NSC LM4872IBPX, LM4872IBP Datasheet

February 2000

LM4872

1 Watt Audio Power Amplifier in micro SMD package

LM4872 1 Watt Audio Power Amplifier micro SMD package

General Description

The LM4872 is a bridge-connected audio power amplifier ca­pable of delivering1Wofcontinuous average power to an
8Ω load with less than .2% (THD) 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 LM4872 does not require
output coupling capacitors or bootstrap capacitors. It is opti­mally suited for low-power portable applications.

The LM4872 features an externally controlled, low-power
consumption shutdown mode, as well as an internal thermal
shutdown protection mechanism.

The unity-gain stable LM4872 can be configured by external
gain-setting resistors.

Key Specifications

n Power Output at 0.2% THD 1 W (typ)
n Shutdown Current 0.01 µA (typ)

Features

n micro SMD package (see App. note AN-1112)
n 5V - 2V operation
n No output coupling capacitors or bootstrap capacitors.
n Unity-gain stable
n External gain configuration capability

Applications

n Cellular Phones
n Portable Computers
n Low Voltage Audio Systems

Typical Application Connection Diagram

8 Bump micro SMD

DS101230-23

Top View

Order Number LM4872IBP, LM4872IBPX

See NS Package Number BPA08B6B

DS101230-1

FIGURE 1. Typical Audio Amplifier Application Circuit

Boomer®is a registered trademark of National Semiconductor Corporation.

© 2000 National Semiconductor Corporation DS101230 www.national.com

Absolute Maximum Ratings (Note 2)

If Military/Aerospace specified devices are required,

LM4872

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

DD

+0.3V
Power Dissipation (Note 3) Internally Limited
ESD Susceptibility (Note 4) 2500V
ESD Susceptibility (Note 5) 250V
Junction Temperature 150˚C

Electrical Characteristics VDD=5V(Notes 1, 2, 9)

The following specifications apply for V

= 5V and 8Ω Load unless otherwise specified. Limits apply for TA= 25˚C.

DD

Soldering Information
See AN-1112 ″Micro-SMD Wafers Level Chip Scale

Package″.

Operating Ratings

Temperature Range

T

≤ TA≤ T

MIN

MAX

Supply Voltage 2.0V ≤ V

−40˚C ≤ TA≤ 85˚C

DD

≤ 5.5V

Symbol Parameter Conditions

V

DD

I

DD

I

SD

V

OS

P

o

THD+N Total Harmonic Distortion+Noise P

Supply Voltage 2.0 V (min)

Quiescent Power Supply Current VIN= 0V, Io= 0A 5.3 7 mA (max)
Shutdown Current V

PIN1=VDD

Output Offset Voltage VIN= 0V 5 50 mV (max)
Output Power THD = 0.2% (max);f=1kHz 1 W

= 0.25 Wrms; AVD=2;20Hz≤

o

f≤20 kHz

PSRR Power Supply Rejection Ratio V

= 4.9V to 5.1V 65 dB

DD

Electrical Characteristics VDD= 3.3V (Notes 1, 2, 9)

The following specifications apply for V

Symbol Parameter Conditions

V

DD

I

DD

I

SD

V

OS

P

o

Supply Voltage 2.0 V (min)

Quiescent Power Supply Current VIN= 0V, Io= 0A 4 mA (max)
Shutdown Current V
Output Offset Voltage VIN= 0V 5 mV (max)
Output Power THD = 1% (max);f=1kHz .5 .45 W

THD+N Total Harmonic Distortion+Noise P

PSRR Power Supply Rejection Ratio V

= 3.3V and 8Ω Load unless otherwise specified. Limits apply for TA= 25˚C.

DD

PIN1=VDD

= 0.25 Wrms; AVD=2;20Hz≤

o

f≤20 kHz

= 3.2V to 3.4V 65 dB

DD

LM4872

Typical Limit

(Note 6) (Note 7)

Units

(Limits)

5.5 V (max)

0.01 2 µA (max)

0.1 %

LM4872

Typical Limit

(Note 6) (Note 7)

Units

(Limits)

5.5 V (max)

0.01 µA (max)

0.15 %

Electrical Characteristics VDD= 2.6V (Notes 1, 2, 8, 9)

The following specifications apply for V

Symbol Parameter Conditions

V

DD

I

DD

www.national.com 2

Supply Voltage 2.0 V (min)

Quiescent Power Supply Current VIN= 0V, Io= 0A 3.4 mA (max)

= 2.6V and 8Ω Load unless otherwise specified. Limits apply for TA= 25˚C.

DD

LM4872

Typical Limit

(Note 6) (Note 7)

5.5 V (max)

Units

(Limits)

Electrical Characteristics VDD= 2.6V (Notes 1, 2, 8, 9)

The following specifications apply for V
25˚C. (Continued)

= 2.6V and 8Ω Load unless otherwise specified. Limits apply for TA=

DD

LM4872

Symbol Parameter Conditions

I

SD

V

OS

P

0

THD+N Total Harmonic Distortion+Noise P

Shutdown Current V

PIN1=VDD

Output Offset Voltage VIN= 0V 5 mV (max)
Output Power ( 8Ω )

Output Power ( 4Ω )

THD = 0.3% (max);f=1kHz
THD = 0.5% (max);f=1kHz

= 0.25 Wrms; AVD=2;20Hz≤

o

LM4872

Typical Limit

(Note 6) (Note 7)

0.01 µA (max)

0.25

0.5

0.25 %

Units

(Limits)

f≤20 kHz

PSRR Power Supply Rejection Ratio V

Note 1: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 2:

Absolute Maximum Ratings

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 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
allowable power dissipation is P
typical junction-to-ambient thermal resistance is 150˚C/W.

Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 5: Machine Model, 220 pF–240 pF discharged through all pins.
Note 6: Typicals are measured at 25˚C and represent the parametric norm.
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: Low Voltage Circuit - See Fig. 4
Note 9: Shutdown current is measured in a Normal Room Environment. Exposure to direct sunlight will increase I

indicate limits beyond which damage to the device may occur.

=(T

DMAX

JMAX–TA

Electrical Characteristics

)/θJAor the number given in Absolute Maximum Ratings, whichever is lower. For the LM4872, T

External Components Description (

= 2.5V to 2.7V 65 dB

DD

state DC andAC electrical specifications under particular test conditions which guar-

Figure 1

)

Operating Ratings

JMAX

indicate conditions for which the device is func-

, θJA, and the ambient temperature TA. The maximum

by a maximum of 2µA.

SD

JMAX

= 150˚C. The

W
W

Components Functional Description

1. R

2. C

3. R

4. C

Inverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a

i

high pass filter with C
Input coupling capacitor which blocks the DC voltage at the amplifiers input terminals. Also creates a

i

highpass filter with R
for an explanation of how to determine the value of C

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

f

Supply bypass capacitor which provides power supply filtering. Refer to the Power Supply Bypassing

S

at fC= 1/(2π RiCi).

i

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

i

.

i

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

5. C

Bypass pin capacitor which provides half-supply filtering. Refer to the section, Proper Selection of External

B

Components, for information concerning proper placement and selection of C

.

B

www.national.com3

Typical Performance Characteristics

LM4872

THD+N vs Frequency
at 5V and 8Ω

THD+N vs Frequency
at 3.3V and 8Ω

THD+N vs Frequency
at 2.6V and 8Ω

THD+N vs Output Power
V

=5V

DD

DS101230-3

DS101230-5

THD+N vs Frequency
at 2.6V and 4Ω

THD+N vs Output Power
V

= 3.3V

DD

DS101230-6

DS101230-4

DS101230-7

www.national.com 4

DS101230-8

Typical Performance Characteristics (Continued)

LM4872

THD+N vs
Output Power

2.6V at 8Ω

Output Power vs
Supply Voltage

DS101230-9

THD+N vs
Output Power

2.6V at 4Ω

DS101230-10

Output Power vs
Load Resistance

Power Derating Curve

DS101230-11

DS101230-14

Power Dissipation vs
Output Power
V

=5V

DD

DS101230-12

DS101230-26

www.national.com5