MAX9776EVKIT+ Maxim Integrated Products, MAX9776EVKIT+ Datasheet - Page 31

• Manufacturer Part Number: MAX9776EVKIT+
• Description: EVALUATION KIT FOR MAX9776
• Manufacturer: Maxim Integrated Products
• Series: DirectDrive™r

Specifications of MAX9776EVKIT+

• Amplifier Type: Class D
• Output Type: 1-Channel (Mono) with Stereo Headphones
• Max Output Power X Channels @ Load: 1.5W x 1 @ 4 Ohm; 60mW x 2 @ 16 Ohm
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Board Type: Fully Populated
• Utilized Ic / Part: MAX9776
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The Global Control Register is used for global configu-
rations, those affecting all inputs and outputs. The bits
Traditional Class D amplifiers require an output filter to
recover the audio signal from the amplifier’s PWM out-
put. The filters add cost, increase the solution size of
the amplifier, and can decrease efficiency. The tradi-
tional PWM scheme uses large differential output
swings (2 x V
Any parasitic resistance in the filter components results
in a loss of power, lowering the efficiency.
The MAX9775/MAX9776 do not require an output filter.
The device relies on the inherent inductance of the
speaker coil and the natural filtering of both the speak-
er and the human ear to recover the audio component
of the square-wave output. Eliminating the output filter
results in a smaller, less costly, more efficient solution.
Because the switching frequency of the MAX9775/
MAX9776 speaker output is well beyond the bandwidth
Table 10. Global Control Register
Table 11. Global Control Register Configurations
Global Control Register
BIT
B4
B3
B2
B1
B0
REGISTER
2 x 1.5W, Stereo Class D Audio Subsystem
DD(P-P)
3D/MONO
Applications Information
IN+6dB
NAME
SHDN
MUTE
______________________________________________________________________________________
SSM
Class D Filterless Operation
) and causes large ripple currents.
with DirectDrive Headphone Amplifier
1 = Normal operation
0 = Low-power shutdown mode. I
1 = All input signals are boosted by 6dB.
0 = All input signals are passed un-amplified.
This bit does not affect INA if the INA+20dB bit (B4 of the Input Mode Control Register) is set to
1, in which case INA is boosted by 20dB.
1 = Mute all outputs.
0 = All outputs are active.
1 = Spread-spectrum Class D modulation.
0 = Fixed-frequency Class D modulation.
MAX9775:
1 = 3D Enhancement is on.
0 = 3D Enhancement is off.
1 = Speakers will output L+R in modes 7, 8, 12, and 13 (see Table 9).
0 = Speakers will output L in modes 7, 8, 12, and 13 (see Table 9).
B7
1
B6
0
B5
1
2
in the control register are shown in Table 11.
of most speakers, voice coil movement due to the
square-wave frequency is very small. Although this move-
ment is small, a speaker not designed to handle the addi-
tional power may be damaged. For optimum results use a
speaker with a series inductance > 10µH. Typical 8Ω
speakers, for portable audio applications, exhibit series
inductances in the 20µH to 100µH range.
The MAX9775/MAX9776 feature a programmable differ-
ential input structure, making it compatible with many
CODECs, and offering improved noise immunity over a
single-ended input amplifier. In devices such as cell
phones, high-frequency signals from the RF transmitter
can be picked up by the amplifier’s input traces. The
signals appear at the amplifier’s inputs as common-
mode noise. A differential input amplifier amplifies the
difference of the two inputs and any signal common to
both is cancelled.
C settings are saved.
SHDN
FUNCTION
B4
IN+6dB
B3
MUTE
B2
Global Control Register
Input Amplifier
Differential Input
SSM
B1
3D/MONO
B0
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