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LM4951A

www.ti.com

SNAS453C –AUGUST 2008–REVISED APRIL 2013

LM4951A Wide Voltage Range 1.8 Watt Audio Amplifier

With Short Circuit Protection

Check for Samples: LM4951A

FEATURES

DESCRIPTION

The LM4951A is an audio power amplifier designed

• Pop & Click Circuitry Eliminates Noise During

for applications with supply voltages ranging from

Turn-On and Turn-Off Transitions

2.7V up to 9V. The LM4951A is capable of delivering

• Wide Supply Voltage Range: 2.7V to 9V

1.8W continuous average power with less than 1%

• Low Current, Active-Low Shutdown Mode

THD+N into a bridge connected 8Ω load when

operating from a 7.5VDC power supply.

• Low Quiescent Current

Boomer™ audio power amplifiers were designed

• Thermal Shutdown Protection

specifically to provide high quality output power with a

• Short Circuit Protection

minimal amount of external components. The

• Unity-Gain Stable

LM4951A does not require bootstrap capacitors, or

• External Gain Configuration Capability

snubber circuits.

The LM4951A features a low-power consumption

APPLICATIONS

active-low shutdown mode. Additionally, the

LM4951A features an internal thermal shutdown

• Portable Devices

protection mechanism and short circuit protection.

• Cell Phones

The LM4951A contains advanced pop & click circuitry

• Laptop Computers

that eliminates noises which would otherwise occur

• Computer Speaker Systems

during turn-on and turn-off transitions.

• MP3 Player Speakers

The LM4951A is unity-gain stable and can be

configured by external gain-setting resistors.

KEY SPECIFICATIONS

• Wide Voltage Range 2.7V to 9V

• Quiescent Power Supply Current (V

= 7.5V)

2.5mA (typ)

• Power Output BTL at 7.5V, 1% THD

1.8 W (typ)

• Shutdown Current 0.01µA (typ)

• Fast Turn on Time 25ms (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.

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 (23 pages)

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LM4951A www.ti.com LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 Wide Voltage Range 1.8 Watt Audio Amplifier With Short Circuit Protection Check for Samples: LM4951A FEATURES DESCRIPTION • The LM4951A is an audio power amplifier designed for applications with supply voltages ranging from 2.7V up to 9V. The LM4951A is capable of delivering 1.8W continuous average power with less than 1% THD+N into a bridge connected 8Ω load when operating from a 7.5VDC power supply.
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LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com Typical Application Rf VDD Cs 1.0 PF VDD Ri 20k Ci 0.39 PF VIN - Vo- AMPA 1k Rc CBYPASS VIH 1.0 PF + CCHG 20k Control Bias Bypass 8: VIL Shutdown control 20k Shutdown + AMPB Vo+ GND Figure 1. Typical Bridge-Tied-Load (BTL) Audio Amplifier Application Circuit Connection Diagram Top View + Bypass 1 10 VO Shutdown 2 9 VDD CCHG 3 8 NC NC 4 7 GND VIN 5 6 VO - Figure 2.
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LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 Pin Name and Function (continued) Pin Number Name Function Type Input capacitor charge to decrease turn on time. See section Selecting Value A For RCfor more information. 3 CCHG Analog Output 4 NC No connection to die. Pin can be connected to any potential. No Connect 5 VIN Single-ended signal input pin. Analog Input 6 VO- Inverting output of amplifier. 7 GND 8 NC No connection to die.
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LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com Electrical Characteristics VDD = 7.5V (1) (2) The following specifications apply for VDD = 7.5V, AV-BTL = 6dB, RL = 8Ω unless otherwise specified. Limits apply for TA = 25°C. Parameter LM4951A Test Conditions Typ (3) Limit (4) Units (Limits) mA (max) IDD Quiescent Power Supply Current VIN = 0V, IO = 0A, RL = 8Ω BTL 2.5 4.5 ISD Shutdown Current VSD = GND (5) 0.
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LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 Electrical Characteristics VDD = 3.3V (1) (2) The following specifications apply for VDD = 3.3V, AV-BTL = 6dB, RL = 8Ω unless otherwise specified. Limits apply for TA = 25°C. Parameter Test Conditions LM4951A Typ (3) Limit (4) Units (Limits) mA (max) IDD Quiescent Power Supply Current VIN = 0V, IO = 0A, RL = 8Ω BTL 2.5 4.5 ISD Shutdown Current VSHUTDOWN = GND (5) 0.
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LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics 10 THD+N vs Frequency VDD = 3.3V, PO = 100mW, AV = 6dB 10 THD+N vs Frequency VDD = 3.3V, PO = 100mW, AV = 26dB 5 2 1 THD+N (%) THD+N (%) 1 0.5 0.2 0.1 0.1 0.05 0.02 0.01 20 200 2k 0.01 20 20k Figure 4. THD+N vs Frequency VDD = 5V, PO = 400mW, AV = 6dB THD+N vs Frequency VDD = 5V, PO = 400mW, AV = 26dB 10 5 5 2 2 1 1 0.5 0.2 0.5 0.2 0.1 0.1 0.05 0.05 0.02 0.02 0.
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LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 Typical Performance Characteristics (continued) 10 THD+N vs Output Power VDD = 3.3V, f = 1kHz, AV = 6dB THD+N vs Output Power VDD = 3.3V, f = 1kHz, AV = 26dB 10 1 THD+N (%) THD+N (%) 5 0.1 2 1 0.5 0.2 0.01 30m 10m 0.1 10m 500m 100m 20m OUTPUT POWER (W) 30m 50m 70m 100m 300m 500m 40m 60m 80m 200m 400m OUTPUT POWER (W) Figure 9. Figure 10.
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LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics (continued) Power Supply Rejection vs Frequency VDD = 3.3V, AV = 6dB, VRIPPLE = 200mVP-P Input Terminated into 10Ω Power Supply Rejection vs Frequency VDD = 3.3V, AV = 26dB, VRIPPLE = 200mVP-P Input Terminated into 10Ω +0 -10 -20 PSRR (dB) PSRR (dB) -30 -40 -50 -60 -70 -80 -90 -100 20 50 100 200 500 1k 2k +0 -2.5 -5 -7.5 -10 -12.5 -15 -17.5 -20 -22.5 -25 -27.5 -30 -32.5 -35 -37.5 -40 -42.5 -45 -47.
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LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 Typical Performance Characteristics (continued) Noise Floor VDD = 3.
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LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com Typical Performance Characteristics (continued) Power Dissipation vs Output Power VDD = 3.3V, RL = 8Ω, f = 1kHz Power Dissipation vs Output Power VDD = 7.5V, RL = 8Ω, f = 1kHz 1600 300 POWER DISSIPATION (mW) POWER DISSIPATION (mW) 1400 250 200 150 100 50 1200 1000 800 600 400 200 0 0 0 50 100 150 200 250 0 300 200 400 600 800 1000 1200 1400 OUTPUT POWER (mW) OUTPUT POWER (mW) Figure 27. Figure 28.
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LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 Typical Performance Characteristics (continued) Output Power vs Load Resistance VDD = 7.5V, f = 1kHz from top to bottom: THD+N = 10%, THD+N = 1% Frequency Response vs Input Capacitor Size RL = 8Ω from top to bottom: Ci = 1.0µF, Ci = 0.39µF, Ci = 0.
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LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com APPLICATION INFORMATION BRIDGE CONFIGURATION EXPLANATION As shown in Figure 1, the LM4951A consists of two operational amplifiers that drive a speaker connected between their outputs. The value of input and feedback resistors determine the gain of each amplifier. External resistors Ri and Rf set the closed-loop gain of AMPA, whereas two 20kΩ internal resistors set AMPB's gain to -1. Figure 1 shows that AMPA's output serves as AMPB's input.
PAGE 13
LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 If the result of Equation 2 is greater than that of Equation 3, then decrease the supply voltage, increase the load impedance, or reduce the ambient temperature. Further, ensure that speakers rated at a nominal 8Ω do not fall below 6Ω. If these measures are insufficient, a heat sink can be added to reduce θJA.
PAGE 14
LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com The gain of the internal amplifiers remains unity until the voltage on the bypass pin reaches VDD/2. As soon as the voltage on the bypass pin is stable, there is a delay to prevent undesirable output transients (“click and pops”). After this delay, the device becomes fully functional. THERMAL SHUTDOWN AND SHORT CIRCUIT PROTECTION The LM4951A has thermal shutdown and short circuit protection to fully protect the device.
PAGE 15
LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 Demonstration Board Layout Figure 36. Top Silkscreen Figure 37.
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LM4951A SNAS453C – AUGUST 2008 – REVISED APRIL 2013 www.ti.com Figure 38. Bottom Layer Bill Of Materials Table 1. Bill Of Materials Designator Value Tolerance RIN1 20kΩ 1% 1/8W, 0805 Resistor Part Description R1 200kΩ 1% 1/8W, 0805 Resistor RPULLUP 100kΩ 1% 1/8W, 0805 Resistor R2 1kΩ 1% 1/8W, 0805 Resistor R4, R5 0Ω 1% 1/8W, 0805 Resistor Comments CIN1 0.39μF 10% Ceramic Capacitor, 25V, Size 1206 CSUPPLY 4.
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LM4951A www.ti.com SNAS453C – AUGUST 2008 – REVISED APRIL 2013 REVISION HISTORY Rev Date 1.0 08/13/08 Initial release. Description 1.01 09/05/08 Text edits. Changes from Revision B (April 2013) to Revision C • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 14-Feb-2014 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.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-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 LM4951ASD/NOPB WSON DPR 10 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM4951ASDX/NOPB WSON DPR 10 4500 330.0 12.4 4.3 4.3 1.3 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM4951ASD/NOPB WSON DPR 10 1000 210.0 185.0 35.0 LM4951ASDX/NOPB WSON DPR 10 4500 367.0 367.0 35.
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MECHANICAL DATA DPR0010A SDC10A (Rev A) www.ti.
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