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
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.