80mW, Capless, Stereo Headphone Amplifier with Shutdown
80mW, Capless, Stereo Headphone Amplifier with Shutdown

The SGM4918 is stereo headphone amplifier which is designed for portable applications and can operate from a 2.7V to 5.1V single supply. Capless design can produce a ground-referenced output from a single power supply, and can eliminate output DC-blocking capacitors for less-component height and low-cost. For SGM4918B, the internal gain setting (-2V/V) is to further reduce component count. For SGM4918A, the gain can be adjusted by external feedback resistors.

The SGM4918 has low quiescent current 5.8mA at 5V supply, low 0.03% THD+N, 80mW per channel into 32Ω load from 5V power supply at THD+N = 0.1%. The high supply rejection ratio (PSRR) of -78dB at 217Hz allows the device to operate from noisy digital supplies without an additional linear regulator. The device provides short-circuit and thermal-overload protections. Build-in shutdown control also helps for pop/click-free on/off control.

The SGM4918 is available in a Green TQFN-3×3-10L package. It operates over an ambient temperature range of -40 to +85.



  • Supply Voltage Range: 2.7V to 5.1V

  • SGM4918A: External Feedback Gain Network

    SGM4918B: Fixed -2V/V Gain

  • Capless Structure

    Eliminates Ground-Referenced Outputs

    Eliminates Output DC-Blocking Capacitors

    Provides Flat Frequency Response

  • 80mW into 32Ω Load from 5V Power Supply at THD+N = 0.1% (Typical, per Channel)

  • THD+N = 0.03% (f = 1kHz)

  • High PSRR: -78dB (at 217Hz)

  • Quiescent Current: 5.8mA (TYP)

  • Shutdown Control

  • Short-Circuit and Thermal-Overload Protections

  • Under-Voltage Lockout Function

  • -40 to +85 Operating Temperature Range

  • Available in a Green TQFN-3×3-10L Package


Smart Phones

Portable Audio Equipment

Notebook PCs


Part Number Status Package Pins Pb-Free Temp Range
SGM4918AYD10G/TR Production TDFN-3×3-10L 10 Y -40℃ to +85℃ Samples
SGM4918BYD10G/TR Production TDFN-3×3-10L 10 Y -40℃ to +85℃ Samples