LM4841MT [NSC]
Stereo 2W Amplifiers with DC Volume Control, Transient Free Outputs, and Cap-less Headphone Drive; 立体声2W放大器，提供直流音量控制，瞬态自由输出和无盖耳机驱动器
| 型号： | LM4841MT |
| 厂家： | 
National Semiconductor |
| 描述： | Stereo 2W Amplifiers with DC Volume Control, Transient Free Outputs, and Cap-less Headphone Drive |
| 文件： | 总31页 (文件大小：1131K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
August 2002
LM4841
Stereo 2W Amplifiers with DC Volume Control,
Transient Free Outputs, and Cap-less Headphone Drive
General Description
Key Specifications
n PO at 1% THD+N
The LM4841 is a monolithic integrated circuit that provides
DC volume control and stereo bridged audio power amplifi-
ers capable of producing 2W into 4Ω (Note 1) or 2.2W into
3Ω (Note 2) with less than 1.0% THD.
n
n
n
into 3Ω (MH and LQ)
into 4Ω ( MH and LQ)
into 8Ω (MT, MH, and LQ)
2.2W (typ)
2.0W (typ)
1.1W (typ)
1.0%(typ)
0.7µA (typ)
The LM4841 uses advanced, latest generation circuitry to
eliminate all traces of clicks and pops when the supply
voltages is first applied. The amplifier has a headphone-
amplifier-select input pin that is used to switch the amplifiers
from bridge to single-ended mode for driving headphones. A
new circuit topology eliminates headphone output coupling
capacitors (patent pending).
Boomer® audio integrated circuits are designed specifically
to provide high quality audio while requiring a minimum
amount of external components. The LM4841 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.
n Single-ended THD+N at 85mW into 32Ω
n Shutdown current
Features
n Stereo headphone amplifier mode that eliminates the
Output Coupling Capacitors (patent pending)
n Acoustically Enhanced DC Volume Control Taper
n System Beep Detect
n Stereo switchable bridged/single-ended power amplifiers
n Selectable internal/external gain and bass boost
n Advanced “click and pop” suppression circuitry
n Thermal shutdown protection circuitry
The LM4841 features an externally controlled, low-power
consumption shutdown mode (Shutdown Low), and both a
power amplifier and headphone mute for maximum system
flexibility and performance.
Note 1: When properly mounted to the circuit board, LM4841MH and
LM4841LQ will deliver 2W into 4Ω. The LM4841MT will deliver 1.1W into 8Ω.
See the Application Information section for LM4841MH usage information.
Applications
n Portable and Desktop Computers
n Multimedia Monitors
n Portable Radios, PDAs, and Portable TVs
Note 2: An LM4841MH that has been properly mounted to the circuit board
and forced-air cooled will deliver 2.2W into 3Ω.
Connection Diagrams
TSSOP Package
20028002
Top View
Order Number LM4841MT or LM4841MH
See NS Package Number MTC28 for TSSOP and MXA28A for Exposed-DAP TSSOP
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2002 National Semiconductor Corporation
DS200280
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Connection Diagrams (Continued)
LLP Package
20028097
Top View
Order Number LM4841LQ
See NS Package Number LQA028AA for Exposed-DAP LLP
Block Diagram
20028001
FIGURE 1. LM4841 Block Diagram
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2
Absolute Maximum Ratings (Note 10)
θJC (typ)—LQA028A
θJA (typ)—LQA028A
θJC (typ)—MTC28
3˚C/W
42˚C/W
20˚C/W
80˚C/W
2˚C/W
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
θJA (typ)—MTC28
Supply Voltage
6.0V
-65˚C to +150˚C
θJC (typ)—MXA28A
θJA (typ)—MXA28A (exposed
DAP) (Note 4)
Storage Temperature
Input Voltage
41˚C/W
−0.3V to VDD +0.3V
Internally limited
Power Dissipation (Note 11)
ESD Susceptibility (Note 12)
All pins except Pin 28
Pin 28
θJA (typ)—MXA28A (exposed
DAP) (Note 3)
54˚C/W
59˚C/W
93˚C/W
2500V
6500V
200V
θJA (typ)—MXA28A (exposed
DAP) (Note 5)
θJA (typ)—MXA28A (exposed
DAP) (Note 6)
ESD Susceptibility (Note 13)
Junction Temperature
Soldering Information
Small Outline Package
Vapor Phase (60 sec.)
Infrared (15 sec.)
150˚C
Operating Ratings
Temperature Range
TMIN ≤ TA ≤TMAX
Supply Voltage
215˚C
220˚C
−40˚C ≤TA ≤ 85˚C
2.7V≤ VDD ≤ 5.5V
See AN-450 “Surface Mounting and their Effects on
Product Reliability” for other methods of soldering surface
mount devices.
Electrical Characteristics for Entire IC (Notes 7, 10)
The following specifications apply for VDD = 5V unless otherwise noted. Limits apply for TA = 25˚C.
LM4841
Units
(Limits)
Symbol
VDD
Parameter
Supply Voltage
Conditions
Typical
(Note 14)
Limit
(Note 15)
2.7
V (min)
V (max)
mA (max)
µA (max)
V (min)
V (max)
mVrms
5.5
IDD
Quiescent Power Supply Current
Shutdown Current
VIN = 0V, IO = 0A
15
30
ISD
Vshutdown = GND
0.7
2.0
VIH
VIL
Headphone Sense High Input Voltage
Headphone Sense Low Input Voltage
Un-Mute Threshold Voltage
4
0.8
10
40
THum
Gain 1st Stage = 1
Vshutdown = VDD
22
mVrms
VIN applied to A or B input
Electrical Characteristics for Volume Attenuators (Notes 7, 10)
The following specifications apply for VDD = 5V. Limits apply for TA = 25˚C.
LM4841
Units
(Limits)
Symbol
Parameter
Attenuator Range
Conditions
Typical
(Note 14)
Limit
(Note 15)
0.75
CRANGE
Gain with VDCVol = 5V, No Load
Attenuation with VDCVol = 0V (BM &
SE)
dB (max)
dB (min)
-75
AM
Mute Attenuation
Vmute = 5V, Bridged Mode (BM)
Vmute = 5V, Single-Ended Mode (SE)
-78
-78
dB (min)
dB (min)
3
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Electrical Characteristics for Single-Ended Mode Operation (Notes 7, 10)
The following specifications apply for VDD = 5V. Limits apply for TA = 25˚C.
LM4841
Units
(Limits)
Symbol
PO
Parameter
Output Power
Conditions
Typical
(Note 14)
85
Limit
(Note 15)
THD = 1.0%; f = 1kHz; RL = 32Ω
THD = 10%; f = 1 kHz; RL = 32Ω
VOUT = 1VRMS, f=1kHz, RL = 10kΩ,
AVD = 1
mW
mW
%
95
THD+N
PSRR
SNR
Total Harmonic Distortion+Noise
Power Supply Rejection Ratio
Signal to Noise Ratio
0.065
CB = 1.0 µF, f =120 Hz,
VRIPPLE = 200 mVrms
58
102
65
dB
dB
dB
POUT =75 mW, R = 32Ω, A-Wtd
L
Filter
Xtalk
Channel Separation
f=1kHz, CB = 1.0 µF
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.
LM4841
Units
(Limits)
Symbol
VOS
Parameter
Conditions
VIN = 0V, No Load
Typical
(Note 14)
5
Limit
(Note 15)
50
Output Offset Voltage
Output Power
mV (max)
W
PO
THD + N = 1.0%; f=1kHz; RL = 3Ω
(Note 8)
2.2
THD + N = 1.0%; f=1kHz; RL = 4Ω
(Note 9)
2
W
THD = 1% (max);f = 1 kHz;
RL = 8Ω
1.1
1.0
W (min)
THD+N = 10%;f = 1 kHz; RL = 8Ω
1.5
0.3
W
%
< <
20 kHz,
THD+N
Total Harmonic Distortion+Noise
PO = 1W, 20 Hz
RL = 8Ω, AVD = 2
f
PO = 340 mW, RL = 32Ω
CB = 1.0 µF, f = 120 Hz,
VRIPPLE = 200 mVrms; RL = 8Ω
VDD = 5V, POUT = 1.1W, RL = 8Ω,
A-Wtd Filter
1.0
74
%
PSRR
SNR
Xtalk
Power Supply Rejection Ratio
Signal to Noise Ratio
dB
93
70
dB
dB
Channel Separation
f=1kHz, CB = 1.0 µF
2
Note 3: The θ given is for an MXA28A package whose exposed-DAP is soldered to an exposed 2in piece of 1 ounce printed circuit board copper.
JA
2
Note 4: The θ given is for an MXA28A package whose exposed-DAP is soldered to a 2in piece of 1 ounce printed circuit board copper on a bottom side layer
JA
through 21 8mil vias.
2
Note 5: The θ given is for an MXA28A package whose exposed-DAP is soldered to an exposed 1in piece of 1 ounce printed circuit board copper.
JA
Note 6: The θ given is for an MXA28A package whose exposed-DAP is not soldered to any copper.
JA
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, LM4841MH and LM4841LQ must be mounted to the circuit board and forced-air cooled.
Note 9: When driving 4Ω loads from a 5V supply, the LM4841MH and LM4841LQ 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. 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
, θ , and the ambient temperature T . The maximum
JA A
JMAX
allowable power dissipation is P
= (T
− T )/θ . For the LM4841MT and LM4841LQ, T
= 150˚C. See Power Dissipation for further information.
DMAX
JMAX
A
JA
JMAX
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). Datasheet min/max specification limits are guaranteed by design, test, or
statistical analysis.
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4
Typical Application
20028003
FIGURE 2. Typical Application Circuit ( MT / MH Package Pinout )
Truth Table for Logic Inputs (Note 16)
Headphone
Gain Select
Mode
Mute
Output Stage Set
To
Volume Control
Sense
X
0
0
1
1
0
0
1
1
X
0
0
0
0
1
1
1
1
X
0
0
0
0
0
0
0
0
1
Internal Gain
Internal Gain
External Gain
External Gain
Internal Gain
External Gain
External Gain
Internal Gain
X
On
On
X
X
On
X
On
On
Off
On
Off
X
On
On
On
On
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.
5
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Typical Performance Characteristics
MH/LQ Specific Characteristics
LM4841MH/LQ
LM4841MH/LQ
THD+N vs Output Power
THD+N vs Frequency
20028070
20028071
LM4841MH/LQ
LM4841MH/LQ
THD+N vs Output Power
THD+N vs Frequency
20028072
20028073
LM4841MH/LQ
LM4841MH/LQ (Note 17)
Power Dissipation vs Output Power
Power Derating Curve
20028065
20028064
Note 17: These curves show the thermal dissipation ability of the LM4841MH/LQ at different ambient temperatures given these conditions:
2
2
500LFPM + 2in : The part is soldered to a 2in , 1 oz. copper plane with 500 linear feet per minute of forced-air flow across it.
2
2
2in on bottom: The part is soldered to a 2in , 1oz. copper plane that is on the bottom side of the PC board through 21 8 mil vias.
2
2
2in : The part is soldered to a 2in , 1oz. copper plane.
2
2
1in : The part is soldered to a 1in , 1oz. copper plane.
Not Attached: The part is not soldered down and is not forced-air cooled.
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6
Non-MH/LQ Specific Characteristics
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
20028058
20028057
THD+N vs Frequency
20028014
20028015
THD+N vs Frequency
20028017
20028016
7
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Non-MH/LQ Specific Characteristics (Continued)
THD+N vs Frequency
THD+N vs Frequency
20028018
20028019
THD+N vs Frequency
THD+N vs Frequency
20028021
20028020
THD+N vs Frequency
THD+N vs Output Power
20028024
20028022
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8
Non-MH/LQ Specific Characteristics (Continued)
THD+N vs Output Power
THD+N vs Output Power
20028025
20028026
THD+N vs Output Power
THD+N vs Output Power
20028027
20028028
THD+N vs Output Power
THD+N vs Output Power
20028030
20028029
9
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Non-MH/LQ Specific Characteristics (Continued)
THD+N vs Output Power
THD+N vs Output Power
20028031
20028032
THD+N vs Output Power
THD+N vs Output Power
20028034
20028033
THD+N vs Output Voltage
Docking Station Pins
THD+N vs Output Voltage
Docking Station Pins
20028059
20028060
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10
Typical Performance Characteristics
Output Power vs
Load Resistance
Output Power vs
Load Resistance
20028062
20028006
Output Power vs
Load Resistance
Power Supply
Rejection Ratio
20028039
20028007
Output Power vs
Load Resistance
Dropout Voltage
20028053
20028008
11
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Typical Performance Characteristics (Continued)
Volume Control
Characteristics
Power Dissipation vs
Output Power
20028040
20028051
Power Dissipation vs
Output Power
External Gain/
Bass Boost Characteristics
20028052
20028061
Power Derating Curve
Crosstalk
20028063
20028049
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12
Typical Performance Characteristics (Continued)
Output Power
Output Power
vs Supply voltage
vs Supply Voltage
20028054
20028056
Supply Current
vs Supply Voltage
20028009
13
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Application Information
ELIMINATING OUTPUT COUPLING CAPACITORS
LM4841’s one-half supply voltage on a plug’s sleeve con-
nection. Driving portable notebook computer or
a
Typical single-supply audio amplifiers that can switch be-
tween driving bridge-tied-load (BTL) speakers and
single-ended (SE) headphones use a coupling capacitor on
each SE output. This capacitor blocks the half-supply volt-
age to which the output amplifiers are typically biased and
couples the audio signal to the headphones. The signal
return to circuit ground is through the headphone jack’s
sleeve.
audio-visual display equipment is possible. This presents no
difficulty when the external equipment uses capacitively
coupled inputs. For the very small minority of equipment that
is DC-coupled, the LM4841 monitors the current supplied by
the amplifier that drives the headphone jack’s sleeve. If this
current exceeds 500mAPK, the amplifier is shutdown, pro-
tecting the LM4841 and the external equipment.
The LM4841 eliminates these coupling capacitors. Amplifi-
erA+ (pin 28 on MT/MH) is internally configured to apply
VDD/2 to a stereo headphone jack’s sleeve. This voltage
matches the quiescent voltage present on the AmpAout- and
AmpBout- outputs that drive the headphones. The head-
OUTPUT TRANSIENT (’POPS AND CLICKS’)
ELIMINATED
The LM4841 contains advanced circuitry that eliminates out-
put transients (’pop and click’). This circuitry prevents all
traces of transients when the supply voltage is first applied,
when the part resumes operation after shutdown, or when
switching between BTL speakers and SE headphones. Two
circuits combine to eliminate pop and click. One circuit
mutes the output when switching between speaker loads.
Another circuit monitors the input signal. It maintains the
muted condition until there is sufficient input signal magni-
phones operate in
a
manner very similar to
a
bridge-tied-load (BTL). The same DC voltage is applied to
both headphone speaker terminals. This results in no net DC
current flow through the speaker. AC current flows through a
headphone speaker as an audio signal’s output amplitude
increases on the speaker’s terminal.
When operating as a headphone amplifier, the headphone
jack sleeve is not connected to circuit ground. Using the
headphone output jack as a line-level output will place the
>
tude ( 22mVRMS, typ) to mask any remaining transient that
may occur. (See Turn On Characteristics).
20028095
FIGURE 3. Differential output signal (Trace B) is devoid of transients. The SHUTDOWN pin is driven by a shutdown
signal (Trace A). The inverting output (Trace C) and the non-inverting output (Trace D) are applied across an 8Ω BTL
load.
Figure 3 shows the LM4841’s lack of transients in the differ-
ential signal (Trace B) across a BTL 8Ω load. The LM4841’s
active-high SHUTDOWN pin is driven by the logic signal
shown in Trace A. Trace C is the VOUT- output signal and
trace D is the VOUT+ output signal. The shutdown signal
frequency is 1Hz with a 50% duty cycle. Figure 4 is gener-
ated with the same conditions except that the output drives a
32Ω single-ended (SE) load. Again, no trace of output tran-
sients on Trace B can be observed.
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14
Application Information (Continued)
20028096
FIGURE 4. Single-ended output signal (Trace B) is devoid of transients. The SHUTDOWN pin is driven by a shutdown
signal (Trace A). The inverting output (Trace C) and the VBYPASS output (Trace D) are applied across a 32Ω BTL load.
EXPOSED-DAP PACKAGE PCB MOUNTING
CONSIDERATIONS
PCB LAYOUT AND SUPPLY REGULATION
CONSIDERATIONS FOR DRIVING 3Ω AND 4Ω LOADS
The LM4841’s exposed-DAP (die attach paddle) packages
(MH,LQ) provide 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, finally, surrounding
air. The result is a low voltage audio power amplifier that
produces 2.1W at ≤ 1% THD with a 4Ω load. This high power
is achieved through careful consideration of necessary ther-
mal design. Failing to optimize thermal design may compro-
mise the LM4841’s high power performance and activate
unwanted, though necessary, thermal shutdown protection.
Power dissipated by a load is a function of the voltage swing
across the load and the load’s impedance. As load imped-
ance decreases, load dissipation becomes increasingly de-
pendent on the interconnect (PCB trace and wire) resistance
between the amplifier output pins and the load’s connec-
tions. Residual trace resistance causes a voltage drop,
which results in power dissipated in the trace and not in the
load as desired. For example, 0.1Ω trace resistance reduces
the output power dissipated by a 4Ω load from 2.1W to 2.0W.
This problem of decreased load dissipation is exacerbated
as load impedance decreases. Therefore, to maintain the
highest load dissipation and widest output voltage swing,
PCB traces that connect the output pins to a load must be as
wide as possible.
The MH and LQ packages must have their exposed DAPs
soldered to a grounded copper pad on the PCB. The DAP’s
PCB copper pad is connected to a large grounded plane of
continuous unbroken copper. This plane forms a thermal
mass heat sink and radiation area. Place the heat sink area
on either outside plane in the case of a two-sided PCB, or on
an inner layer of a board with more than two layers. Connect
the DAP copper pad to the inner layer or backside copper
heat sink area with 32(4x8) (MH) vias or 6(3x2) LQ. The via
diameter should be 0.012in–0.013in with a 1.27mm pitch.
Ensure efficient thermal conductivity by plating-through and
solder-filling the vias.
Poor power supply regulation adversely affects maximum
output power. A poorly regulated supply’s output voltage
decreases with increasing load current. Reduced supply
voltage causes decreased headroom, output signal clipping,
and reduced output power. Even with tightly regulated sup-
plies, trace resistance creates the same effects as poor
supply regulation. Therefore, making the power supply
traces as wide as possible helps maintain full output voltage
swing.
Best thermal performance is achieved with the largest prac-
tical copper heat sink area. If the heatsink and amplifier
share the same PCB layer, a nominal 2.5in2 (min) area is
necessary for 5V operation with a 4Ω load. Heatsink areas
not placed on the same PCB layer as the LM4841MH and
LQ packages should be 5in2 (min) for the same supply
voltage and load resistance. The last two area recommen-
dations apply for 25˚C ambient temperature. Increase the
area to compensate for ambient temperatures above 25˚C.
The junction temperature must be held below 150˚C to pre-
vent activating the LM4841’s thermal shutdown protection.
The LM4841’s power de-rating curve in the Typical Perfor-
mance Characteristics shows the maximum power dissipa-
tion versus temperature. Example PCB layouts for the
exposed-DAP TSSOP and LQ packages are shown in the
Demonstration Board Layout section. Further detailed and
specific information concerning PCB layout and fabrication is
available in National Semiconductor’s AN1187.
BRIDGE CONFIGURATION EXPLANATION
As shown in Figure 2, the LM4841 output stage consists of
two pairs of operational amplifiers, forming a two-channel
(channel A and channel B) stereo amplifier. (Though the
following discusses channel A, it applies equally to channel
B.)
Figure 2 shows that the first amplifier’s negative (-) output
serves as the second amplifier’s input. This results in both
amplifiers producing signals identical in magnitude, but 180˚
out of phase. Taking advantage of this phase difference, a
load is placed between −OUTA and +OUTA and driven dif-
ferentially (commonly referred to as “bridge mode”). This
results in a differential gain of
*
AVD = 2 (RGFA/RGIA
)
(1)
15
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mum ambient temperature that still allows maximum stereo
power dissipation without violating the LM4841’s maximum
junction temperature.
Application Information (Continued)
Bridge mode amplifiers are different from single-ended am-
plifiers that drive loads connected between a single amplifi-
er’s output and ground. For a given supply voltage, bridge
mode has a distinct advantage over the single-ended con-
figuration: its differential output doubles the voltage
swing across the load. This produces four times the output
power when compared to a single-ended amplifier under the
same conditions. This increase in attainable output power
assumes that the amplifier is not current limited or that the
output signal is not clipped. To ensure minimum output sig-
nal clipping when choosing an amplifier’s closed-loop gain,
refer to the Audio Power Amplifier Design section.
TA = TJMAX – 2*PDMAX θJA
(5)
For a typical application with a 5V power supply and an 4Ω
load, the maximum ambient temperature that allows maxi-
mum stereo power dissipation without exceeding the maxi-
mum junction temperature is approximately 45˚C for the MH
package.
TJMAX = PDMAX θJA + TA
(6)
Another advantage of the differential bridge output is no net
DC voltage across the load. This is accomplished by biasing
channel A’s and channel B’s outputs at half-supply. This
eliminates the coupling capacitor that single supply, single-
ended amplifiers require. Eliminating an output coupling ca-
pacitor in a single-ended configuration forces a single-supply
amplifier’s half-supply bias voltage across the load. This
increases internal IC power dissipation and may perma-
nently damage loads such as speakers.
Equation (6) gives the maximum junction temperature
TJMAX. If the result violates the LM4841’s 150˚C TJMAX
reduce the maximum junction temperature by reducing the
power supply voltage or increasing the load resistance. Fur-
ther allowance should be made for increased ambient tem-
peratures.
,
The above examples assume that a device is a surface
mount part operating around the maximum power dissipation
point. Since internal power dissipation is a function of output
power, higher ambient temperatures are allowed as output
power or duty cycle decreases.
POWER DISSIPATION
Power dissipation is a major concern when designing a
successful single-ended or bridged amplifier. Equation (2)
states the maximum power dissipation point for a single-
ended amplifier operating at a given supply voltage and
driving a specified output load.
If the result of Equation (2) is greater than that of Equation
(3), then decrease the supply voltage, increase the load
impedance, or reduce the ambient temperature. If these
measures are insufficient, a heat sink can be added to
reduce θJA. The heat sink can be created using additional
copper area around the package, with connections to the
ground pin(s), supply pin and amplifier output pins. External,
solder attached SMT heatsinks such as the Thermalloy
7106D can also improve power dissipation. When adding a
heat sink, the θJA is the sum of θJC, θCS, and θSA. (θJC is the
junction-to-case thermal impedance, θCS is the case-to-sink
thermal impedance, and θSA is the sink-to-ambient thermal
impedance.) Refer to the Typical Performance Character-
istics curves for power dissipation information at lower out-
put power levels.
PDMAX = (VDD)2/(2π2RL) Single-Ended
(2)
However, a direct consequence of the increased power de-
livered to the load by a bridge amplifier is higher internal
power dissipation for the same conditions.
The LM4841 has two operational amplifiers per channel. The
maximum internal power dissipation per channel operating in
the bridge mode is four times that of a single-ended ampli-
fier. From Equation (3), assuming a 5V power supply and a
4Ω load, the maximum single channel power dissipation is
1.27W or 2.54W for stereo operation.
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 10 µF in parallel with a 0.1 µF filter capacitor to
stabilize 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 1.0 µF
tantalum bypass capacitance connected between the
LM4841’s supply pins and ground. Do not substitute a ce-
ramic capacitor for the tantalum. Doing so may cause oscil-
lation. Keep the length of leads and traces that connect
capacitors between the LM4841’s power supply pin and
ground as short as possible. Connecting a 1µF capacitor,
CB, between the BYPASS pin and ground improves the
internal bias voltage’s stability and the amplifier’s PSRR. The
PSRR improvements increase as the bypass pin capacitor
value increases. Too large a capacitor, however, increases
turn-on time and can compromise the amplifier’s click and
pop performance. The selection of bypass capacitor values,
especially CB, depends on desired PSRR requirements,
click and pop performance (as explained in the following
section, Selecting Proper External Components), system
cost, and size constraints.
PDMAX = 4 (VDD)2/(2π2RL) Bridge Mode
(3)
*
The LM4841’s power dissipation is twice that given by Equa-
tion (2) or Equation (3) when operating in the single-ended
mode or bridge mode, respectively. Twice the maximum
power dissipation point given by Equation (3) must not ex-
ceed the power dissipation given by Equation (4):
PDMAX' = (TJMAX − TA)/θJA
(4)
The LM4841’s TJMAX = 150˚C. In the LQ package soldered
to a DAP pad that expands to a copper area of 5in2 on a
PCB, the LM4841’s θJA is 20˚C/W. In the MH and LQ pack-
ages soldered to a DAP pad that expands to a copper area
of 2in2 on a PCB, the LM4841MH’s and LQ’s θJA is 41˚C/W.
For the LM4841MT package, θJA = 80˚C/W. At any given
ambient temperature TA, use Equation (4) to find the maxi-
mum internal power dissipation supported by the IC packag-
ing. Rearranging Equation (4) and substituting PDMAX for
PDMAX' results in Equation (5). This equation gives the maxi-
www.national.com
16
the BYPASS pin in a controlled, linear manner. Ideally, the
input and outputs track the voltage applied to the BYPASS
pin. The gain of the internal amplifiers remains unity until the
voltage on the BYPASS pin reaches 1/2 VDD. As soon as the
voltage on the BYPASS pin is stable, the LM4841 is ready to
be fully turned on. To turn the device on, the input signal
must exceed 22mVrms. This is accomplished through a
threshold detect circuit that enables all appropriate output
amplifiers after the 22mVrms limit is reached. Until this
threshold is reached, some of the amplifiers remain in a
tri-state mode. This insures that there is no current flowing
through to the speakers or headphones during power up.
Without current flow, the speakers or headphones remain
silent. During headphone mode, A+, B-, and B+ are in tri-
state mode during power up. During speaker mode, A+ and
B+ are in tri-state mode during power up.
Application Information (Continued)
SELECTING PROPER EXTERNAL COMPONENTS
Optimizing the LM4841’s performance requires properly se-
lecting external components. Though the LM4841 operates
well when using external components with wide tolerances,
best performance is achieved by optimizing component val-
ues.
The LM4841 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 circuits demand input
signals with greater voltage swings to achieve maximum
output power. Fortunately, many signal sources such as
audio CODECs have outputs of 1VRMS (2.83VP-P). Please
refer to the Audio Power Amplifier Design section for more
information on selecting the proper gain.
Although the BYPASS pin current cannot be modified,
changing the size of CBYP alters the device’s turn-on time. As
the size of CBYP increases, the turn-on time increases. There
is a linear relationship between the size of CBYP and the
turn-on time. Here are some typical turn-on times for various
Input Capacitor Value Selection
Amplifying the lowest audio frequencies requires a high
value input coupling capacitor (0.33µF in Figure 2), but high
value capacitors can be expensive and may compromise
space efficiency in portable designs. In many cases, how-
ever, the speakers used in portable systems, whether inter-
nal or external, have little ability to reproduce signals below
150 Hz. Applications using speakers with this limited fre-
quency response reap little improvement by using a large
input capacitor.
values of CBYP
:
CBYP
0.01µF
TON
2ms
0.1µF
0.22µF
0.47µF
1.0µF
20ms
44ms
94ms
200ms
Besides effecting system cost and size, the input coupling
capacitor has an affect on the LM4841’s click and pop per-
formance. When the supply voltage is first applied, a tran-
sient (pop) is created as the charge on the input capacitor
changes from zero to a quiescent state. The magnitude of
the pop is directly proportional to the input capacitor’s size.
Higher value capacitors need more time to reach a quiescent
DC voltage (usually VDD/2) when charged with a fixed cur-
rent. The amplifier’s output charges the input capacitor
through the feedback resistor, Rf. Thus, pops can be mini-
mized by selecting an input capacitor value that is no higher
than necessary to meet the desired −6dB frequency.
DOCKING STATION INTERFACE
Applications such as notebook computers can take advan-
tage of a docking station to connect to external devices such
as monitors or audio/visual equipment that sends or receives
line level signals. The LM4841 has two outputs, Dock A and
Dock B, which connect to outputs of the internal input am-
plifiers that drive the volume control inputs. These input
>
amplifiers can drive loads of 1kΩ (such as powered speak-
ers) with a rail-to-rail signal. Since the output signal present
on the Dock A and Dock B pins are biased to VDD/2, coupling
capacitors should be connected in series with the load when
using these outputs. Typical values for the output coupling
capacitors are 0.33µF to 1.0µF. If polarized coupling capaci-
tors are used, connect their ’+’ terminals to the respective
output pin.
As shown in Figure 2, the input resistor (RIA, RIB = 20k) ( and
the input capacitor (CIA, CIB = 0.33µF) produce a −6dB high
pass filter cutoff frequency that is found using Equation (7).
Since the Dock outputs precede the internal volume control,
the signal amplitude will be equal to the input signal’s mag-
nitude and cannot be adjusted. However, the input amplifi-
er’s closed-loop gain can be adjusted using external resis-
tors. These 20k resistors (RFA and RFB) are shown in Figure
2 and they set each input amplifier’s gain to -1. Use Equation
7 to determine the input and feedback resistor values for a
desired gain.
(7)
As an example when using a speaker with a low frequency
limit of 150Hz, the input coupling capacitor, using Equation
(7), is 0.063µF. The 0.33µF input coupling capacitor shown
in Figure 2 allows the LM4841 to drive a high efficiency, full
range speaker whose response extends below 30Hz.
TURN ON Characteristics
- Av = RF / RIN
(8)
The LM4841 contains advanced circuitry that minimizes
turn-on and shutdown transients or “clicks and pops”. For
this discussion, turn-on refers to either applying the power
supply voltage or when the shutdown mode is deactivated.
While the power supply is ramping to its final value, the
LM4841’s internal amplifiers are configured as unity gain
buffers. An internal current source changes the voltage of
Adjusting the input amplifier’s gain sets the minimum gain for
that channel. Although the single ended output of the Bridge
Output Amplifiers can be used to drive line level outputs, it is
recommended that the A & B Dock Outputs simpler signal
path be used for better performance.
17
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When activated, the LM4841’s micro-power shutdown fea-
ture turns off the amplifier’s bias circuitry, reducing the sup-
ply current. On the demo board, the micro-power shutdown
feature is controlled by a single pole switch that connects the
shutdown pin to either VDD, for normal operation, or directly
to ground to enable shutdown. In a system with a micropro-
cessor or a microcontroller, use a digital output to apply the
control voltage to the SHUTDOWN pin.
Application Information (Continued)
BEEP DETECT FUNCTION
Computers and notebooks produce a system “beep“ signal
that drives a small speaker. The speaker’s auditory output
signifies that the system requires user attention or input. To
accommodate this system alert signal, the LM4841’s beep
input pin is a mono input that accepts the beep signal.
Internal level detection circuitry at this input monitors the
beep signal’s magnitude. When a signal level greater than
VDD/2 is detected on the BEEP IN pin, the bridge output
amplifiers are enabled. The beep signal is amplified and
applied to the load connected to the output amplifiers. A valid
beep signal will be applied to the load even when MUTE is
active. Use the input resistors connected between the BEEP
IN pin and the stereo input pins to accommodate different
beep signal amplitudes. These resistors are shown as
200kΩ devices in Figure 2. Use higher value resistors to
reduce the gain applied to the beep signal. The resistors
must be used to pass the beep signal to the stereo inputs.
The BEEP IN pin is used only to detect the beep signal’s
magnitude: it does not pass the signal to the output amplifi-
ers. The LM4841’s shutdown mode must be deactivated
before a system alert signal is applied to BEEP IN pin.
MODE FUNCTION
The LM4841’s MODE function has 2 states controlled by the
voltage applied to the MODE pin. In Mode 0 (mode pin at
GND), the HP Sense has no effect on the gain setting (only
the Gain Select Input Controls either internal or external
gain). In Mode 1 (mode pin tied high), the HP Sense and
Gain Select both can toggle between Internal and External
Gain. See ’Truth Table for Logic Inputs’ on page 5.
MUTE FUNCTION
The LM4841 mutes the amplifier and DOCK outputs when
VDD is applied to the MUTE pin. Even while muted, the
LM4841 will amplify a system alert (beep) signal whose
magnitude satisfies the BEEP DETECT circuitry. Applying
0V to the MUTE pin returns the LM4841 to normal, unmuted
operation. Prevent unanticipated mute behavior by connect-
ing the MUTE pin to VDD or ground. Do not let the mute pin
float.
MICRO-POWER SHUTDOWN
The voltage applied to the SHUTDOWN pin controls the
LM4841’s shutdown function. Activate micro-power shut-
down by applying ground (logic low) to the SHUTDOWN pin.
20028087
FIGURE 5. Headphone Sensing Circuit (MT & MH Packages)
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18
input signal from an audio signal to the VDD/2 DC voltage
present on pin 28, and mutes the bridge-connected loads.
Amp A -OUT and Amp B -OUT drive the headphones.
Application Information (Continued)
CAP-LESS HEADPHONE (SINGLE-ENDED) AMPLIFIER
OPERATION
Figures 2 and 6 also show suggested headphone jack elec-
trical connections. The jack is designed to mate with a
three−wire plug. The plug’s tip and ring should each carry
one of the two stereo output signals, whereas the sleeve
provides the return to Amp A +OUT. A headphone jack with
one control pin contact is sufficient to drive the HP−IN pin
when connecting headphones
An internal pull−up circuit is connected to the HP Sense (Pin
21 HP-IN) headphone amplifier control pin. When this pin is
left unconnected, VDD is applied to the HP−IN. This turns off
Amp B +OUT (not seen in Fig 5, see Fig 2 Pin 15) and
switches Amp A +OUT’s input signal from an audio signal to
the VDD/2 voltage present on pin 28 (Amp A + OUT). The
result is muted bridge-connected loads. Quiescent current
consumption is reduced when the IC is in this single−ended
mode.
A switch can replace the headphone jack contact pin. When
a switch shorts the HP−IN pin to VDD (An open switch
contact will accomplish this because there is an internal
pull-up resistor), the bridge−connected speakers are muted
and Amp A -OUT and Amp B -OUT drive the stereo head-
phones. When a switch shorts the HP−IN pin to GND (pulling
down the internal pull-up resistor), the LM4841 operates in
bridge mode. If headphone drive is not needed, short the
HP−IN pin to the −OUTB pin.
Figure 5 above shows the implementation of the LM4841’s
headphone control function. An internal comparator with a
nominal 400mV offset monitors the signal present at the
−OUT B output. It compares this signal against the signal
applied to the HP−IN pin (Notice in Figure 5, Pin 21 is
shorted to Pin 17 without a headphone plugged in). When
these signals are equal, as in the case when a BTL is
connected to the amplifier, an internal comparator forces the
LM4841 to maintain bridged−amplifier operation. When the
HP−IN pin is externally floated, such as when headphones
are connected to the jack shown in Figure 5, an internal
pull−up forces VDD on the internal comparator’s HP−IN in-
puts. This changes the comparator’s output state and en-
ables the headphone function: it turns off Amp B +OUT (not
seen in Fig 5, see Fig 2 Pin 15), switches the Amp A +OUT
ESD Protection
As stated in the Absolute Maximum Ratings, pin 28 on the
MT/MH packages and pin 25 on the LQ package, have a
maximum ESD susceptibility rating of 6500V. For higher
ESD voltages, the addition of a PCDN042 dual transil (from
California Micro Devices), as shown in Figure 6, will provide
additional protection.
20028094
FIGURE 6. The PCDN042 provides additional ESD protection beyond the 6500V shown in the
Absolute Maximum Ratings for the AMP2A output
GAIN SELECT FUNCTION (Bass Boost)
In some cases a designer may want to improve the low
frequency response of the bridged amplifier or incorporate a
bass boost feature. This bass boost can be useful in systems
where speakers are housed in small enclosures. A resistor,
RBA, and a capacitor, CBA, in parallel, can be placed in series
with the feedback resistor of the bridged amplifier as seen in
Figure 7.
The LM4841 features selectable gain, using either internal or
external feedback resistors. Either set of feedback resistors
set the gain of the output amplifiers. The voltage applied to
the GAIN SELECT pin controls which gain is selected. Ap-
plying VDD to the GAIN SELECT pin selects the external gain
mode. Applying 0V to the GAIN SELECT pin selects the
internally set unity gain.
19
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Application Information (Continued)
20028011
FIGURE 7. Low Frequency Enhancement ( MT/MH PINOUT )
The LM4841 volume control consists of 31 steps that are
individually selected by a variable DC voltage level on the
volume control pin. The range of the steps, controlled by the
DC voltage, are from 0dB - 78dB. Each gain step corre-
sponds to a specific input voltage range, as shown in table 2,
(on the following page.)
At low, frequencies CBA is a virtual open circuit and at high
frequencies, its nearly zero ohm impedance shorts RBA. The
result is increased bridge-amplifier gain at low frequencies.
The combination of RBA and CBA form a -6dB corner fre-
quency at
To minimize the effect of noise on the volume control pin,
which can affect the selected gain level, hysteresis has been
implemented. The amount of hysteresis corresponds to half
of the step width, as shown in Volume Control Characteriza-
tion Graph (DS200133-40).
fC = 1/(2πRBACBA
)
(9)
The bridged-amplifier low frequency differential gain is:
AVD = 2(RGFA + RBA) / RGIA
For highest accuracy, the voltage shown in the ’recom-
mended voltage’ column of the table is used to select a
desired gain. This recommended voltage is exactly halfway
between the two nearest transitions to the next highest or
next lowest gain levels.
(10)
Using the component values shown in Figure 2 (RGFA
20kΩ, RBA = 20kΩ, and CBA = 0.068µF), a first-order, -6dB
pole is created at 120Hz. Assuming R = 20kΩ, the low
frequency differential gain is 4. The input (Cin A and B) capaci-
tor values must be selected for a low frequency response
that covers the range of frequencies affected by the desired
bass-boost operation.
=
The gain levels are 1dB/step from 0dB to -6dB, 2dB/step
from -6dB to -36dB, 3dB/step from -36dB to -47dB, 4dB/step
from -47db to -51dB, 5dB/step from -51dB to -66dB, and
12dB to the last step at -78dB.
GIA
DC VOLUME CONTROL
The LM4841 has an internal stereo volume control whose
setting is a function of the DC voltage applied to the DC VOL
CONTROL pin.
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20
Application Information (Continued)
VOLUME CONTROL TABLE ( Table 2 )
Gain
(dB)
Voltage Range (% of Vdd)
Voltage Range (Vdd = 5)
Voltage Range (Vdd = 3)
Low
High Recommended Low
High
Recommended Low
High
Recommended
0
77.5% 100.00%
75.0% 78.5%
72.5% 76.25%
70.0% 73.75%
67.5% 71.25%
65.0% 68.75%
62.5% 66.25%
60.0% 63.75%
57.5% 61.25%
55.0% 58.75%
52.5% 56.25%
50.0% 53.75%
47.5% 51.25%
45.0% 48.75%
42.5% 46.25%
40.0% 43.75%
37.5% 41.25%
35.0% 38.75%
32.5% 36.25%
30.0% 33.75%
27.5% 31.25%
25.0% 28.75%
22.5% 26.25%
20.0% 23.75%
17.5% 21.25%
15.0% 18.75%
12.5% 16.25%
10.0% 13.75%
100.000%
76.875%
74.375%
71.875%
69.375%
66.875%
64.375%
61.875%
59.375%
56.875%
54.375%
51.875%
49.375%
46.875%
44.375%
41.875%
39.375%
36.875%
34.375%
31.875%
29.375%
26.875%
24.375%
21.875%
19.375%
16.875%
14.375%
11.875%
9.375%
3.875
3.750
3.625
3.500
3.375
3.250
3.125
3.000
2.875
2.750
2.625
2.500
2.375
2.250
2.125
2.000
1.875
1.750
1.625
1.500
1.375
1.250
1.125
1.000
0.875
0.750
0.625
0.500
0.375
0.250
0.000
5.000
3.938
3.813
3.688
3.563
3.438
3.313
3.188
3.063
2.938
2.813
2.688
2.563
2.438
2.313
2.188
2.063
1.938
1.813
1.688
1.563
1.438
1.313
1.188
1.063
0.937
0.812
0.687
0.562
0.437
0.312
5.000
3.844
3.719
3.594
3.469
3.344
3.219
3.094
2.969
2.844
2.719
2.594
2.469
2.344
2.219
2.094
1.969
1.844
1.719
1.594
1.469
1.344
1.219
1.094
0.969
0.844
0.719
0.594
0.469
0.344
0.000
2.325
2.250
2.175
2.100
2.025
1.950
1.875
1.800
1.725
1.650
1.575
1.500
1.425
1.350
1.275
1.200
1.125
1.050
0.975
0.900
0.825
0.750
0.675
0.600
0.525
0.450
0.375
0.300
0.225
0.150
0.000
3.000
2.363
2.288
2.213
2.138
2.063
1.988
1.913
1.838
1.763
1.688
1.613
1.538
1.463
1.388
1.313
1.238
1.163
1.088
1.013
0.937
0.862
0.787
0.712
0.637
0.562
0.487
0.412
0.337
0.262
0.187
3.000
2.306
2.231
2.156
2.081
2.006
1.931
1.856
1.781
1.706
1.631
1.556
1.481
1.406
1.331
1.256
1.181
1.106
1.031
0.956
0.881
0.806
0.731
0.656
0.581
0.506
0.431
0.356
0.281
0.206
0.000
-1
-2
-3
-4
-5
-6
-8
-10
-12
-14
-16
-18
-20
-22
-24
-26
-28
-30
-32
-34
-36
-39
-42
-45
-47
-51
-56
-61
-66
-78
7.5%
5.0%
0.0%
11.25%
8.75%
6.25%
6.875%
0.000%
21
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Application Information (Continued)
AUDIO POWER AMPLIFIER DESIGN
The last step in this design example is setting the amplifier’s
−6dB frequency bandwidth. To achieve the desired 0.25dB
pass band magnitude variation limit, the low frequency re-
sponse must extend to at least 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 Amplifier Design: Driving 1W into an 8Ω Load
The following are the desired operational parameters:
Power Output:
Load Impedance:
Input Level:
1 WRMS
8Ω
1 VRMS
Input Impedance:
Bandwidth:
20 kΩ
fL = 100Hz/5 = 20Hz
(14)
100 Hz−20 kHz 0.25 dB
and an
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 (10), 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 (10). The result is
Equation (11).
fH = 20kHz x 5 = 100kHz
(15)
As mentioned in the Selecting Proper External Compo-
nents section, Rin A and B and Cin A and B create a highpass
filter that sets the amplifier’s lower bandpass frequency limit.
Find the input coupling capacitor’s value using Equation
(14).
Cin A and B≥ 1/(2πRin A and BfL)
(16)
The result is
*
*
1/(2π 20kΩ 20Hz) = 0.397µF
(17)
(11)
Use a 0.39µF capacitor, the closest standard value.
VDD ≥ (VOUTPEAK+ (VOD
+ VODBOT))
(12)
TOP
The product of the desired high frequency cutoff (100kHz in
this example) and the differential gain AVD, determines the
The Output Power vs Supply Voltage graph for an 8Ω load
indicates a minimum supply voltage of 4.6V. This is easily
met by the commonly used 5V supply voltage. The additional
voltage creates the benefit of headroom, allowing the
LM4841 to produce peak output power in excess of 1W
without clipping or other audible distortion. The choice of
supply voltage must also not create a situation that violates
of maximum power dissipation as explained above in the
Power Dissipation section.
upper passband response limit. With AVD = 3 and fH
=
100kHz, the closed-loop gain bandwidth product (GBWP) is
300kHz. This is less than the LM4841’s 3.5MHz GBWP. With
this margin, the amplifier can be used in designs that require
more differential gain while avoiding performance,restricting
bandwidth limitations.
Recommended Printed Circuit
Board Layout
Figures 8 through 14 show the recommended PC board
layout that is optimized for the LM4841 and associated
external components. This circuit is designed for use with an
external 5V supply and 8Ω speakers.
After satisfying the LM4841’s power dissipation require-
ments, the minimum differential gain needed to achieve 1W
dissipation in an 8Ω load is found using Equation (12).
This circuit board is easy to use. Apply 5V and ground to the
board’s VDD and GND pads, respectively. Connect 8Ω
speakers between the board’s −OUTA and +OUTA and
-OUTB and +OUTB pads.
(13)
Thus, a minimum overall gain of 2.83 allows the LM4841’s to
reach full output swing and maintain low noise and THD+N
performance.
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22
LM4841LQ Demo Board Artworks
20028098
FIGURE 8. Top Layer SilkScreen
20028099
FIGURE 9. Top Layer LQ
23
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LM4841LQ Demo Board Artworks (Continued)
200280A0
FIGURE 10. Bottom Layer LQ
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24
Analog Audio LM4841LQ Eval Board
Assembly Part Number: 5510118313-001
Revision: A
Bill of Material
Item Part Number
Part Description
Qty Ref Designator
Remark
1
551011373-001 LM4841 Eval Board PCB
1
etch 001
482911373-001 LM4841LQ
151911368-001 Cer Cap 0.068µF 50V
10% 1206
10
20
1
2
CBA, CBB
25
26
27
28
31
33
40
152911368-001 Tant Cap 0.1µF 10V 10%
Size = A 3216
3
C2, C3, C4
152911368-002 Tant Cap 0.33µF 10V
10% Size = A 3216
3
CinA, CinB, Cinbeep
CBYP, CoutA, CoutB
C1
152911368-003 Tant Cap 1µF 16V 10%
Size = A 3216
3
152911368-004 Tant Cap 10µF 10V 10%
Size = C 6032
1
472911368-002 Res 20K Ohm 1/8W 1%
1206
10
2
RINAandB, RGFAandB, RBA,
RBB, RGIAandB, RFAandB
RBeepAandB
472911368-004 Res 200K Ohm 1/16W
1% 0603
131911368-001 Stereo Headphone Jack
W/ Switch
1
Switchcraft 35RAPC4BH3
41
42
43
44
45
131911368-002 Slide Switch
131911368-003 Potentiometer
131911368-004 RCA Jack
131911368-005 Banana Jack, Black
131911368-006 Banana Jack, Red
4
1
3
3
3
mute, mode, Gain, SD
Volume Control
Mouser # 10SP003
Mouser # 317-2090-100K
Mouser # 16PJ097
InA, InB, BeepIn
GND, AOUT-, BOUT-
VDD, AOUT+, BOUT+
Mouser # ME164-6219
Mouser # ME164-6218
25
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LM4841 MT & MH Demo Board Artworks
20028088
FIGURE 11. Top Layer SilkScreen
20028089
FIGURE 12. Top Layer TSSOP
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26
LM4841 MT & MH Demo Board Artworks (Continued)
20028090
FIGURE 13. Bottom Layer TSSOP
20028091
FIGURE 14. Drill Drawing
27
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Analog Audio LM4841 MSOP Eval Board
Assembly Part Number: 980011373-100
Revision: A
Bill of Material
Item Part Number
Part Description
Qty Ref Designator
Remark
1
551011373-001 LM4841 Eval Board PCB 1
etch 001
482911373-001 LM4841 MSOP
151911368-001 Cer Cap 0.068µF 50V
10% 1206
10
20
1
2
CBA, CBB
25
26
27
28
31
33
40
152911368-001 Tant Cap 0.1µF 10V 10% 3
Size = A 3216
C2, C3, C4
152911368-002 Tant Cap 0.33µF 10V
10% Size = A 3216
3
3
1
CinA, CinB, Cinbeep
CBYP, CoutA, CoutB
C1
152911368-003 Tant Cap 1µF 16V 10%
Size = A 3216
152911368-004 Tant Cap 10µF 10V 10%
Size = C 6032
472911368-002 Res 20K Ohm 1/8W 1% 10
1206
RINAandB, RGFAandB, RBA,
RBB, RGIAandB, RFAandB
RBeepAandB
472911368-004 Res 200K Ohm 1/16W
1% 0603
2
131911368-001 Stereo Headphone Jack
W/ Switch
1
Switchcraft 35RAPC4BH3
41
42
43
44
45
131911368-002 Slide Switch
131911368-003 Potentiometer
131911368-004 RCA Jack
131911368-005 Banana Jack, Black
131911368-006 Banana Jack, Red
4
1
3
3
3
mute, mode, Gain, SD
Volume Control
Mouser # 10SP003
Mouser # 317-2090-100K
Mouser # 16PJ097
InA, InB, BeepIn
GND, AOUT-, BOUT-
VDD, AOUT+, BOUT+
Mouser # ME164-6219
Mouser # ME164-6218
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28
Physical Dimensions inches (millimeters) unless otherwise noted
LLP Package
Order Number LM4841LQ
NS Package Number LQA028A for Exposed-DAP LLP
29
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
TSSOP Package
Order Number LM4841MT
NS Package Number MTC28 for TSSOP
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30
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Exposed-DAP TSSOP Package
Order Number LM4841MH
NS Package Number MXA28A for Exposed-DAP TSSOP
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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.
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Response Group
Tel: 65-2544466
Fax: 65-2504466
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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.
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