Catalog
30 W, Filterless, Class-D, Output Sensing Audio Amplifier
Key Features
• Filterless digital input, mono Class D amplifier with Σ-Δ modulation
• Digitized output of output voltage, output current, and PVDDsupply voltage
• Operates from 4.5 V to 17 V supply, such as a 2- or 3-cell battery
• Input/output supply operation from 1.1 V to 1.98 V
• 30.2 W output power, 17 V supply and 4 Ω load at 1% THD+N
• 37.5 μV rms noise, 107 dB A weighted signal-to-noise ratio
• I2C control with up to 4 pin selectable addresses
• Multiple serial data formatsTDM, I2S, or left justified slavePDM input/output operating from 2.048 MHz to 6.144 MHz
• TDM, I2S, or left justified slave
• PDM input/output operating from 2.048 MHz to 6.144 MHz
• Support sample rates from 8 kHz to 192 kHz
• Flexible digital and analog gain adjustment
• AGC with battery voltage-based limiter
• 74 dB SNR on output current sensing and 85 dB SNR on voltage sensing
• 6.62 mA quiescent current at 12 V PVDDsupply
• Temperature sensor with 1°C readout
• Short-circuit, thermal protection, and thermal warning
• 23-ball, 2.26 mm × 2.38 mm ,0.4 mm pitch WLCSP
• Pop and click suppression
• User-selectable ultralow EMI emissions mode
• Power-on reset
Description
AI
The SSM3525 is a fully integrated, high efficiency, mono Class D audio amplifier with digital input and digitized output of output voltage, output current, and PVDDsupply. The application circuit requires few external components and can operate from 4.5 V to 17 V (PVDD) and 1.8 V (IOVDD) supplies. It is capable of delivering 8.3 W of continuous output power into an 8 Ω load (or 15.3 W into 4 Ω) with <1% THD + N from a 12 V supply, or 30.2 W into an 4 Ω load from a 17 V power supply, all with <1% THD + N.The SSM3525 features a high efficiency, low noise modulation scheme that requires no external inductor/capacitor (LC) output filters. This scheme continues to provide high efficiency even at low output power. It operates with 92% efficiency at 9W into an 8 Ω load, 12V or 89% efficiency at 20 W into 4 Ω from a 17 V supply, (should now match the table)and it has an signal-to-noise ratio (SNR) of 107 dB A weighted.Spread spectrum pulse density modulation provides lower electromagnetic interference (EMI) radiated emissions compared with other Class-D architectures, particularly above 100 MHz.The digital input eliminates the need of an external digital-to-analog converter (DAC). The SSM3525 has a micropower shutdown mode with a typical shut¬down current of 90 nA at 12 V PVDDsupply. Individual sense blocks can be powered down to save power when sense is not needed.The device also includes pop and click suppression circuitry that minimizes voltage glitches at the output during turn on and turn off.Current sensing is accomplished using an integrated analog-to-digital converter (ADC) and internal sense resistor. The digitized voltage and current information can be returned in various serial audio formats, including I2S, time division multiplexing (TDM) and pulse density modulation (PDM).The SSM3525 includes an integrated regulator to generate the required 5 V analog supply. Alternatively, if an external 5 V rail from a dc-to-dc converter is available, it can improve system efficiency.The SSM3525 is designed to operate with an I2C control interface and specified over the temperature range −40°C to +85°C. It has built-in thermal shutdown and output short-circuit protection. It is available in a halide free, 23-ball, 2.26 mm × 2.38 mm wafer-level chip scale package (WLCSP).ApplicationsMobile computingPortable electronics