LM4990MMX/NOPB National Semiconductor, LM4990MMX/NOPB Datasheet - Page 15

• Manufacturer Part Number: LM4990MMX/NOPB
• Description: IC AMP AUDIO PWR 2W MONO 8MSOP
• Manufacturer: National Semiconductor
• Series: Boomer®r
• Type: Class ABr

Specifications of LM4990MMX/NOPB

• Output Type: 1-Channel (Mono)
• Max Output Power X Channels @ Load: 2W x 1 @ 4 Ohm
• Voltage - Supply: 2.2 V ~ 5.5 V
• Features: Depop, Shutdown
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Operational Class: Class-AB
• Audio Amplifier Output Configuration: 1-Channel Mono
• Output Power (typ): 2x1@4OhmW
• Audio Amplifier Function: Speaker
• Total Harmonic Distortion: 0.2@500mW%
• Single Supply Voltage (typ): 3/5V
• Dual Supply Voltage (typ): Not RequiredV
• Power Supply Requirement: Single
• Rail/rail I/o Type: No
• Power Supply Rejection Ratio: 64dB
• Single Supply Voltage (min): 2.2V
• Single Supply Voltage (max): 5.5V
• Dual Supply Voltage (min): Not RequiredV
• Dual Supply Voltage (max): Not RequiredV
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Package Type: MSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: LM4990MMX

Application Information
The LM4990 is unity-gain stable and requires no external
components besides gain-setting resistors, an input coupling
capacitor, and proper supply bypassing in the typical appli-
cation. However, if a closed-loop differential gain of greater
than 10 is required, a feedback capacitor (C4) may be
needed as shown in Figure 2 to bandwidth limit the amplifier.
This feedback capacitor creates a low pass filter that elimi-
FIGURE 3. HIGHER GAIN AUDIO AMPLIFIER
(Continued)
15
nates possible high frequency oscillations. Care should be
taken when calculating the -3dB frequency in that an incor-
rect combination of R
20kHz. A typical combination of feedback resistor and ca-
pacitor that will not produce audio band high frequency rolloff
is R
-3dB point of approximately 320kHz.
3
= 20kΩ and C
4
= 25pf. These components result in a
3
and C
4
will cause rolloff before
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