier
♦ 200mW Stereo Headphone Amplifier
♦ Low 0.002% THD+N 
♦ Click-and-Pop Suppression
♦ ESD-Protected Outputs
♦ Low Quiescent Current: 13mA 
♦ Low-Power Shutdown Mode: 10µA
♦ MUTE Function
♦ Headphone Sense Input 
♦ Stereo 2:1 Input Multiplexer 
♦ Optional 2-Wire, I

♦ Tiny 28-Pin Thin QFN (5mm 

SE/

BTL

SINGLE SUPPLY

4.5V TO 5.5V

I

2

C-

COMPATIBLE

LEFT IN

1

LEFT IN

2

RIGHT IN

1

RIGHT IN

2

CONTROL

19-0509; Rev 0; 4/06

MAX9777ETI+

I

2

C Compatible

28 Thi n QFN - E P * T2855-6

MAX9778ETI+

Parallel

28 Thi n QFN - E P * T2855-6

Note: All devices are specified over the -40°C to +85°C operat-
ing temperature range.
+Denotes lead-free package.
*EP = Exposed paddle.

Notebooks

Portable DVD Players

Tablet PCs

PC Audio Peripherals

Camcorders

Multimedia Monitor