SSM2377 Filterless, High Efficiency, Mono 2.5 W Class-D Audio Amplifier

The SSM2377 is a fully integrated, high efficiency, Class-D audio amplifier. It is designed to maximize performance for mobile phone applications. The application circuit requires a minimum of external components and operates from a single 2.5 V to 5.5 V supply. It is capable of delivering 2.5 W of continuous output power with <1% THD + N driving a 4 Ω load from a 5.0 V supply.

The SSM2377 features a high efficiency, low noise modulation scheme that requires no external LC output filters. The modulation operates with high efficiency even at low output power.

The SSM2377 operates with 92% efficiency at 1.4 W into 8 Ω from a 5.0 V supply and has an SNR of >100 dB.

Spread-spectrum pulse density modulation (PDM) is used to provide lower EMI-radiated emissions compared with other Class-D architectures. The inherent randomized nature of spread-spectrum PDM eliminates the clock intermodulation (beating effect) of several amplifiers in close proximity.

The SSM2377 produces ultralow EMI emissions that significantly reduce the radiated emissions at the Class-D outputs, particularly above 100 MHz. The SSM2377 passes FCC Class B radiated emission testing with 50 cm, unshielded speaker cable without any external filtering. The ultralow EMI emissions of the SSM2377 are also helpful for antenna and RF sensitivity problems.

The device is configured for either a 6 dB or a 12 dB gain setting by connecting the GAIN pin to the VDD pin or the GND pin, respectively. Input impedance is a fixed value of 80 kΩ, independent of the gain select operation.

The SSM2377 has a micropower shutdown mode with a typical shutdown current of 100 nA. Shutdown is enabled by applying a logic low to the SD pin.

The device also includes pop-and-click suppression circuitry, which minimizes voltage glitches at the output during turn-on and turn-off, reducing audible noise on activation and deactivation. Built-in input low-pass filtering is also included to suppress outof-band noise interference to the PDM modulator.

The SSM2377 is specified over the industrial temperature range of −40°C to +85°C. It has built-in thermal shutdown and output short-circuit protection. It is available in a halide-free, 9-ball, 0.4 mm pitch, 1.2 mm × 1.2 mm wafer level chip scale package (WLCSP).

  • Mobile phones
  • MP3 players
  • Portable electronics
Features and Benefits
  • Filterless, Class-D amplifier with spread-spectrum Σ-Δ modulation
  • 2.5 W into 4 Ω load and 1.4 W into 8 Ω load at 5.0 V supply with <1% total harmonic distortion plus noise (THD + N)
  • 92% efficiency at 5.0 V, 1.4 W into 8 Ω speaker
  • >100 dB signal-to-noise ratio (SNR)
  • High PSRR at 217 Hz: 80 dB
  • Ultralow EMI emissions
  • Single-supply operation from 2.5 V to 5.5 V
  • Gain select function: 6 dB or 12 dB
  • Fixed input impedance of 80 kΩ
  • 100 nA shutdown current
  • Short-circuit and thermal protection with autorecovery
  • Available in a 9-ball, 1.2 mm × 1.2 mm WLCSP
  • Pop-and-click suppression
  • Audio & Video Products
    Data Sheets
    SSM2377: Filterless, High Efficiency,Mono 2.5 W Class-D Audio Amplifier (Rev. 0)PDF 474 kB
    User Guides
    UG-298: Evaluation Board for the SSM2377 Filterless, Class-D Audio AmplifierPDF 289 kB
    Order Information
    Part NumberPackagePacking QtyTemp RangePrice 100-499Price 1000+RoHS
    SSM2377ACBZ-R7 Production9 ball WLCSP (1.24x1.24)REEL 3000-40 to 85C00.59Y
    SSM2377ACBZ-RL Production9 ball WLCSP (1.24x1.24)REEL 10000-40 to 85C00.59Y
    Evaluation Boards
    Part NumberDescriptionPriceRoHS
    EVAL-SSM2377ZEvaluation Board60Y
    SSM2377:无滤波器、高效率、单声道2.5 W D类音频放大器 (Rev. 0) ssm2377
    SSM2377: Filterless, High Efficiency,Mono 2.5 W Class-D Audio Amplifier (Rev. 0) ssm2377
    UG-298: Evaluation Board for the SSM2377 Filterless, Class-D Audio Amplifier ssm2377