NSC LM4835MTEX, LM4835MTE, LM4835MTX Datasheet

LM4835
Stereo 2W Audio Power Amplifiers
with DC Volume Control and Selectable Gain

General Description

The LM4835 is a monolithic integrated circuit that provides
DC volume control, and stereo bridged audio power amplifi­ers capable of producing 2W into 4Ω (Note 1) with less than

1.0%THD or 2.2W into 3Ω (Note 2) with less than 1.0

%

THD.
Boomer

®

audio integrated circuits were designed specifically
to provide high quality audio while requiring a minimum
amount of external components. The LM4835 incorporates a
DC volume control, stereo bridged audio power amplifiers
and a selectable gain or bass boost, making it optimally
suited for multimedia monitors, portable radios, desktop, and
portable computer applications.

The LM4835 features an externally controlled, low-power
consumption shutdown mode, and both a power amplifier
and headphone mute for maximum system flexibility and
performance.

Note 1: When properly mounted to the circuit board, the LM4835MTE will
deliver 2W into 4Ω. TheLM4835MTwill deliver 1.1W into 8Ω. See the Appli­cation Information section for LM4835MTE usage information.

Note 2: An LM4835MTE which has been properly mounted to the circuit
board and forced-air cooled will deliver 2.2W into 3Ω.

Key Specifications

n POat 1%THD+N

into 3Ω (LM4835MTE) 2.2W(typ)
into 4Ω (LM4835MTE) 2.0W(typ)
into 8Ω (LM4835) 1.1W(typ)

n Single-ended mode - THD+N

at 85mW into 32Ω

1.0%(typ)

n Shutdown current 0.7µA(typ)

Features

n PC98 Compliant
n DC Volume Control Interface
n System Beep Detect
n Stereo switchable bridged/single-ended power amplifiers
n Selectable internal/external gain and bass boost

configurable

n “Click and pop” suppression circuitry
n Thermal shutdown protection circuitry

Applications

n Portable and Desktop Computers
n Multimedia Monitors
n Portable Radios, PDAs, and Portable TVs

Block Diagram Connection Diagram

Boomer®is a registered trademark of NationalSemiconductor Corporation.

DS100139-1

FIGURE 1. LM4835 Block Diagram

TSSOP Package

DS100139-2

Top View

Order Number LM4835MT

See NS Package Number MTC28 for TSSOP

Order Number LM4835MTE

See NS Package Number MXA28A for Exposed DAP

TSSOP

March 1999

LM4835 Stereo 2W Audio Power Amplifiers with DC Volume Control and Selectable Gain

© 1999 National Semiconductor Corporation DS100139 www.national.com

Absolute Maximum Ratings (Note 10)

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
Input Voltage −0.3V to V

DD

+0.3V
Power Dissipation Internally limited
ESD Susceptibility (Note 12) 2000V
ESD Susceptibility (Note 13) 200V
Junction Temperature 150˚C
Soldering Information

Small Outline Package

Vapor Phase (60 sec.) 215˚C
Infrared (15 sec.) 220˚C

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

θ

JC

(typ)— MTC28 20˚C/W

θ

JA

(typ)— MTC28 80˚C/W

θ

JC

(typ)— MXA28A 2˚C/W

θ

JA

(typ)— MXA28A (Note 4) 41˚C/W

θ

JA

(typ)— MXA28A (Note 3) 54˚C/W

θ

JA

(typ)— MXA28A (Note 5) 59˚C/W

θ

JA

(typ)— MXA28A (Note 6) 93˚C/W

Operating Ratings

Temperature Range

T

MIN

≤ TA≤T

MAX

−40˚C ≤TA ≤ 85˚C

Supply Voltage 2.7V≤ V

DD

≤ 5.5V

Electrical Characteristics for Entire IC

(Notes 7, 10)
The following specifications apply for V

DD

= 5V unless otherwise noted. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4835

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

V

DD

Supply Voltage 2.7 V (min)

5.5 V (max)

I

DD

Quiescent Power Supply Current VIN= 0V, IO= 0A 15 30 mA (max)

I

SD

Shutdown Current V

pin 2=VDD

0.7 2.0 µA (max)

V

IH

Headphone Sense High Input Voltage 4 V (min)

V

IL

Headphone Sense Low Input Voltage 0.8 V (max)

Electrical Characteristics for Volume Attenuators

(Notes 7, 10)
The following specifications apply for VDD= 5V. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4835

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

C

RANGE

Attenuator Range Gain with V

pin 7

=5V 0

±

0.5 dB (max)

Attenuation with V

pin 7

= 0V -81 -80 dB (min)

A

M

Mute Attenuation V

pin 5

= 5V, Bridged Mode -88 -80 dB (min)

V

pin 5

= 5V, Single-Ended Mode -88 -80 dB (min)

Electrical Characteristics for Single-Ended Mode Operation

(Notes 7, 10)
The following specifications apply for VDD= 5V. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4835

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

P

O

Output Power THD = 1.0%; f = 1kHz; RL=32Ω 85 mW

THD=10%;f=1kHz; R

L

=32Ω 95 mW

THD+N Total Harmonic Distortion+Noise V

OUT

=1V

RMS

, f=1kHz, RL= 10kΩ,

A

VD

=1

0.065

%

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Electrical Characteristics for Single-Ended Mode Operation (Continued)

(Notes 7, 10)
The following specifications apply for VDD= 5V. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4835

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

PSRR Power Supply Rejection Ratio C

B

= 1.0 µF, f =120 Hz,

V

RIPPLE

= 200 mVrms

58 dB

SNR Signal to Noise Ratio P

OUT

=75 mW, RL=32Ω, A-Wtd

Filter

102 dB

X

talk

Channel Separation f=1kHz, CB= 1.0 µF 65 dB

Electrical Characteristics for Bridged Mode Operation

(Notes 7, 10)
The following specifications apply for VDD= 5V, unless otherwise noted. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4835

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

V

OS

Output Offset Voltage VIN= 0V 5 30 mV (max)

P

O

Output Power THD+N=1.0%; f=1kHz; RL=3Ω

(Note 8)

2.2 W

THD+N=1.0%; f=1kHz; R

L

=4Ω

(Note 9)

2W

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

L

=8Ω

1.1 1.0 W (min)

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

L

=8Ω 1.5 W

THD+N Total Harmonic Distortion+Noise P

O

= 1W, 20 Hz<f<20 kHz,

R

L

=8Ω,AVD=2

0.3

%

P

O

= 340 mW, RL=32Ω 1.0

%

PSRR Power Supply Rejection Ratio C

B

= 1.0 µF, f = 120 Hz,

V

RIPPLE

= 200 mVrms; RL=8Ω

74 dB

SNR Signal to Noise Ratio V

DD

= 5V, P

OUT

= 1.1W, RL=8Ω,

A-Wtd Filter

93 dB

X

talk

Channel Separation f=1kHz, CB= 1.0 µF 70 dB

Note 3: The θJAgiven is for an MXA28A package whose exposed-DAP is soldered to an exposed 2in2piece of 1 ounce printed circuit board copper.
Note 4: The θ

JA

given is for an MXA28A package whose exposed-DAP is soldered to a 2in2piece of 1 ounce printed circuit board copper on a bottom side layer

through 21 8mil vias.
Note 5: The θ

JA

given is for an MXA28A package whose exposed-DAP is soldered to an exposed 1in2piece of 1 ounce printed circuit board copper.

Note 6: The θ

JA

given is for an MXA28A package whose exposed-DAP is not soldered to any copper.

Note 7: All voltages are measured with respect to the ground pins, unless otherwise specified. All specifications are tested using the typical application as shown
in

Figure 1

.

Note 8: When driving 3Ω loads from a 5V supply the LM4835MTE must be mounted to the circuit board and forced-air cooled.
Note 9: When driving 4Ω loads from a 5V supply the LM4835MTE must be mounted to the circuit board.
Note 10:

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. Marshall Chiu feels there are better ways to obtain ″More Watt­age in the Cottage.″ Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance.

Note 11: The maximum power dissipation must be derated at elevated temperatures and is dictated by T

JMAX

, θJA, and the ambient temperature TA. The maximum

allowable power dissipation is P

DMAX

=(T

JMAX−TA

)/θJA. For the LM4835MT,T

JMAX

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

mounted, is 80˚C/W assuming the MTC28 package.

Note 12: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 13: Machine Model, 220 pF–240 pF discharged through all pins.
Note 14: Typicals are measured at 25˚C and represent the parametric norm.
Note 15: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

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Typical Application

Truth Table for Logic Inputs

(Note 16)

Mute Mode HP Sense DC Vol. Control Bridged Output Single-Ended Output

0 0 0 Fixed Level Vol. Fixed _
0 0 1 Fixed Level Muted Vol. Fixed
0 1 0 Adjustable Vol. Changes _
0 1 1 Adjustable Muted Vol. Changes
1 X X _ Muted Muted

Note 16: If system beep is detected on the Beep In pin (pin 11), the system beep will be passed through the bridged amplifier regardless of the logic of the Mute
and HP sense pins.

DS100139-3

FIGURE 2. Typical Application Circuit

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Typical Performance Characteristics
MTE Specific Characteristics

Note 17: These curves show the thermal dissipation ability of the LM4835MTE at different ambient temperatures given these conditions:

500LFPM + 2in

2

: The part is soldered to a 2in2, 1 oz. copper plane with 500 linear feet per minute of forced-air flow across it.

2in

2

on bottom: The part is soldered to a 2in2, 1oz. copper plane that is on the bottom side of the PC board through 21 8 mil vias.

2in

2

: The part is soldered to a 2in2, 1oz. copper plane.

1in

2

: The part is soldered to a 1in2, 1oz. copper plane.

Not Attached: The part is not soldered down and is not forced-air cooled.

Non-MTE Specific Characteristics

LM4835MTE
THD+N vs Output Power

DS100139-70

LM4835MTE
THD+N vs Frequency

DS100139-71

LM4835MTE
THD+N vs Output Power

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LM4835MTE
THD+N vs Frequency

DS100139-73

LM4835MTE
Power Dissipation vs Output Power

DS100139-65

LM4835MTE(Note 17)
Power Derating Curve

DS100139-64

THD+N vs Frequency

DS100139-57

THD+N vs Frequency

DS100139-58

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