Datasheet

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LM4818

www.ti.com

SNAS163B –APRIL 2002–REVISED MAY 2013

LM4818 350mW Audio Power Amplifier with Shutdown

Mode

Check for Samples: LM4818

FEATURES

DESCRIPTION

The LM4818 is a mono bridged power amplifier that

• SOIC Surface Mount Packaging.

is capable of delivering 350mW

RMS

output power into

• Switch On/Off Click Suppression.

a 16Ω load or 300mW

RMS

output power into an 8Ω

• Unity-Gain Stable.

load with 10% THD+N from a 5V power supply.

• Minimum External Components.

The LM4818 Boomer™ audio power amplifier is

designed specifically to provide high quality output

APPLICATIONS

power and minimize PCB area with surface mount

packaging and a minimal amount of external

• General Purpose Audio

components. Since the LM4818 does not require

• Portable Electronic Devices

output coupling capacitors, bootstrap capacitors or

• Information Appliances (IA)

snubber networks, it is optimally suited for low-power

portable applications.

KEY SPECIFICATIONS

The closed loop response of the unity-gain stable

LM4818 can be configured using external gain-setting

• THD+N at 1kHz, 350mW Continuous Average

resistors. The device is available in SOIC package

Output Power into 16Ω 10% (max)

type to suit various applications.

• THD+N at 1kHz, 300mW Continuous Average

Output Power into 8Ω 10% (max)

• Shutdown Current 0.7µA (typ)

Typical Application

Figure 1. Typical Audio Amplifier Application Circuit

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.

2Boomer is a trademark of Texas Instruments.

3All other 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 (22 pages)

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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 LM4818 350mW Audio Power Amplifier with Shutdown Mode Check for Samples: LM4818 FEATURES DESCRIPTION • • • • The LM4818 is a mono bridged power amplifier that is capable of delivering 350mWRMS output power into a 16Ω load or 300mWRMS output power into an 8Ω load with 10% THD+N from a 5V power supply. 1 23 SOIC Surface Mount Packaging. Switch On/Off Click Suppression. Unity-Gain Stable. Minimum External Components.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com Connection Diagram Figure 2. SOIC Package - Top View See Package Number D 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. ABSOLUTE MAXIMUM RATINGS (1) (2) (3) Supply Voltage 6.0V −65°C to +150°C Storage Temperature −0.3V to VDD +0.
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 ELECTRICAL CHARACTERISTICS VDD = 5V (1) (2) The following specifications apply for VDD = 5V, RL = 16Ω unless otherwise stated. Limits apply for TA = 25°C. Symbol Parameter Conditions LM4818 Typical (3) Limit (4) (5) Units (Limits) IDD Quiescent Power Supply Current VIN = 0V, Io = 0A 1.5 3.0 mA (max) ISD Shutdown Current VPIN1 = VDD (6) 1.0 5.0 µA (max) ISDIH Shutdown Voltage Input High 4.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com EXTERNAL COMPONENTS DESCRIPTION (Figure 1) Components 4 Functional Description 1. Ri Combined with Rf, this inverting input resistor sets the closed-loop gain. Ri also forms a high pass filter with Ci at fc = 1/(2πRiCi). 2. Ci This input coupling capacitor blocks DC voltage at the amplifier's terminals. Combined with Ri, it creates a high pass filter with Ri at fc = 1/(2πRiCi).
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) 6 Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14.
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 TYPICAL PERFORMANCE CHARACTERISTICS (continued) Output Power vs Supply Voltage RL = 8Ω Output Power vs Supply Voltage RL = 16Ω Figure 15. Figure 16. Output Power vs Supply Voltage RL = 32Ω Output Power vs Load Resistance Figure 17. Figure 18. Power Dissipation vs Output Power VDD = 5V Power Dissipation vs Output Power VDD = 3V Figure 19. Figure 20.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com TYPICAL PERFORMANCE CHARACTERISTICS (continued) Power Derating Curves Frequency Response vs Input Capacitor Size Figure 21. Figure 22. Supply Current vs Supply Voltage Figure 23.
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 APPLICATION INFORMATION BRIDGE CONFIGURATION EXPLANATION As shown in Figure 1, the LM4818 consist of two operational amplifiers. External resistors, Ri and RF set the closed-loop gain of the first amplifier (and the amplifier overall), whereas two internal 20kΩ resistors set the second amplifier's gain at -1. The LM4818 is typically used to drive a speaker connected between the two amplifier outputs.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com power dissipation, the graph Figure 20 must be used. From the graph, the maximum power dissipation for an 8Ω load and a 5V supply is approximately 575mW. Substituting this value back into Equation 4 for PDMAX and using θJA = 170°C/W for the D package, the maximum ambient temperature is 52°C.
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 Besides affecting system cost and size, Ci has an effect on the LM4818's click and pop performance. When the supply voltage is first applied, a transient (pop) is created as the charge on the input capacitor changes from zero to a quiescent state. The magnitude of the pop is directly proportional to the input capacitor's value.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com In order to eliminate "clicks and pops", all capacitors must be discharged before turn-on. Rapidly switching VDD may not allow the capacitors to fully discharge, which may cause "clicks and pops". AUDIO POWER AMPLIFIER DESIGN EXAMPLE The following are the desired operational parameters: Given: Power Output 100mW Load Impedance 16Ω Input Level 1Vrms (max) Input Impedance 20kΩ Bandwidth 100Hz–20kHz ± 0.
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 Figure 24. HIGHER GAIN AUDIO AMPLIFIER The LM4818 is unity-gain stable and requires no external components besides gain-setting resistors, an input coupling capacitor, and proper supply bypassing in the typical application. However, if a closed-loop differential gain of greater than 10 is required, a feedback capacitor (C4) may be needed as shown in Figure 24 to bandwidth limit the amplifier.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com Figure 25.
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 Top Layer Bottom Layer Table 1. Mono LM4818 Reference Design Boards Bill of Material for all Demo Boards Item Part Number Part Description Qty Ref Designator 1 551011208-001 LM4818 Mono Reference Design Board 1 10 482911183-001 LM4818 Audio AMP 1 U1 20 151911207-001 Tant Cap 1uF 16V 10 1 C1 21 151911207-002 Cer Cap 0.
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LM4818 SNAS163B – APRIL 2002 – REVISED MAY 2013 www.ti.com Avoiding Typical Design / Layout Problems Avoid ground loops or running digital and analog traces parallel to each other (side-by-side) on the same PCB layer. When traces must cross over each other do it at 90 degrees. Running digital and analog traces at 90 degrees to each other from the top to the bottom side as much as possible will minimize capacitive noise coupling and cross talk.
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LM4818 www.ti.com SNAS163B – APRIL 2002 – REVISED MAY 2013 REVISION HISTORY Changes from Revision A (May 2013) to Revision B • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.com 2-May-2013 PACKAGING INFORMATION Orderable Device Status (1) LM4818MX/NOPB ACTIVE Package Type Package Pins Package Drawing Qty SOIC D 8 2500 Eco Plan Lead/Ball Finish (2) Green (RoHS & no Sb/Br) MSL Peak Temp Op Temp (°C) Top-Side Markings (3) CU SN Level-1-260C-UNLIM (4) -40 to 85 LM48 18M (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM4818MX/NOPB Package Package Pins Type Drawing SOIC D 8 SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) 2500 330.0 12.4 Pack Materials-Page 1 6.5 B0 (mm) K0 (mm) P1 (mm) 5.4 2.0 8.0 W Pin1 (mm) Quadrant 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) LM4818MX/NOPB SOIC D 8 2500 367.0 367.0 35.
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