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 modu-lation 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 signifi-cantly 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, indepen-dent of the gain select operation.
The SSM2377 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, 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 out-of-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).
|Title||Content Type||File Type|
|SSM2377: Filterless, High Efficiency,Mono 2.5 W Class-D Audio Amplifier (Rev 0, 05/2011) (pdf, 474 kB)||Data Sheets|
|UG-298: Evaluation Board for the SSM2377 Filterless, Class-D Audio Amplifier (PDF, 289 kB)||User Guides|
|Glossary of EE Terms||Glossary||HTML|
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