LM4675SDX/NOPB - NATIONAL SEMICONDUCTOR

LM4675

LM4675 Ultra-Low EMI, Filterless, 2.65W, Mono, Class D Audio Power

Amplifier withSpread Spectrum

Literature Number: SNAS353B

July 2, 2008

LM4675

Ultra-Low EMI, Filterless, 2.65W, Mono, Class D Audio

Power Amplifier with Spread Spectrum

General Description

The LM4675 is a single supply, high efficiency, 2.65W, mono,

Class D audio amplifier. A spread spectrum, filterless PWM

architecture reduces EMI and eliminates the output filter, re-

ducing external component count, board area consumption,

system cost, and simplifying design.

The LM4675 is designed to meet the demands of mobile

phones and other portable communication devices. Operat-

ing on a single 5V supply, it is capable of driving a 4Ω speaker

load at a continuous average output of 2.2W with less than

1% THD+N. Its flexible power supply requirements allow op-

eration from 2.4V to 5.5V. The wide band spread spectrum

architecture of the LM4675 reduces EMI-radiated emissions

due to the modulator frequency.

The LM4675 has high efficiency with speaker loads compared

to a typical Class AB amplifier. With a 3.6V supply driving an

8Ω speaker, the IC's efficiency for a 100mW power level is

80%, reaching 89% at 400mW output power.

The LM4675 features a low-power consumption shutdown

mode. Shutdown may be enabled by driving the Shutdown

pin to a logic low (GND).

The gain of the LM4675 is externally configurable which al-

lows independent gain control from multiple sources by sum-

ming the signals. Output short circuit and thermal overload

protection prevent the device from damage during fault con-

ditions.

Key Specifications

■ Efficiency at 3.6V, 400mW into

8Ω speaker 89% (typ)

■ Efficiency at 3.6V, 100mW into

8Ω speaker 80% (typ)

■ Efficiency at 5V, 1W into

8Ω speaker 89% (typ)

■ Quiescent current, 3.6V supply 2.2mA (typ)

■ Total shutdown power

supply current 0.01µA (typ)

■ Single supply range 2.4V to 5.5V

■ PSRR, f = 217Hz 82dB

Features

■Spread spectrum architecture reduces EMI

■Mono Class D Operation

■No output filter required for inductive loads

■Externally configurable gain

■Very fast turn on time: 17μs (typ)

■Minimum external components

■"Click and pop" suppression circuitry

■Micro-power shutdown mode

■Available in space-saving 0.5mm pitch micro SMD and

LLP packages

Applications

■Mobile phones

■PDAs

■Portable electronic devices

Boomer® is a registered trademark of National Semiconductor Corporation.

LM4675 Ultra-Low EMI, Filterless, 2.65W, Mono, Class D Audio Power Amplifier with Spread

Spectrum

20182721

LM4675 Rf Emissions — 6in cable

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LM4675

Typical Application

201827j3

FIGURE 1. Typical Audio Amplifier Application Circuit

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LM4675

Connection Diagrams

9 Bump micro SMD Package

20182736

Top View

Order Number LM4675TL

See NS Package Number TLA09AAA

micro SMD Marking

20182757

Top View

X — Date Code

T— Die Traceability

G — Boomer Family

H8 — LM4675TL

Leadless Leadframe Package (LLP)

20182703

Top View

Order Number LM4675SD

See NS Package Number SDA08A

LLP Marking

20182704

Top View

Z — Plant Code

XY — Date Code

TT — Die Traceability

L4675 — LM4675SD

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LM4675

Absolute Maximum Ratings (Notes 1, 2)

If Military/Aerospace specified devices are required,

please contact the National Semiconductor Sales Office/

Distributors for availability and specifications.

Supply Voltage (Note 1) 6.0V

Storage Temperature −65°C to +150°C

Voltage at Any Input Pin VDD + 0.3V ≥ V ≥ GND - 0.3V

Power Dissipation (Note 3) Internally Limited

ESD Susceptibility, all other pins (Note 4) 2.0kV

ESD Susceptibility (Note 5) 200V

Junction Temperature (TJMAX)150°C

Thermal Resistance

θJA (micro SMD) 220°C/W

θJA (LLP) 73°C/W

Soldering Information

See AN-1112 "microSMD Wafers Level Chip

Scale Package."

Operating Ratings (Notes 1, 2)

Temperature Range

TMIN ≤ TA ≤ TMAX −40°C ≤ TA ≤ 85°C

Supply Voltage 2.4V ≤ VDD ≤ 5.5V

Electrical Characteristics (Notes 1, 2)

The following specifications apply for AV = 2V/V (RI = 150kΩ), RL = 15µH + 8Ω + 15µH unless otherwise specified. Limits apply for

TA = 25°C.

Symbol Parameter Conditions

LM4675 Units

(Limits)

Typical Limit

(Note 6) (Notes 7, 8)

|VOS|Differential Output Offset Voltage VI = 0V, AV = 2V/V,

VDD = 2.4V to 5.0V 3 mV

|IIH| Logic High Input Current VDD = 5.0V, VI = 5.5V 17 100 μA (max)

|IIL| Logic Low Input Current VDD = 5.0V, VI = –0.3V 0.9 5 μA (max)

VIN = 0V, No Load, VDD = 5.0V 2.8 3.9 mA (max)

IDD Quiescent Power Supply Current

VIN = 0V, No Load, VDD = 3.6V 2.2 2.9 mA

VIN = 0V, No Load, VDD = 2.4V 1.6 2.3 mA (max)

VIN = 0V, RL = 8Ω, VDD = 5.0V 2.8

VIN = 0V, RL = 8Ω, VDD = 3.6V 2.2

VIN = 0V, RL = 8Ω, VDD = 2.4V 1.6

ISD Shutdown Current VSHUTDOWN = 0V

VDD = 2.4V to 5.0V 0.01 1.0 μA (max)

VSDIH Shutdown voltage input high 1.4 V (min)

VSDIL Shutdown voltage input low 0.4 V (max)

ROSD Output Impedance VSHUTDOWN = 0.4V 100 kΩ

AVGain 300kΩ/RI V/V (min)

V/V (max)

RSD

Resistance from Shutdown Pin to

GND

300 kΩ

fSW Switching Frequency 300±30% kHz

POOutput Power

RL = 15μH + 4Ω + 15μH

THD = 10% (max)

f = 1kHz, 22kHz BW

VDD = 5V

VDD = 3.6V

VDD = 2.5V

2.7

1.3

560

RL = 15μH + 4Ω + 15μH

THD = 1% (max)

f = 1kHz, 22kHz BW

VDD = 5V

VDD = 3.6V

VDD = 2.5V

2.2

1.08

450

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LM4675

Symbol Parameter Conditions

LM4675 Units

(Limits)

Typical Limit

(Note 6) (Notes 7, 8)

POOutput Power

RL = 15μH + 8Ω + 15μH

THD = 10% (max)

f = 1kHz, 22kHz BW

VDD = 5V 1.6 W

VDD = 3.6V 820 mW

VDD = 2.5V 350 mW

RL = 15μH + 8Ω + 15μH

THD = 1% (max)

f = 1kHz, 22kHz BW

VDD = 5V 1.3 W

VDD = 3.6V 650 600 mW

VDD = 2.5V 290 mW

THD+N Total Harmonic Distortion + Noise

VDD = 5V, PO = 0.1W, f = 1kHz 0.03 %

VDD = 3.6V, PO = 0.1W, f = 1kHz 0.02 %

VDD = 2.5V, PO = 0.1W, f = 1kHz 0.04 %

PSRR Power Supply Rejection Ratio

(Input Referred)

VRipple = 200mVPP Sine,

fRipple = 217Hz, VDD = 3.6, 5V

Inputs to AC GND, CI = 2μF

VRipple = 200mVPP Sine,

fRipple = 1kHz, VDD = 3.6, 5V

Inputs to AC GND, CI = 2μF

SNR Signal to Noise Ratio VDD = 5V, PO = 1WRMS 97 dB

εOUT

Output Noise

(Input Referred)

VDD = 3.6V, f = 20Hz – 20kHz

Inputs to AC GND, CI = 2μF

No Weighting

μVRMS

VDD = 3.6V, Inputs to AC GND

CI = 2μF, A Weighted 22 μVRMS

CMRR Common Mode Rejection Ratio

(Input Referred)

VDD = 3.6V, VRipple = 1VPP Sine

fRipple = 217Hz 80 dB

TWU Wake-up Time VDD = 3.6V 17 μs

TSD Shutdown Time 140 μs

ηEfficiency

VDD = 3.6V, POUT = 400mW

RL = 8Ω 89 %

VDD = 5V, POUT = 1W

RL = 8Ω 89 %

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LM4675

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

Note 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.

Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX, θJA, and the ambient temperature TA. The maximum

allowable power dissipation is PDMAX = (TJMAX–TA)/θJA or the number given in Absolute Maximum Ratings, whichever is lower. For the LM4675, TJMAX = 150°C.

The typical θJA is 99.1°C/W for the micro SMD package.

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

Note 5: Machine Model, 220pF – 240pF discharged through all pins.

Note 6: Typical specifications are specified at 25°C and represent the parametric norm.

Note 7: Tested limits are guaranteed to National's AOQL (Average Outgoing Quality Level).

Note 8: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

Note 9: Shutdown current is measured in a normal room environment. Exposure to direct sunlight will increase ISD by a maximum of 2µA. The Shutdown pin

should be driven as close as possible to GND for minimal shutdown current and to VDD for the best THD performance in PLAY mode. See the Application

Information section under SHUTDOWN FUNCTION for more information.

Note 10: The performance graphs were taken using the Audio Precision AUX-0025 Switching Amplifier measurement Filter in series with the LC filter on the

demo board.

External Components Description

(Figure 1)

Components Functional Description

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

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

2. CIInput AC coupling capacitor which blocks the DC voltage at the amplifier's input terminals.

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LM4675

Typical Performance Characteristics

THD + N vs Output Power

f = 1kHz, RL = 8Ω

20182706

THD + N vs Output Power

f = 1kHz, RL = 4Ω

20182707

THD + N vs Frequency

VDD = 2.5V, POUT = 100mW, RL = 8Ω

20182708

THD + N vs Frequency

VDD = 3.6V, POUT = 150mW, RL = 8Ω

20182709

THD + N vs Frequency

VDD = 5V, POUT = 200mW, RL = 8Ω

20182710

THD + N vs Frequency

VDD = 2.5V, POUT = 100mW, RL = 4Ω

20182711

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LM4675

THD + N vs Frequency

VDD = 3.6V, POUT = 100mW, RL = 4Ω

20182712

THD + N vs Frequency

VDD = 5V, POUT = 150mW, RL = 4Ω

20182713

Efficiency vs. Output Power

RL = 4Ω, f = 1kHz

20182714

Efficiency vs. Output Power

RL = 8Ω, f = 1kHz

20182715

Power Dissipation vs. Output Power

RL = 4Ω, f = 1kHz

20182716

Power Dissipation vs. Output Power

RL = 8Ω, f = 1kHz

20182717

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LM4675

Output Power vs. Supply Voltage

RL = 4Ω, f = 1kHz

20182718

Output Power vs. Supply Voltage

RL = 8Ω, f = 1kHz

20182719

PSRR vs. Frequency

VDD = 3.6V ,VRIPPLE = 200mVP-P, RL = 8Ω

20182720

CMRR vs. Frequency

VDD = 3.6V, VCM = 1VP-P, RL = 8Ω

20182729

Supply Current vs. Supply Voltage

No Load

20182730

Shutdown Supply Current vs. Supply Voltage

No Load

20182731

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LM4675

Fixed Frequency FFT

VDD = 3.6V

20182734

Spread Spectrum FFT

VDD = 3.6V

20182735

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LM4675

Application Information

GENERAL AMPLIFIER FUNCTION

The LM4675 features a filterless modulation scheme. The

differential outputs of the device switch at 300kHz from VDD

to GND. When there is no input signal applied, the two outputs

(VO1 and VO2) switch with a 50% duty cycle, with both outputs

in phase. Because the outputs of the LM4675 are differential,

the two signals cancel each other. This results in no net volt-

age across the speaker, thus there is no load current during

an idle state, conserving power.

With an input signal applied, the duty cycle (pulse width) of

the LM4675 outputs changes. For increasing output voltages,

the duty cycle of VO1 increases, while the duty cycle of VO2

decreases. For decreasing output voltages, the converse oc-

curs, the duty cycle of VO2 increases while the duty cycle of

VO1 decreases. The difference between the two pulse widths

yields the differential output voltage.

SPREAD SPECTRUM MODULATION

The LM4675 features a fitlerless spread spectrum modulation

scheme that eliminates the need for output filters, ferrite

beads or chokes. The switching frequency varies by ±30%

about a 300kHz center frequency, reducing the wideband

spectral contend, improving EMI emissions radiated by the

speaker and associated cables and traces. Where a fixed fre-

quency class D exhibits large amounts of spectral energy at

multiples of the switching frequency, the spread spectrum ar-

chitecture of the LM4675 spreads that energy over a larger

bandwidth. The cycle-to-cycle variation of the switching peri-

od does not affect the audio reproduction of efficiency.

POWER DISSIPATION AND EFFICIENCY

In general terms, efficiency is considered to be the ratio of

useful work output divided by the total energy required to pro-

duce it with the difference being the power dissipated, typi-

cally, in the IC. The key here is “useful” work. For audio

systems, the energy delivered in the audible bands is con-

sidered useful including the distortion products of the input

signal. Sub-sonic (DC) and super-sonic components

(>22kHz) are not useful. The difference between the power

flowing from the power supply and the audio band power be-

ing transduced is dissipated in the LM4675 and in the trans-

ducer load. The amount of power dissipation in the LM4675

is very low. This is because the ON resistance of the switches

used to form the output waveforms is typically less than

0.25Ω. This leaves only the transducer load as a potential

"sink" for the small excess of input power over audio band

output power. The LM4675 dissipates only a fraction of the

excess power requiring no additional PCB area or copper

plane to act as a heat sink.

DIFFERENTIAL AMPLIFIER EXPLANATION

As logic supply voltages continue to shrink, designers are in-

creasingly turning to differential analog signal handling to

preserve signal to noise ratios with restricted voltage swing.

The LM4675 is a fully differential amplifier that features dif-

ferential input and output stages. A differential amplifier am-

plifies the difference between the two input signals. Tradition-

al audio power amplifiers have typically offered only single-

ended inputs resulting in a 6dB reduction in signal to noise

ratio relative to differential inputs. The LM4675 also offers the

possibility of DC input coupling which eliminates the two ex-

ternal AC coupling, DC blocking capacitors. The LM4675 can

be used, however, as a single ended input amplifier while still

retaining it's fully differential benefits. In fact, completely un-

related signals may be placed on the input pins. The LM4675

simply amplifies the difference between the signals. A major

benefit of a differential amplifier is the improved common

mode rejection ratio (CMRR) over single input amplifiers. The

common-mode rejection characteristic of the differential am-

plifier reduces sensitivity to ground offset related noise injec-

tion, especially important in high noise applications.

PCB LAYOUT CONSIDERATIONS

As output power increases, interconnect resistance (PCB

traces and wires) between the amplifier, load and power sup-

ply create a voltage drop. The voltage loss on the traces

between the LM4675 and the load results is lower output

power and decreased efficiency. Higher trace resistance be-

tween the supply and the LM4675 has the same effect as a

poorly regulated supply, increased ripple on the supply line

also reducing the peak output power. The effects of residual

trace resistance increases as output current increases due to

higher output power, decreased load impedance or both. To

maintain the highest output voltage swing and corresponding

peak output power, the PCB traces that connect the output

pins to the load and the supply pins to the power supply

should be as wide as possible to minimize trace resistance.

The use of power and ground planes will give the best THD

+N performance. While reducing trace resistance, the use of

power planes also creates parasite capacitors that help to fil-

ter the power supply line.

The inductive nature of the transducer load can also result in

overshoot on one or both edges, clamped by the parasitic

diodes to GND and VDD in each case. From an EMI stand-

point, this is an aggressive waveform that can radiate or

conduct to other components in the system and cause inter-

ference. It is essential to keep the power and output traces

short and well shielded if possible. Use of ground planes,

beads, and micro-strip layout techniques are all useful in pre-

venting unwanted interference.

As the distance from the LM4675 and the speaker increase,

the amount of EMI radiation will increase since the output

wires or traces acting as antenna become more efficient with

length. What is acceptable EMI is highly application specific.

Ferrite chip inductors placed close to the LM4675 may be

needed to reduce EMI radiation. The value of the ferrite chip

is very application specific.

POWER SUPPLY BYPASSING

As with any power amplifier, proper supply bypassing is crit-

ical for low noise performance and high power supply rejec-

tion ratio (PSRR). The capacitor (CS) location should be as

close as possible to the LM4675. Typical applications employ

a voltage regulator with a 10µF and a 0.1µF bypass capacitors

that increase supply stability. These capacitors do not elimi-

nate the need for bypassing on the supply pin of the LM4675.

A 4.7µF tantalum capacitor is recommended.

SHUTDOWN FUNCTION

In order to reduce power consumption while not in use, the

LM4675 contains shutdown circuitry that reduces current

draw to less than 0.01µA. The trigger point for shutdown is

shown as a typical value in the Electrical Characteristics Ta-

bles and in the Shutdown Hysteresis Voltage graphs found in

the Typical Performance Characteristics section. It is best

to switch between ground and supply for minimum current

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LM4675

usage while in the shutdown state. While the LM4675 may be

disabled with shutdown voltages in between ground and sup-

ply, the idle current will be greater than the typical 0.01µA

value.

The LM4675 has an internal resistor connected between

GND and Shutdown pins. The purpose of this resistor is to

eliminate any unwanted state changes when the Shutdown

pin is floating. The LM4675 will enter the shutdown state when

the Shutdown pin is left floating or if not floating, when the

shutdown voltage has crossed the threshold. To minimize the

supply current while in the shutdown state, the Shutdown pin

should be driven to GND or left floating. If the Shutdown pin

is not driven to GND, the amount of additional resistor current

due to the internal shutdown resistor can be found by Equa-

tion (1) below.

(VSD - GND) / 300kΩ(1)

With only a 0.5V difference, an additional 1.7µA of current will

be drawn while in the shutdown state.

PROPER SELECTION OF EXTERNAL COMPONENTS

The gain of the LM4675 is set by the external resistors, Ri in

Figure 1, The Gain is given by Equation (2) below. Best THD

+N performance is achieved with a gain of 2V/V (6dB).

AV = 2 * 150 kΩ / Ri (V/V) (2)

It is recommended that resistors with 1% tolerance or better

be used to set the gain of the LM4675. The Ri resistors should

be placed close to the input pins of the LM4675. Keeping the

input traces close to each other and of the same length in a

high noise environment will aid in noise rejection due to the

good CMRR of the LM4675. Noise coupled onto input traces

which are physically close to each other will be common mode

and easily rejected by the LM4675.

Input capacitors may be needed for some applications or

when the source is single-ended (see Figures 3, 5). Input ca-

pacitors are needed to block any DC voltage at the source so

that the DC voltage seen between the input terminals of the

LM4675 is 0V. Input capacitors create a high-pass filter with

the input resistors, Ri. The –3dB point of the high-pass filter

is found using Equation (3) below.

fC = 1 / (2πRi Ci ) (Hz) (3)

The input capacitors may also be used to remove low audio

frequencies. Small speakers cannot reproduce low bass fre-

quencies so filtering may be desired . When the LM4675 is

using a single-ended source, power supply noise on the

ground is seen as an input signal by the +IN input pin that is

capacitor coupled to ground (See Figures 5 – 7). Setting the

high-pass filter point above the power supply noise frequen-

cies, 217Hz in a GSM phone, for example, will filter out this

noise so it is not amplified and heard on the output. Capacitors

with a tolerance of 10% or better are recommended for

impedance matching.

DIFFERENTIAL CIRCUIT CONFIGURATIONS

The LM4675 can be used in many different circuit configura-

tions. The simplest and best performing is the DC coupled,

differential input configuration shown in Figure 2. Equation (2)

above is used to determine the value of the Ri resistors for a

desired gain.

Input capacitors can be used in a differential configuration as

shown in Figure 3. Equation (3) above is used to determine

the value of the Ci capacitors for a desired frequency re-

sponse due to the high-pass filter created by Ci and Ri.

Equation (2) above is used to determine the value of the Ri

resistors for a desired gain.

The LM4675 can be used to amplify more than one audio

source. Figure 4 shows a dual differential input configuration.

The gain for each input can be independently set for maxi-

mum design flexibility using the Ri resistors for each input and

Equation (2). Input capacitors can be used with one or more

sources as well to have different frequency responses de-

pending on the source or if a DC voltage needs to be blocked

from a source.

SINGLE-ENDED CIRCUIT CONFIGURATIONS

The LM4675 can also be used with single-ended sources but

input capacitors will be needed to block any DC at the input

terminals. Figure 5 shows the typical single-ended application

configuration. The equations for Gain, Equation (2), and fre-

quency response, Equation (3), hold for the single-ended

configuration as shown in Figure 5.

When using more than one single-ended source as shown in

Figure 6, the impedance seen from each input terminal should

be equal. To find the correct values for Ci3 and Ri3 connected

to the +IN input pin the equivalent impedance of all the single-

ended sources are calculated. The single-ended sources are

in parallel to each other. The equivalent capacitor and resis-

tor, Ci3 and Ri3, are found by calculating the parallel combi-

nation of all Civalues and then all Ri values. Equations (4) and

(5) below are for any number of single-ended sources.

Ci3 = Ci1 + Ci2 + Cin (F) (4)

Ri3 = 1 / (1/Ri1 + 1/Ri2 + 1/Rin) (Ω) (5)

The LM4675 may also use a combination of single-ended and

differential sources. A typical application with one single-end-

ed source and one differential source is shown in Figure 7.

Using the principle of superposition, the external component

values can be determined with the above equations corre-

sponding to the configuration.

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LM4675

20182722

FIGURE 2. Differential Input Configuration

20182723

FIGURE 3. Differential Input Configuration with Input Capacitors

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LM4675

20182724

FIGURE 4. Dual Differential Input Configuration

20182725

FIGURE 5. Single-Ended Input Configuration

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LM4675

20182726

FIGURE 6. Dual Single-Ended Input Configuration

20182727

FIGURE 7. Dual Input with a Single-Ended Input and a Differential Input

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LM4675

REFERENCE DESIGN BOARD SCHEMATIC

20182728

FIGURE 8.

In addition to the minimal parts required for the application

circuit, a measurement filter is provided on the evaluation cir-

cuit board so that conventional audio measurements can be

conveniently made without additional equipment. This is a

balanced input, grounded differential output low pass filter

with a 3dB frequency of approximately 35kHz and an on board

termination resistor of 300Ω (see schematic). Note that the

capacitive load elements are returned to ground. This is not

optimal for common mode rejection purposes, but due to the

independent pulse format at each output there is a significant

amount of high frequency common mode component on the

outputs. The grounded capacitive filter elements attenuate

this component at the board to reduce the high frequency

CMRR requirement placed on the analysis instruments.

Even with the grounded filter the audio signal is still differen-

tial, necessitating a differential input on any analysis instru-

ment connected to it. Most lab instruments that feature BNC

connectors on their inputs are NOT differential responding

because the ring of the BNC is usually grounded.

The commonly used Audio Precision analyzer is differential,

but its ability to accurately reject high frequency signals is

questionable necessitating the on board measurement filter.

When in doubt or when the signal needs to be single-ended,

use an audio signal transformer to convert the differential out-

put to a single ended output. Depending on the audio

transformer's characteristics, there may be some attenuation

of the audio signal which needs to be taken into account for

correct measurement of performance.

Measurements made at the output of the measurement filter

suffer attenuation relative to the primary, unfiltered outputs

even at audio frequencies. This is due to the resistance of the

inductors interacting with the termination resistor (300Ω) and

is typically about -0.25dB (3%). In other words, the voltage

levels (and corresponding power levels) indicated through the

measurement filter are slightly lower than those that actually

occur at the load placed on the unfiltered outputs. This small

loss in the filter for measurement gives a lower output power

reading than what is really occurring on the unfiltered outputs

and its load.

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LM4675

Revision History

Rev Date Description

1.0 08/16/06 Initial release.

1.1 09/01/06 Added the uSMD (TL) package.

1.2 10/12/06 Text edit (X-axis label) on Rf Emissions on page 1.

1.3 07/02/08 Text edits.

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LM4675

Physical Dimensions inches (millimeters) unless otherwise noted

9 Bump micro SMD

Order Number LM4675TL

NS Package Number TLA09AAA

X1 = 1.514 X2 = 1.514 X3 = 0.600

LLP

Order Number LM4675SD

NS Package Number SDA08A

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LM4675

Notes

LM4675 Ultra-Low EMI, Filterless, 2.65W, Mono, Class D Audio Power Amplifier with Spread

Spectrum

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