LM4838MTX/NOPB [NSC]
IC 2 CHANNEL(S), VOLUME CONTROL CIRCUIT, PDSO28, TSSOP-28, Audio Control IC;
| 型号： | LM4838MTX/NOPB |
| 厂家： | 
National Semiconductor |
| 描述： | IC 2 CHANNEL(S), VOLUME CONTROL CIRCUIT, PDSO28, TSSOP-28, Audio Control IC 光电二极管 商用集成电路 |
| 文件： | 总38页 (文件大小：2330K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
November 2004
LM4838
Stereo 2W Audio Power Amplifiers
with DC Volume Control and Selectable Gain
General Description
Key Specifications
n PO at 1% THD+N
The LM4838 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) with less than
1.0% THD or 2.2W into 3Ω (Note 2) with less than 1.0%
THD.
n
n
n
into 3Ω (LQ & MTE)
into 4Ω (LQ, MTE, GR)
into 8Ω (MT, MTE, ITL, LQ, & GR)
2.2W (typ)
2.0W (typ)
1.1W (typ)
n Single-ended mode - THD+N at 85mW into
Boomer® audio integrated circuits were designed specifically
to provide high quality audio while requiring a minimum
amount of external components. The LM4838 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.
32Ω
1.0%(typ)
0.7µA (typ)
n Shutdown current
Features
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
n “Click and pop” suppression circuitry
The LM4838 features an externally controlled, low-power
consumption shutdown mode, and both a power amplifier
and headphone mute for maximum system flexibility and
performance.
n Thermal shutdown protection circuitry
Note 1: When properly mounted to the circuit board, the LM4838LQ,
LM4838MTE, and LM4838GR will deliver 2W into 4Ω. The LM4838MT and
LM4838ITL will deliver 1.1W into 8Ω. See Application Information section
Exposed-DAP package PCB Mounting Considerations for more informa-
tion.
Applications
n Portable and Desktop Computers
n Multimedia Monitors
Note 2: An LM4838LQ and LM4838MTE that have been properly mounted
to the circuit board and forced-air cooled will deliver 2.2W into 3Ω.
n Portable Radios, PDAs, and Portable TVs
Block Diagram
20013301
FIGURE 1. LM4838 Block Diagram
Boomer® is a registered trademark of NationalSemiconductor Corporation.
© 2004 National Semiconductor Corporation
DS200133
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Connection Diagrams
LLP Package
20013335
Top View
Order Number LM4838LQ
See NS Package Number LQA028AA for Exposed-DAP LLP
TSSOP Package
20013302
Top View
Order Number LM4838MT
See NS Package Number MTC28 for TSSOP
Order Number LM4838MTE
See NS Package Number MXA28A for Exposed-DAP TSSOP
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2
Connection Diagrams (Continued)
36 Bump micro SMD
20013388
Top View
Order Number LM4838ITL, LM4838ITLX
See NS Package Number TLA36AAA
micro SMD Marking
20013387
Top View
X - Date Code
T - Die Traceability
G - Boomer Family
A4 - LM4838ITL
36 Bump micro SMD Pinout Table
6
NC
GND
Right Out -
Right Gain 2
NC
VDD
Right Gain 1
NC
Right Out +
Gain Select
DC Vol
GND
Shutdown
Mute
NC
Mode
VDD
5
4
Bypass
HP Sense
GND
3
NC
NC
Beep In
Right Dock
Left Dock
GND
GND
Right In
NC
2
Left Gain 2
Left Out -
Left Gain 1
VDD
Left In
1
NC
Left Out +
Pin
A
B
C
D
E
F
Designator
3
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Connection Diagrams
49 Bump micro Array
20013344
Top View
Order Number LM4838GR
See NS Package Number GRA49A
49 Bump micro Array Marking
20013343
Top View
NS - Standard National Logo
U - Wafer Fab Code
Z - Assembly Plant Code
XY - 2 Digit Datecode
TT - Dierun Traceability
L4838GR - LM4838GR
49 Bump LM4838GR Pinout Table
7
Right Out -
Right Out -
VDD
Right Gain 1
Right Gain 2
VDD
GND
GND
GND
GND
GND
VDD
Bypass
GND
GND
GND
GND
GND
GND
HP Sense
GND
GND
Left Gain 2
Left Out -
Left Out +
GND
Left Gain 1
Left Out -
VDD
6
5
GND
4
Right Out +
GND
Right Out +
GND
GND
VDD
3
GND
Left Out +
GND
2
Shutdown
Mode
Gain Select
Mute
Right In
Right Dock
Left In
1
DC Vol
Beep In
Left Dock
Pin
A
B
C
D
E
F
G
Designator
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4
Absolute Maximum Ratings (Note 10)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
θJA (typ)—MTC28
80˚C/W
2˚C/W
θJC (typ)—MXA28A
θJA (typ)—MXA28A (exposed
DAP) (Note 4)
41˚C/W
Supply Voltage
6.0V
-65˚C to +150˚C
−0.3V to VDD +0.3V
Internally limited
2000V
θJA (typ)—MXA28A (exposed
DAP) (Note 3)
54˚C/W
59˚C/W
93˚C/W
Storage Temperature
Input Voltage
θJA (typ)—MXA28A (exposed
DAP) (Note 5)
Power Dissipation (Note 11)
ESD Susceptibility (Note 12)
ESD Susceptibility (Note 13)
Junction Temperature
Soldering Information
Small Outline Package
Vapor Phase (60 sec.)
Infrared (15 sec.)
θJA (typ)—MXA28A (exposed
DAP) (Note 6)
200V
θJA (typ)—ITL36AAA
θJC (typ)—ITL36AAA (Note 16)
θJA (typ)—GRA49A
100˚C/W
65˚C/W
100˚C/W
54˚C/W
150˚C
215˚C
220˚C
θJC (typ)—GRA49A (Note 17)
See AN-450 “Surface Mounting and their Effects on
Product Reliability” for other methods of soldering surface
mount devices.
Operating Ratings
Temperature Range
TMIN ≤ TA ≤TMAX
Supply Voltage
−40˚C ≤TA ≤ 85˚C
2.7V≤ VDD ≤ 5.5V
θJC (typ)—LQA028AA
θJA (typ)—LQA028AA
θJC (typ)—MTC28
3˚C/W
42˚C/W
20˚C/W
Electrical Characteristics for Entire IC (Notes 7, 10)
The following specifications apply for VDD = 5V unless otherwise noted. Limits apply for TA = 25˚C.
LM4838
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)
5.5
IDD
ISD
VIH
VIL
Quiescent Power Supply Current
Shutdown Current
VIN = 0V, IO = 0A
Vshutdown = VDD
15
30
0.7
2.0
Headphone Sense High Input Voltage
Headphone Sense Low Input Voltage
4
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.
LM4838
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)
Electrical Characteristics for Single-Ended Mode Operation (Notes 7, 10)
The following specifications apply for VDD = 5V. Limits apply for TA = 25˚C.
LM4838
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
mW
mW
95
5
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Electrical Characteristics for Single-Ended Mode Operation (Notes 7,
10) (Continued)
The following specifications apply for VDD = 5V. Limits apply for TA = 25˚C.
LM4838
Units
(Limits)
Symbol
THD+N
Parameter
Total Harmonic Distortion+Noise
Power Supply Rejection Ratio
Signal to Noise Ratio
Conditions
Typical
(Note 14)
0.065
Limit
(Note 15)
VOUT = 1VRMS, f=1kHz, RL = 10kΩ,
AVD = 1
%
PSRR
SNR
Xtalk
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
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.
LM4838
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 the LM4838LQ and LM4838MTE must be mounted to the circuit board and forced-air cooled.
Note 9: When driving 4Ω loads from a 5V supply the LM4838LQ, LM4838MTE, and LM4838GR 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 LM4838, T
= 150˚C, and the typical junction-to-ambient thermal resistance for each package
DMAX
JMAX
A
JA
JMAX
can be found in the Absolute Maximum Ratings section above.
Note 12: Human body model, 100pF discharged through a 1.5kΩ resistor.
Note 13: Machine Model, 220pF – 240pF 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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6
Electrical Characteristics for Bridged Mode Operation (Notes 7, 10) (Continued)
Note 16: All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The LM4838ITL demo board (views featured
in the Application Information section) is a four layer board with two inner layers. The second inner layer is a V plane with the bottom outside layer a GND plane.
DD
The planes measure 1,900mils x 1,750mils (48.26mm x 44.45mm) and aid in spreading heat due to power dissipation within the IC.
Note 17: All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The LM4838GR Demo Board is a four layer
PC Board with 2 inner layers. The second inner layer and bottom outside layers are both grounded. The planes measure 3200 x 3700 mills and aid in spreading
heat due to power dissipation within the IC.
Typical Application
20013303
FIGURE 2. Typical Application Circuit ( LQ Package Pinout )
Truth Table for Logic Inputs (Note 18)
Gain
Sel
0
Mode Headphone Mute Shutdown Output Stage Set To
Sense
DC Volume
Output Stage
Configuration
0
0
1
1
0
0
1
1
X
X
0
1
0
1
0
1
0
1
X
X
0
0
0
0
0
0
0
0
1
X
0
0
0
0
0
0
0
0
0
1
Internal Gain
Internal Gain
Internal Gain
Internal Gain
External Gain
External Gain
External Gain
External Gain
Muted
Fixed
Fixed
BTL
SE
0
0
Adjustable
Adjustable
Fixed
BTL
SE
0
1
BTL
SE
1
Fixed
1
Adjustable
Adjustable
X
BTL
SE
1
X
Muted
X
X
Shutdown
X
Note 18: If system beep is detected on the Beep In pin, the system beep will be passed through the bridged amplifier regardless of the logic of the Mute and HP
sense pins.
7
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Typical Performance Characteristics
MTE Specific Characteristics
LM4838MTE
LM4838MTE
THD+N vs Output Power
THD+N vs Frequency
20013370
20013371
LM4838MTE
LM4838MTE
THD+N vs Output Power
THD+N vs Frequency
20013372
20013373
LM4838MTE
LM4838MTE (Note 19)
Power Dissipation vs Output Power
Power Derating Curve
20013365
20013364
Note 19: These curves show the thermal dissipation ability of the LM4838MTE 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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Typical Performance Characteristics
Non-MTE Specific Characteristics
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
THD+N vs Frequency
20013358
20013357
THD+N vs Frequency
20013314
20013315
THD+N vs Frequency
20013317
20013316
9
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Typical Performance Characteristics
Non-MTE Specific Characteristics (Continued)
THD+N vs Frequency
THD+N vs Frequency
20013318
20013319
THD+N vs Frequency
THD+N vs Frequency
20013321
20013320
THD+N vs Frequency
THD+N vs Output Power
20013324
20013322
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Typical Performance Characteristics
Non-MTE Specific Characteristics (Continued)
THD+N vs Output Power
THD+N vs Output Power
20013325
20013326
THD+N vs Output Power
THD+N vs Output Power
20013327
20013328
THD+N vs Output Power
THD+N vs Output Power
20013330
20013329
11
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Typical Performance Characteristics
Non-MTE Specific Characteristics (Continued)
THD+N vs Output Power
THD+N vs Output Power
20013331
20013332
THD+N vs Output Power
THD+N vs Output Power
20013334
20013333
THD+N vs Output Voltage
Docking Station Pins
THD+N vs Output Voltage
Docking Station Pins
20013359
20013360
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Typical Performance Characteristics
Output Power vs
Load Resistance
Dropout Voltage
20013362
20013353
20013307
20013308
Output Power vs
Load Resistance
Output Power vs
Load Resistance
20013306
Power Supply
Rejection Ratio
Output Power vs
Load Resistance
20013339
13
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Typical Performance Characteristics (Continued)
Noise Floor
Noise Floor
20013341
20013342
Volume Control
Characteristics
External Gain/
Bass Boost Characteristics
20013340
20013361
Power Dissipation vs
Output Power
Power Dissipation vs
Output Power
20013351
20013352
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Typical Performance Characteristics (Continued)
Power Derating Curve
Crosstalk
20013363
20013349
Output Power
Output Power
vs Supply voltage
vs Supply Voltage
20013354
20013356
Supply Current
LM4838ITL (Note 20)
vs Supply Voltage
Power Derating Curve
20013394
20013309
Note 20: These curves show the thermal dissipation of the LM4838ITL at different ambient temperatures with a thermal plane of size shown on an outside PCB layer
using 1oz. copper.
15
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plane as given above apply for the ITL and GR packages,
namely 2.5in2 minimum for top layer thermal plane and 5in2
minimum for internal or bottom layers.
Application Information
EXPOSED-DAP PACKAGE PCB MOUNTING
CONSIDERATIONS
PCB LAYOUT AND SUPPLY REGULATION
The LM4838’s exposed-DAP (die attach paddle) packages
(MTE, 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 LM4838’s high power performance and activate
unwanted, though necessary, thermal shutdown protection.
CONSIDERATIONS FOR DRIVING 3Ω AND 4Ω LOADS
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 MTE 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) (MTE) or 6(3x2) (LQ) vias. 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 LM4838 MTE 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.
In systems using cooling fans, the LM4838MTE can take
advantage of forced air cooling. With an air flow rate of 450
linear-feet per minute and a 2.5in2 exposed copper or 5.0in2
inner layer copper plane heatsink, the LM4838MTE can
continuously drive a 3Ω load to full power. The LM4838LQ
achieves the same output power level without forced air
cooling. In all circumstances and conditions, the junction
temperature must be held below 150˚C to prevent activating
the LM4838’s thermal shutdown protection. The LM4838’s
power de-rating curve in the Typical Performance Charac-
teristics shows the maximum power dissipation versus tem-
perature. Example PCB layouts for the exposed-DAP
TSSOP and LQ packages are shown in the Demonstration
Board Layout section. Further detailed and specific infor-
mation concerning PCB layout, fabrication, and mounting an
LQ (LLP) package is available in National Semiconductor’s
AN1187.
BRIDGE CONFIGURATION EXPLANATION
As shown in Figure 2, the LM4838 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 * (Rf/R )
(1)
i
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.
The micro SMD and GR packages (LM4838ITL and
LM4838GR) thermals work in a similar way to the LQ and
MTE packages in that a thermal plane increases the heat
transfer from the die. The thermal plane can be any electrical
potential but needs to be below the package to aid in the
spreading the heat from the die out to surrounding PCB
areas to reduce the thermal resistance of the micro SMD
package. The thermal plane is most effective when placed
on the top or first internal PCB layers. The traces connecting
the bumps also contribute to spreading heat away from the
die. The same recommendations for the size of the thermal
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
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16
power supply voltage or increasing the load resistance. Fur-
ther allowance should be made for increased ambient tem-
peratures.
Application Information (Continued)
amplifier’s half-supply bias voltage across the load. This
increases internal IC power dissipation and may perma-
nently damage loads such as speakers.
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 LM4838 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 1.0µF
tantalum bypass capacitance connected between the
LM4838’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 LM4838’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 LM4838’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 LM4838’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 LM4838’s θJA is 20˚C/W. In the MTE package
soldered to a DAP pad that expands to a copper area of 2in2
on a PCB, the LM4838MTE’s θJA is 41˚C/W. For the
LM4838MT package, θJA = 80˚C/W. At any given ambient
temperature TA, use Equation (4) to find the maximum inter-
nal power dissipation supported by the IC packaging. Rear-
ranging Equation (4) and substituting PDMAX for PDMAX' re-
sults in Equation (5). This equation gives the maximum
ambient temperature that still allows maximum stereo power
dissipation without violating the LM4838’s maximum junction
temperature.
SELECTING PROPER EXTERNAL COMPONENTS
Optimizing the LM4838’s performance requires properly se-
lecting external components. Though the LM4838 operates
well when using external components with wide tolerances,
best performance is achieved by optimizing component val-
ues.
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 99˚C for the LQ
package and 45˚C for the MTE package.
The LM4838 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.
TJMAX = PDMAX θJA + TA
(6)
Equation (6) gives the maximum junction temperature
TJMAX. If the result violates the LM4838’s 150˚C TJMAX
reduce the maximum junction temperature by reducing the
,
17
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Application Information (Continued)
INPUT CAPACITOR VALUE SELECTION
CB
TON
2ms
0.01µF
0.1µF
0.22µF
0.47µF
1.0µF
20ms
44ms
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.
94ms
200ms
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 LM4838 has two outputs, Right Dock
and Left Dock, which connect to outputs of the internal input
amplifiers that drive the volume control inputs. These input
Besides effecting system cost and size, the input coupling
capacitor has an affect on the LM4838’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.
>
amplifiers can drive loads of 1kΩ (such as powered speak-
ers) with a rail-to-rail signal. Since the output signal present
on the RIGHT DOCK and LEFT DOCK pins is 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 polar-
ized coupling capacitors are used, connect their "+" termi-
nals to the respective output pin, see Figure 2.
As shown in Figure 2, the input resistor (RIR, RIL = 20k) ( and
the input capacitor (CIR, CIL = 0.33µF) produce a −6dB high
pass filter cutoff frequency that is found using Equation (7).
Since the DOCK outputs precede the internal volume con-
trol, the signal amplitude will be equal to the input signal’s
magnitude and cannot be adjusted. However, the input am-
plifier’s closed-loop gain can be adjusted using external
resistors. These 20k resistors (RFR, RFL) are shown in Fig-
ure 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)
- AVR = RFR/RIR and - AVL = RFL/RIL
(8)
As an example when using a speaker with a low frequency
limit of 150Hz, the input coupling capacitor, using Equation
(7), is 0.053µF. The 0.33µF input coupling capacitor shown
in Figure 2 allows the LM4838 to drive a high efficiency, full
range speaker whose response extends below 30Hz.
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 R & L Dock Outputs simpler signal
path be used for better performance.
OPTIMIZING CLICK AND POP REDUCTION
PERFORMANCE
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 LM4838’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 (RBEEP) 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 LM4838’s shutdown mode must be deactivated
before a system alert signal is applied to BEEP IN pin.
The LM4838 contains circuitry that minimizes turn-on and
shutdown transients or “clicks and pops”. For this discus-
sion, turn-on refers to either applying the power supply volt-
age or when the shutdown mode is deactivated. While the
power supply is ramping to its final value, the LM4838’s
internal amplifiers are configured as unity gain buffers. An
internal current source changes the voltage of 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 device becomes fully
operational. Although the BYPASS pin current cannot be
modified, changing the size of CB alters the device’s turn-on
time and the magnitude of “clicks and pops”. Increasing the
value of CB reduces the magnitude of turn-on pops. How-
ever, this presents a tradeoff: as the size of CB increases, the
turn-on time increases. There is a linear relationship be-
tween the size of CB and the turn-on time. Here are some
typical turn-on times for various values of CB:
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18
Application Information (Continued)
MICRO-POWER SHUTDOWN
The voltage applied to the SHUTDOWN pin controls the
LM4838’s shutdown function. Activate micro-power shut-
down by applying VDD to the SHUTDOWN pin. When active,
the LM4838’s micro-power shutdown feature turns off the
amplifier’s bias circuitry, reducing the supply current. The
logic threshold is typically VDD/2. The low 0.7 µA typical
shutdown current is achieved by applying a voltage that is as
near as VDD as possible to the SHUTDOWN pin. A voltage
that is less than VDD may increase the shutdown current.
There are a few ways to control the micro-power shutdown.
These include using a single-pole, single-throw switch, a
microprocessor, or a microcontroller. When using a switch,
connect an external 10kΩ pull-up resistor between the
SHUTDOWN pin and VDD. Connect the switch between the
SHUTDOWN pin and ground. Select normal amplifier opera-
tion by closing the switch. Opening the switch connects the
SHUTDOWN pin to VDD through the pull-up resistor, activat-
ing micro-power shutdown. The switch and resistor guaran-
tee that the SHUTDOWN pin will not float. This prevents
unwanted state changes. In a system with a microprocessor
or a microcontroller, use a digital output to apply the control
voltage to the SHUTDOWN pin. Driving the SHUTDOWN pin
with active circuitry eliminates the need for a pull up resistor.
20013304
FIGURE 3. Headphone Sensing Circuit
HP SENSE FUNCTION ( Head Phone In )
Applying a voltage between 4V and VDD to the LM4838’s
HP-IN headphone control pin turns off the amps that drive
the Left out "+" and Right out "+" pins. This action mutes a
bridged-connected load. Quiescent current consumption is
reduced when the IC is in this single-ended mode.
MODE FUNCTION
The LM4838’s MODE function has 2 states controlled by the
voltage applied to the MODE pin. Mode 0, selected by
applying 0V to the MODE pin, forces the LM4838 to effec-
tively function as a "line-out," unity-gain amplifier. Mode 1,
which uses the internal DC controlled volume control is
selected by applying VDD to the MODE pin. This mode sets
the amplifier’s gain according to the DC voltage applied to
the DC VOL CONTROL pin. Unanticipated gain behavior can
be prevented by connecting the MODE pin to VDD or ground.
Note: Do not let the mode pin float.
Figure 3 shows the implementation of the LM4838’s head-
phone control function. With no headphones connected to
the headphone jack, the R1-R2 voltage divider sets the
voltage applied to the HP SENSE pin at approximately
50mV. This 50mV puts the LM4838 into bridged mode op-
eration. The output coupling capacitor blocks the amplifier’s
half supply DC voltage, protecting the headphones.
MUTE FUNCTION
The HP-IN threshold is set at 4V. While the LM4838 operates
in bridged mode, the DC potential across the load is essen-
tially 0V. Therefore, even in an ideal situation, the output
swing cannot cause a false single-ended trigger. Connecting
headphones to the headphone jack disconnects the head-
phone jack contact pin from R2 and allows R1 to pull the HP
Sense pin up to VDD through R4. This enables the head-
phone function, turns off both of the "+" output amplifiers,
and mutes the bridged speaker. The remaining single-ended
amplifiers then drive the headphones, whose impedance is
in parallel with resistors R2 and R3. These resistors have
negligible effect on the LM4838’s output drive capability
since the typical impedance of headphones is 32Ω.
The LM4838 mutes the amplifier and DOCK outputs when
VDD is applied to the MUTE pin. Even while muted, the
LM4838 will amplify a system alert (beep) signal whose
magnitude satisfies the BEEP DETECT circuitry. Applying
0V to the MUTE pin returns the LM4838 to normal, unmuted
operation. Prevent unanticipated mute behavior by connect-
ing the MUTE pin to VDD or ground. Do not let the mute pain
float.
Figure 3 also shows the suggested headphone jack electri-
cal 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 should
carry the ground return. A headphone jack with one control
pin contact is sufficient to drive the HP-IN pin when connect-
ing headphones.
A microprocessor or a switch can replace the headphone
jack contact pin. When a microprocessor or switch applies a
voltage greater than 4V to the HP-IN pin, a bridge-connected
speaker is muted and the single ended output amplifiers 1A
and 2A will drive a pair of headphones.
19
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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,
RLFE, and a capacitor, CLFE, in parallel, can be placed in
series with the feedback resistor of the bridged amplifier as
seen in Figure 4.
Application Information (Continued)
GAIN SELECT FUNCTION (Bass Boost)
The LM4838 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.
20013311
FIGURE 4. Low Frequency Enhancement
DC VOLUME CONTROL
At low, frequencies CLFE is a virtual open circuit and at high
The LM4838 has an internal stereo volume control whose
setting is a function of the DC voltage applied to the DC VOL
CONTROL pin.
frequencies, its nearly zero ohm impedance shorts RLFE
.
The result is increased bridge-amplifier gain at low frequen-
cies. The combination of RLFE and CLFE form a -6dB corner
frequency at
The LM4838 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.
fC = 1/(2πRLFE
C
)
(9)
LFE
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).
The bridged-amplifier low frequency differential gain is:
AVD = 2(RF + RLFE) / R
(10)
i
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.
Using the component values shown in Figure 1 (RF = 20kΩ,
RLFE = 20kΩ, and CLFE = 0.068µF), a first-order, -6dB pole is
created at 120Hz. Assuming R = 20kΩ, the low frequency
i
differential gain is 4. The input (Ci) and output (CO) capacitor
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.
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20
Application Information (Continued)
VOLUME CONTROL TABLE ( Table 2 )
Gain
(dB)
Voltage Range (% of Vdd)
Voltage Range (Vdd = 5)
Recommended Low
Voltage Range (Vdd = 3)
Recommended
Low
High Recommended Low
High
3.875 5.000
3.750 3.938
3.625 3.813
3.500 3.688
3.375 3.563
3.250 3.438
3.125 3.313
3.000 3.188
2.875 3.063
2.750 2.938
2.625 2.813
2.500 2.688
2.375 2.563
2.250 2.438
2.125 2.313
2.000 2.188
1.875 2.063
1.750 1.938
1.625 1.813
1.500 1.688
1.375 1.563
1.250 1.438
1.125 1.313
1.000 1.188
0.875 1.063
0.750 0.937
0.625 0.812
0.500 0.687
0.375 0.562
0.250 0.437
0.000 0.312
High
2.325 3.000
2.250 2.363
2.175 2.288
2.100 2.213
2.025 2.138
1.950 2.063
1.875 1.988
1.800 1.913
1.725 1.838
1.650 1.763
1.575 1.688
1.500 1.613
1.425 1.538
1.350 1.463
1.275 1.388
1.200 1.313
1.125 1.238
1.050 1.163
0.975 1.088
0.900 1.013
0.825 0.937
0.750 0.862
0.675 0.787
0.600 0.712
0.525 0.637
0.450 0.562
0.375 0.487
0.300 0.412
0.225 0.337
0.150 0.262
0.000 0.187
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%
7.5% 11.25%
5.0% 8.75%
0.0% 6.25%
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%
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
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
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, Ri (Right & Left) and Ci (Right & Left) create
a highpass filter that sets the amplifier’s lower bandpass
frequency limit. Find the input coupling capacitor’s value
using Equation (14).
Ci≥ 1/(2πRifL)
(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
LM4838 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 LM4838’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
The following figures show the recommended PC board
layouts that are optimized for the different package options
of the LM4838 and associated external components. This
circuit is designed for use with an external 5V supply and 4Ω
speakers.
After satisfying the LM4838’s power dissipation require-
ments, the minimum differential gain needed to achieve 1W
dissipation in an 8Ω load is found using Equation (12).
(13)
This circuit board is easy to use. Apply 5V and ground to the
board’s VDD and GND pads, respectively. Connect 4Ω
speakers between the board’s −OUTA and +OUTA and
OUTB and +OUTB pads.
Thus, a minimum overall gain of 2.83 allows the LM4838’s to
reach full output swing and maintain low noise and THD+N
performance.
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22
Recommended Printed Circuit Board Layout (Continued)
20013377
FIGURE 5. Recommended LQ PC Board Layout:
Component-Side Silkscreen
20013378
FIGURE 6. Recommended LQ PC Board Layout:
Component-Side Layout
23
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Recommended Printed Circuit Board Layout (Continued)
20013379
FIGURE 7. Recommended LQ PC Board Layout:
Upper Inner-Layer Layout
20013380
FIGURE 8. Recommended LQ PC Board Layout:
Lower Inner-Layer Layout
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24
Recommended Printed Circuit Board Layout (Continued)
20013381
FIGURE 9. Recommended LQ PC Board Layout:
Bottom-Side Layout
25
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Analog Audio LM4838 LLP28 Eval Board
Assembly Part Number: 980011368-100
Revision: A1
Bill of Material
Item Part Number Part Description
Qty Ref Designator
Remark
1
551011368-001 LM4838 Eval Board PCB etch 001
1
1
2
3
10
20
25
26
27
28
29
30
31
482911368-001 LM4838 28L LLP
U4
151911368-001 Cer Cap 0.068µF 50V 10% 1206
152911368-001 Tant Cap 0.1µF 10V 10% Size = A 3216
CBS1, CBS2
CS1, CS2, CV
Cin1, Cin2, Cin3
CB, C01, C02
CS3
152911368-002 Tant Cap 0.33µF 10V 10% Size = A 3216 3
152911368-003 Tant Cap 1µF 16V 10% Size = A 3216
152911368-004 Tant Cap 10µF 10V 10% Size = C 6032
152911368-005 Tant Cap 220µF 16V 10% Size = D 7343
472911368-001 Res 1.5K Ohm 1/8W 1% 1206
3
1
2
2
Cout1, Cout2
RL1, RL2
472911368-002 Res 20k Ohm 1/8W 1% 1206
10 Rin1, Rin2, RF1, RF2
Rl1, Rl2, RBS1, RBS2
Rdock1, Rdock2
32
33
40
41
42
43
44
45
472911368-003 Res 100k Ohm 1/8W 1% 1206
472911368-004 Res 200k Ohm 1/16W 1% 0603
131911368-001 Stereo Headphone Jack W/ Switch
131911368-002 Slide Switch
2
2
1
4
1
3
3
3
RS, RPU
Rbeep1, Rbeep2
U2
Mouser # 161-3500
Mouser # 10SP003
Mouser # 317-290-100K
Mouser # 16PJ097
Mode, Mute, Gain, SD
U1
131911368-003 Potentiometer
131911368-004 RCA Jack
RightIn, BeepIn, LeftIn
131911368-005 Banana Jack, Black
131911368-006 Banana Jack, Red
GND, Right Out-, Left Out- Mouser # ME164-6219
Vdd, Right Out+, Left Out+ Mouser # ME164-6218
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26
LM4838 MT & MTE Demo Board Artwork
20013382
Top Layer SilkScreen
20013383
Top Layer TSSOP
27
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LM4838 MT & MTE Demo Board Artwork (Continued)
20013385
Inner Layer (2) LM4838MT/MTE
20013386
Inner Layer (3) LM4838MT/MTE
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28
LM4838 MT & MTE Demo Board Artwork (Continued)
20013384
Bottom Layer TSSOP
Analog Audio LM4838 TSSOP Eval Board
Assembly Part Number: 980011373-100
Revision: A
Bill of Material
Item
Part Number
Part Description
LM4838 Eval Board PCB
etch 001
Qty
Ref Designator
Remark
1
551011373-001
1
10
20
482911373-001
151911368-001
LM4838 TSSOP
1
2
Cer Cap 0.068µF 50V
10% 1206
CBS
25
26
27
28
29
30
31
152911368-001
152911368-002
152911368-003
152911368-004
152911368-005
472911368-001
472911368-002
Tant Cap 0.1µF 10V 10%
Size = A 3216
3
3
3
1
CS, CS, CV
CIN
Tant Cap 0.33µF 10V
10% Size = A 3216
Tant Cap 1µF 16V 10%
Size = A 3216
CB, CO1, CO2
CS1
Tant Cap 10µF 10V 10%
Size = C 6032
Tant Cap 220µF 16V 10% 2
Size = D 7343
CoutL, R
RL
Res 1.5K Ohm 1/8W 1%
2
1206
Res 20K Ohm 1/8W 1%
1206
10
RIN(4), RF(2),
RDOCK(2),
RBS(2)
32
33
472911368-003
472911368-004
Res 100K Ohm 1/8W 1%
1206
2
2
RPU, RS
Res 200K Ohm 1/16W
1% 0603
RBEEP
29
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Analog Audio LM4838 TSSOP Eval Board
Assembly Part Number: 980011373-100
Revision: A
Bill of Material (Continued)
Item
Part Number
Part Description
Stereo Headphone Jack
W/ Switch
Qty
Ref Designator
Remark
40
131911368-001
1
Mouser #
161-3500
41
42
43
44
45
131911368-002
131911368-003
131911368-004
131911368-005
131911368-006
Slide Switch
4
1
3
3
3
mute, mode, Gain, Mouser #
SD
10SP003
Potentiometer
Volume Control
Mouser #
317-2090-100K
RCA Jack
Right-In, Beep-In, Mouser #
Left-In
16PJ097
Banana Jack, Black
Banana Jack, Red
Mouser #
ME164-6219
Mouser #
ME164-6218
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30
LM4838 ITL Demo Board Artwork
20013392
FIGURE 10. LM4838 micro SMD Silk Screen
20013389
FIGURE 11. LM4838 micro SMD Top Layer
31
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LM4838 ITL Demo Board Artwork (Continued)
20013390
FIGURE 12. LM4838 micro SMD Upper Inner Layer
20013391
FIGURE 13. LM4838 micro SMD Lower Inner Layer
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32
LM4838 ITL Demo Board Artwork (Continued)
20013393
FIGURE 14. LM4838 micro SMD Bottom Layer
33
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Analog Audio LM4838 TLA36 Board
Bill of Material
Part Description µΩ
LM4838 TLA36 Evaluation Board PCB
LM4838ITL
Qty
1
Reference Designator
P/N: 551011755 - 002 rev A
1
U1
Ceramic Capacitor 0.068µF 50V 10%
Size = 1206
2
CBS1, CBS2
Tantalum Capacitor 0.1µF 10V 10%
Size = 1206
3
3
CS1, CS2, CV
CIN1, CIN2, CIN3
CS3, CB, CO1, CO2
COUT1, COUT2
RL1, RL2
Tantalum Capacitor 0.33µF 10V 10%
Size = 1206
Tantalum Capacitor 1.0µF 16V 10%
Size = 1210
4
Tantalum Capacitor 220µF 16V 10%
Size = 7343
2
Resistor 1.5kΩ 1/10W 1%
Size = 0805
2
Resistor 20kΩ 1/10W 1%
Size = 0805
10
2
RIN1, RIN2, RF1, RF2, Rl1, Rl2, RBS1,
RBS2, RDOCK1, RDOCK2
RS, RPU
Resistor 100kΩ 1/10W 1%
Size = 0805
Resistor 120kΩ 1/10W 1%
Size = 0805
2
RBEEP1, RBEEP2
RV
Resistor 1MΩ 1/10W 1%
Size = 0805
1
Jumper Header Vertical Mount
0.100” spacing
1
J1 (Docking RT LF)
RCA Jack PCB mount
Banana Jack, Black
3
3
J2 (LeftIn), J3 (Beep In), J4 (Right In)
J5B (GND), J6A (Right Out -), J7A (Left Out
-)
Banana Jack, Red
3
J5A (VDD), J6B (Right Out +), J7B (Left Out
+)
Stereo Headphone Jack W/Switch
Single Turn Potentiometer 100kΩ 20%
Jumper Header Vertical Mount
0.100” spacing 3x4
1
1
1
J8
J9
Mute, SD, Gain, Mode
Jumper Header Vertical Mount
0.100” spacing 1x3
1
DC IN
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34
Physical Dimensions inches (millimeters) unless otherwise noted
LLP Package
Order Number LM4838LQ
NS Package Number LQA028AA For Exposed-DAP LLP
35
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
TSSOP Package
Order Number LM4838MT
NS Package Number MTC28 for TSSOP
Exposed-DAP TSSOP Package
Order Number LM4838MTE
NS Package Number MXA28A for Exposed-DAP TSSOP
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36
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
36-Bump micro SMD
Order Number LM4838ITL, LM4838ITLX
NS Package Number TLA36AAA
X1 = 3.000 0.03 X2 = 3.000 0.03 X3 = 0.600 0.075
37
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
49-Bump mico Array
Order Number LM4838GR
NS Package Number GRA49A
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.
For the most current product information visit us at www.national.com.
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NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS
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device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
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Substances’’ as defined in CSP-9-111S2.
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