The SSM2317 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 3 W of continuous output power with <1% THD + N driving a 3 Ω load from a 5.0 V supply.
The SSM2317 features a high efficiency, low noise modulation scheme that does not require any external LC output filters. The modulation continues to provide high efficiency even at low output power. It operates with 93% efficiency at 1.4 W into 8 Ω or 85% efficiency at 3 W into 3 Ω from a 5.0 V supply and has an SNR of >93 dB. Spread-spectrum pulse density modulation is used to provide lower EMI radiated emissions compared with other Class-D architectures.
Automatic level control (ALC) can be activated to suppress clipping and improve dynamic range. This feature only requires one external resistor tied to GND via the VTH pin and an activation voltage on the ALC_EN pin.
The SSM2317 has a micropower shutdown mode with a typical shutdown current of 20 nA. Shutdown is enabled by applying a logic low to the SD pin.
The device also includes pop-and-click suppression circuitry. This minimizes voltage glitches at the output during turn-on and turn-off, reducing audible noise on activation and deactivation.
The default gain of the SSM2317 is 18 dB, but users can reduce the gain by using a pair of external resistors.
The SSM2317 is specified over the commercial temperature range of −40°C to +85°C. It has built-in thermal shutdown and output short-circuit protection. It is available in a 9-ball, 1.5 mm × 1.5 mm wafer level chip scale package (WLCSP).
**Applications**
Mobile phones
MP3 players
Portable gaming
Portable electronics
Educational toys
### Features and Benefits
Filterless Class-D amplifier with Σ-Δ modulation
Automatic level control (ALC) improves dynamic range and prevents clipping
3 W into 3 Ω load and 1.4 W into 8 Ω load at 5.0 V supply with <10% total harmonic distortion (ALC off)
700 mW into 8 Ω load at 4.2 V supply (ALC 80%)
93% efficiency at 5.0 V, 1.4 W into 8 Ω speaker
>93 dB signal-to-noise ratio (SNR)
Single-supply operation from 2.5 V to 5.5 V
20 nA ultralow shutdown current
Short-circuit and thermal protection
Available in 9-ball, 1.5 mm × 1.5 mm WLCSP
Pop-and-click suppression
Built-in resistors reduce board component count
Default fixed 18 dB or user-adjustable gain setting
