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Filterless High Efficiency 2.5W Switching Audio Amplifier


Package | PIN: YZR | 9
Temp: I (-40 to 85)
Carrier: Cut Tape
Qty Price
1-9 $1.21
10-24 $1.08
25-99 $1.00
100-249 $0.86
250-499 $0.79
500-749 $0.64
750-999 $0.51
1000+ $0.46


  • No Output Filter Required for Inductive Loads
  • Externally Configurable Gain
  • Very Fast Turn On Time: 17μs (typ)
  • Minimum External Components
  • Click and pop Suppression Circuitry
  • Micro-Power Shutdown Mode
  • Available in Space-Saving DSBGA Package

Key Specifications

  • Efficiency @ 3.6V, 100mW into 8Ω Speaker: 80 % (typ)
  • Efficiency @ 3.6V, 400mW into 8Ω Speaker: 88 % (typ)
  • Efficiency @ 5V, 1W into 8Ω Speaker: 86 % (typ)
  • Quiescent Current, 3.6V Supply: 2.8 mA (typ)
  • Total Shutdown Power Supply Current: 0.01 µA (typ)
  • Single Supply Range: 2.4 to 5.5 V

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Texas Instruments  LM4671ITL/NOPB

The LM4671 is a single supply, high efficiency 2.5W switching audio amplifier. A low noise, filterless PWM architecture eliminates the output filter, reducing external component count, board area consumption, system cost, and simplifying design.

The LM4671 is designed to meet the demands of mobile phones and other portable communication devices. Operating on a single 5V supply, it is capable of driving a 4Ω speaker load at a continuous average output of 2.1W with less than 1% THD+N. Its flexible power supply requirements allow operation from 2.4V to 5.5V.

The LM4671 has high efficiency with speaker loads compared to a typical Class AB amplifier. With a 3V supply driving an 8Ω speaker, the IC's efficiency for a 100mW power level is 80%, reaching 88% at 400mW output power.

The LM4671 features a low-power consumption shutdown mode. Shutdown may be enabled by driving the Shutdown pin to a logic low (GND).

The gain of the LM4671 is externally configurable which allows independent gain control from multiple sources by summing the signals.