NSC LM4808MM, LM4808M Datasheet

LM4808

Dual 105 mW Headphone Amplifier

LM4808 Dual 105 mW Headphone Amplifier

February 2000

General Description

The LM4808 is a dual audio power amplifier capable of deliv­ering 105 mW per channel of continuous average power into
a16Ωload 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 using surface mount packaging. Since
the LM4808 does not require bootstrap capacitors or snub­ber networks, it is optimally suited for low-power portable
systems.

The unity-gain stable LM4808 can be configured by external
gain-setting resistors.

Key Specifications

n THD+N at 1 kHz at 105 mW

continuous average output
power into 16Ω 0.1% (max)

n THD+N at 1 kHz at 70 mW

continuous average output
power into 32Ω 0.1% (typ)

n Output power at 0.1% THD+N

at 1 kHz into 32Ω 70 mW (typ)

Features

n SOP and MSOP surface mount packaging
n Switch on/off click suppression
n Excellent power supply ripple rejection
n Unity-gain stable
n Minimum external components

Applications

n Headphone Amplifier
n Personal Computers
n Microphone Preamplifier

Typical Application Connection Diagram

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*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

Boomer®is a registered trademark of National Semiconductor Corporation.

SOP & MSOP Package

DS101276-2

Top View

Order Number LM4808M, LM4808MM

See NS Package Number M08A, MUA08A

© 2000 National Semiconductor Corporation DS101276 www.national.com

Absolute Maximum Ratings (Note 3)

If Military/Aerospace specified devices are required,

LM4808

please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage 6.0V
Storage Temperature −65˚C to +150˚C
Input Voltage −0.3V to V
Power Dissipation (Note 4) Internally limited
ESD Susceptibility (Note 5) 3500V
ESD Susceptibility (Note 6) 250V
Junction Temperature 150˚C
Soldering Information (Note 1)

Small Outline Package

DD

+ 0.3V

Infrared (15 seconds) 220˚C

Thermal Resistance

(MSOP) 56˚C/W

θ

JC

(MSOP) 210˚C/W

θ

JA

(SOP) 35˚C/W

θ

JC

(SOP) 170˚C/W

θ

JA

Operating Ratings

Temperature Range

≤ TA≤ T

T

MIN

MAX

Supply Voltage 2.0V ≤ V

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

−40˚C ≤ TA≤ 85˚C

Vapor Phase (60 seconds) 215˚C

Electrical Characteristics (Notes 2, 3)

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

Symbol Parameter Conditions LM4808 Units (Limits)

Typ (Note 7) Limit (Note 8)

V

DD

I

DD

P

tot

V

OS

Ibias Input Bias Current 10 pA
V

CM

G

V

Io Max Output Current THD+N
R

O

V

O

PSRR Power Supply Rejection Ratio Cb = 1.0µF, Vripple = 100mV

Crosstalk Channel Separation R
THD+N Total Harmonic Distortion +

SNR Signal-to-Noise Ratio V
f

G

P

o

C

I

C

L

SR Slew Rate Unity Gain Inverting 3 V/µs

Supply Voltage 2.0 V (min)

5.5 V (max)
Supply Current VIN= 0V, IO= 0A 1.2 3.0 mA (max)
Total Power Dissipation VIN= 0V, IO= 0A 6 16.5 mW (max)
Input Offset Voltage VIN= 0V 10 50 mV (max)

Common Mode Voltage

0V

4.3 V

Open-Loop Voltage Gain RL=5kΩ 67 dB

<

0.1 % 70 mA
Output Resistance 0.1 Ω
Output Swing RL=32Ω, 0.1% THD+N, Min .3

=32Ω, 0.1% THD+N, Max 4.7

R

L

,

PP

89 dB

f = 100Hz

=32Ω 75 dB

L

f=1kHz

Noise

R

=16Ω,

L

=3.5VPP(at 0 dB)

V

O

R

=32Ω,

L

=3.5VPP(at 0 dB)

V

O

= 3.5Vpp(at 0 dB) 105 dB

O

0.05 %
66 dB

0.05 %
66 dB

Unity Gain Frequency Open Loop, RL=5kΩ 5.5 MHz
Output Power THD+N = 0.1%,f=1kHz

R

=16Ω 105 mW

L

R

=32Ω 70 60 mW

L

THD+N = 10%,f=1kHz
R

=16Ω 150 mW

L

R

=32Ω 90 mW

L

Input Capacitance 3 pF
Load Capacitance 200 pF

DD

≤ 5.5V

V

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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 Conditions Units (Limits)

Typ (Note 7) Limit (Note 8)

I

DD

V

OS

P

o

Supply Current VIN= 0V, IO= 0A 1.0 mA (max)
Input Offset Voltage VIN= 0V 7 mV (max)
Output Power THD+N = 0.1%,f=1kHz

R

=16Ω 40 mW

L

R

=32Ω 28 mW

L

THD+N = 10%,f=1kHz
R

=16Ω 56 mW

L

R

=32Ω 38 mW

L

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 Conditions Units (Limits)

Typ (Note 7) Limit (Note 8)

I

DD

V

OS

P

o

Note 2: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 3:

tional, but do not guarantee specific performance limits.
antee 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.

Note 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
allowable power dissipation is P
mounted, is 210˚C/W for the MSOP Package and 107˚C/W for package N08E.

Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 6: Machine Model, 220 pF–240 pF discharged through all pins.
Note 7: Typicals are measured at 25˚C and represent the parametric norm.
Note 8: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Supply Current VIN= 0V, IO= 0A 0.9 mA (max)
Input Offset Voltage VIN= 0V 5 mV (max)
Output Power THD+N = 0.1%,f=1kHz

R

=16Ω 20 mW

L

R

=32Ω 16 mW

L

THD+N = 10%,f=1kHz
R

=16Ω 31 mW

L

R

=32Ω 22 mW

L

Absolute Maximum Ratings

indicate limits beyond which damage to the device may occur.

=(T

DMAX

JMAX−TA

Electrical Characteristics

)/θJA. For the LM4808, T

state DC and AC electrical specifications under particular test conditions which guar-

= 150˚C, and the typical junction-to-ambient thermal resistance, when board

JMAX

Operating Ratings

, θJA, and the ambient temperature TA. The maximum

JMAX

indicate conditions for which the device is func-

LM4808

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External Components Description (

LM4808

Compo-

nents

1. R

i

2. C

i

3. R

f

4. C

S

5. C

B

6. C

O

7. R

B

Inverting input resistance which sets the closed-loop gain in conjuction with Rf. This resistor also
forms a high pass filter with C

Input coupling capacitor which blocks the DC voltage at the amplifier’s input terminals. Also creates a
highpass filter with R

at fc=1/(2πRiCi). Refer to the section, Proper Selection of External

i

Components, for and explanation of how to determine the value of C
Feedback resistance which sets closed-loop gain in conjuction with Ri.
Supply bypass capacitor which provides power supply filtering. Refer to the Application Information

section for proper placement and selection of the supply bypass capacitor.
Bypass pin capacitor which provides half-supply filtering. Refer to the section, Proper Selection of

External Components, for information concerning proper placement and selection of C
Output coupling capacitor which blocks the DC voltage at the amplifier’s output. Forms a high pass

filter with R

at fO= 1/(2πRLCO)

L

Resistor which forms a voltage divider that provides a half-supply DC voltage to the non-inverting
input of the amplifier.

Typical Performance Characteristics

Figure 1

)

Functional Description

at fc=1/(2πRiCi).

i

.

i

.

B

THD+N vs Frequency

THD+N vs Frequency

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THD+N vs Frequency

THD+N vs Frequency

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THD+N vs Frequency

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THD+N vs Frequency

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