NSC LM4840MTX, LM4840MHX, LM4840LQX, LM4840LQ, LM4840MH Datasheet

LM4840

Stereo 2W Audio Power Amplifiers
with Digital Volume Control and Input Mux

General Description

The LM4840 is a monolithic integrated circuit that provides
digital 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 weredesignedspecifically
to provide high quality audio while requiring a minimum
amount of external components. The LM4840 incorporates a
digital volume control,stereobridged audio power amplifiers,
an input mux, and a last volume level memory function to
save the volume setting during shutdown. These features
make it optimally suited for multimedia monitors, portable
radios, desktop, and portable computer applications.

The LM4840 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 LM4840LQ and
LM4840MH will deliver 2W into 4Ω. The LM4840MT will deliver 1.1W into 8Ω.
See the Application Information section LM4840LQ and for LM4840MH us­age information.

Note 2: An LM4840LQ and LM4840MH that have been properly mounted to
the circuit board and forced-air cooled will deliver 2.2W into 3Ω.

Key Specifications

n POat 1% THD+N
n into 3Ω (LM4840LQ, LM4840MH) 2.2W (typ)
n into 4Ω (LM4840LQ, LM4840MH) 2.0W (typ)
n into 8Ω (LM4840) 1.1W (typ)
n Single-ended mode - THD+N at 85mW into 32Ω 1.0%

(typ)

n Shutdown current 0.2µA (typ)

Features

n PC98 and PC99 Compliant
n Digital Volume Control Interface
n System Beep Detect
n Stereo switchable bridged/single-ended power amplifiers
n “Click and pop” suppression circuitry
n Thermal shutdown protection circuitry
n Input Mux
n Capless headphone drivers
n Last volume memory from shutdown

Applications

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

Connection Diagram

Boomer®is a registered trademark of NationalSemiconductor Corporation.

LLP Package

DS200104-35

Top View

Order Number LM4840LQ

See NS Package Number LQA028A for Exposed-DAP LLP

December 2001

LM4840 Stereo 2W Audio Power Amplifiers with Digital Volume Control and Input Mux

© 2001 National Semiconductor Corporation DS200104 www.national.com

Connection Diagram (Continued)

Block Diagram

TSSOP Package

DS200104-2

Top View

Order Number LM4840MT

See NS Package Number MTC28 for TSSOP

Order Number LM4840MH

See NS Package Number MXA28A for Exposed-DAP TSSOP

DS200104-1

FIGURE 1. LM4840 Block Diagram

LM4840

www.national.com 2

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.

See AN-1187 “Leadless Leadframe Package” for
detailed information on usage of LLP devices.

θ

JC

(typ)—LQA028A (Note

16)

3˚C/W

θ

JA

(typ)—LQA028A (Note

16)

42˚C/W

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

LM4840

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 12 30 mA (max)

I

SD

Shutdown Current V

SHUTDOWN

=V

DD

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 V

DD

= 5V. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4840

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

C

RANGE

Attenuator Range Gain with Digital Volume Max 0

±

0.5 dB (max)

Attenuation with Digital Volume Min -81 -75 dB (min)

A

M

Mute Attenuation V

MUTE=VDD

, Bridged Mode -88 -78 dB (min)

V

MUTE=VDD

, Single-Ended Mode -88 -78 dB (min)

Electrical Characteristics for Single-Ended Mode Operation

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

DD

= 5V. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4840

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

LM4840

www.national.com3

Electrical Characteristics for Single-Ended Mode Operation (Continued)

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

DD

= 5V. Limits apply for TA= 25˚C.

Symbol Parameter Conditions

LM4840

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

THD+N Total Harmonic Distortion+Noise V

OUT

=1V

RMS

, f=1kHz, RL= 10kΩ,

A

VD

=1

0.065 %

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 V

DD

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

Symbol Parameter Conditions

LM4840

Units

(Limits)

Typical

(Note 14)

Limit

(Note 15)

V

OS

Output Offset Voltage VIN= 0V, No Load 5 50 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 = 1.5% (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 LM4840LQ and LM4840MH must be mounted to the circuit board and forced-air cooled.
Note 9: When driving 4Ω loads from a 5V supply the LM4840LQ and LM4840MH 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 LM4840LQ and LM4840MT, T

JMAX

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

resistance, when board mounted, is 80˚C/W for the MTC28 package and 42˚C/W for the LM4840LQ 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 specified at 25˚C and represent the parametric norm.
Note 15: Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.
Note 16: Number given is for an LQA028A package whose exposed-DAP is soldered to an exposed 2.5in

2

piece of 1 ounce PCB copper.

LM4840

www.national.com 4

MH and LQ Specific Characteristics

Note 17: These curves show the thermal dissipation ability of the LM4840MH 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.

Typical Performance Characteristics

LM4840MH, LM4840LQ
THD+N vs Output Power

DS200104-70

LM4840MH, LM4840LQ
THD+N vs Frequency

DS200104-71

LM4840MH, LM4840LQ
THD+N vs Output Power

DS200104-72

LM4840MH, LM4840LQ
THD+N vs Frequency

DS200104-73

LM4840MH, LM4840LQ
Power Dissipation vs Output Power

DS200104-65

LM4840MH(Note 17)
Power Derating Curve

DS200104-64

THD+N vs Frequency

DS200104-57

THD+N vs Frequency

DS200104-58

THD+N vs Frequency

DS200104-14

LM4840

www.national.com5

Typical Performance Characteristics (Continued)

THD+N vs Frequency

DS200104-15

THD+N vs Frequency

DS200104-16

THD+N vs Frequency

DS200104-17

THD+N vs Frequency

DS200104-18

THD+N vs Frequency

DS200104-19

THD+N vs Frequency

DS200104-20

THD+N vs Frequency

DS200104-21

THD+N vs Frequency

DS200104-22

THD+N vs Output Power

DS200104-24

LM4840

www.national.com 6