MAX9789AETJ+ Maxim Integrated Products, MAX9789AETJ+ Datasheet - Page 17

• 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
The MAX9789/MAX9790 feature control inputs for the
independent enabling of the speaker and headphone
amplifiers, allowing both to be active simultaneously if
required. Driving SPKR_EN high disables the speaker
amplifiers. Driving HP_EN low independently disables
the headphone amplifiers. For applications that require
only one of the amplifiers to be on at a given time,
SPKR_EN and HP_EN can be tied together allowing a
single logic voltage to enable either the speaker or the
headphone amplifier as shown in Figure 4.
The MAX9789/MAX9790 allow for the speaker and
headphone amplifiers to be muted. By driving MUTE
low, both the speaker and headphone amplifiers are
muted. When muted, the speaker outputs remain
biased at V
The MAX9789/MAX9790 feature a low-power shutdown
mode, drawing 0.3µA of supply current. By disabling the
speaker, headphone amplifiers and the LDO (for
MAX9789), the MAX9789/MAX9790 enter low-power
shutdown mode. Set SPKR_EN to V
LDO_EN to GND to disable the speaker amplifiers, head-
phone amplifiers, and LDO, respectively.
The MAX9789/MAX9790 speaker amplifiers feature
Maxim’s comprehensive, industry-leading click-and-
pop suppression. During startup, the click-and-pop
suppression circuitry eliminates any audible transient
sources internal to the device. When entering shut-
down, the differential speaker outputs ramp to GND
quickly and simultaneously.
Figure 4. Enabling Either the Speaker or Headphone Amplifier
with a Single Control Pin
CONTROL PIN
Amplifiers and DirectDrive Headphone Amplifiers
SINGLE
DD
/ 2.
______________________________________________________________________________________
Click-and-Pop Suppression
Speaker and Headphone
SPKR_EN
HP_EN
MAX9789/MAX9790
Amplifier Enable
DD
Speaker Amplifier
and HP_EN and
Shutdown
MUTE
In conventional single-supply headphone amplifiers, the
output-coupling capacitor is a major contributor of audi-
ble clicks and pops. Upon startup, the amplifier charges
the coupling capacitor to its bias voltage, typically
V
charged to GND. A DC shift across the capacitor results,
which in turn, appears as an audible transient at the
headphone. Since the MAX9789/MAX9790 do not require
output-coupling capacitors, no audible transient occurs.
Additionally, the MAX9789/MAX9790 features extensive
click-and-pop suppression that eliminates any audible
transient sources internal to the device. The
startup/shutdown waveform in the Typical Operating
Characteristics shows that there are minimal spectral
components in the audible range at the output.
The MAX9789/MAX9790 feature speaker amplifiers
designed to drive a load differentially, a configuration
referred to as bridge-tied load (BTL). The BTL configu-
ration (Figure 5) offers advantages over the single-
ended configuration, where one side of the load is
connected to ground. Driving the load differentially
doubles the output voltage compared to a single-
ended amplifier operating under similar conditions. The
doubling of the output voltage yields four times the out-
put power at the load.
Since the differential outputs are biased at mid-supply,
there is no net DC voltage across the load. This elimi-
nates the need for DC-blocking capacitors required for
single-ended amplifiers. These capacitors can be
large, expensive, consume board space, and degrade
low-frequency performance.
Figure 5. Bridge-Tied Load Configuration
DD
/ 2. Likewise, during shutdown, the capacitor is dis-
Applications Information
+1
-1
BTL Speaker Amplifiers
Headphone Amplifier
V
2 x V
V
OUT(P-P)
OUT(P-P)
OUT(P-P)
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