LM4810LDX/NOPB [TI]

IC 0.105 W, 2 CHANNEL, AUDIO AMPLIFIER, DSO8, LLP-8, Audio/Video Amplifier;


型号：	LM4810LDX/NOPB
厂家：	TEXAS INSTRUMENTS
描述：	IC 0.105 W, 2 CHANNEL, AUDIO AMPLIFIER, DSO8, LLP-8, Audio/Video Amplifier 放大器商用集成电路
文件：	总19页 (文件大小：958K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

National Semiconductor is now part of

Texas Instruments.

Search http://www.ti.com/ for the latest technical

information and details on our current products and services.

November 2002

LM4810

Dual 105mW Headphone Amplifier with Active-High

Shutdown Mode

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

General Description

32Ω

0.1% (typ)

The LM4810 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.

n Shutdown Current

0.4µA (typ)

Features

Boomer audio power amplifiers were designed specifically to

provide high quality output power with a minimal amount of

external components. Since the LM4810 does not require

bootstrap capacitors or snubber networks, it is optimally

suited for low-power portable systems.

n Active-high shutdown mode

n LLP, MSOP, and SO surface mount packaging

n "Click and Pop" suppression circuitry

n Low shutdown current

n No bootstrap capacitors required

n Unity-gain stable

The unity-gain stable LM4810 can be configured by external

gain-setting resistors.

The LM4810 features an externally controlled, active-high,

micropower consumption shutdown mode, as well as an

internal thermal shutdown protection mechanism.

Applications

n Cellular Phones

n Personal Computers

n Microphone Preamplifier

n PDA’s

Key Specifications

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

16Ω

0.1% (typ)

Typical Application

20008901

*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.

DS200089

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Connection Diagrams

MSOP Package

SO Package

20008902

Top View

Order NumberLM4810MM

See NS Package Number MUA08A

Top View

Order NumberLM4810MA

See NS Package Number M08A

LLP Package

MSOP Marking

20008991

20008986

Top View

Order NumberLM4810LD

See NS Package Number LDA08B

SO Marking

LLP Marking

20008992

20008993

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Absolute Maximum Ratings (Note 2)

θ_JC(SO)

35˚C/W

210˚C/W

θ_JA(MSOP)

θ_JC(MSOP)

θ_JA(LLP)

θ_JC(LLP)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

56˚C/W

117˚C/W (Note 9)

150˚C/W (Note 10)

15˚C/W

Supply Voltage

6.0V

−65˚C to +150˚C

3.5kV

Storage Temperature

ESD Susceptibility (Note 4)

ESD Machine Model (Note 8)

Junction Temperature (T_J)

Soldering Information (Note 1)

Small Outline Package

Vapor Phase (60 sec.)

Infrared (15 sec.)

250V

Operating Ratings (Note 2)

Temperature Range

150˚C

T_MIN≤ T_A≤ T_MAX

−40˚C ≤ T ≤ 85˚C

Supply Voltage (V_CC

2.0V ≤ V

≤ 5.5V

215˚C

220˚C

Note 1: See AN-450 “Surface Mounting and their Effects on Product Reli-

ability” for other methods of soldering surface mount devices.

Thermal Resistance

θ_JA(SO)

170˚C/W

Electrical Characteristics (Notes 2, 3)

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

Symbol Parameter Conditions LM4810

Units

(Limits)

Typ

Limit

(Note 5)

(Note 7)

V_DD

Supply Voltage

2.0

5.5

V (min)

V (max)

mA(max)

µA(max)

mV(max)

I_DD

I_SD

V_OS

P_O

Supply Current

V_IN= 0V, I_O= 0A

1.3

0.4

4.0

Shutdown Current

Output Offset Voltage

Output Power

V_IN= 0V, V_SHUTDOWN= V_DD

V_IN= 0V

THD+N = 0.1%, f = 1kHz

R_L= 16Ω

105

mW(min)

R_L= 32Ω

THD+N

Total Harmonic Distortion

P_O= 50mW, R_L= 32Ω

f = 20Hz to 20kHz

R_L= 32Ω; P_O= 70mW

C_B= 1.0µF; V_RIPPLE= 200mV_PP

0.3

Crosstalk

PSRR

Channel Separation

Power Supply Rejection Ratio

f = 1kHz; Input terminated into 50Ω

V_SDIH

V_SDIL

Shutdown Voltage Input High

Shutdown Voltage Input Low

0.8 x V_DD

0.2 x V_DD

V (min)

V (max)

Electrical Characteristics (Notes 2, 3)

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

Symbol Parameter Conditions LM4810

Units

(Limits)

Typ

(Note 5)

1.0

Limit

(Note 7)

I_DD

I_SD

V_OS

P_O

Supply Current

V_IN= 0V, I_O= 0A

µA

Shutdown Current

Output Offset Voltage

Output Power

V_IN= 0V, V_SHUTDOWN= V_DD

V_IN= 0V

0.4

4.0

THD+N = 0.1%, f = 1kHz

R_L= 16Ω

R_L= 32Ω

THD+N

Total Harmonic Distortion

Channel Separation

P_O= 25mW, R_L= 32Ω

f = 20Hz to 20kHz

R_L= 32Ω; P_O= 25mW

0.4

Crosstalk

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Electrical Characteristics (Notes 2, 3) (Continued)

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

Symbol

Parameter

Conditions

LM4810

Units

(Limits)

Typ

Limit

(Note 5)

(Note 7)

PSRR

Power Supply Rejection Ratio

C_B= 1.0µF; Vripple = 200mV_PP

f = 1kHz; Input terminated into 50Ω

V_SDIH

V_SDIL

Shutdown Voltage Input High

Shutdown Voltage Input Low

0.8 x V_DD

0.2 x V_DD

V (min)

V (max)

Electrical Characteristics (Notes 2, 3)

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

Symbol Parameter Conditions LM4810

Units

(Limits)

Typ

(Note 5)

0.9

Limit

(Note 7)

I_DD

I_SD

V_OS

P_O

Supply Current

V_IN= 0V, I_O= 0A

µA

Shutdown Current

Output Offset Voltage

Output Power

V_IN= 0V, V_SHUTDOWN= V_DD

V_IN= 0V

0.2

4.0

THD+N = 0.1%, f = 1kHz

R_L= 16Ω

R_L= 32Ω

THD+N

Total Harmonic Distortion

P_O= 15mW, R_L= 32Ω

f = 20Hz to 20kHz

R_L= 32Ω; P_O= 15mW

C_B= 1.0µF; Vripple = 200mV_PP

0.6

Crosstalk

PSRR

Channel Separation

Power Supply Rejection Ratio

f = 1kHz; Input terminated into 50Ω

V_SDIH

V_SDIL

Shutdown Voltage Input High

Shutdown Voltage Input Low

0.8 x V_DD

0.2 x V_DD

V (min)

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 max/min 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 LM4810 packaged in an LDA08B with 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 LM4810 packaged in an LDA08B with the Exposed-Dap not soldered to any circuit board copper.

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External Components Description (Figure 1)

Components

Functional Description

The inverting input resistance, along with R_f, set the closed-loop gain. R_i, along with C_i, form a high

pass filter with f_c= 1/(2πR_iC_i).

1. R_i

The input coupling capacitor blocks DC voltage at the amplifier’s input terminals. C_i, along with R_i,

create a highpass filter with f_c= 1/(2πR_iC_i). Refer to the section, Selecting Proper External

Components, for an explanation of determining the value of C_i.

2. C_i

3. R_f

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

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.

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_B.

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

pass filter with R_Lat f_O= 1/(2πR_LC_O)

4. C_S

5. C_B

6. C_O

Typical Performance Characteristics

THD+N vs Frequency

20008985

20008964

THD+N vs Frequency

20008965

20008966

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Typical Performance Characteristics (Continued)

THD+N vs Frequency

20008967

20008968

20008970

20008972

THD+N vs Frequency

20008969

THD+N vs Frequency

20008971

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Typical Performance Characteristics (Continued)

THD+N vs Output Power

20008973

20008974

THD+N vs Output Power

20008975

20008976

THD+N vs Output Power

20008977

20008978

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Typical Performance Characteristics (Continued)

THD+N vs Output Power

20008979

20008980

Output Power vs

Load Resistance

THD+N vs Output Power

20008922

20008981

Output Power vs

Load Resistance

Output Power vs

Load Resistance

20008923

20008924

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Typical Performance Characteristics (Continued)

Output Power vs

Supply Voltage

Output Power vs

Power Supply

20008925

20008926

20008984

20008930

Output Power vs

Power Supply

Dropout Voltage vs

Supply Voltage

20008927

Power Dissipation vs

Output Power

Power Dissipation vs

Output Power

20008929

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Typical Performance Characteristics (Continued)

Power Dissipation vs

Output Power

Channel Separation

20008931

20008982

Noise Floor

Power Supply Rejection Ratio

20008983

20008934

Open Loop

Frequency Response

20008950

20008951

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Typical Performance Characteristics (Continued)

Open Loop

Frequency Response

Supply Current vs

Supply Voltage

20008944

20008938

Application Information

MICRO-POWER SHUTDOWN

copper pad is not required. The LM4810’s Power Dissipation

vs Output Power Curve in the Typical Performance Char-

acteristics shows that the maximum power dissipated is just

45mW per amplifier with a 5V power supply and a 32Ω load.

Further detailed and specific information concerning PCB

layout, fabrication, and mounting an LD (LLP) package is

available from National Semiconductor’s Package Engineer-

ing Group under application note AN1187.

The voltage applied to the SHUTDOWN pin controls the

LM4810’s shutdown function. Activate micro-power shut-

down by applying a logic high voltage to the SHUTDOWN

pin. The logic threshold is typically V_DD/2. When active, the

LM4810’s micro-power shutdown feature turns off the ampli-

fier’s bias circuitry, reducing the supply current. The low

0.4µA typical shutdown current is achieved by applying a

voltage that is as near as V_DDas possible to the SHUT-

DOWN pin. A voltage that is less than V_DDmay increase the

shutdown current.

POWER DISSIPATION

Power dissipation is a major concern when using any power

amplifier and must be thoroughly understood to ensure a

successful design. Equation 1 states the maximum power

dissipation point for a single-ended amplifier operating at a

given supply voltage and driving a specified output load.

There are a few ways to control the micro-power shutdown.

These include using a single-pole, single-throw switch, a

microprocessor, or a microcontroller. When using a switch,

connect an external 100kΩ pull-up resistor between the

SHUTDOWN pin and V_DD. Connect the switch between the

SHUTDOWN pin and GND. Select normal amplifier opera-

tion by closing the switch. Opening the switch connects the

SHUTDOWN pin to V_DDthrough the pull-up resistor, activat-

ing micro-power shutdown. The switch and resistor guaran-

tee that the SHUTDOWN pin will not float. This prevents

unwanted state changes. In a system with a microprocessor

or a microcontroller, use a digital output to apply the control

voltage to the SHUTDOWN pin. Driving the SHUTDOWN pin

with active circuitry eliminates the pull-up resistor.

P_DMAX= (V_DD

)

/ (2π²R_L)

(1)

Since the LM4810 has two operational amplifiers in one

package, the maximum internal power dissipation point is

twice that of the number which results from Equation 1. Even

with the large internal power dissipation, the LM4810 does

not require heat sinking over a large range of ambient tem-

perature. From Equation 1, assuming a 5V power supply and

a 32Ω load, the maximum power dissipation point is 40mW

per amplifier. Thus the maximum package dissipation point

is 80mW. The maximum power dissipation point obtained

must not be greater than the power dissipation that results

from Equation 2:

EXPOSED-DAP PACKAGE PCB MOUNTING

CONSIDERATION

The LM4810’s exposed-Dap (die attach paddle) package

(LD) provides a low thermal resistance between the die and

the PCB to which the part is mounted and soldered. This

allows rapid heat transfer from the die to the surrounding

PCB copper traces, ground plane, and surrounding air.

P_DMAX= (T_JMAX− T_A) / θ_JA

(2)

The LD package should have its DAP soldered to a copper

pad on the PCB. The DAP’s PCB copper pad may be con-

nected to a large plane of continuous unbroken copper. This

plane forms a thermal mass, heat sink, and radiation area.

For package MUA08A, θ_JA= 210˚C/W. T_JMAX= 150˚C for

the LM4810. Depending on the ambient temperature, T_A, of

the system surroundings, Equation 2 can be used to find the

maximum internal power dissipation supported by the IC

packaging. If the result of Equation 1 is greater than that of

Equation 2, then either the supply voltage must be de-

However, since the LM4810 is designed for headphone ap-

plications, connecting a copper plane to the DAP’s PCB

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the pop is directly proportional to the input capacitor’s size.

Thus, pops can be minimized by selecting an input capacitor

value that is no higher than necessary to meet the desired

−3dB frequency. Please refer to the Optimizing Click and

Pop Reduction Performance section for a more detailed

discussion on click and pop performance.

Application Information (Continued)

creased, the load impedance increased or T_Areduced. For

the typical application of a 5V power supply, with a 32Ω load,

the maximum ambient temperature possible without violating

the maximum junction temperature is approximately 133.2˚C

provided that device operation is around the maximum

power dissipation point. Power dissipation is a function of

output power and thus, if typical operation is not around the

maximum power dissipation point, the ambient temperature

may be increased accordingly. Refer to the Typical Perfor-

mance Characteristics curves for power dissipation infor-

mation for lower output powers.

As shown in Figure 1, the input resistor, R_Iand the input

capacitor, C_I, produce a −3dB high pass filter cutoff fre-

quency that is found using Equation (3). In addition, the

output load R_L, and the output capacitor C_O, produce a -3db

high pass filter cutoff frequency defined by Equation (4).

f_I-3db=1/2πR_IC_I

(3)

(4)

POWER SUPPLY BYPASSING

As with any power amplifier, proper supply bypassing is

critical for low noise performance and high power supply

rejection. Applications that employ a 5V regulator typically

use a 10µF in parallel with a 0.1µF filter capacitors to stabi-

lize the regulator’s output, reduce noise on the supply line,

and improve the supply’s transient response. However, their

presence does not eliminate the need for a local 1.0µF

tantalum bypass capacitance connected between the

LM4810’s supply pins and ground. Keep the length of leads

and traces that connect capacitors between the LM4810’s

power supply pin and ground as short as possible. Connect-

ing a 4.7µF capacitor, C_B, between the BYPASS pin and

ground improves the internal bias voltage’s stability and

improves the amplifier’s PSRR. The PSRR improvements

increase as the bypass pin capacitor value increases. Too

large, however, increases the amplifier’s turn-on time. The

selection of bypass capacitor values, especially C_B, depends

on desired PSRR requirements, click and pop performance

(as explained in the section, Selecting Proper External

Components), system cost, and size constraints.

f_O-3db=1/2πR_LC_O

Also, careful consideration must be taken in selecting a

certain type of capacitor to be used in the system. Different

types of capacitors (tantalum, electrolytic, ceramic) have

unique performance characteristics and may affect overall

system performance.

Bypass Capacitor Value Selection

Besides minimizing the input capacitor size, careful consid-

eration should be paid to the value of C_B, the capacitor

connected to the BYPASS pin. Since C_Bdetermines how

fast the LM4810 settles to quiescent operation, its value is

critical when minimizing turn-on pops. The slower the

LM4810’s outputs ramp to their quiescent DC voltage (nomi-

nally 1/2 V_DD), the smaller the turn-on pop. Choosing C_B

equal to 4.7µF along with a small value of C_i(in the range of

0.1µF to 0.47µF), produces a click-less and pop-less shut-

down function. As discussed above, choosing C_ino larger

than necessary for the desired bandwith helps minimize

clicks and pops.

SELECTING PROPER EXTERNAL COMPONENTS

Optimizing the LM4810’s performance requires properly se-

lecting external components. Though the LM4810 operates

well when using external components with wide tolerances,

best performance is achieved by optimizing component val-

ues.

OPTIMIZING CLICK AND POP REDUCTION

PERFORMANCE

The LM4810 contains circuitry that minimizes turn-on and

shutdown transients or “clicks and pop”. For this discussion,

turn-on refers to either applying the power supply voltage or

when the shutdown mode is deactivated. During turn-on, the

LM4810’s internal amplifiers are configured as unity gain

buffers. An internal current source charges up the capacitor

on the BYPASS pin in a controlled, linear manner. The gain

of the internal amplifiers remains unity until the voltage on

the BYPASS pin reaches 1/2 V_DD. As soon as the voltage on

the BYPASS pin is stable, the device becomes fully opera-

tional. During device turn-on, a transient (pop) is created

from a voltage difference between the input and output of the

The LM4810 is unity-gain stable, giving a designer maximum

design flexibility. The gain should be set to no more than a

given application requires. This allows the amplifier to

achieve minimum THD+N and maximum signal-to-noise ra-

tio. These parameters are compromised as the closed-loop

gain increases. However, low gain demands input signals

with greater voltage swings to achieve maximum output

power. Fortunately, many signal sources such as audio

CODECs have outputs of 1V_RMS(2.83V_P-P). Please refer to

the Audio Power Amplifier Design section for more infor-

mation on selecting the proper gain.

amplifier as the voltage on the BYPASS pin reaches 1/2 V_DD

For this discussion, the input of the amplifier refers to the

node between R_Iand C_I. Ideally, the input and output track

the voltage applied to the BYPASS pin. During turn-on, the

buffer-configured amplifier output charges the input capaci-

tor, C_I, through the input resistor, R_I. This input resistor

delays the charging time of C_Ithereby causing the voltage

difference between the input and output that results in a

transient (pop). Higher value capacitors need more time to

reach a quiescent DC voltage (usually 1/2 V_DD) when

charged with a fixed current. Decreasing the value of C_Iand

R_Iwill minimize the turn-on pops at the expense of the

desired -3dB frequency.

Input and Output Capacitor Value Selection

Amplifying the lowest audio frequencies requires high value

input and output coupling capacitors (C_Iand C_Oin Figure 1).

A high value capacitor can be expensive and may compro-

mise 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. Applications using speakers with this limited

frequency response reap little improvement by using high

value input and output capacitors.

Besides affecting system cost and size, C_ihas an effect on

the LM4810’s click and pop performance. The magnitude of

Although the BYPASS pin current cannot be modified,

changing the size of C_Balters the device’s turn-on time and

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V_DD≥ (2V_OPEAK+ (V_OD

+ V_OD_BOT))

(6)

Application Information (Continued)

TOP

the magnitude of “clicks and pops”. Increasing the value of

C_Breduces the magnitude of turn-on pops. However, this

presents a tradeoff: as the size of C_Bincreases, the turn-on

time increases. There is a linear relationship between the

size of C_Band the turn-on time. Here are some typical

turn-on times for various values of C_B:

The Output Power vs Supply Voltage graph for a 32Ω load

indicates a minimum supply voltage of 4.8V. This is easily

met by the commonly used 5V supply voltage. The additional

voltage creates the benefit of headroom, allowing the

LM4810 to produce peak output power in excess of 70mW

without clipping or other audible distortion. The choice of

supply voltage must also not create a situation that violates

maximum power dissipation as explained above in the

Power Dissipation section. Remember that the maximum

power dissipation point from Equation (1) must be multiplied

by two since there are two independent amplifiers inside the

package. Once the power dissipation equations have been

addressed, the required gain can be determined from Equa-

tion (7).

C_B

T_ON

0.1µF

0.22µF

0.33µF

0.47µF

0.68µF

1.0µF

2.2µF

3.3µF

4.7µF

10µF

80ms

170ms

270ms

370ms

490ms

920ms

1.8sec

2.8sec

3.4sec

7.7sec

(7)

Thus, a minimum gain of 1.497 allows the LM4810 to reach

full output swing and maintain low noise and THD+N perfro-

mance. For this example, let A_V=1.5.

The amplifiers overall gain is set using the input (R_i) and

feedback (R_f) resistors. With the desired input impedance

set at 20kΩ, the feedback resistor is found using Equation

(8).

In order eliminate “clicks and pops”, all capacitors must be

discharged before turn-on. Rapidly switching V_DDmay not

allow the capacitors to fully discharge, which may cause

“clicks and pops”. In a single-ended configuration, the output

is coupled to the load by C_O. This capacitor usually has a

high value. C_Odischarges through internal 20kΩ resistors.

Depending on the size of C_O, the discharge time constant

can be relatively large. To reduce transients in single-ended

mode, an external 1kΩ–5kΩ resistor can be placed in par-

allel with the internal 20kΩ resistor. The tradeoff for using

this resistor is increased quiescent current.

A_V= R_f/R_i

(8)

The value of R_fis 30kΩ.

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. The results are an

AUDIO POWER AMPLIFIER DESIGN

Design a Dual 70mW/32Ω Audio Amplifier

Given:

Power Output

Load Impedance

Input Level

70 mW

32Ω

f_L= 100Hz/5 = 20Hz

(9)

1 Vrms (max)

and a

f_H= 20kHz^*5 = 100kHz

(10)

Input Impedance

Bandwidth

20kΩ

100 Hz–20 kHz 0.50dB

As stated in the External Components section, both R_iin

conjunction with C_i, and C_owith R_L, create first order high-

pass filters. Thus to obtain the desired low frequency re-

sponse of 100Hz within 0.5dB, both poles must be taken

into consideration. The combination of two single order filters

at the same frequency forms a second order response. This

results in a signal which is down 0.34dB at five times away

from the single order filter −3dB point. Thus, a frequency of

20Hz is used in the following equations to ensure that the

response is better than 0.5dB down at 100Hz.

The design begins by specifying the minimum supply voltage

necessary to obtain the specified output power. One way to

find the minimum supply voltage is to use the Output Power

vs Supply Voltage curve in the Typical Performance Char-

acteristics section. Another way, using Equation (5), is to

calculate the peak output voltage necessary to achieve the

desired output power for a given load impedance. To ac-

count for the amplifier’s dropout voltage, two additional volt-

ages, based on the Dropout Voltage vs Supply Voltage in the

Typical Performance Characteristics curves, must be

added to the result obtained by Equation (5). For

C_i≥ 1 / (2π * 20kΩ * 20Hz) = 0.397µF; use 0.39µF.(11)

C_o≥ 1 / (2π * 32Ω * 20Hz) = 249µF; use 330µF. (12)

single-ended application, the result is Equation (6).

(5)

The high frequency pole is determined by the product of the

desired high frequency pole, f_H, and the closed-loop gain,

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designer has a need to design an amplifier with a higher

gain, the LM4810 can still be used without running into

bandwidth limitations.

Application Information (Continued)

A_V. With a closed-loop gain of 1.5 and f_H= 100kHz, the

resulting GBWP = 150kHz which is much smaller than the

LM4810’s GBWP of 900kHz. This figure displays that if a

Demonstration Board Schematic

20008959

FIGURE 2. LM4810 Demonstration Board Schematic

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Demonstration Board Layout

20008960

FIGURE 3. Recommended PC Board Layout

Component-Side Silkscreen

20008961

FIGURE 4. Recommended PC Board Layout

Component-Side Layout

20008962

FIGURE 5. Recommended PC Board Layout

Bottom-Side Layout

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Demonstration Board Layout (Continued)

20008987

FIGURE 6. Recommended LD PC Board Layout

Component-Side Silkreen

20008988

FIGURE 7. Recommended LD PC Board Layout

Component-Side Layout

20008989

FIGURE 8. Recommended LD PC Board Layout

Bottom-Side Layout

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Physical Dimensions inches (millimeters) unless otherwise noted

Order Number LM4810MM

NS Package Number MUA08A

Order Number LM4810MA

NS Package Number M08A

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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)

Order Number LM4810LD

NS Package Number LDA08B

LIFE SUPPORT POLICY

NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT

DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL

COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:

1. Life support devices or systems are devices or

systems which, (a) are intended for surgical implant

into the body, or (b) support or sustain life, and

whose failure to perform when properly used in

accordance with instructions for use provided in the

labeling, can be reasonably expected to result in a

significant injury to the user.

2. A critical component is any component of a life

support device or system whose failure to perform

can be reasonably expected to cause the failure of

the life support device or system, or to affect its

safety or effectiveness.

National Semiconductor

Corporation

Americas

National Semiconductor

Europe

National Semiconductor

Asia Pacific Customer

Response Group

Tel: 65-2544466

Fax: 65-2504466

National Semiconductor

Japan Ltd.

Tel: 81-3-5639-7560

Fax: 81-3-5639-7507

Fax: +49 (0) 180-530 85 86

Email: support@nsc.com

Email: europe.support@nsc.com

Deutsch Tel: +49 (0) 69 9508 6208

English Tel: +44 (0) 870 24 0 2171

Français Tel: +33 (0) 1 41 91 8790

Email: ap.support@nsc.com

www.national.com

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.

LM4810LDX/NOPB [TI]

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