Datasheet

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LM48511

www.ti.com

SNAS416G –JULY 2007–REVISED MAY 2013

LM48511 3W, Ultra-Low EMI, Filterless, Mono, Class D

Audio Power Amplifier with Spread Spectrum

Check for Samples: LM48511

FEATURES

DESCRIPTION

The LM48511 integrates a boost converter with a

• 3W Output into 8Ω at 5V with THD+N = 1%

high efficiency Class D audio power amplifier to

• Selectable Spread Spectrum Mode Reduces

provide 3W continuous power into an 8Ω speaker

EMI

when operating from a 5V power supply. When

• 80% Efficiency

operating from a 3V to 4V power supply, the

LM48511 can be configured to drive 1 to 2.5W into

• Independent Regulator and Amplifier

an 8Ω load with less than 1% distortion (THD+N).

Shutdown Controls

The Class D amplifier features a low noise PWM

• Dynamically Selectable Regulator Output

architecture that eliminates the output filter, reducing

Voltages

external component count, board area consumption,

system cost, and simplifying design. A selectable

• Filterless Class D

spread spectrum modulation scheme suppresses RF

• 3.0V – 5.5V Operation

emissions, further reducing the need for output filters.

• Low Shutdown Current

The LM48511’s switching regulator is a current-mode

• Click and Pop Suppression

boost converter operating at a fixed frequency of

1MHz. Two selectable feedback networks allow the

APPLICATIONS

LM48511 regulator to dynamically switch between

two different output voltages, improving efficiency by

• GPS

optimizing the amplifier’s supply voltage based on

• Portable media

battery voltage and output power requirements.

• Cameras

The LM48511 is designed for use in portable devices,

• Mobile Phones

such as GPS, mobile phones, and MP3 players. The

• Handheld games

high, 80% efficiency at 5V, extends battery life when

compared to Boosted Class AB amplifiers.

KEY SPECIFICATIONS

Independent regulator and amplifier shutdown

controls optimize power savings by disabling the

• Quiescent Power Supply Current

regulator when high output power is not required.

– V

= 3V 9mA (typ)

The gain of the LM48511 is set by external resistors,

– V

= 5V 13.5mA (typ)

which allows independent gain control from multiple

• P

at V

= 5V, PV1 = 7.8V, R

= 8Ω,

sources by summing the signals. Output short circuit

THD+N = 1% 3.0W (typ)

and thermal overload protection prevent the device

from damage during fault conditions. Superior click

• P

at V

= 3V, PV1 = 4.8V, R

= 8Ω,

and pop suppression eliminates audible transients

THD+N = 1% 1W (typ)

during power-up and shutdown.

• P

at V

= 5V, PV1 = 7.8V, R

= 4Ω,

THD+N = 1% 5.4W (typ)

• Shutdown Current at V

= 3V 0.01μA (typ)

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (25 pages)

PAGE 1
LM48511 www.ti.com LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 3W, Ultra-Low EMI, Filterless, Mono, Class D Audio Power Amplifier with Spread Spectrum Check for Samples: LM48511 FEATURES DESCRIPTION • • The LM48511 integrates a boost converter with a high efficiency Class D audio power amplifier to provide 3W continuous power into an 8Ω speaker when operating from a 5V power supply. When operating from a 3V to 4V power supply, the LM48511 can be configured to drive 1 to 2.
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LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com EMI Graph 55.0 FCC Class B Limit AMPLITUDE (dBPV/m) 50.0 45.0 40.0 LM45811 EMI Spectrum 35.0 30.0 25.0 20.0 30.0 100.0 200.0 300.0 400.0 500.0 600.0 700.0 800.0 900.0 1000.0 FREQUENCY (MHz) Figure 1. LM48511 RF Emissions — 3 inch cable Typical Application +3.0V to +5.5V L1 6.8 PH CS1 10 PF VDD D1 C2 100 PF SW C1 280 pF R3 25.5 k: SD_BOOST REGGND R4 2.5 k: MODULATOR FB SOFTSTART R2 9.31 k: CSS 0.1 PF R1 4.
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LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 SD_BOOST REGGND REGGND FB_GND0 FB_GND1 Connection Diagram 24 23 22 21 20 18 VDD SW 3 17 VGO- SOFTSTART 4 16 IN+ SD_AMP 5 15 IN- SS/FF 6 14 VGO+ GND 7 13 V1 8 9 10 11 12 LS- 2 LSGND SW PV1 19 FB LSGND 1 LS+ FB_SEL Figure 3. 24-Pin WQFN Top View See NHZ0024B Package PIN DESCRIPTIONS WQFN-24 Pin 1 Name Function Regulator Feedback Select. Connect to VDD to select feedback network connected to FB_GND1.
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LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com PIN DESCRIPTIONS (continued) WQFN-24 Pin Name Function To be soldered to board for enhanced thermal dissipation. Connect to GND plane. DAP These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.
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LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 Electrical Characteristics VDD = 5.0V (1) (2) (3) The following specifications apply for VDD = 5.0V, PV1 = 7.8V (continuos mode), AV = 2V/V, R3 = 25.5kΩ, RLS = 4.87kΩ, RL = 8Ω, f = 1kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA = 25°C. Symbol Parameter Conditions LM48511 Typical (4) Limit (5) Units (Limits) VIN = 0, RLOAD = ∞ IDD Quiescent Power Supply Current Fixed Frequency Mode (FF) 13.
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LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com Electrical Characteristics VDD = 5.0V(1)(2)(3) (continued) The following specifications apply for VDD = 5.0V, PV1 = 7.8V (continuos mode), AV = 2V/V, R3 = 25.5kΩ, RLS = 4.87kΩ, RL = 8Ω, f = 1kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA = 25°C.
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LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 Electrical Characteristics VDD = 3.6V(1)(2)(3) (continued) The following specifications apply for VDD = 3.6V, PV1 = 7V (continuous mode), AV = 2V/V, R3 = 25.5kΩ, RLS = 5.36kΩ, RL = 8Ω, f = 1kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA = 25°C. Symbol Parameter Conditions LM48511 Typical (4) Limit (5) Units (Limits) RL = 8Ω, f = 1kHz, BW = 22kHz PO Output Power THD+N = 1% FF SS 2.5 2.5 W W THD+N = 10% FF SS 3.0 3.
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LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com Electrical Characteristics VDD = 3.0V (1) (2) (3) The following specifications apply for VDD = 3.0V, PV1 = 4.8V (continuos mode), AV = 2V/V, R3 = 25.5kΩ, RLS = 9.31kΩ, RL = 8Ω, f = 1kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA = 25°C.
PAGE 9
LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 Electrical Characteristics VDD = 3.0V(1)(2)(3) (continued) The following specifications apply for VDD = 3.0V, PV1 = 4.8V (continuos mode), AV = 2V/V, R3 = 25.5kΩ, RLS = 9.31kΩ, RL = 8Ω, f = 1kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA = 25°C.
PAGE 10
LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics THD+N vs Frequency VDD = 3.6V, RL = 8Ω PO = 500mW, filter = 22kHz, PV1 = 4.8V 10 10 1 1 FIXED FREQUENCY FIXED FREQUENCY THD+N (%) THD+N (%) THD+N vs Frequency VDD = 5V, RL = 8Ω PO = 2W, filter = 22kHz, PV1 = 7.8V 0.1 0.1 0.01 0.01 SPREAD SPECTRUM SPREAD SPECTRUM 0.001 20 200 2k 20k 0.001 20 2k 20k FREQUENCY (Hz) Figure 4. Figure 5. THD+N vs Frequency VDD = 3V, RL = 8Ω PO = 1.
PAGE 11
LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 Typical Performance Characteristics (continued) THD+N vs Output Power VDD = 3V, 3.6V, 5V, RL = 8Ω f = 1kHz, filter = 22kHz, R1 = 4.87kΩ, FF THD+N vs Output Power VDD = 3.6V, RL = 8Ω filter = 22kHz, PV1 = 7.8V, PV1 = 7V, PV1 = 4.8V, FF 10 10 3V 9.31 k: THD+N (%) 1 THD+N (%) 1 3.6V 5.35 k: 0.1 4.87 k: 0.1 5V 0.01 10m 100m 1 0.01 10m 5 100m OUTPUT POWER (W) Figure 11.
PAGE 12
LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) PSRR vs Frequency VDD = 3V, RL = 8Ω VRIPPLE = 200mVPP, PV1 = 4.8V 0 0 -20 -20 -40 PSRR (dB) PSRR (dB) PSRR vs Frequency VDD = 3.6V, RL = 8Ω VRIPPLE = 200mVPP, PV1 = 7V FIXED FREQUENCY -60 SPREAD SPECTRUM -40 -60 SPREAD SPECTRUM -80 -80 -100 20 200 2k FIXED FREQUENCY -100 20 20k 200 2k 20k FREQUENCY (Hz) FREQUENCY (Hz) Figure 16. Figure 17.
PAGE 13
LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 Typical Performance Characteristics (continued) Power Dissipation vs Output Power VDD = 3.6V, RL = 8Ω PV1 = 7V, FF Power Dissipation vs Output Power VDD = 3V, RL = 8Ω PV1 = 4.8V, FF 1.8 0.5 0.4 POWER DISSIPATION (W) POWER DISSIPATION (W) 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.3 0.2 0.1 0.2 0 0.5 1.0 1.5 2.0 2.5 3.0 0 3.5 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 OUTPUT POWER (W) OUTPUT POWER (W) Figure 22. Figure 23.
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LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com APPLICATION INFORMATION GENERAL AMPLIFIER FUNCTION The LM48511 features a Class D audio power amplifier that utilizes a filterless modulation scheme, reducing external component count, conserving board space and reducing system cost. The outputs of the device transition from PV1 to GND with a 300kHz switching frequency. With no signal applied, the outputs (VLS+ and VLS-) switch with a 50% duty cycle, in phase, causing the two outputs to cancel.
PAGE 15
LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 SHUTDOWN FUNCTION The LM48511 features independent amplifier and regulator shutdown controls, allowing each portion of the device to be disabled or enabled independently. SD_AMP controls the Class D amplifiers, while SD_BOOST controls the regulator. Driving either inputs low disables the corresponding portion of the device, and reducing supply current.
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LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com PROPER SELECTION OF EXTERNAL COMPONENTS Proper selection of external components in applications using integrated power amplifiers, and switching DC-DC converters, is critical for optimizing device and system performance. Consideration to component values must be used to maximize overall system quality. The best capacitors for use with the switching converter portion of the LM48511 are multi-layer ceramic capacitors.
PAGE 17
LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 SELECTING REGULATING BYPASS CAPACITOR A supply bypass capacitor is required to serve as an energy reservoir for the current which must flow into the coil each time the switch turns on. This capacitor must have extremely low ESR, so ceramic capacitors are the best choice. A nominal value of 10μF is recommended, but larger values can be used.
PAGE 18
LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com INDUCTOR SUPPLIES The recommended inductor for the LM48511 is the IHLP-2525CZ-01 from Vishay Dale. When selecting an inductor, the continuous current rating must be high enough to avoid saturation at peak currents. A suitable core type must be used to minimize switching losses, and DCR losses must be considered when selecting the current rating. Use shielded inductors in systems that are susceptible to RF interference.
PAGE 19
LM48511 www.ti.com SNAS416G – JULY 2007 – REVISED MAY 2013 CALCULATING REGULATOR OUTPUT CURRENT The load current of the boost converter is related to the average inductor current by the relation: IAMP = IINDUCTOR(AVE) x (1 - DC) (A) (12) Where "DC" is the duty cycle of the application.
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LM48511 SNAS416G – JULY 2007 – REVISED MAY 2013 www.ti.com REVISION HISTORY Rev Date 1.0 07/24/07 Initial released. Description 1.1 07/25/07 Input some text edits. 1.2 09/25/07 Changed the Amplifier Voltage (Operating Ratings section) from 5.0V to 4.8V. 1.3 11/06/07 Added another PO (@VDD = 5V, RL = 4Ω) section in the Key Specification division. 1.4 02/25/08 Edited the Notes section. 1.5 02/28/12 Deleted the “Build of Materials” (BOM) table. 1.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM48511SQ/NOPB WQFN NHZ 24 1000 178.0 12.4 4.3 5.3 1.3 8.0 12.0 Q1 LM48511SQX/NOPB WQFN NHZ 24 4500 330.0 12.4 4.3 5.3 1.3 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM48511SQ/NOPB WQFN NHZ 24 1000 210.0 185.0 35.0 LM48511SQX/NOPB WQFN NHZ 24 4500 367.0 367.0 35.
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MECHANICAL DATA NHZ0024B SQA24B (Rev A) www.ti.
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