SSM4567
PRODUCTIONDigital 2.5 W, 5.1 V, Boost Class-D Audio Amplifier with Output Sensing
Part Details
- Filterless Class-D amplifier with spread-spectrum Σ-Δ modulation with integrated boost regulator (5.1 V)
- Digitized output of output voltage, output current, and VBAT supply voltage
- Integrated boost regulator
- Multiple serial data formats
- PDM input/output
- TDM slave with support for up to 8 chips on a single bus
- I2S or left justified slave
- Multichip I2S with support for up to 4 chips on one I2S bus
- 8 kHz to 192 kHz PCM sample rates
- 2.048 to 6.14 MHz PDM input sample rates
- Configurable via I2C control, TDM control, or PDM patterns
- Standalone control modes
- 2.5 W into 4 Ω load and 1.42 W into 8 Ω load at 3.6 V supply with <1% total harmonic distortion plus noise (THD + N)
- Available in 19-ball, 1.74 mm × 2.1 mm, 0.4 mm pitch WLCSP
- 89.7% system efficiency into 8 Ω at 1 W, VBAT = 3.6 V
- Output noise: 21.7 μV rms, A-weighted
- THD + N: 0.025% at 1 kHz, 500 mW output power
- PSSR: 90 dB at 217 Hz, with dither input
- 72 dB signal-to-noise ratio (SNR) on output current sensing and 77 dB SNR on voltage sensing
- Quiescent power consumption: 19.8 mW
- Pop-and-click suppression
- Flexible battery monitoring AGC
- Short-circuit protection for boost and Class-D outputs and thermal protection with automatic recovery
- Smart power-down when PDM stop condition or no clock input detected
- DC blocking high-pass filter and static input DC protection for PDM input
- Selectable ultralow EMI emissions and low latency modes
The SSM4567 is a digital input Class-D power amplifier that includes an integrated boost converter, allowing higher output power than with a normal battery supply. This means that maximum output power is constant across the battery voltage range. The SSM4567 is ideal for power sensitive applications where system noise can corrupt the small analog signal sent to the amplifier, such as mobile phones, tablets, and portable media players.
The SSM4567 combines an audio digital-to-analog converter (DAC), a power amplifier, and PDM or PCM (I2S/TDM) digital audio interfaces on a single chip. Using the SSM4567, audio can be transmitted digitally to the audio amplifier, significantly reducing the effect of noise sources on the transmitted audio and eliminate the need for input coupling capacitors. The SSM4567 is capable of delivering 2.5 W of continuous output power with <1% THD + N driving a 4 Ω load from a 3.6 V supply.
The SSM4567 can be controlled by I2C, PDM pattern control, or TDM control. It can also operate in standalone mode without a control interface.
The SSM4567 includes circuitry to sense output current, output voltage, and the VBAT supply voltage. Current sensing is performed using an on-chip sense resistor that is connected between an output pin and the load. Output current and voltage are sent to an ADC. The outputs of these ADCs are available on the digital serial output port. The VBAT supply voltage can be used with an automatic gain control circuit that is fully configurable. This AGC can limit the maximum output at low battery voltages to avoid drawing too much current from the battery, thereby extending battery life.
The SSM4567 features a high efficiency, low noise modulation scheme that requires no external LC output filters. The closed-loop, five-level modulator design retains the benefits of an all digital amplifier, yet enables very good PSRR and audio performance. The modulation continues to provide high efficiency even at low output power and has an SNR of 104 dB, A-weighted. Spread spectrum pulse density modulation is used to provide lower EMI radiated emissions compared with other Class-D architectures.
The SSM4567 has a micropower shutdown mode with a typical shutdown current of 0.2 μA for the VBAT power supply. Shutdown is enabled automatically by gating input clock and data signals.
The SSM4567 is specified over the industrial temperature range of −40°C to +85°C. It has a built-in thermal shutdown and amplifier and boost output short-circuit protection. It is available in a 19-ball, 1.74 mm × 2.1 mm wafer level chip scale package (WLCSP).
APPLICATIONS
- Mobile handsets
- Tablets
- Portable media players
Documentation
Data Sheet 1
User Guide 1
Device Drivers 1
This is the most up-to-date revision of the Data Sheet.
Software Resources
Device Drivers 1
Evaluation Software 0
Tools & Simulations
IBIS Model 1
Evaluation Kits
SSM4567 Evaluation Board