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Mono Class AB Audio Subsystem with a True Ground Headphone Amplifier and Earpiece Switch


Package | PIN: YFQ | 25
Temp: I (-40 to 85)
Carrier: Cut Tape
Qty Price
1-9 $2.86
10-24 $2.57
25-99 $2.39
100-249 $2.10
250-499 $1.97
500-749 $1.67
750-999 $1.41
1000+ $1.35


  • Differential Mono Input and Stereo Single-Ended Input
  • Separate Earpiece (Receiver) Differential Input
  • Analog Switch for a Separate Earpiece Path
  • 32-Step Digital Volume Control (-80 to +18dB)
  • Three Independent Volume Channels (Left, Right, Mono)
  • Separate Headphone Volume Control
  • Flexible Output for Speaker and Headphone Output
  • True Ground Headphone Amplifier Eliminates Large DC Blocking Capacitors Reducing PCB Space and Cost
  • Hardware Reset Function
  • RF Immunity Topology
  • “Click and Pop” Suppression Circuitry
  • Thermal Shutdown Protection
  • Micro-Power Shutdown
  • I2C Control Interface
  • Available in Space-Saving DSBGA Package

Key Specifications

  • Supply Voltage (VDDLS): 2.7V ≤ VDDLS ≤ 5.5V
  • Supply Voltage (VDDHP): 1.8V ≤ VDDHP ≤ 2.9V
  • I2C Supply Voltage: 1.7V ≤ I2CVDD ≤ 5.5V
  • Output Power, VDDLS = 5V, VDDHP = 2.75V, 1% THD+N
    • RL = 8Ω Speaker 1.3W (Typ)
    • RL = 32Ω Headphone 45mW (Typ)
  • Output Power VDDLS = 3.3V, VDDHP = 2.75V, 1% THD+N
    • RL = 8Ω Speaker 540W (Typ)
    • RL = 32Ω Headphone 40mW (Typ)
  • PSRR: VDD = 3.3V, 217Hz Ripple, Mono In: 90dB (Typ)
  • Shutdown Power Supply Current: 0.01μA (Typ)

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Texas Instruments  LM49101TM/NOPB

The LM49101 is a fully integrated audio subsystem with a mono power amplifier capable of delivering 540mW of continuous average power into an 8Ω BTL speaker load with 1% THD+N using a 3.3V supply. The LM49101 includes a separate stereo headphone amplifier that can deliver 44mW per channel into 32Ω loads using a 2.75V supply.

The LM49101 has four input channels. A pair of single-ended inputs and a fully differential input channel with volume control and amplification stages. Additionally, a bypass differential input is available that connects directly to the mono speaker outputs through an analog switch without any amplification or volume control stages. The LM49101 features a 32–step digital volume control on the input stage and an 8–step digital volume control on the headphone output stage.

The digital volume control and output modes, programmed through a two-wire I2C compatible interface, allows flexibility in routing and mixing audio channels.

The LM49101 is designed for cellular phones, PDAs, and other portable handheld applications. The high level of integration minimizes external components. The True Ground headphone amplifier eliminates the physically large DC blocking output capacitors reducing required board space and reducing cost.