MAX9789AETJ+ Maxim Integrated Products, MAX9789AETJ+ Datasheet - Page 16

• Manufacturer Part Number: MAX9789AETJ+
• Description: IC AMP AUDIO 2W STER AB 32TQFN
• Manufacturer: Maxim Integrated Products
• Series: DirectDrive™r
• Type: Class ABr

Specifications of MAX9789AETJ+

• Output Type: 2-Channel (Stereo) with Stereo Headphones
• Max Output Power X Channels @ Load: 2W x 2 @ 4 Ohm; 100mW x 2 @ 16 Ohm
• Voltage - Supply: 4.5 V ~ 5.5 V
• Features: Depop, Mute, Short-Circuit and Thermal Protection, Shutdown
• Mounting Type: Surface Mount
• Package / Case: 32-TQFN Exposed Pad
• Product: Class-AB
• Output Power: 2 W
• Thd Plus Noise: 0.004 %
• Supply Current: 0.1 mA
• Maximum Power Dissipation: 1990 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Audio Load Resistance: 4 Ohms
• Minimum Operating Temperature: - 40 C
• Amplifier Class: AB
• No. Of Channels: 3
• Supply Voltage Range: 4.5V To 5.5V
• Load Impedance: 4ohm
• Operating Temperature Range: -40°C To +85°C
• Amplifier Case Style: TQFN
• Rohs Compliant: Yes
• For Use With: MAX9789AEVKIT+ - EVALUATION KIT FOR MAX9789A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Windows Vista-Compliant, Stereo Class AB Speaker
Amplifiers and DirectDrive Headphone Amplifiers
• The voltage coefficient of the capacitor, the change
• The combination of low-frequency attenuation and fre-
The MAX9789/MAX9790 feature a low-noise charge
pump. The 550kHz switching frequency is well beyond
the audio range, and does not interfere with the audio
signals. The switch drivers feature a controlled switching
Figure 2. Low-Frequency Attenuation of Common DC-Blocking
Capacitor Values
Table 2. Low-Frequency Rolloff
*Vista requirement for 32 Ω load.
16
in capacitance due to a change in the voltage
across the capacitor, distorts the audio signal. At
frequencies around the -3dB point, this effect is
maximized and the voltage coefficient appears as
frequency-dependent distortion. Figure 3 shows the
THD+N introduced by two different capacitor
dielectrics. Note that around the -3dB point, THD+N
increases dramatically.
quency-dependent distortion compromises audio
reproduction. DirectDrive improves low-frequency
reproduction in portable audio equipment that empha-
sizes low-frequency effects, such as multimedia lap-
tops, MP3, CD, and DVD players (See Table 2).
______________________________________________________________________________________
C
OUT
330*
100
220
470
22
33
(µF)
-12
-15
-18
-21
-24
-27
-30
-3
-6
-9
0
1
LOW-FREQUENCY ROLLOFF
10
FREQUENCY (Hz)
R
100
(R
L
L
452
301
= 16Ω
99
45
30
21
= 16Ω)
33μF
100μF
220μF
DirectDrive
330μF
1k
f
-3dB
10k
(Hz)
Charge Pump
100k
R
L
226
151
= 32Ω
50
23
15
11
speed that minimizes noise generated by switching
transients. Limiting the switching speed of the charge
pump minimizes the di/dt noise caused by the parasitic
bond wire and trace inductance.
The MAX9789/MAX9790 feature an internally generat-
ed, power-supply independent, common-mode bias
voltage of 1.8V referenced to GND. BIAS provides both
click-and-pop suppression and sets the DC bias level
for the amplifiers. The BIAS pin should be bypassed to
GND with a 1µF capacitor. No external load should be
applied to BIAS. Any load lowers the BIAS voltage,
affecting the overall performance of the device.
The MAX9789/MAX9790 feature programmable speak-
er amplifier gain, set by the logic voltages applied to
pins GAIN1 and GAIN2. Table 3 shows the logic com-
binations that can be applied to pins GAIN1 and GAIN2
and their affects on the speaker amplifier gain. The
headphone amplifier gain is fixed at 3.5dB.
Figure 3. Distortion Contributed by DC-Blocking Capacitors
Table 3. MAX9789/MAX9790
Programmable Gain Settings
GAIN1
0
0
1
1
Headphone and Speaker Amplifier Gain
0.0001
0.001
0.01
0.1
GAIN2
10
1
0
1
0
1
10
ALUM/ELEC
DC-BLOCKING CAPACITORS
ADDITIONAL THD+N DUE TO
MAX9789/MAX9790
SPEAKER MODE
100
GAIN (dB)
FREQUENCY (Hz)
TANTALUM
15.6
21.6
10
6
1k
C
R
OUT
L
10k
= 16Ω
= 100μF
MODE GAIN (dB)
HEADPHONE
100k
3.5
3.5
3.5
3.5
BIAS