MAX9752CETI+ Maxim Integrated Products, MAX9752CETI+ Datasheet - Page 12

• Manufacturer Part Number: MAX9752CETI+
• Description: IC AMP AUDIO PWR 1.7W D 28TQFN
• Manufacturer: Maxim Integrated Products
• Series: DirectDrive™r
• Type: Class Dr

Specifications of MAX9752CETI+

• Output Type: 2-Channel (Stereo) with Stereo Headphones
• Max Output Power X Channels @ Load: 1.7W x 2 @ 4 Ohm; 62mW x 2 @ 16 Ohm
• Voltage - Supply: 4.5 V ~ 5.5 V
• Features: Depop, Short-Circuit and Thermal Protection, Shutdown, Volume Control
• Mounting Type: Surface Mount
• Package / Case: 28-TQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX9752/MAX9753/MAX9754 combine a 2.2W,
Class D speaker amplifier and a 62mW DirectDrive
headphone amplifier with integrated headphone sens-
ing and comprehensive click-and-pop suppression.
The speaker amplifiers offer Class AB performance with
Class D efficiency, while occupying minimal board
space. A unique filterless modulation scheme and
spread-spectrum switching create a compact, flexible,
low-noise, efficient audio power amplifier.
The MAX9752 features an analog volume control, BEEP
input, and four-level gain control. The MAX9753 fea-
tures a 2:1 input stereo multiplexer and two-level gain
control. The MAX9754 has only the Class D amplifiers
and the headphone amplifiers.
An input amplifier sets the gain of the signal path, and
feeds both the speaker and headphone amplifier
(Figure 1). The speaker amplifier uses a low-EMI, Class
D architecture to drive the speakers, eliminating the
need for an external filter for short speaker cables.
The headphone amplifiers use Maxim’s DirectDrive
architecture eliminating the bulky output DC-blocking
capacitors required by traditional headphone amplifiers.
A charge pump inverts the positive supply (CPV
ating a negative supply (CPV
fiers operate from these bipolar supplies with their
outputs biased about GND (Figure 2). The amplifiers
2.2W, Low-EMI, Stereo, Class D Power Amplifiers
with DirectDrive Headphone Amplifiers
Figure 1. MAX9752/MAX9753/MAX9754 Signal Path
12
VOL
IN_
______________________________________________________________________________________
BIAS
MAX9752 ONLY
CONTROL
VOLUME
Detailed Description
SS
BIAS
BIAS
GND
). The headphone ampli-
DD
HPOUT_
OUT_+
OUT_
), cre-
have almost twice the supply range compared to other
single-supply amplifiers, nearly quadrupling the available
output power. The benefit of the GND bias is that the
amplifier outputs no longer have a DC component (typi-
cally V
capacitors required with conventional headphone ampli-
fiers, removing the dominant source of click and pop,
conserving board space, system cost, and improving
frequency response.
An undervoltage lockout prevents operation from an
insufficient power supply. The amplifiers include ther-
mal-overload and short-circuit protection, and can with-
stand ±8kV ESD strikes on the headphone amplifier
outputs (IEC Air-Gap Discharge). An additional feature
of the speaker amplifiers is that there is no phase inver-
sion from input to output.
The MAX9752/MAX9753/MAX9754 feature a unique
spread-spectrum mode that flattens the wideband spec-
tral components, improving EMI emissions that may be
radiated by the speaker and cables. The switching fre-
quency varies randomly by ±90kHz around the center
frequency (1200kHz). Instead of a large amount of spec-
tral energy present at multiples of the switching frequen-
cy, the energy is now spread over a bandwidth that
increases with frequency. Above a few megahertz, the
wideband spectrum looks like white noise for EMI pur-
poses (Figure 3).
Figure 2. Traditional Amplifier Output vs. DirectDrive Output
DD
/ 2). This eliminates the large DC-blocking
CONVENTIONAL DRIVER-BIASING SCHEME
DirectDrive BIASING SCHEME
Class D Speaker Amplifier
V
OUT
V
GND
GND
V
+V
-V
DD
DD
DD
DD
/ 2