LM48511SQ/NOPB - Texas Instruments

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35.0

40.0

45.0

50.0

55.0

AMPLITUDE (dBPV/m)

FREQUENCY (MHz)

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An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

LM48511

SNAS416J –JULY 2007–REVISED OCTOBER 2017

LM48511 3-W, Ultra-Low EMI, Filterless, Mono, Class D Audio Power Amplifier With

Spread Spectrum

1 Features

1• 3-W Output into 8 Ωat 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)

– POat VDD = 5 V, PV1 = 7.8 V, RL= 8 Ω,

THD+N = 1% 3 W (Typical)

– POat VDD = 3 V, PV1 = 4.8 V, RL= 8 Ω,

THD+N = 1% 1 W (Typical)

– POat 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)

2 Applications

• GPS

• Portable media

• Cameras

• Mobile Phones

• Handheld games

3 Description

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-Ωspeaker

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-Ωload 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.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)

LM48511 WQFN (24) 5.00 mm × 4.00 mm

(1) For all available packages, see the orderable addendum at

the end of the data sheet.

EMI Graph: LM48511 RF Emissions — 3-Inch

Cable

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Table of Contents

1 Features.................................................................. 1

2 Applications ........................................................... 1

3 Description............................................................. 1

4 Revision History..................................................... 2

5 Pin Configuration and Functions......................... 4

6 Specifications......................................................... 5

6.1 Absolute Maximum Ratings ...................................... 5

6.2 ESD Ratings.............................................................. 5

6.3 Recommended Operating Conditions....................... 5

6.4 Thermal Information.................................................. 5

6.5 Electrical Characteristics VDD = 5 V.......................... 6

6.6 Electrical Characteristics VDD = 3.6 V....................... 7

6.7 Electrical Characteristics VDD = 3 V.......................... 8

6.8 Typical Characteristics.............................................. 9

7 Detailed Description............................................ 13

7.1 Overview................................................................. 13

7.2 Functional Block Diagram....................................... 13

7.3 Feature Description................................................. 14

7.4 Device Functional Modes........................................ 15

8 Application and Implementation ........................ 16

8.1 Application Information............................................ 16

8.2 Typical Application ................................................. 16

9 Power Supply Recommendations...................... 22

10 Layout................................................................... 22

10.1 Layout Guidelines ................................................. 22

10.2 Layout Example .................................................... 22

11 Device and Documentation Support................. 23

11.1 Receiving Notification of Documentation Updates 23

11.2 Community Resources.......................................... 23

11.3 Trademarks........................................................... 23

11.4 Electrostatic Discharge Caution............................ 23

11.5 Glossary................................................................ 23

12 Mechanical, Packaging, and Orderable

Information........................................................... 23

4 Revision History

NOTE: Page numbers for previous revisions may differ from page numbers in the current version.

Changes from Revision I (August 2017) to Revision J Page

• Changed Pin 20 From: FB_GND0 To: FB_GND1 in the Pin Image and Pin Functions table................................................ 4

• Changed Pin 21 From: FB_GND1 To: FB_GND0 in the Pin Image and Pin Functions table................................................ 4

Changes from Revision H (August 2015) to Revision I Page

• Changed Pin 20 From: FB_GND1 To: FB_GND0 in the Pin Image and Pin Functions table................................................ 4

• Changed Pin 21 From: FB_GND0 To: FB_GND1 in the Pin Image and Pin Functions table................................................ 4

Changes from Revision G (May 2013) to Revision H Page

• Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional

Modes,Application and Implementation section, Power Supply Recommendations section, Layout section, Device

and Documentation Support section, and Mechanical, Packaging, and Orderable Information section .............................. 1

Changes from Revision F (October 2012) to Revision G Page

• Changed layout of National Data Sheet to TI format ........................................................................................................... 20

Changes from Revision D (February 2012) to Revision E Page

• Deleted the Typical limits (Vih and Vil) EC table.................................................................................................................... 6

Changes from Revision C (November 2007) to Revision D Page

• Deleted the “Build of Materials” (BOM) table........................................................................................................................ 20

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Changes from Revision B (September 2007) to Revision C Page

• Edited the Notes section and added another PO(@VDD = 5 V, RL= 4 Ω) section in the Key Specification division............. 1

Changes from Revision A (July 2007) to Revision B Page

• Changed the Amplifier Voltage (Operating Ratings section) from 5 V to 4.8 V..................................................................... 5

Changes from Original (July 2007) to Revision A Page

• Input some text edits .............................................................................................................................................................. 1

1515

FB_SEL

SOFTSTART

GND

LS+

SS/FF

VGO+

IN+

VGO-

REGGND

FB_GND1

FB_GND0

SD_AMP

LSGND

PV1

LSGND

8 9 10 11 12

LS-

IN-

SD_BOOST

24 23 22 21 20

VDD

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5 Pin Configuration and Functions

NHZ Package

24-Pin WQFN

Top View

Pin Functions

PIN I/O DESCRIPTION

NAME NO.

DAP – — To be soldered to board for enhanced thermal dissipation. Connect to GND plane.

FB 19 — Regulator feedback input

Connect FB to an external resistive voltage divider to set the boost output voltage.

FB_GND0 21 — Ground return for R3, R1resistor divider

FB_GND1 20 — Ground return for R3, R2resistor divider

FB_SEL 1 I Regulator feedback select

Connect to VDD to select feedback network connected to FB_GND1. Connect to GND to select feedback network

connected to FB_GND0.

GND 7 — Signal ground

IN– 15 I Amplifier inverting input

IN+ 16 I Amplifier noninverting input

LS+ 8 O Amplifier noninverting output

LS– 12 O Amplifier inverting output

LSGND 9, 11 — Amplifier H-Bridge ground

PV1 10 — Amplifier H-Bridge power supply

Connect to V1.

REGGND 22, 23 — Power ground (booster)

SD_AMP 5 I Amplifier active-low shutdown

Connect to VDD for normal operation. Connect to GND to disable amplifier.

SD_BOOST 24 I Regulator active-low shutdown.

Connect to VDD for normal operation. Connect to GND to disable regulator.

SOFT-START 4 — Soft-start capacitor

SS/FF 6 I Modulation mode select.

Connect to VDD for spread spectrum mode (SS). Connect to GND for fixed frequency mode (FF).

SW 2, 3 — Drain of the internal FET switch

V1 13 — Amplifier supply voltage

Connect to PV1

VDD 18 — Power supply

VG0+ 14 O Amplifier noninverting gain output

VG0– 17 O Amplifier inverting gain output

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(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur, including inoperability and degradation of

device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or

other conditions beyond those indicated in the Recommended Operating Conditions is not implied. TheRecommended Operating

Conditions indicate conditions at which the device is functional and the device must not be operated beyond such conditions. All

voltages are measured with respect to the ground pin, unless otherwise specified.

(2) If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.

(3) The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX,θJJA, and the ambient temperature,

TA. The maximum allowable power dissipation is PDMAX = (TJMAX - TA) / θJA or the number given in Absolute Maximum Ratings,

whichever is lower. For the LM48511, see Figure 20 for additional information.

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2).MIN MAX UNIT

Supply voltage (VDD, PV1, V1) 9 V

Input voltage −0.3 VDD + 0.3 V

Power dissipation(3) Internally limited

Junction temperature 150 °C

Storage temperature −65 150 °C

(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

(2) Machine model, applicable std. JESD22-A115-A.

6.2 ESD Ratings VALUE UNIT

V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V

Machine model(2) ±200

6.3 Recommended Operating Conditions MIN MAX UNIT

Temperature range TMIN ≤TA≤TMAX −40 85 °C

Supply voltage (VDD) 3 5.5 V

Amplifier voltage (PV1, V1) 4.8 8 V

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application

report, SPRA953.

6.4 Thermal Information

THERMAL METRIC(1) LM48511

UNITNHZ (WQFN)

24 PINS

RθJA Junction-to-ambient thermal resistance 32.8 °C/W

RθJC(top) Junction-to-case (top) thermal resistance 3.8 °C/W

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(1) RLis a resistive load in series with two inductors to simulate an actual speaker load for RL= 8Ω, the load is 15μH+8Ω+15μH. For

RL= 4 Ω, the load is 15 μH + 4 Ω+ 15 μH.

(2) Typical values represent most likely parametric norms at TA= +25ºC, and at the Recommended Operation Conditions at the time of

product characterization and are not specified.

(3) Shutdown current is measured with components R1 and R2 removed.

(4) Offset voltage is determined by: (IDD (with load) — IDD (no load)) x RL.

(5) Feedback pin reference voltage is measured with the Audio Amplifier disconnected from the Boost converter (the Boost converter is

unloaded).

6.5 Electrical Characteristics VDD = 5 V

The following specifications apply for VDD = 5 V, PV1= 7.8 V (continuos mode), AV= 2 V/V, R3= 25.5 kΩ, RLS = 4.87 kΩ,

RL= 8 Ω, f = 1 kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA= 25°C.(1)

PARAMETER TEST CONDITIONS MIN TYP(2) MAX UNIT

IDD Quiescent Power Supply

Current VIN = 0, RLOAD =∞Fixed Frequency Mode (FF) 13.5 mA

Spread Spectrum Mode (SS) 14.5 22 mA

ISD Shutdown Current(3) VSD_BOOST = VSD_AMP = SS = FB_SEL = GND 0.11 1 μA

VIH Logic Voltage Input High 1.4 V

VIL Logic Voltage Input Low 0.4 V

TWU Wake-up Time CSS = 0.1 μF 49 ms

VOS Output Offset Voltage See (4) 0.04 3 mV

POOutput Power

RL= 8 Ω

f = 1 kHz, BW = 22 kHz

THD+N = 1%

FF 3 W

SS 2.6 3

RL= 8 Ω

f = 1 kHz, BW = 22 kHz

THD+N = 10%

FF 3.8 W

SS 3.8

RL= 4 Ω

f = 1 kHz, BW = 22 kHz

THD+N = 1%

FF 5.4 W

SS 5.4

RL= 4 Ω

f = 1 kHz, BW = 22 kHz

THD+N = 10%

FF 6.7 W

SS 6.7

THD+N Total Harmonic

Distortion + Noise

PO= 2 W, f = 1 kHz,

RL= 8 Ω

FF 0.03%

SS 0.03%

PO= 3 W, f = 1 kHz,

RL= 4 Ω

FF 0.04%

SS 0.05%

εOS Output Noise

f = 20 Hz to 20 kHz

Inputs to AC GND, No

weighting

FF 32 µVRMS

SS 32

f = 20 Hz to 20 kHz

Inputs to AC GND, A

weighted

FF 22 µVRMS

SS 22

PSRR Power Supply Rejection

Ratio

(Input Referred)

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 217 Hz

FF 88 dB

SS 87

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 1 kHz

FF 88 dB

SS 85

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 10 kHz

FF 77 dB

SS 76

CMRR Common-Mode

Rejection Ratio

(Input Referred)

VRIPPLE = 1 VP-P, fRIPPLE = 217 Hz 73 dB

ηEfficiency f = 1 kHz, RL= 8 Ω, PO= 1 W 80%

VFB Feedback Pin Reference

Voltage(5) 1.23 V

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(1) RLis a resistive load in series with two inductors to simulate an actual speaker load for RL= 8Ω, the load is 15μH+8Ω+15μH. For

RL= 4 Ω, the load is 15 μH + 4 Ω+ 15 μH.

(2) Typical values represent most likely parametric norms at TA= +25ºC, and at the Recommended Operation Conditions at the time of

product characterization and are not specified.

(3) Shutdown current is measured with components R1 and R2 removed.

(4) Offset voltage is determined by: (IDD (with load) — IDD (no load)) x RL.

(5) Feedback pin reference voltage is measured with the Audio Amplifier disconnected from the Boost converter (the Boost converter is

unloaded).

6.6 Electrical Characteristics VDD = 3.6 V

The following specifications apply for VDD = 3.6 V, PV1 = 7 V (continuous mode), AV= 2 V/V, R3= 25.5 kΩ, RLS = 5.36 kΩ,

RL= 8 Ω, f = 1 kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA= 25°C.(1)

PARAMETER TEST CONDITIONS MIN TYP(2) MAX UNIT

IDD Quiescent Power Supply

Current VIN = 0, RLOAD =∞

Fixed Frequency Mode

(FF) 16 mA

Spread Spectrum Mode

(SS) 17.5 26.6 mA

ISD Shutdown Current(3) VSD_BOOST = VSD_AMP = SS = FB_SEL = GND 0.03 1 μA

VIH Logic Voltage Input High 1.4 0.96 V

VIL Logic Voltage Input Low 0.4 0.84 V

TWU Wake-up Time CSS = 0.1 μF 50 ms

VOS Output Offset Voltage See (4) 0.04 mV

POOutput Power

RL= 8 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 1%

FF 2.5 W

SS 2.5

RL= 8 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 10%

FF 3 W

SS 3

RL= 4 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 1%

FF 4.3 W

SS 4.2

RL= 4 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 10%

FF 5.4 W

SS 5.3

THD+N Total Harmonic

Distortion + Noise

PO= 1.5 W, f = 1 kHz,

RL= 8 Ω

FF 0.03%

SS 0.03%

PO= 3 W, f = 1 kHz,

RL= 4 Ω

FF 0.04%

SS 0.05%

εOS Output Noise

f = 20 Hz to 20 kHz

Inputs to AC GND, No

weighting

FF 35 µVRMS

SS 36

f = 20 Hz to 20 kHz

Inputs to AC GND, A

weighted

FF 25 µVRMS

SS 26

PSRR Power Supply Rejection

Ratio

(Input Referred)

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 217 Hz

FF 85 dB

SS 86

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 1 kHz

FF 87 dB

SS 86

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 10 kHz

FF 78 dB

SS 77

CMRR Common-Mode

Rejection Ratio

(Input Referred)

VRIPPLE = 1 VP-P, fRIPPLE = 217 Hz 73 dB

ηEfficiency f = 1 kHz, RL= 8 Ω, PO= 1 W 77%

VFB Feedback Pin Reference

Voltage(5) 1.23 V

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(1) RLis a resistive load in series with two inductors to simulate an actual speaker load for RL= 8Ω, the load is 15μH+8Ω+15μH. For

RL= 4 Ω, the load is 15 μH + 4 Ω+ 15 μH.

(2) Typical values represent most likely parametric norms at TA= +25ºC, and at the Recommended Operation Conditions at the time of

product characterization and are not specified.

(3) Shutdown current is measured with components R1 and R2 removed.

(4) Offset voltage is determined by: (IDD (with load) — IDD (no load)) x RL.

(5) Feedback pin reference voltage is measured with the Audio Amplifier disconnected from the Boost converter (the Boost converter is

unloaded).

6.7 Electrical Characteristics VDD = 3 V

The following specifications apply for VDD = 3 V, PV1 = 4.8 V (continuos mode), AV= 2V/V, R3= 25.5 kΩ, RLS = 9.31 kΩ,

RL= 8 Ω, f = 1 kHz, SS/FF = GND, unless otherwise specified. Limits apply for TA= 25°C.(1)

PARAMETER TEST CONDITIONS MIN TYP(2) MAX UNIT

IDD Quiescent Power Supply

Current VIN = 0, RLOAD =∞Fixed Frequency Mode (FF) 9 mA

Spread Spectrum Mode (SS) 9.5 mA

ISD Shutdown Current(3) VSD_BOOST = VSD_AMP = SS = FB_SEL = GND 0.01 1 μA

VIH Logic Voltage Input High 0.91 V

VIL Logic Voltage Input Low 0.79 V

TWU Wake-up Time CSS = 0.1μF 49 ms

VOS Output Offset Voltage(4) 0.04 mV

POOutput Power

RL= 8 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 1%

FF 1 W

SS 0.84 1

RL= 8 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 10%

FF 1.3 W

SS 1.3

RL= 4 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 1%

FF 1.8 W

SS 1.8

RL= 4 Ω, f = 1 kHz,

BW = 22 kHz

THD+N = 10%

FF 2.2 W

SS 2.2

THD+N Total Harmonic

Distortion + Noise

PO= 500 mW, f = 1 kHz,

RL= 8 Ω

FF 0.02%

SS 0.03%

PO= 500 mW, f = 1 kHz,

RL= 4 Ω

FF 0.04%

SS 0.06%

εOS Output Noise

f = 20Hz to 20kHz

Inputs to AC GND, No

weighting

FF 35 µVRMS

SS 35

f = 20 Hz to 20 kHz

Inputs to AC GND, A

weighted

FF 25 µVRMS

SS 25

PSRR Power Supply Rejection

Ratio

(Input Referred)

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 217 Hz

FF 89 dB

SS 89

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 1 kHz

FF 88 dB

SS 88

VRIPPLE = 200 mVP-P

Sine,

fRIPPLE = = 10 kHz

FF 78 dB

SS 78

CMRR Common-Mode

Rejection Ratio

(Input Referred) VRIPPLE = 1 VP-P, fRIPPLE = 217 Hz 71 dB

ηEfficiency f = 1 kHz, RL= 8 Ω, PO= 1 W 75%

VFB Feedback Pin Reference

Voltage(5) 1.23 V

0.1

0.01

10m 100m 1 5

OUTPUT POWER (W)

THD+N (%)

SPREAD SPECTRUM

FIXED FREQUENCY

0.1

0.01

10m 100m 1 5

OUTPUT POWER (W)

THD+N (%)

SPREAD SPECTRUM

FIXED FREQUENCY

0.1

0.01

10m 100m 1 5

OUTPUT POWER (W)

THD+N (%)

SPREAD SPECTRUM

FIXED FREQUENCY

0.01

0.1

20 200 2k 20k

FREQUENCY (Hz)

THD+N (%)

0.001

SPREAD SPECTRUM, CIN = 1 PF

FIXED FREQUENCY, CIN = 1 PF

SPREAD SPECTRUM,

CIN = 180 nF

FIXED FREQUENCY,

CIN = 180 nF

0.01

0.1

20 200 2k 20k

FREQUENCY (Hz)

THD+N (%)

0.001

FIXED FREQUENCY

SPREAD SPECTRUM

0.01

0.1

20 200 2k 20k

FREQUENCY (Hz)

THD+N (%)

0.001

FIXED FREQUENCY

SPREAD SPECTRUM

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6.8 Typical Characteristics

Figure 1. THD+N vs Frequency

VDD = 5 V, RL= 8 Ω

PO= 2 W, Filter = 22 kHz, PV1= 7.8 V

Figure 2. THD+N vs Frequency

VDD = 3.6 V, RL= 8 Ω

PO= 500 mW, Filter = 22 kHz, PV1= 4.8 V

Figure 3. THD+N vs Frequency

VDD = 3 V, RL= 8 Ω

PO= 1.5 W, Filter = 22 kHz, PV1= 7 V

Figure 4. THD+N vs Output Power

VDD = 5 V, RL= 8 Ω

PO= 1.5 W, f = 1 kHz, Filter = 22 kHz, PV1= 7.8 V

Figure 5. THD+N vs Output Power

VDD = 3.6 V, RL= 8 Ω

f = 1 kHz, Filter = 22 kHz, PV1= 7 V

Figure 6. THD+N vs Output Power

VDD = 3 V, RL= 8 Ω

f = 1 kHz, Filter = 22 kHz, PV1= 4.8 V

100

1.60

OUTPUT POWER (W)

EFFICIENCY (%)

0.2 0.4 0.6 0.8 1.0 1.2 1.4

-20

-40

-60

-80

-10020 200 2k 20k

FREQUENCY (Hz)

PSRR (dB)

FIXED FREQUENCY

SPREAD SPECTRUM

100

4.00

OUTPUT POWER (W)

EFFICIENCY (%)

0.5 1.0 1.5 2.0 2.5 3.0 3.5

100

3.00

OUTPUT POWER (W)

EFFICIENCY (%)

0.5 1.0 1.5 2.0 2.5

0.1

0.01

10m 100m 1 5

OUTPUT POWER (W)

THD+N (%)

3.6V

0.1

0.01

10m 100m 1 5

OUTPUT POWER (W)

THD+N (%)

4.87 k:

5.35 k:

9.31 k:

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Typical Characteristics (continued)

Figure 7. THD+N vs Output Power

VDD = 3 V, 3.6 V, 5 V, RL= 8 Ω

f = 1kHz, Filter = 22 kHz, R1= 4.87 kΩ, FF

Figure 8. THD+N vs Output Power

VDD = 3.6 V, RL= 8 Ω

Filter = 22 kHz, PV1= 7.8 V, PV1= 7 V, PV1= 4.8 V, FF

Figure 9. Boost Amplifier vs Output Power

VDD = 5 V, RL= 8 Ω

f = 1 kHz, PV1= 7.8 V

Figure 10. Boost Amplifier vs Output Power

VDD = 3.6 V, RL= 8 Ω

f = 1 kHz, PV1= 7 V

Figure 11. Boost Amplifier vs Output Power

VDD = 3 V, RL= 8 Ω

f = 1 kHz, PV1= 4.8 V

Figure 12. PSRR vs Frequency

VDD = 5 V, RL= 8 Ω

VRIPPLE = 200 mVPP, PV1= 7.8 V

52.5 6.03.0 3.5 4.0 4.5 5.0 5.5

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

SPREAD

SPECTRUM

FIXED FREQUENCY

POWER DISSIPATION (W)

0 4.0

OUTPUT POWER (W)

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0.5 1.0 1.5 2.0 2.5 3.0 3.5

1.8

2.5 6.03.0 3.5 4.0 4.5 5.0 5.5

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

SPREAD SPECTRUM

FIXED FREQUENCY

2.5 6.0

3.0 3.5 4.0 4.5 5.0 5.5

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

SPREAD SPECTRUM

FIXED FREQUENCY

-20

-40

-60

-80

-10020 200 2k 20k

FREQUENCY (Hz)

PSRR (dB)

SPREAD SPECTRUM

FIXED FREQUENCY

-20

-40

-60

-80

-100

20 200 2k 20k

PSRR (dB)

FREQUENCY (Hz)

FIXED FREQUENCY

SPREAD SPECTRUM

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Typical Characteristics (continued)

Figure 13. PSRR vs Frequency

VDD = 3.6 V, RL= 8 Ω

VRIPPLE = 200 mVPP, PV1= 7 V

Figure 14. PSRR vs Frequency

VDD = 3 V, RL= 8 Ω

VRIPPLE = 200 mVPP, PV1= 4.8 V

Figure 15. Supply Current vs Supply Voltage

PV1= 7.8 V Figure 16. Supply Current vs Supply Voltage

PV1= 7 V

Figure 17. Supply Current vs Supply Voltage

PV1= 4.8 V

Figure 18. Power Dissipation vs Output Power

VDD = 5 V, RL= 8 Ω

PV1= 7.8 V, FF

100

0.40

LOAD CURRENT (A)

EFFICIENCY (%)

0.05 0.10 0.15 0.20 0.25 0.30 0.35

100

0.70

LOAD CURRENT (A)

EFFICIENCY (%)

0.1 0.2 0.3 0.4 0.5 0.6

100

0.60

LOAD CURRENT (A)

EFFICIENCY (%)

0.1 0.2 0.3 0.4 0.5

POWER DISSIPATION (W)

0 3.5

OUTPUT POWER (W)

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

0.5 1.0 1.5 2.0 2.5 3.0

1.8

POWER DISSIPATION (W)

0 1.6

OUTPUT POWER (W)

0.4 0.6 0.8 1.0 1.2 1.4

0.5

00.2

0.4

0.3

0.2

0.1

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Typical Characteristics (continued)

Figure 19. Power Dissipation vs Output Power

VDD = 3.6 V, RL= 8 Ω

PV1= 7 V, FF

Figure 20. Power Dissipation vs Output Power

VDD = 3 V, RL= 8 Ω

PV1= 4.8 V, FF

Figure 21. Boost Converter Efficiency vs ILOAD(DC)

VDD = 5 V, PV1= 7.8 V Figure 22. Boost Converter Efficiency vs ILOAD(DC)

VDD = 3.6 V, PV1= 7 V

Figure 23. Boost Converter Efficiency vs ILOAD(DC)

VDD = 3 V, PV1= 4.8 V

H-BRIDGE

OSCILLATOR

IN+

IN-

SS/FF

LS+

LS-

CIN

MODULATOR

OSCILLATOR

VGO+

VGO-

SD_AMP

SD_BOOST

SOFTSTART

FB_SEL

FB_GND1

FB_GND0

REGGND

VDD

PV1

LSGNDGND

CSS

0.1 PF

20 k:

25.5 k:R4

2.5 k:

9.31 k:R1

4.87 k:

1 PF

100 PF

280 pF

6.8 PH

+3.0V to +5.5V

CS1

10 PF

VIN

VIN-

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7 Detailed Description

7.1 Overview

The LM48511 integrates a boost converter with a high-efficiency Class D audio power amplifier, which 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. 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 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.

7.2 Functional Block Diagram

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7.3 Feature Description

7.3.1 General Amplifier Function

The LM48511 features a Class D audio power amplifier that uses 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 300-kHz 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. This cancellation results in no

net voltage across the speaker, thus there is no current to the load in the idle state.

With the input signal applied, the duty cycle (pulse width) of the LM48511 outputs changes. For increasing output

voltage, the duty cycle of VLS+ increases, while the duty cycle of VLS-decreases. For decreasing output voltages,

the converse occurs. The difference between the two pulse widths yields the differential output voltage.

7.3.2 Differential Amplifier Explanation

The LM48511 includes fully differential amplifier that features differential input and output stages. A differential

amplifier amplifies the difference between the two input signals. Traditional audio power amplifiers have typically

offered only single-ended inputs resulting in a 6dB reduction in signal to noise ratio relative to differential inputs.

The LM48511 also offers the possibility of DC input coupling which eliminates the two external AC coupling, DC

blocking capacitors. The LM48511 can be used, however, as a single-ended input amplifier while still retaining

the fully differential benefits of the device. In fact, completely unrelated signals may be placed on the input pins.

The LM48511 simply amplifies the difference between the signals. A major benefit of a differential amplifier is the

improved common-mode rejection ratio (CMRR) over single input amplifiers. The common-mode rejection

characteristic of the differential amplifier reduces sensitivity to ground offset related noise injection, especially

important in high noise applications.

7.3.3 Audio Amplifier Power Dissipation and Efficiency

The major benefit of a Class D amplifier is increased efficiency versus a Class AB. The efficiency of the

LM48511 is attributed to the region of operation of the transistors in the output stage. The Class D output stage

acts as current steering switches, consuming negligible amounts of power compared to their Class AB

counterparts. Most of the power loss associated with the output stage is due to the IR loss of the MOSFET ON-

resistance, along with switching losses due to gate charge.

7.3.4 Regulator Power Dissipation

At higher duty cycles, the increased ON-time of the switch FET means the maximum output current will be

determined by power dissipation within the LM48511 FET switch. The switch power dissipation from ON-time

conduction is calculated by:

PD(SWITCH) = DC × (IINDUCTOR(AVE))2× RDS(ON) (W)

where

• DC is the duty cycle. (1)

7.3.5 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.

When the regulator is disabled, both FB_GND switches open, further reducing shutdown current by eliminating

the current path to GND through the regulator feedback network. Without the GND switches, the feedback

resistors as shown in Figure 1 would consume an additional 165 μA from a 5-V supply. With the regulator

disabled, there is still a current path from VDD, through the inductor and diode, to the amplifier power supply. This

allows the amplifier to operate even when the regulator is disabled. The voltage at PV1 and V1 will be:

(VDD – [VD+ (ILx DCR)]

Where

• VDis the forward voltage of the Schottky diode

• ILis the current through the inductor

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Feature Description (continued)

• DCR is the DC resistance of the inductor (2)

Additionally, when the regulator is disabled, an external voltage from 5 V to 8 V can be applied directly to PV1

and V1 to power the amplifier.

It is best to switch between ground and VDD for minimum current consumption while in shutdown. The LM48511

may be disabled with shutdown voltages in between GND and VDD, the idle current will be greater than the

typical 0.1-µA value. Increased THD+N may also be observed when a voltage of less than VDD is applied to

SD_AMP .

7.3.6 Regulator Feedback Select

The LM45811 regulator features two feedback paths as shown in Figure 1, which allow the regulator to easily

switch between two different output voltages. The voltage divider consists of the high side resistor, R3, and the

low side resistors (RLS), R1 and R2. R3 is connected to the output of the boost regulator, the mid-point of each

divider is connected to FB, and the low side resistors are connected to either FB_GND1 or FB_GND0. FB_SEL

determines which FB_GND switch is closed, which in turn determines which feedback path is used. For example

if FB_SEL = VDD, the FB_GND1 switch is closed, while the FB_GND0 switch remains open, creating a current

path through the resistors connected to FB_GND1. Conversely, if FB_SEL = GND, the FB_GND0 switch is

closed, while the FB_GND1 switch remains open, creating a current path through the resistors connected to

FB_GND0.

FB_SEL can be susceptible to noise interference. To prevent an accidental state change, either bypass FB_SEL

with a 0.1µF capacitor to GND, or connect the higher voltage feedback network to FB_GND0, and the lower

voltage feedback network to FB_GND1. Because the higher output voltage configuration typically generates

more noise on VDD, this configuration minimizes the VDD noise exposure of FB_SEL, as FB_SEL = GND for

FB_GND0 (high voltage output) and FB_SEL = VDD for FB_GND1 (low voltage output).

The selectable feedback networks maximize efficiency in two ways. In applications where the system power

supply voltage changes, such as a mobile GPS receiver, that transitions from battery power, to AC line, to a car

power adapter, the LM48511 can be configured to generate a lower voltage when the system power supply

voltages is lower, and conversely, generate a higher voltage when the system power supply is higher. See the

Setting the Regulator Output Voltage (PV1) section.

In applications where the same speaker/amplifier combination is used for different purposes with different audio

power requirements, such as a cell phone ear piece/speaker phone speaker, the ability to quickly switch between

two different voltages allows for optimization of the amplifier power supply, increasing overall system efficiency.

When audio power demands are low (ear piece mode) the regulator output voltage can be set lower, reducing

quiescent current consumption. When audio power demands increase (speaker phone mode), a higher voltage

increases the amplifier headroom, increasing the audio power delivered to the speaker.

7.4 Device Functional Modes

The LM48511 features two modulations schemes, a fixed frequency mode (FF) and a spread spectrum mode

(SS).

7.4.1 7.4.1 Fixed Frequency

Select the fixed frequency mode by setting SS/FF = GND. In fixed frequency mode, the amplifier outputs switch

at a constant 300 kHz. In fixed frequency mode, the output spectrum consists of the fundamental and its

associated harmonics (see Typical Characteristics).

7.4.2 7.4.2 Spread Spectrum Mode

Set SS/FF = VDD for spread spectrum mode. The logic selectable spread spectrum mode eliminates the need

for output filters, ferrite beads or chokes. In spread spectrum mode, the switching frequency varies randomly by

10% about a 330-kHz center frequency, reducing the wideband spectral contend, improving EMI emissions

radiated by the speaker and associated cables and traces. Where a fixed frequency class D exhibits large

amounts of spectral energy at multiples of the switching frequency, the spread spectrum architecture of the

LM48511 spreads that energy over a larger bandwidth (see Typical Characteristics). The cycle-to-cycle variation

of the switching period does not affect the audio reproduction, efficiency, or PSRR.

4Softstart

19 FB

20 FB_GND0

21 FB_GND1

1FB_SEL

24 /SD_Boost

5/SD_Amp

17 VGO-

16 IN+

15 IN-

14 VGO+

LM48511SQ

LS+

LS-

GND3 22

GND3 23

GND3

VDD

PV1 10

V1 13

6.8 PH

10 PF

CS1

GND3

1 PF

CS2

GND3

1 PF

CS3

GND2

VDD D1

100 PF

GND3 GND2 GND1

+C3

1 PFC4

1 PF

Speaker

100 nF

CSoftstart

GND2

9.31k

4.87k

2.5k

25.5k

280 pF

GND2

GND1

SS-EN

SS_EN1

VDD

GND2

20k

CIN+

180 nF

CIN-

180 nF

GND3

GND2

GND1

GND

FB_SEL

VDD

GND2

SD_Boost

VDD

GND2

GND1 (Class D GND)

GND2 (AGND)

GND3 (Switch GND)

SD_Amp

VDD

GND2

Audio Input

4GND2

VDD VDD

GND2

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8 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The LM48511 integrates a boost converter with a high-efficiency Class D audio power amplifier, which uses a

filterless modulation scheme, reducing external component count, board area consumption and system cost. The

major benefit of a Class D amplifier is increased efficiency versus a Class AB. The LM48511 regulator has two

selectable feedback paths, which allow the regulator to dynamically switch between two different output voltages

easily. In addition, the LM48511 regulator features two different switching modes, improving light load efficiency

by minimizing losses due to MOSFET gate charge. The amplifier gain of the LM48511 is set by four external

resistors. Careful matching of those resistor pairs is required for optimum performance.

8.2 Typical Application

Figure 24. Typical LM48511 Audio Amplifier Application Circuit

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Typical Application (continued)

8.2.1 Design Requirements

Table 1 lists the design parameters for this example.

Table 1. Design Parameters

PARAMETERS VALUES

Supply voltage range 3.0 V to 5.5 V

Amplifier range 4.8 V to 8 V

Temperature range –40°C to 85°C

8.2.2 Detailed Design Procedure

8.2.2.1 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. They have the lowest ESR (equivalent series resistance) and

highest resonance frequency, which makes them optimum for high-frequency switching converters. When

selecting a ceramic capacitor, only X5R and X7R dielectric types must be used. Other types such as Z5U and

Y5F have such severe loss of capacitance due to effects of temperature variation and applied voltage, they may

provide as little as 20% of rated capacitance in many typical applications. Always consult capacitor

manufacturer’s data curves before selecting a capacitor. High-quality ceramic capacitors can be obtained from

Taiyo-Yuden and Murata.

8.2.2.2 Power Supply Bypassing

As with any amplifier, proper supply bypassing is critical for low noise performance and high power supply

rejection. The capacitor location on both PV1, V1 and VDD pins must be as close to the device as possible.

8.2.2.3 Audio Amplifier Gain Setting Resistor Selection

The amplifier gain of the LM48511 is set by four external resistors, the input resistors, R5 and R7, and the feed

back resistors R6 and R8.. The amplifier gain is given by:

Where RIN is the input resistor and RFis the feedback resistor.

AVD = 2 × RF/ RIN (3)

Careful matching of the resistor pairs, R6 and R8, and R5 and R7, is required for optimum performance. Any

mismatch between the resistors results in a differential gain error that leads to an increase in THD+N, decrease

in PSRR and CMRR, as well as an increase in output offset voltage. Resistors with a tolerance of 1% or better

are recommended.

The gain setting resistors must be placed as close to the device as possible. Keeping the input traces close

together and of the same length increases noise rejection in noisy environments. Noise coupled onto the input

traces which are physically close to each other will be common mode and easily rejected.

8.2.2.4 Audio Amplifier Input Capacitor Selection

Input capacitors may be required for some applications, or when the audio source is single-ended. Input

capacitors block the DC component of the audio signal, eliminating any conflict between the DC component of

the audio source and the bias voltage of the LM48511. The input capacitors create a highpass filter with the input

resistors RIN. The -3dB point of the highpass filter is found by:

f = 1 / 2πRINCIN (4)

In single-ended configurations, the input capacitor value affects click-and-pop performance. The LM48511

features a 50-mg turnon delaly. Choose the input capacitor / input resistor values such that the capacitor is

charged before the 50-ms turnon delay expires. A capacitor value of 0.18 μF and a 20-kΩinput resistor are

recommended. In differential applications, the charging of the input capacitor does not affect click-and-pop

significantly.

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(1) VDD = 5 V, PV1= 7.8 V (continuous mode)

The input capacitors can also be used to remove low-frequency content from the audio signal. Highpass filtering

the audio signal helps protect speakers that can not reproduce or may be damaged by low frequencies. When

the LM48511 is using a single-ended source, power supply noise on the ground is seen as an input signal.

Setting the highpass filter point above the power supply noise frequencies, 217 Hz in a GSM phone, for example,

filters out the noise such that it is not amplified and heard on the output. Capacitors with a tolerance of 10% or

better are recommended for impedance matching and improved CMRR and PSRR.

8.2.2.5 Selecting Regulator Output Capacitor

A single 100-µF low ESR tantalum capacitor provides sufficient output capacitance for most applications. Higher

capacitor values improve line regulation and transient response. Typical electrolytic capacitors are not suitable

for switching converters that operate above 500 kHz because of significant ringing and temperature rise due to

self-heating from ripple current. An output capacitor with excessive ESR reduces phase margin and causes

instability.

8.2.2.6 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 10 μF is recommended, but larger values can be used. Because this capacitor

reduces the amount of voltage ripple seen at the input pin, it also reduces the amount of EMI passed back along

that line to other circuitry.

8.2.2.7 Selecting the Soft-Start (CSS) Capacitor

The soft-start function charges the boost converter reference voltage slowly. This allows the output of the boost

converter to ramp up slowly thus limiting the transient current at start-up. Selecting a soft-start capacitor (CSS)

value presents a trade off between the wake-up time and the start-up transient current. Using a larger capacitor

value will increase wake-up time and decrease start-up transient current while the apposite effect happens with a

smaller capacitor value. A general guideline is to use a capacitor value 1000 times smaller than the output

capacitance of the boost converter (C2). A 0.1-uF soft-start capacitor is recommended for a typical application.

Table 2 shows the relationship between CSS start-up time and surge current.

Table 2. Soft-Start Capacitor Start-Up Time and Surge Current (1)

CSS

(μF) BOOST SET-UP TIME

(ms) INPUT SURGE CURRENT

(mA)

0.1 5.1 330

0.22 10.5 255

0.47 21.7 220

8.2.2.8 Selecting Diode (D1)

Use a Schottkey diode, as shown in Figure 1. A 30-V diode such as the DFLS230LH from Diodes Incorporated is

recommended. The DFLS230LH diodes are designed to handle a maximum average current of 2 A.

8.2.2.9 Duty Cycle

The maximum duty cycle of the boost converter determines the maximum boost ratio of output-to-input voltage

that the converter can attain in continuous mode of operation. The duty cycle for a given boost application is

defined by:

Duty Cycle = (PV1 + VD– VDD) / (PV1 + VD– VSW) (5)

This applies for continuous mode operation.

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(1) The values of PV1 are for continuous mode operation.

8.2.2.10 Selecting Inductor Value

Inductor value involves trade-offs in performance. Larger inductors reduce inductor ripple current, which typically

means less output voltage ripple (for a given size of output capacitor). Larger inductors also mean more load

power can be delivered because the energy stored during each switching cycle is:

E = L / 2 × (IP)2

Where

• IPis the peak inductor current (6)

The LM48511 will limit its switch current based on peak current. With IPfixed, increasing L will increase the

maximum amount of power available to the load. Conversely, using too little inductance may limit the amount of

load current which can be drawn from the output. Best performance is usually obtained when the converter is

operated in “continuous” mode at the load current range of interest, typically giving better load regulation and

less output ripple. Continuous operation is defined as not allowing the inductor current to drop to zero during the

cycle. Boost converters shift over to discontinuous operation if the load is reduced far enough, but a larger

inductor stays continuous over a wider load current range.

8.2.2.11 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.

8.2.2.12 Setting the Regulator Output Voltage (PV1)

The output voltage of the regulator is set through one of two external resistive voltage-dividers (R3 in

combination with either R1 or R2) connected to FB (Figure 1). The resistor, R4 is only for compensation

purposes and does not affect the regulator output voltage. The regulator output voltage is set by the following

equation:

PV1 = VFB [1 + R3 / RLS]

Where

• VFB is 1.23 V, and RLS is the low side resistor (R1 or R2) (7)

To simplify resistor selection:

RLS = (R3VFB) / (PV1 – VFB) (8)

A value of approximately 25.5 kΩis recommended for R3.

The quiescent current of the boost regulator is directly related to the difference between its input and output

voltages, the larger the difference, the higher the quiescent current. For improved power consumption the

following regulator input/output voltage combinations are recommended:

Table 3. Recommended Regulator Input and Output Voltages (1)

VDD (V) PV1 (V) R3 (kΩ) RLS (kΩ) POUT into 8 Ω(W)

3.0 4.8 25.5 9.31 1

3.6 7.1 25.5 5.35 2.5

5 7.8 25.5 4.87 3

For feedback path selection, see Regulator Feedback Select.

8.2.2.13 Discontinuous and Continuous Operation

The LM48511 regulator features two different switching modes. Under light-load conditions, the regulator

operates in a variable frequency, discontinuous, pulse-skipping mode, that improves light load efficiency by

minimizing losses due to MOSFET gate charge. Under heavy loads, the LM48511 regulator automatically

switches to a continuous, fixed-frequency PWM mode, improving load regulation. In discontinuous mode, the

regulator output voltage is typically 400 mV higher than the expected (calculated) voltage in continuous mode.

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8.2.2.14 ISW Feed-Forward Compensation for Boost Converter

Although the LM48511 regulator is internally compensated, an external feed-forward capacitor, (C1) may be

required for stability. The compensation capacitor places a zero in regulator loop response. The recommended

frequency of the zero (fZ) is 22.2 kHz. The value of C1 is given by:

C1 = 1 / 2πR3fZ(9)

In addition to C1, a compensation resistor, R4 is required to cancel the zero contributed by the ESR of the

regulator output capacitor. Calculate the zero frequency of the output capacitor by:

fCO = 1 / 2πRCOCO

where

• R CO is the ESR of the output capacitor (10)

The value of RFB3 is given by:

R4 = 1 / 2πfCOC1 (11)

8.2.2.15 Calculating Regulator Output Current

The load current of the boost converter is related to the average inductor current by the relation:

IAMP = IINDUCTOR(AVE) × (1 – DC) (A)

where

• DC is the duty cycle of the application (12)

The switch current can be found by:

ISW = IINDUCTOR(AVE) + 1/2 (IRIPPLE) (A) (13)

Inductor ripple current is dependent on inductance, duty cycle, supply voltage and frequency:

IRIPPLE = DC × (VDD – VSW) / (f × L) (A)

where

• f = switching frequency = 1MHz (14)

combining all terms, we can develop an expression which allows the maximum available load current to be

calculated:

IAMP(max) = (1–DC) × [ISW(max)– DC (V – VSW)] / 2fL (A) (15)

The equation shown to calculate maximum load current takes into account the losses in the inductor or turnoff

switching losses of the FET and diode.

8.2.2.16 Design Parameters VSW and ISW

The value of the FET "ON" voltage (referred to as VSW in Equation 9 thru Equation 12) is dependent on load

current. A good approximation can be obtained by multiplying the ON-resistance (RDS(ON) of the FET times the

average inductor current. The maximum peak switch current the device can deliver is dependent on duty cycle.

VDD (V)

POUT (W) IDD (A) K (%)

3 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 5

0.1

100

D001

POUT (W)

THD+N (%)

IDD (A)

K (%)

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8.2.3 Application Curve

Figure 25. VDD vs POUT, IDD, and Efficiency With 4-ΩLoad

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9 Power Supply Recommendations

The devices are designed to operate from an input supply voltage (VDD) operating range from 3 V to 5.5 V, but

the absolute maximum rating is 9 V.

As with any amplifier, proper supply bypassing is critical for low noise performance and high power supply

rejection. The capacitor location on both PV1, V1 and VDD pins must be as close to the device as possible.

10 Layout

10.1 Layout Guidelines

This section provides general practical guidelines for PCB layouts that use various power and ground traces.

Designers must note that these are only rule-of-thumb recommendations and the actual results are predicated on

the final layout.

10.1.1 Power and Ground Circuits

Star trace routing techniques can have a major positive impact on low-level signal performance. Star trace

routing refers to using individual traces that radiate from a signal point to feed power and ground to each circuit

or even device.

10.1.2 Layout Helpful Hints

• Avoid routing traces under the inductor.

• Use three separate grounds that eventually connect to one point:

– Signal or quiet ground (GND)

– Ground for the LM48511 device (LSGND)

– SW (REGGND) (switch ground). This trace for the switch ground carries the heaviest current (3 A) and

therefore is the nosiest. Make this trace as wide and short as possible and keep at a distance from the

quiet ground and device ground. Give distance priority to the quiet ground.

10.2 Layout Example

Figure 26. Layout Example

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11 Device and Documentation Support

11.1 Receiving Notification of Documentation Updates

To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper

right corner, click on Alert me to register and receive a weekly digest of any product information that has

changed. For change details, review the revision history included in any revised document.

11.2 Community Resources

The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective

contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of

Use.

TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration

among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help

solve problems with fellow engineers.

Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and

contact information for technical support.

11.3 Trademarks

E2E is a trademark of Texas Instruments.

All other trademarks are the property of their respective owners.

11.4 Electrostatic Discharge Caution

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.

11.5 Glossary

SLYZ022 —TI Glossary.

This glossary lists and explains terms, acronyms, and definitions.

12 Mechanical, Packaging, and Orderable Information

The following pages include mechanical, packaging, and orderable information. This information is the most

current data available for the designated devices. This data is subject to change without notice and revision of

this document. For browser-based versions of this data sheet, refer to the left-hand navigation.

PACKAGE OPTION ADDENDUM

www.ti.com 16-Oct-2017

Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM48511SQ/NOPB ACTIVE WQFN NHZ 24 1000 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 48511SQ

LM48511SQX/NOPB ACTIVE WQFN NHZ 24 4500 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 85 48511SQ

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance

do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may

reference these types of products as "Pb-Free".

RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.

Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based

flame retardants must also meet the <=1000ppm threshold requirement.

(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish

value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

PACKAGE OPTION ADDENDUM

www.ti.com 16-Oct-2017

Addendum-Page 2

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type Package

Drawing Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm) B0

(mm) K0

(mm) P1

(mm) W

(mm) Pin1

Quadrant

LM48511SQ/NOPB WQFN NHZ 24 1000 178.0 12.4 4.3 5.3 1.3 8.0 12.0 Q1

PACKAGE MATERIALS INFORMATION

www.ti.com 19-Aug-2018

Pack Materials-Page 1

*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

PACKAGE MATERIALS INFORMATION

www.ti.com 19-Aug-2018

Pack Materials-Page 2

MECHANICAL DATA

NHZ0024B

www.ti.com

SQA24B (Rev A)

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Mouser Electronics

Authorized Distributor

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