NSC LM4809MMX, LM4809MM, LM4809MDC, LM4809MAX, LM4809MA Datasheet

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LM4809

Dual 105mW Headphone Amplifier with Active-Low Shutdown Mode

General Description

The LM4809 is a dual audio power amplifier capable of delivering 105mW per channel of continuous average power into a 16Ω load with 0.1% (THD+N) from a 5V power supply.

Boomer audio power amplifiers were designed specifically to provide high quality output power with a minimal amount of external components. Since the LM4809 does not require bootstrap capacitors or snubber networks, it is optimally suited for low-power portable systems.

The unity-gain stable LM4809 can be configured by external gain-setting resistors.

The LM4809 features an externally controlled, active-low, micropower consumption shutdown mode, as well as an internal thermal shutdown protection mechanism.

Key Specifications

n THD+N at 1kHz at 105mW continuous average power

into 16Ω 0.1% (typ)

n THD+N at 1kHz at 70mW continuous average power

into 32Ω 0.1% (typ)

n Shutdown Current 0.4µA (typ)

Features

n Active-low shutdown mode n "Click and Pop" reduction circuitry n Low shutdown current n LLP, MSOP, and SO surface mount packaging n No bootstrap capacitors required n Unity-gain stable

Applications

n Headphone Amplifier n Personal Computers n Microphone Preamplifier n PDA’s

Typical Application

Boomer®is a registered trademark of National Semiconductor Corporation.

20009001

*Refer to the Application Information Section for information concerning proper selection of the input and output coupling capacitors.

FIGURE 1. Typical Audio Amplifier Application Circuit

November 2002

LM4809 Dual 105mW Headphone Amplifier with Active-Low Shutdown Mode

Connection Diagrams

MSOP Package MSOP Marking

20009002

Top View

Order Number LM4809MM

See NS Package Number MUA08A

20009066

SO Package SO Marking

20009002

Top View

Order Number LM4809MA

See NS Package Number M08A

20009067

LLP Package LLP Marking

20009061

Top View

Order Number LM4809LD

See NS Package Number LDA08B

20009068

LM4809

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Absolute Maximum Ratings (Note 2)

If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications.

Supply Voltage 6.0V

Storage Temperature −65˚C to +150˚C

ESD Susceptibility (Note 4) 3.5kV

ESD Machine model (Note 8) 250V

Junction Temperature (T

) 150˚C

Soldering Information (Note 1)

Small Outline Package

Vapor Phase (60 sec.) 215˚C

Infrared (15 sec.) 220˚C

Thermal Resistance

(SO) 170˚C/W

(SO) 35˚C/W

(MSOP) 210˚C/W

(MSOP) 56˚C/W

(LLP) 117˚C/W (Note 9)

(LLP) 150˚C/W (Note 10)

(LLP) 15˚C/W

Operating Ratings

Temperature Range

MIN

≤ TA≤ T

MAX

−40˚C ≤ TA≤ 85˚C

Supply Voltage (V

) 2.0V ≤ VCC≤ 5.5V

Note 1: See AN-450 “Surface Mounting and their Effects on Product Reliability” for other methods of soldering surface mount devices.

Electrical Characteristics (Notes 2, 3)

The following specifications apply for VDD= 5V unless otherwise specified, limits apply to TA= 25˚C.

Symbol Parameter Conditions LM4809 Units

(Limits)

Typ

(Note 5)

Limit

(Note 7)

Supply Voltage 2.0 V (min)

5.5 V (max)

Supply Current VIN= 0V, IO= 0A 1.4 3 mA (max)

Shutdown Current VIN= 0V, V

SHUTDOWN

= GND 0.4 2 µA(max)

Output Offset Voltage VIN= 0V 4.0 50 mV(max)

Output Power THD+N = 0.1%, f = 1kHz

=16Ω 105 mW

=32Ω 70 65 mW (min)

THD+N Total Harmonic Distortion P

= 50mW, RL=32Ω

f = 20Hz to 20kHz

0.3 %

Crosstalk Channel Separation RL=32Ω;PO= 70mW 70 dB

PSRR Power Supply Rejection Ratio C

= 1.0µF; V

RIPPLE

= 200mVPP,

f = 1kHz; Input terminated into 50Ω

70 dB

SDIH

Shutdown Voltage Input High 0.8 x V

V (min)

SDIL

Shutdown Voltage Input Low 0.2 x V

V (max)

Electrical Characteristics (Notes 2, 3)

The following specifications apply for VDD= 3.3V unless otherwise specified, limits apply to TA= 25˚C.

Symbol Parameter Conditions LM4809 Units

(Limits)

Typ

(Note 5)

Limit

(Note 7)

Supply Current VIN= 0V, IO= 0A 1.1 mA

Shutdown Current VIN= 0V, V

SHUTDOWN

= GND 0.4 µA

Output Offset Voltage VIN= 0V 4.0 mV

Output Power THD+N = 0.1%, f = 1kHz

=16Ω 40 mW

=32Ω 28 mW

THD+N Total Harmonic Distortion P

= 25mW, RL=32Ω

f = 20Hz to 20kHz

0.4 %

Crosstalk Channel Separation R

=32Ω;PO= 25mW 70 dB

LM4809

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Electrical Characteristics (Notes 2, 3) (Continued)

The following specifications apply for VDD= 3.3V unless otherwise specified, limits apply to TA= 25˚C.

Symbol Parameter Conditions LM4809 Units

(Limits)

Typ

(Note 5)

Limit

(Note 7)

PSRR Power Supply Rejection Ratio C

= 1.0µF; V

RIPPLE

= 200mVPP,

f = 1kHz; Input terminated into 50Ω

70 dB

SDIH

Shutdown Voltage Input High 0.8 x V

V (min)

SDIL

Shutdown Voltage Input Low 0.2 x V

V (max)

Electrical Characteristics (Notes 2, 3)

The following specifications apply for VDD= 2.6V unless otherwise specified, limits apply to TA= 25˚C.

Symbol Parameter Conditions LM4809 Units

(Limits)

Typ

(Note 5)

Limit

(Note 7)

Supply Current VIN= 0V, IO= 0A 0.9 mA

Shutdown Current VIN= 0V, V

SHUTDOWN

= GND 0.2 µA

Output Offset Voltage VIN= 0V 4.0 mV

Output Power THD+N = 0.1%, f = 1kHz

=16Ω 20 mW

=32Ω 16 mW

THD+N Total Harmonic Distortion P

= 15mW, RL=32Ω

f = 20Hz to 20kHz

0.6 %

Crosstalk Channel Separation R

=32Ω;PO= 15mW 70 dB

PSRR Power Supply Rejection Ratio C

= 1.0µF; V

RIPPLE

= 200mVPP,

f = 1kHz; Input terminated into 50Ω

70 dB

SDIH

Shutdown Voltage Input High 0.8 x V

V (min)

SDIL

Shutdown Voltage Input Low 0.2 x V

V (max)

Note 2: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.

Note 3: All voltages are measured with respect to the ground pin, unless otherwise specified.

Note 4: Human body model, 100pF discharged through a 1.5kΩ resistor.

Note 5: Typical specifications are specified at +25OC and represent the most likely parametric norm.

Note 6: Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 7: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

Note 8: Machine Model ESD test is covered by specification EIAJ IC-121-1981. A 200pF cap is charged to the specified voltage, then discharged directly into the

IC with no external series resistor (resistance of discharge path must be under 50Ohms).

Note 9: The given θ

is for an LM4809 packaged in an LDA08B wit the Exposed-Dap soldered to a printed circuit board copper pad with an area equivalent to that

of the Exposed-Dap itself.

Note 10: The given θ

is for an LM4809 packaged in an LDA08B with the Exposed-Dap not soldered to any printed circuit board copper.

External Components Description (Figure 1)

Components Functional Description

1. R

The inverting input resistance, along with Rf, set the closed-loop gain. Ri, along with Ci, form a high pass filter with f

= 1/(2πRiCi).

2. C

The input coupling capacitor blocks DC voltage at the amplifier’s input terminals. Ci, along with Ri, create a highpass filter with f

= 1/(2πRiCi). Refer to the section, Selecting Proper External

Components, for an explanation of determining the value of C

3. R

The feedback resistance, along with Ri, set closed-loop gain.

4. C

This is the supply bypass capacitor. It provides power supply filtering. Refer to the Application Information section for proper placement and selection of the supply bypass capacitor.

5. C

This is the BYPASS pin capacitor. It provides half-supply filtering. Refer to the section, Selecting Proper External Components, for information concerning proper placement and selection of C

6. C

This is the output coupling capacitor. It blocks the DC voltage at the amplifier’s output and forms a high pass filter with R

at fO= 1/(2πRLCO)

LM4809

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