Texas Instruments LM4910 Boomer User Manual

LM4910

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SNAS151G –MAY 2004–REVISED MARCH 2007

LM4910 Output Capacitor-less Stereo 35mW Headphone

Amplifier

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1

FEATURES

2

• Eliminates headphone amplifier output
coupling capacitors

• Eliminates half-supply bypass capacitor

• Advanced pop & click circuitry eliminates
noises during turn-on and turn-off

• Ultra-low current shutdown mode

• Unity-gain stable

• 2.2V - 5.5V operation

DESCRIPTION

The LM4910 is an audio power amplifier primarily designed for headphone applications in portable device
applications. It is capable of delivering 35mW of continuous average power to a 32Ω load with less than 1%
distortion (THD+N) from a 3.3VDCpower supply.

The LM4910 utilizes a new circuit topology that eliminates output coupling capacitors and half-supply bypass
capacitors. The LM4910 contains advanced pop & click circuitry which eliminates noises caused by transients
that would otherwise occur during turn-on and turn-off.

Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal
amount of external components. Since the LM4910 does not require any output coupling capacitors, half-supply
bypass capacitors, or bootstrap capacitors, it is ideally suited for low-power portable applications where minimal
space and power consumption are primary requirements.

The LM4910 features a low-power consumption shutdown mode, activated by driving the shutdown pin with logic
low. Additionally, the LM4910 features an internal thermal shutdown protection mechanism. The LM4910 is also
unity-gain stable and can be configured by external gain-setting resistors.

• Available in space-saving MSOP, LLP, and
SOIC packages

APPLICATIONS

• Mobile Phones

• PDAs

• Portable electronics devices

• Portable MP3 players

Table 1. Key Specifications

VALUE UNIT

PSRR at f = 217Hz 65 dB (typ)
Power Output at VDD= 3.3V, RL= 32Ω, and THD ≤ 1% 35 mW (typ)
Shutdown Current 0.1 µA (typ)

1

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.

Copyright © 2004–2007, Texas Instruments Incorporated

LM4910

SNAS151G –MAY 2004–REVISED MARCH 2007

Typical Application

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Connection Diagram

Figure 1. Typical Audio Amplifier Application Circuit

Figure 2. MSOP/SO Package Top View

Figure 3. MSOP Marking Top View

G - Boomer Family

C2 - LM4910MM

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Figure 4. SO Marking Top View

TT - Die Traceability

Bottom 2 lines - Part Number

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Figure 5. LLP Package Top View

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

Supply Voltage
Storage Temperature −65°C to +150°C
Input Voltage -0.3V to VDD+ 0.3V
Power Dissipation
ESD Susceptibility Pin 6
ESD Susceptibility
ESD Susceptibility
Junction Temperature 150°C
Thermal Resistance

θ

(MSOP) 56°C/W

JC

θ

(MSOP) 190°C/W

JA

θ

(SOP) 35°C/W

JC

θ

(SOP) 150°C/W

JA

θ

(LQ) 57°C/W

JC

θ

(LQ) 140°C/W

JA

(1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for

which the device is functional but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good
indication of device performance.

(2) If the product is in shutdown mode and VDDexceeds 6V (to a max of 8V VDD) then most of the excess current will flow through the ESD

protection circuits. If the source impedance limits the current to a max of 10ma then the part will be protected. If the part is enabled
when VDDis above 6V circuit performance will be curtailed or the part may be permanently damaged.

(3) The maximum power dissipation must be derated at elevated temperatures and is dictated by T

TA. The maximum allowable power dissipation is P

whichever is lower. For the LM4910, see power derating currents for more information.
(4) Human body model, 100pF discharged through a 1.5kΩ resistor, Pin 6 to ground.
(5) Human body model, 100pF discharged through a 1.5kΩ resistor.
(6) Machine Model, 220pF-240pF discharged through all pins.

(2)

(3)

(4)
(5)
(6)

(1)

DMAX

= (T

, θJA, and the ambient temperature,

- TA)/ θJAor the number given in Absolute Maximum Ratings,

JMAX

JMAX

6.0V

Internally Limited

10kV

2000V

200V

Operating Ratings

Temperature Range

T

≤ TA≤ T

MIN

Supply Voltage (VDD) 2.2V ≤ VCC≤ 5.5V

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MAX

−40°C ≤ TA≤ 85°C

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Electrical Characteristics VDD= 3.3V

(1) (2)

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The following specifications apply for VDD= 3.3V, AV= 1, and 32Ω load unless otherwise specified. Limits apply to TA= 25°C.

Symbol Parameter Conditions LM4910 Units

Typ Limit

(3) (4) (5)

I

DD

I

SD

V

OS

P

O

THD+N Total Harmonic Distortion + Noise PO= 30mW

Quiescent Power Supply Current VIN= 0V, 32Ω Load 3.5 6 mA (max)
Standby Current V

SHUTDOWN

= GND 0.1 1.0 µA (max)
Output Offset Voltage 5 30 mV (max)
Output Power THD = 1% (max); f = 1kHz 35 30 mW (min)

; f = 1kHz 0.3 %

rms

65 (f =

V

= 200mV

PSRR Power Supply Rejection Ratio dB

RIPPLE

Input terminated with 10Ω to ground 65 (f =

sinewave 217Hz)

p-p

1kHz)

V

IH

V

IL

Shutdown Input Voltage High 1.5 V (min)
Shutdown Input Voltage Low 0.4 V (max)

(1) All voltages are measured with respect to the GND pin unless otherwise specified.
(2) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for

which the device is functional but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good

indication of device performance.
(3) Typicals are measured at 25°C and represent the parametric norm.
(4) Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
(5) Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

(Limits)

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Electrical Characteristics VDD= 3V

(1) (2)

SNAS151G –MAY 2004–REVISED MARCH 2007

The following specifications apply for VDD= 3V, AV= 1, and 32Ω load unless otherwise specified. Limits apply to TA= 25°C.

Symbol Parameter Conditions LM4910 Units

Typ Limit

(3) (4) (5)

I

DD

I

SD

V

OS

P

O

THD+N Total Harmonic Distortion + Noise PO= 25mW

Quiescent Power Supply Current VIN= 0V, 32Ω Load 3.3 6 mA (max)
Standby Current V

SHUTDOWN

= GND 0.1 1.0 µA (max)
Output Offset Voltage 5 30 mV (max)
Output Power THD = 1% (max); f = 1kHz 30 25 mW (min)

; f = 1kHz 0.3 %

rms

65 (f = 217

V

= 200mV

PSRR Power Supply Rejection Ratio dB

RIPPLE

Input terminated with 10Ω to ground 65 (f =

sinewave Hz)

p-p

1kHz)

V

IH

V

IL

Shutdown Input Voltage High 1.5 V (min)
Shutdown Input Voltage Low 0.4 V (max)

(1) All voltages are measured with respect to the GND pin unless otherwise specified.
(2) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for

which the device is functional but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good

indication of device performance.
(3) Typicals are measured at 25°C and represent the parametric norm.
(4) Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
(5) Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

(Limits)

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SNAS151G –MAY 2004–REVISED MARCH 2007

Electrical Characteristics VDD= 2.6V

(1) (2)

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The following specifications apply for VDD= 2.6V, AV= 1, and 32Ω load unless otherwise specified. Limits apply to TA= 25°C.

Symbol Parameter Conditions LM4910 Units

Typ Limit

(3) (4) (5)

I

DD

I

SD

V

OS

P

O

THD+N Total Harmonic Distortion + Noise PO= 10mW

Quiescent Power Supply Current VIN= 0V, 32Ω Load 3.0 mA (max)
Standby Current V

SHUTDOWN

= GND 0.1 µA (max)
Output Offset Voltage 5 mV (max)
Output Power THD = 1% (max); f = 1kHz 13 mW

; f = 1kHz 0.3 %

rms

55 (f =

V

= 200mV

PSRR Power Supply Rejection Ratio dB

RIPPLE

Input terminated with 10Ω to ground 55 (f =

sinewave 217Hz)

p-p

1kHz)

(1) All voltages are measured with respect to the GND pin unless otherwise specified.
(2) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for

which the device is functional but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good

indication of device performance.
(3) Typicals are measured at 25°C and represent the parametric norm.
(4) Limits are guaranteed to National's AOQL (Average Outgoing Quality Level).
(5) Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

(Limits)

External Components Description

(Figure 1)

Components Functional Description

1. RIInverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a high-pass

2. CIInput coupling capacitor which blocks the DC voltage at the amplifier's input terminals. Also creates a high-pass filter

3. RfFeedback resistance which sets the closed-loop gain in conjunction with Ri.

4. CSSupply bypass capacitor which provides power supply filtering. Refer to the Power Supply Bypassing section for

filter with Ciat fc= 1/(2πRiCi).

with Riat fc= 1/(2πRiCi). Refer to the section Proper Selection of External Components, for an explanation of how to
determine the value of Ci.

information concerning proper placement and selection of the supply bypass capacitor.

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Typical Performance Characteristics

THD+N THD+N

vs vs

Frequency Frequency

THD+N THD+N

vs vs

Frequency Frequency

THD+N THD+N

vs vs

Frequency Frequency

THD+N THD+N

vs vs

Output Power Output Power

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Typical Performance Characteristics (continued)

THD+N THD+N

vs vs

Output Power Output Power

THD+N THD+N

vs vs

Output Power Output Power

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Output Power

vs Output Power vs

Load Resistance Load Resistance

Output Power vs Output Power vs
Load Resistance Supply Voltage

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Typical Performance Characteristics (continued)

Output Power vs Power Dissipation vs

Supply Voltage Output Power

Power Dissipation vs Power Dissipation vs

Output Power Output Power

Channel Separation Power Supply Rejection Ratio

Power Supply Rejection Ratio Power Supply Rejection Ratio

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