Datasheet

MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
18 ______________________________________________________________________________________
Detailed Description
The MAX9791 combines a stereo 2W Class D power
amplifier, a stereo 175mW DirectDrive headphone
amplifier, and a 120mA LDO linear regulator in a single
device. The MAX9792 combines a mono 3W Class D
power amplifier, a stereo 175mW DirectDrive head-
phone amplifier, and a 120mA LDO linear regulator in a
single device.
The MAX9791/MAX9792 feature wake-on-beep detec-
tion, comprehensive click-and-pop suppression, low-
power shutdown mode, and excellent RF immunity.
These devices incorporate an integrated LDO that
serves as a clean power supply for CODEC or other cir-
cuits. The MAX9791/MAX9792 are Windows Vista
Premium compliant. See Table 1 for a comparison of the
Windows Vista Premium specifications and MAX9791/
MAX9792 specifications.
The MAX9791/MAX9792 feature spread-spectrum mod-
ulation and active emission limiting circuitry that offers
significant improvements to switch-mode amplifier tech-
nology. These devices offer Class AB performance with
Class D efficiency in a minimal board-space solution.
The headphone amplifiers use Maxim’s DirectDrive
architecture to eliminate the bulky output DC-blocking
capacitors required by traditional headphone ampli-
fiers. A charge pump inverts the positive supply
(HPVDD) to create a negative supply (CPVSS). The
headphone amplifiers operate from these bipolar sup-
plies with their outputs biased about GND. The bene-
fit of the GND bias is that the amplifier outputs no
longer have a DC component (typically V
DD
/2). This
feature eliminates the large DC-blocking capacitors
required with conventional headphone amplifiers to
MAX9792 Pin Description
PIN NAME FUNCTION
1, 5 GND Signal Ground. Star connect to PGND.
2 HP_INR Right-Channel Headphone Amplifier Input
3 HP_INL Left-Channel Headphone Amplifier Input
4 COM Common-Mode Voltage Sense Input
6 LDO_OUT LDO Output. Bypass with two 1µF ceramic low ESR capacitors to GND.
7 AVDD Positive Power Supply and LDO Input. Bypass with a 0.1µF and two 1µF capacitors to GND.
8 LDO_EN LDO Enable. Connect LDO_EN to AVDD to enable the LDO.
9 HPR Right-Channel Headphone Amplifier Output
10 HPL Left-Channel Headphone Amplifier Output
11 SENSE Headphone Ground Sense
12 CPVSS Headphone Amplifier Negative Power Supply. Connect a 1µF capacitor between CPVSS and PGND.
13 C1N Charge-Pump Flying Capacitor Negative Terminal. Connect a 1µF capacitor between C1P and C1N.
14 CPGND Charge-Pump Ground. Connect directly to PGND plane.
15 C1P Charge-Pump Flying Capacitor Positive Terminal. Connect a 1µF capacitor between C1P and C1N.
16 HPVDD H ead p hone Am p l i fi er P osi ti ve P ow er S up p l y. C onnect a 10µF cap aci tor b etw een H P V D D and P GN D .
17, 26 PVDD Speaker Amplifier Power-Supply Input. Bypass with a 0.1µF capacitor to PGND.
18, 25 OUT- Speaker Amplifier Output, Negative Phase
19, 24 OUT+ Speaker Amplifier Output, Positive Phase
20, 23 PGND Power Ground. Star connect to GND.
21 BEEP PC Beep Input. Connect to GND if beep detection function is disabled.
22 HP_EN Active-High Headphone Amplifier Enable
27 SPKR_EN Active-Low Speaker Amplifier Enable
28 SPKR_IN Speaker Amplifier Input
— EP Exposed Pad. Connect to GND.