Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsLinear ICsLinear IC - Audio amplifier Headphones (2-channel, stereo) Class AB TSSOP 14

LM4917

www.ti.com

SNAS238G –AUGUST 2004–REVISED MAY 2013

LM4917 Boomer™ Audio Power Amplifier Series Ground-Referenced, 95mW Stereo

Headphone Amplifier

Check for Samples: LM4917

FEATURES

DESCRIPTION

The LM4917 is a stereo, output capacitor-less

• Ground Referenced Outputs

headphone amplifier capable of delivering 95mW of

• High PSRR

continuous average power into a 16Ω load with less

• Available in Space-Saving TSSOP Package

than 1% THD+N from a single 3V power supply.

• Ultra Low Current Shutdown Mode

The LM4917 provides high quality audio reproduction

• Improved Pop and Click Circuitry eliminates

with minimal external components. A ground

referenced output eliminates the output coupling

Noises During Turn-On and Turn-Off

capacitors typically required by single-ended loads,

Transitions

reducing component count, cost and board space

• 1.4 – 3.6V Operation

consumption. This makes the LM4917 ideal for

• No Output Coupling Capacitors, Snubber

mobile phones and other portable equipment where

Networks, Bootstrap Capacitors

board space is at a premium. Eliminating the output

coupling capacitors also improves low frequency

• Shutdown Either Channel Independently

response.

APPLICATIONS

The LM4917 operates from a single 1.4V to 3.6V

power supply, features low 0.02% THD+N and 70dB

• Notebook PCs

PSRR. Independent right/left channel low-power

• Desktop PCs

shutdown controls provide power saving flexibility for

• Mobile Phone

mono/stereo applications. Superior click and pop

suppression eliminates audible transients during start

• PDAs

up and shutdown. Short circuit and thermal overload

• Portable Electronic Devices

protection protects the device during fault conditions.

KEY SPECIFICATIONS

• Improved PSRR at 1kHz: 70dB (Typ)

• Power Output at V

= 3V, R

= 16Ω, THD ≦≦

1%: 95mW (Typ)

• Shutdown Current: 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.

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 (25 pages)

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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 LM4917 Boomer™ Audio Power Amplifier Series Ground-Referenced, 95mW Stereo Headphone Amplifier Check for Samples: LM4917 FEATURES DESCRIPTION • • • • • The LM4917 is a stereo, output capacitor-less headphone amplifier capable of delivering 95mW of continuous average power into a 16Ω load with less than 1% THD+N from a single 3V power supply.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com Block Diagram 2 9 10 - 8 + 1 Shutdown Control 12 Click/Pop Suppression 3 Charge Pump + 5 11 13 6 7 4 14 Figure 1. Circuit Block Diagram Typical Application 20 k: CPVDD Rf + C3 Ci 20 k: C4 0.1 PF 2 9 0.39 PF + 4.7 PF 10 - 8 Ri + SD_LC 1 VIN1 Shutdown Control Headphone Jack SD_RC 12 Click/Pop Suppression C1 2.2 PF 0.39 PF + Ci 20 k: 3 Charge Pump + 5 11 Ri 13 6 VIN2 2.2 PF 7 4 14 C2 20 k: Rf Figure 2.
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LM4917 www.ti.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure.
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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 Electrical Characteristics VDD = 3V (1) The following specifications apply for VDD = 3V, AV = 1, and 16Ω load unless otherwise specified. Limits apply to TA = 25°C. Symbol Parameter IDD LM4917 Conditions Quiescent Power Supply Current Limit (3) (4) Units (Limits) 20 mA (max) 0.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics 6 THD+N vs Frequency VDD = 1.4V, RL = 32Ω, PO = 1mW THD+N vs Frequency VDD = 1.8V, RL = 16Ω, PO = 5mW Figure 3. Figure 4. THD+N vs Frequency VDD = 1.8V, RL = 32Ω, PO = 5mW THD+N vs Frequency VDD = 1.8V, RL = 32Ω, PO = 10mW Figure 5. Figure 6. THD+N vs Frequency VDD = 3.0V, RL = 16Ω, PO = 10mW THD+N vs Frequency VDD = 3.0V, RL = 16Ω, PO = 25mW Figure 7. Figure 8.
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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 Typical Performance Characteristics (continued) THD+N vs Frequency VDD = 3.0V, RL = 16Ω, PO = 50mW THD+N vs Frequency VDD = 3.0V, RL = 32Ω, PO = 5mW Figure 9. Figure 10. THD+N vs Frequency VDD = 3.0V, RL = 32Ω, PO = 10mW THD+N vs Frequency VDD = 3.0V, RL = 32Ω, PO = 25mW Figure 11. Figure 12. Gain Flatness vs Frequency RIN = 20kΩ, CIN = 0.39µF Output Power vs Supply Voltage RL = 16Ω Figure 13. Figure 14.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) Output Power vs Supply Voltage RL = 32Ω PSRR vs Frequency VDD = 1.8V, RL = 16Ω 180 OUTPUT POWER (mW) 160 140 10% THD+N 120 1% THD+N 100 80 60 40 20 0 1.5 2.0 2.5 3.0 3.5 4.0 SUPPLY VOLTAGE (V) 8 Figure 15. Figure 16. PSRR vs Frequency VDD = 1.8V, RL = 32Ω PSRR vs Frequency VDD = 3.0V, RL = 16Ω Figure 17. Figure 18. PSRR vs Frequency VDD = 3.
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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 Typical Performance Characteristics (continued) THD+N vs Output Power VDD = 1.8V, RL = 16Ω, f = 1kHz THD+N vs Output Power VDD = 1.8V, RL = 32Ω, f = 1kHz Figure 21. Figure 22. THD+N vs Output Power VDD = 3.0V, RL = 16Ω, f = 1kHz THD+N vs Output Power VDD = 3.0V, RL = 32Ω, f = 1kHz Figure 23. Figure 24. Power Dissipation vs Output Power VDD = 1.8V, RL = 16Ω Power Dissipation vs Output Power VDD = 1.8V, RL = 32Ω Figure 25. Figure 26.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com Typical Performance Characteristics (continued) Power Dissipation vs Output Power VDD = 3V, RL = 16Ω Power Dissipation vs Output Power VDD = 3V, RL = 32Ω Figure 27. Figure 28. Supply Current vs Supply Voltage Figure 29.
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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 APPLICATION INFORMATION ELIMINATING THE OUTPUT COUPLING CAPACITOR The LM4917 features a low noise inverting charge pump that generates an internal negative supply voltage. This allows the outputs of the LM4917 to be biased about GND instead of a nominal DC voltage, like traditional headphone amplifiers. Because there is no DC component, the large DC blocking capacitors (typically 220µF) are not necessary.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com For package TSSOP, θJA = 109°C/W. TJMAX = 150°C for the LM4917. Depending on the ambient temperature, TA, of the system surroundings, Equation 3 can be used to find the maximum internal power dissipation supported by the IC packaging. If the result of Equation 2 is greater than that of Equation 3, then either the supply voltage must be decreased, the load impedance increased or TA reduced.
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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 Input Capacitor Value Selection Amplifying the lowest audio frequencies requires high value input coupling capacitor (Ci in Figure 2). A high value capacitor can be expensive and may compromise space efficiency in portable designs. In many cases, however, the speakers used in portable systems, whether internal or external, have little ability to reproduce signals below 150Hz.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com The last step in this design is setting the amplifier's −3db frequency bandwidth. To achieve the desired ±0.25dB pass band magnitude variation limit, the low frequency response must extend to at lease one−fifth the lower bandwidth limit and the high frequency response must extend to at least five times the upper bandwidth limit. The gain variation for both response limits is 0.17dB, well within the ±0.25dB desired limit.
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LM4917 www.ti.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.
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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 LM4917 Reference Design Boards Bill Of Materials Part Description Qty Ref Designator LM4917 Mono Reference Design Board 1 LM4917 Audio AMP 1 U1 Tantalum Cap 1µF 16V 10 1 Cs Ceramic Cap 0.39µF 50V Z50 20 2 Ci Resistor 20kΩ 1/10W 5 4 Ri, Rf Resistor 100kΩ 1/10W 5 1 Rpu Jumper Header Vertical Mount 2X1, 0.
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LM4917 SNAS238G – AUGUST 2004 – REVISED MAY 2013 www.ti.com Single-Point Power / Ground Connections The analog power traces should be connected to the digital traces through a single point (link). A "PI-filter" can be helpful in minimizing high frequency noise coupling between the analog and digital sections. Further, place digital and analog power traces over the corresponding digital and analog ground traces to minimize noise coupling.
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LM4917 www.ti.com SNAS238G – AUGUST 2004 – REVISED MAY 2013 REVISION HISTORY Changes from Revision F (May 2013) to Revision G • Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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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 LM4917MTX/NOPB TSSOP PW 14 2500 330.0 12.4 6.95 8.3 1.6 8.0 12.0 Q1 LM4917SD/NOPB WSON NHK 14 1000 178.0 12.4 3.3 4.3 1.0 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) LM4917MTX/NOPB LM4917SD/NOPB TSSOP PW 14 2500 367.0 367.0 35.0 WSON NHK 14 1000 210.0 185.0 35.
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MECHANICAL DATA NHK0014A SDA14A (Rev A) www.ti.
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