Product details

Audio input type Analog Input Architecture Class-D Boosted Speaker channels (max) Mono Rating Catalog Power stage supply (max) (V) 5.5 Power stage supply (min) (V) 3 Load (min) (Ω) 4 Output power (W) 6.7 SNR (dB) 97 THD + N at 1 kHz (%) 0.04 Iq (typ) (mA) 13.5 Control interface Hardware Closed/open loop Open Analog supply (min) (V) 3 Analog supply voltage (max) (V) 5.5 PSRR (dB) 88 Operating temperature range (°C) -40 to 85
Audio input type Analog Input Architecture Class-D Boosted Speaker channels (max) Mono Rating Catalog Power stage supply (max) (V) 5.5 Power stage supply (min) (V) 3 Load (min) (Ω) 4 Output power (W) 6.7 SNR (dB) 97 THD + N at 1 kHz (%) 0.04 Iq (typ) (mA) 13.5 Control interface Hardware Closed/open loop Open Analog supply (min) (V) 3 Analog supply voltage (max) (V) 5.5 PSRR (dB) 88 Operating temperature range (°C) -40 to 85
WQFN (NHZ) 24 20 mm² 5 x 4
  • 3-W Output into 8 Ω at 5 V With THD+N = 1%
  • Selectable spread spectrum mode reduces EMI
  • 80% Efficiency
  • Independent regulator and amplifier shutdown controls
  • Dynamically Selectable Regulator Output Voltages
  • Filterless Class D
  • 3-V to 5.5-V Operation
  • Low shutdown current
  • Click and pop suppression
  • Key specifications
    • Quiescent power supply current
      • VDD = 3 V 9 mA (Typical)
      • VDD = 5 V 13.5 mA (Typical)
    • PO at VDD = 5 V, PV1 = 7.8 V, RL = 8 Ω,
      THD+N = 1% 3 W (Typical)
    • PO at VDD = 3 V, PV1 = 4.8 V, RL = 8 Ω,
      THD+N = 1% 1 W (Typical)
    • PO at VDD = 5 V, PV1 = 7.8 V, RL = 4 Ω,
      THD+N = 1% 5.4 W (Typical)
    • Shutdown Current at VDD = 3 V, 0.01 µA (Typical)
  • 3-W Output into 8 Ω at 5 V With THD+N = 1%
  • Selectable spread spectrum mode reduces EMI
  • 80% Efficiency
  • Independent regulator and amplifier shutdown controls
  • Dynamically Selectable Regulator Output Voltages
  • Filterless Class D
  • 3-V to 5.5-V Operation
  • Low shutdown current
  • Click and pop suppression
  • Key specifications
    • Quiescent power supply current
      • VDD = 3 V 9 mA (Typical)
      • VDD = 5 V 13.5 mA (Typical)
    • PO at VDD = 5 V, PV1 = 7.8 V, RL = 8 Ω,
      THD+N = 1% 3 W (Typical)
    • PO at VDD = 3 V, PV1 = 4.8 V, RL = 8 Ω,
      THD+N = 1% 1 W (Typical)
    • PO at VDD = 5 V, PV1 = 7.8 V, RL = 4 Ω,
      THD+N = 1% 5.4 W (Typical)
    • Shutdown Current at VDD = 3 V, 0.01 µA (Typical)

The LM48511 device integrates a boost converter with a high-efficiency Class D audio power amplifier to provide 3-W continuous power into an 8-Ω speaker when operating from a 5-V power supply.

When operating from a 3-V to 4-V power supply, the LM48511 can be configured to drive 1 to 2.5 W into an 8-Ω load with less than 1% distortion (THD+N). The Class D amplifier features a low-noise PWM architecture that eliminates the output filter, reducing external component count, board area consumption, system cost, and simplifying design. A selectable spread spectrum modulation scheme suppresses RF emissions, further reducing the need for output filters.

The switching regulator of the LM48511 is a current-mode boost converter operating at a fixed frequency of 1 MHz. Two selectable feedback networks allow the LM48511 regulator to dynamically switch between two different output voltages, improving efficiency by optimizing the amplifier’s supply voltage based on battery voltage and output power requirements.

The LM48511 is designed for use in portable devices, such as GPS, mobile phones, and MP3 players. The high, 80% efficiency at 5 V, extends battery life when compared to Boosted Class AB amplifiers. Independent regulator and amplifier shutdown controls optimize power savings by disabling the regulator when high-output power is not required.

The gain of the LM48511 is set by external resistors, which allows independent gain control from multiple sources by summing the signals. Output short circuit and thermal overload protection prevent the device from damage during fault conditions. Superior click and pop suppression eliminates audible transients during power-up and shutdown.

The LM48511 device integrates a boost converter with a high-efficiency Class D audio power amplifier to provide 3-W continuous power into an 8-Ω speaker when operating from a 5-V power supply.

When operating from a 3-V to 4-V power supply, the LM48511 can be configured to drive 1 to 2.5 W into an 8-Ω load with less than 1% distortion (THD+N). The Class D amplifier features a low-noise PWM architecture that eliminates the output filter, reducing external component count, board area consumption, system cost, and simplifying design. A selectable spread spectrum modulation scheme suppresses RF emissions, further reducing the need for output filters.

The switching regulator of the LM48511 is a current-mode boost converter operating at a fixed frequency of 1 MHz. Two selectable feedback networks allow the LM48511 regulator to dynamically switch between two different output voltages, improving efficiency by optimizing the amplifier’s supply voltage based on battery voltage and output power requirements.

The LM48511 is designed for use in portable devices, such as GPS, mobile phones, and MP3 players. The high, 80% efficiency at 5 V, extends battery life when compared to Boosted Class AB amplifiers. Independent regulator and amplifier shutdown controls optimize power savings by disabling the regulator when high-output power is not required.

The gain of the LM48511 is set by external resistors, which allows independent gain control from multiple sources by summing the signals. Output short circuit and thermal overload protection prevent the device from damage during fault conditions. Superior click and pop suppression eliminates audible transients during power-up and shutdown.

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Technical documentation

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Type Title Date
* Data sheet LM48511 3-W, Ultra-Low EMI, Filterless, Mono, Class D Audio Power Amplifier With Spread Spectrum datasheet (Rev. K) PDF | HTML 08 Oct 2019
Application note Guidelines for Measuring Audio Power Amplifier Performance (Rev. A) 26 Aug 2019
Application note AN-1849 An Audio Amplifier Power Supply Design (Rev. C) 27 Jun 2019
Application note AN-1737 Managing EMI in Class D Audio Applications (Rev. A) 01 May 2013
EVM User's guide AN-1922 LM48511 Evaluation Board User's Guide (Rev. C) 01 May 2013
More literature LM48511SQ Demo Board Description and Setup Instructions 26 Jan 2012

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Evaluation board

LM48511SQBD — The LM48511 Integrates a Boost Converter with a High Efficiency

This LM48511SQDB is an evaluation board designed to ease the evaluation and effort during the development of a circuit using the LM48511SQ. It is an easy to use stand-alone board that requires power and GND, an input signal and an output load.

User guide: PDF
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PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
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WQFN (NHZ) 24 Ultra Librarian

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