PDM Input Class D Audio Power Amplifier

 

Part Number	Replacement	Explanation

Description

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The MAX98358 is a digital pulse-density modulated (PDM) input Class D power amplifier that provides Class AB audio performance with Class D efficiency. This IC offers five selectable gain settings (3dB, 6dB, 9dB, 12dB, and 15dB) set by a single gain-select input (GAIN). The IC can be configured to produce a left channel, right channel, or (left/2 + right/2) output from the stereo input data.

The MAX98358 takes a stereo pulse density modulated (SPDM) input signal directly into the DAC. Data on the rising edge of PDM_CLK is considered left-channel data while data on the falling PDM_CLK edge is right channel. A mono sum feature is also implemented with SPDM data input by summing the data from both rising and falling clock edges.

Active emissions-limiting, edge-rate limiting, and overshoot control circuitry greatly reduce EMI. A filterless spread-spectrum modulation scheme eliminates the need for output filtering found in traditional Class D devices and reduces the component count of the solution.

The IC is available in 9-pin WLP (1.345mm x 1.435mm x 0.64mm) and 16-pin TQFN (3mm x 3mm x 0.75mm) packages and is specified over the -40°C to +85°C temperature range.

MAX98358: Simplified Block Diagram Enlarge+

Key Features

• Single-Supply Operation (2.5V to 5.5V)
• 3.2W Output Power into 4Ω at 5V
• 1.8mA Quiescent Current (V_DD = 3.7V)
• 92% Efficiency (R_L = 8Ω, P_OUT = 1.5W)
• 29µV_RMS Output Noise (A_V = 6dB)
• Low 0.013% THD+N at 1kHz
• Supported PDM_CLK Rates of 1.84MHz–4.32MHz and 5.28MHz–8.64MHz
• Supports Left, Right, or Left/2 + Right/2 Outputs
• Sophisticated Edge Rate Control Enables Filterless Class D Outputs
• 77dB PSRR at 217Hz
• Low RF Susceptibility Rejects TDMA Noise from GSM Radios
• Extensive Click-and-Pop Reduction Circuitry
• Robust Short-Circuit and Thermal Protection
• Available in Space-Saving Packages: 1.345mm x 1.435mm WLP (0.4mm Pitch), 3mm x 3mm TQFN

Applications/Uses

• Cellular Phones
• Notebook and Netbook Computers
• Portable Media Players
• Tablets