LM4908MM [NSC]
10kV ESD Rated, Dual 120 mW Headphone Amplifier; 10kV的ESD额定，双120毫瓦耳机放大器
| 型号： | LM4908MM |
| 厂家： | 
National Semiconductor |
| 描述： | 10kV ESD Rated, Dual 120 mW Headphone Amplifier |
| 文件： | 总21页 (文件大小：931K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
February 2004
LM4908
10kV ESD Rated, Dual 120 mW Headphone Amplifier
j
General Description
Output power at 0.1% THD+N
at 1kHz into 32Ω
75mW (typ)
The LM4908 is a dual audio power amplifier capable of
delivering 120mW per channel of continuous average power
into a 16Ω load with 0.1% (THD+N) from a 5V power supply.
Features
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components using surface mount packaging. Since
the LM4908 does not require bootstrap capacitors or snub-
ber networks, it is optimally suited for low-power portable
systems.
n Up to 10kV ESD protection on all pins
n MSOP, SOP, and LLP surface mount packaging
n Switch on/off click suppression
n Excellent power supply ripple rejection
n Unity-gain stable
The unity-gain stable LM4908 can be configured by external
gain-setting resistors.
n Minimum external components
Applications
Key Specifications
n Headphone Amplifier
n Personal Computers
n Portable electronic devices
j
THD+N at 1kHz at 120mW
continuous average output power
into 16Ω
0.1% (typ)
0.1% (typ)
j
THD+N at 1kHz at 75mW
continuous average output power
into 32Ω
Typical Application
20075201
*Refer to the Application Information Section for information concerning proper selection of the input and output coupling capacitors.
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation
DS200752
www.national.com
Connection Diagrams
SOP (MA) and MSOP (MM) Package
20075202
Top View
Order Number LM4908MA, LM4908MM
See NS Package Number M08A, MUA08A
LLP (LQ) Package
200752A2
Top View
Order Number LM4908LQ
See NS Package Number LQB08A
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2
Absolute Maximum Ratings (Note 3)
θJC (MSOP)
θJA (MSOP)
θJC (SOP)
θJA (SOP)
θJC (LLP)
θJA (LLP)
56˚C/W
210˚C/W
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
35˚C/W
170˚C/W
Supply Voltage
6.0V
−65˚C to +150˚C
−0.3V to VDD + 0.3V
Internally limited
10.0kV
15˚C/W
Storage Temperature
Input Voltage
117˚C/W (Note 9)
150˚C/W (Note 10)
θJA (LLP)
Power Dissipation (Note 4)
ESD Susceptibility (Note 5)
ESD Susceptibility (Note 6)
Junction Temperature
Soldering Information (Note 1)
Small Outline Package
Vapor Phase (60 seconds)
Infrared (15 seconds)
Thermal Resistance
Operating Ratings
Temperature Range
TMIN ≤ TA ≤ TMAX
Supply Voltage
500V
150˚C
−40˚C ≤ T ≤ 85˚C
A
2.0V ≤ VDD ≤ 5.5V
Note 1: See AN-450 “Surface Mounting and their Effects on Product Reli-
ability” for other methods of soldering surface mount devices.
215˚C
220˚C
Electrical Characteristics (Notes 2, 3)
The following specifications apply for VDD = 5V unless otherwise specified, limits apply to TA = 25˚C.
Symbol Parameter Conditions LM4908
Units
(Limits)
Typ
(Note 7)
Limit
(Note 8)
2.0
VDD
Supply Voltage
V (min)
5.5
V (max)
IDD
Supply Current
VIN = 0V, IO = 0A
1.6
8
3.0
mA (max)
Ptot
Total Power Dissipation
Input Offset Voltage
Input Bias Current
VIN = 0V, IO = 0A
VIN = 0V
16.5
50
mW (max)
VOS
Ibias
5
mV (max)
10
0
pA
V
VCM
Common Mode Voltage
4.3
67
70
0.1
.3
V
GV
Io
Open-Loop Voltage Gain
Max Output Current
Output Resistance
Output Swing
RL = 5kΩ
dB
mA
Ω
<
THD+N 0.1 %
RO
VO
RL = 32Ω, 0.1% THD+N, Min
RL = 32Ω, 0.1% THD+N, Max
Cb = 1.0µF, Vripple = 100mVPP
f = 40Hz
V
4.7
90
PSRR
Power Supply Rejection Ratio
Channel Separation
,
dB
Crosstalk
THD+N
RL = 32Ω, f = 1kHz
82
dB
Total Harmonic Distortion + Noise f = 1 kHz
RL = 16Ω,
VO =3.5VPP (at 0 dB)
0.05
66
%
dB
RL = 32Ω,
VO =3.5VPP (at 0 dB)
0.05
66
%
dB
SNR
fG
Signal-to-Noise Ratio
Unity Gain Frequency
Output Power
VO = 3.5Vpp (at 0 dB)
Open Loop, RL = 5kΩ
THD+N = 0.1%, f = 1 kHz
RL = 16Ω
100
25
dB
MHz
Po
120
75
mW
mW
RL = 32Ω
60
THD+N = 10%, f = 1 kHz
RL = 16Ω
157
99
3
mW
mW
pF
RL = 32Ω
CI
Input Capacitance
3
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Electrical Characteristics (Notes 2, 3) (Continued)
The following specifications apply for VDD = 5V unless otherwise specified, limits apply to TA = 25˚C.
Symbol
Parameter
Conditions
LM4908
Units
(Limits)
Typ
Limit
(Note 8)
200
(Note 7)
3
CL
Load Capacitance
Slew Rate
pF
SR
Unity Gain Inverting
V/µs
Electrical Characteristics (Notes 2, 3)
The following specifications apply for VDD = 3.3V unless otherwise specified, limits apply to TA = 25˚C.
Symbol Parameter Conditions Conditions
Units
(Limits)
Typ
(Note 7)
1.4
Limit
(Note 8)
IDD
VOS
Po
Supply Current
VIN = 0V, IO = 0A
mA (max)
mV (max)
Input Offset Voltage
Output Power
VIN = 0V
5
THD+N = 0.1%, f = 1 kHz
RL = 16Ω
43
30
mW
mW
RL = 32Ω
THD+N = 10%, f = 1 kHz
RL = 16Ω
61
41
mW
mW
RL = 32Ω
Electrical Characteristics (Notes 2, 3)
The following specifications apply for VDD = 2.6V unless otherwise specified, limits apply to TA = 25˚C.
Symbol Parameter Conditions Conditions
Units
(Limits)
Typ
(Note 7)
1.3
Limit
(Note 8)
IDD
VOS
Po
Supply Current
VIN = 0V, IO = 0A
mA (max)
mV (max)
Input Offset Voltage
Output Power
VIN = 0V
5
THD+N = 0.1%, f = 1 kHz
RL = 16Ω
20
16
mW
mW
RL = 32Ω
THD+N = 10%, f = 1 kHz
RL = 16Ω
34
24
mW
mW
RL = 32Ω
Note 2: All voltages are measured with respect to the ground pin, unless otherwise specified.
Note 3: 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 4: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
, θ , and the ambient temperature T . The maximum
A
JMAX JA
allowable power dissipation is P
= (T
− T ) / θ . For the LM4908, T
= 150˚C, and the typical junction-to-ambient thermal resistance, when board
DMAX
JMAX
A
JA
JMAX
mounted, is 210˚C/W for package MUA08A and 170˚C/W for package M08A.
Note 5: Human body model, 100pF discharged through a 1.5kΩ resistor.
Note 6: Machine Model, 220pF–240pF discharged through all pins.
Note 7: Typicals are measured at 25˚C and represent the parametric norm.
Note 8: Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level). Datasheet min/max specification limits are guaranteed by design, test,
or statistical analysis.
Note 9: The given θ is for an LM4908 packaged in an LQB08A with the Exposed-DAP soldered to a printed circuit board copper pad with an area equivalent to
JA
that of the Exposed-DAP itself.
Note 10: The given θ is for an LM4908 packaged in an LQB08A with the Exposed-DAP not soldered to any printed circuit board copper.
JA
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4
External Components Description (Figure 1)
Components
Functional Description
The inverting input resistance, along with Rf, set the closed-loop gain. Ri, along with Ci, form a high
pass filter with fc = 1/(2πRiCi).
1. Ri
The input coupling capacitor blocks DC voltage at the amplifier’s input terminals. Ci, along with Ri,
create a highpass filter with fC = 1/(2πRiCi). Refer to the section, Selecting Proper External
Components, for an explanation of determining the value of Ci.
The feedback resistance, along with Ri, set closed-loop gain.
2. Ci
3. Rf
This is the supply bypass capacitor. It provides power supply filtering. Refer to the Application
Information section for proper placement and selection of the supply bypass capacitor.
This is the half-supply bypass pin capacitor. It provides half-supply filtering. Refer to the section,
Selecting Proper External Components, for information concerning proper placement and selection
of CB.
4. CS
5. CB
This is the output coupling capacitor. It blocks the DC voltage at the amplifier’s output and forms a high
pass filter with RL at fO = 1/(2πRLCO)
6. CO
7. RB
This is the resistor which forms a voltage divider that provides 1/2 VDD to the non-inverting input of the
amplifier.
Typical Performance
Characteristics
THD+N vs Frequency
VDD = 2.6V, PWR = 15mW, RL = 8Ω
THD+N vs Frequency
VDD = 2.6V, PWR = 15mW, RL = 16Ω
20075267
20075268
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Typical Performance Characteristics (Continued)
THD+N vs Frequency
THD+N vs Frequency
VDD = 2.6V, PWR = 15mW, RL = 32Ω
VDD = 3.3V, PWR = 25mW, RL = 8Ω
20075269
20075270
THD+N vs Frequency
THD+N vs Frequency
VDD = 3.3V, PWR = 25mW, RL = 16Ω
VDD = 3.3V, PWR = 25mW, RL = 32Ω
20075271
20075272
THD+N vs Frequency
THD+N vs Frequency
VDD = 5V, PWR = 50mW, RL = 8Ω
VDD = 5V, PWR = 50mW, RL = 16Ω
20075273
20075274
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Typical Performance Characteristics (Continued)
THD+N vs Frequency
THD+N vs Frequency
VDD = 5V, PWR = 50mW, RL = 32Ω
VDD = 5V, VOUT = 3.5Vpp, RL = 5kΩ
20075275
20075276
THD+N vs Output Power
THD+N vs Output Power
VDD = 2.6V, RL = 8Ω, f = 1kHz
VDD = 2.6V, RL = 16Ω, f = 1kHz
20075277
20075278
THD+N vs Output Power
THD+N vs Output Power
VDD = 2.6V, RL = 32Ω, f = 1kHz
VDD = 3.3V, RL = 8Ω, f = 1kHz
20075279
20075280
7
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Typical Performance Characteristics (Continued)
THD+N vs Output Power
THD+N vs Output Power
VDD = 3.3V, RL = 16Ω, f = 1kHz
VDD = 3.3V, RL = 32Ω, f = 1kHz
20075281
20075282
THD+N vs Output Power
THD+N vs Output Power
VDD = 5V, RL = 8Ω, f = 1kHz
VDD = 5V, RL = 16Ω, f = 1kHz
20075283
20075284
THD+N vs Output Power
VDD = 5V, RL = 32Ω, f = 1kHz
Output Power vs Load Resistance
VDD = 2.6V, f = 1kHz
20075286
20075285
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Typical Performance Characteristics (Continued)
Output Power vs Load Resistance
VDD = 3.3V, f = 1kHz
Output Power vs Load Resistance
VDD = 5V, f = 1kHz
20075287
20075288
Output Power vs Supply Voltage
Output Power vs Supply Voltage
RL = 8Ω, f = 1kHz
RL = 16Ω, f = 1kHz
20075289
20075290
Output Power vs Supply Voltage
Clipping Voltage vs
Supply Voltage
RL = 32Ω, f = 1kHz
20075292
20075291
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Typical Performance Characteristics (Continued)
Power Dissipation vs
Output Power
Power Dissipation vs
Output Power
20075229
20075230
Power Dissipation vs
Output Power
Crosstalk vs Frequency
VDD = 5V, RL = 8Ω
20075231
20075293
Crosstalk vs Frequency
Output Noise vs Frequency
VDD = 5V, RL = 32Ω
VDD = 5V, RL = 32Ω
20075294
20075295
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Typical Performance Characteristics (Continued)
PSRR vs Frequency
VDD = 5V, RL = 32Ω, VRIPPLE = 100mVpp
Pins 3 and 5 directly driven, Inputs Floating
PSRR vs Frequency
VDD = 5V, RL = 32Ω, VRIPPLE = 100mVpp
Inputs Terminated
20075297
20075296
Open Loop Frequency Response
Open Loop Frequency Response
VDD = 5V, RL = 8Ω
VDD = 5V, RL = 32Ω
20075298
20075299
Open Loop Frequency Response
Supply Current vs
VDD = 5V, RL = 5kΩ
Supply Voltage (no Load)
200752A0
200752A1
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Typical Performance Characteristics (Continued)
Frequency Response vs
Output Capacitor Size
Frequency Response vs
Output Capacitor Size
20075245
20075246
Frequency Response vs
Output Capacitor Size
Typical Application
Frequency Response
20075247
20075248
Typical Application
Frequency Response
20075249
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POWER SUPPLY BYPASSING
Application Information
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 10µF in parallel with a 0.1µF filter capacitors to stabi-
lize 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 0.1µF
supply bypass capacitor, CS, connected between the
LM4908’s supply pins and ground. Keep the length of leads
and traces that connect capacitors between the LM4908’s
power supply pin and ground as short as possible. Connect-
ing a 1.0µF capacitor, CB, between the IN A(+) / IN B(+) node
and ground improves the internal bias voltage’s stability and
improves the amplifier’s PSRR. The PSRR improvements
increase as the bypass pin capacitor value increases. Too
large, however, increases the amplifier’s turn-on time. The
selection of bypass capacitor values, especially CB, depends
on desired PSRR requirements, click and pop performance
(as explained in the section, Selecting Proper External
Components), system cost, and size constraints.
EXPOSED-DAP PACKAGE PCB MOUNTING
CONSIDERATION
The LM4908’s exposed-dap (die attach paddle) package
(LQ) provides 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 surrounding air.
The LQ package should have its DAP soldered to a copper
pad on the PCB. The DAP’s PCB copper pad may be con-
nected to a large plane of continuous unbroken copper. This
plane forms a thermal mass, heat sink, and radiation area.
However, since the LM4908 is designed for headphone ap-
plications, connecting a copper plane to the DAP’s PCB
copper pad is not required. The LM4908’s Power Dissipation
vs Output Power Curve in the Typical Performance Char-
acteristics shows that the maximum power dissipated is just
45mW per amplifier with a 5V power supply and a 32Ω load.
Further detailed and specific information concerning PCB
layout, fabrication, and mounting an LQ (LLP) package is
available from National Semiconductor’s Package Engineer-
ing Group under application note AN1187.
SELECTING PROPER EXTERNAL COMPONENTS
Optimizing the LM4908’s performance requires properly se-
lecting external components. Though the LM4908 operates
well when using external components with wide tolerances,
best performance is achieved by optimizing component val-
ues.
POWER DISSIPATION
Power dissipation is a major concern when using any power
amplifier and must be thoroughly understood to ensure a
successful design. Equation 1 states the maximum power
dissipation point for a single-ended amplifier operating at a
given supply voltage and driving a specified output load.
The LM4908 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 demands 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 infor-
mation on selecting the proper gain.
2
PDMAX = (VDD
)
/ (2π2RL)
(1)
Since the LM4908 has two operational amplifiers in one
package, the maximum internal power dissipation point is
twice that of the number which results from Equation 1. Even
with the large internal power dissipation, the LM4908 does
not require heat sinking over a large range of ambient tem-
perature. From Equation 1, assuming a 5V power supply and
a 32Ω load, the maximum power dissipation point is 40mW
per amplifier. Thus the maximum package dissipation point
is 80mW. The maximum power dissipation point obtained
must not be greater than the power dissipation that results
from Equation 2:
Input and Output Capacitor Value Selection
Amplifying the lowest audio frequencies requires high value
input and output coupling capacitors (CI and CO in Figure 1).
A high value capacitor can be expensive and may compro-
mise space efficiency in portable designs. In many cases,
however, the speakers used in portable systems, whether
internal or external, have little ability to reproduce signals
below 150Hz. Applications using speakers with this limited
frequency response reap little improvement by using high
value input and output capacitors.
PDMAX = (TJMAX − TA) / θJA
(2)
For package MUA08A, θJA = 210˚C/W. TJMAX = 150˚C for
the LM4908. Depending on the ambient temperature, TA, of
the system surroundings, Equation 2 can be used to find the
maximum internal power dissipation supported by the IC
packaging. If the result of Equation 1 is greater than that of
Equation 2, then either the supply voltage must be de-
creased, the load impedance increased or TA reduced. For
the typical application of a 5V power supply, with a 32Ω load,
the maximum ambient temperature possible without violating
the maximum junction temperature is approximately 133.2˚C
provided that device operation is around the maximum
power dissipation point. Power dissipation is a function of
output power and thus, if typical operation is not around the
maximum power dissipation point, the ambient temperature
may be increased accordingly. Refer to the Typical Perfor-
mance Characteristics curves for power dissipation infor-
mation for lower output powers.
Besides affecting system cost and size, Ci has an effect on
the LM4908’s click and pop performance. The magnitude of
the pop is directly proportional to the input capacitor’s size.
Thus, pops can be minimized by selecting an input capacitor
value that is no higher than necessary to meet the desired
−3dB frequency.
As shown in Figure 1, the input resistor, RI and the input
capacitor, CI, produce a −3dB high pass filter cutoff fre-
quency that is found using Equation (3). In addition, the
output load RL, and the output capacitor CO, produce a -3db
high pass filter cutoff frequency defined by Equation (4).
fI-3db=1/2πRICI
(3)
fO-3db=1/2πRLCO
(4)
13
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package. Once the power dissipation equations have been
addressed, the required gain can be determined from Equa-
tion (7).
Application Information (Continued)
Also, careful consideration must be taken in selecting a
certain type of capacitor to be used in the system. Different
types of capacitors (tantalum, electrolytic, ceramic) have
unique performance characteristics and may affect overall
system performance.
(7)
Thus, a minimum gain of 1.497 allows the LM4908 to reach
full output swing and maintain low noise and THD+N perfro-
mance. For this example, let AV = 1.5.
Bypass Capacitor Value
Besides minimizing the input capacitor size, careful consid-
eration should be paid to the value of the bypass capacitor,
CB. Since CB determines how fast the LM4908 settles to
quiescent operation, its value is critical when minimizing
turn-on pops. The slower the LM4908’s outputs ramp to their
quiescent DC voltage (nominally 1/2 VDD), the smaller the
turn-on pop. Choosing CB equal to 1.0µF or larger, will
minimize turn-on pops. As discussed above, choosing Ci no
larger than necessary for the desired bandwith helps mini-
mize clicks and pops.
The amplifiers overall gain is set using the input (Ri ) and
feedback (Rf ) resistors. With the desired input impedance
set at 20kΩ, the feedback resistor is found using Equation
(8).
AV = Rf/Ri
(8)
The value of Rf is 30kΩ.
AUDIO POWER AMPLIFIER DESIGN
The last step in this design is setting the amplifier’s −3db
frequency bandwidth. To achieve the desired 0.25dB pass
band magnitude variation limit, the low frequency response
must extend to at lease 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
Design a Dual 70mW/32Ω Audio Amplifier
Given:
Power Output
Load Impedance
Input Level
70mW
32Ω
1Vrms (max)
Input Impedance
Bandwidth
20kΩ
100Hz–20kHz 0.50dB
fL = 100Hz/5 = 20Hz
(9)
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 (5), 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 (5). For a single-
ended application, the result is Equation (6).
and a
fH = 20kHz*5 = 100kHz
(10)
As stated in the External Components section, both Ri in
conjunction with Ci, and Co with RL, create first order high-
pass filters. Thus to obtain the desired low frequency re-
sponse of 100Hz within 0.5dB, both poles must be taken
into consideration. The combination of two single order filters
at the same frequency forms a second order response. This
results in a signal which is down 0.34dB at five times away
from the single order filter −3dB point. Thus, a frequency of
20Hz is used in the following equations to ensure that the
response is better than 0.5dB down at 100Hz.
(5)
VDD ≥ (2VOPEAK + (VOD
+ VODBOT))
(6)
TOP
Ci ≥ 1 / (2π * 20 kΩ * 20 Hz) = 0.397µF; use 0.39µF.
Co ≥ 1 / (2π * 32Ω * 20 Hz) = 249µF; use 330µF.
The high frequency pole is determined by the product of the
desired high frequency pole, fH, and the closed-loop gain,
AV. With a closed-loop gain of 1.5 and fH = 100kHz, the
resulting GBWP = 150kHz which is much smaller than the
LM4908’s GBWP of 3MHz. This figure displays that if a
designer has a need to design an amplifier with a higher
gain, the LM4908 can still be used without running into
bandwidth limitations.
The Output Power vs Supply Voltage graph for a 32Ω load
indicates a minimum supply voltage of 4.8V. This is easily
met by the commonly used 5V supply voltage. The additional
voltage creates the benefit of headroom, allowing the
LM4908 to produce peak output power in excess of 70mW
without clipping or other audible distortion. The choice of
supply voltage must also not create a situation that violates
maximum power dissipation as explained above in the
Power Dissipation section. Remember that the maximum
power dissipation point from Equation (1) must be multiplied
by two since there are two independent amplifiers inside the
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14
Demonstration Board Layout
20075264
Recommended MSOP Board Layout:
Top Overlay
20075265
Recommended MSOP Board Layout:
Top Layer
20075266
Recommended MSOP Board Layout:
Bottom Layer
15
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Demonstration Board Layout (Continued)
200752B1
200752B0
200752A9
Recommended LQ Board Layout:
Top Overlay
Recommended LQ Board Layout:
Top Layer
Recommended LQ Board Layout:
Bottom Layer
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Demonstration Board Layout (Continued)
200752B4
Recommended MA Board Layout:
Top Overlay
200752B3
Recommended MA Board Layout:
Top Layer
200752B2
Recommended MA Board Layout:
Bottom Layer
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LM4908 MDC MWC
Dual 120MW Headphone Amplifier
20075263
Die Layout (A - Step)
DIE/WAFER CHARACTERISTICS
Fabrication Attributes
Physical Die Identification
General Die Information
Bond Pad Opening Size (min)
Bond Pad Metalization
LM4908A
A
70µm x 70µm
ALUMINUM
NITRIDE
Die Step
Physical Attributes
Passivation
Wafer Diameter
150mm
Back Side Metal
Back Side Connection
BARE BACK
Floating
Dise Size (Drawn)
889µm x 622µm
35.0mils x 24.5mils
216µm Nominal
216µm Nominal
Thickness
Min Pitch
Special Assembly Requirements:
Note: Actual die size is rounded to the nearest micron.
Die Bond Pad Coordinate Locations (A - Step)
(Referenced to die center, coordinates in µm) NC = No Connection, N.U. = Not Used
X/Y COORDINATES
PAD SIZE
SIGNAL NAME PAD# NUMBER
X
Y
X
70
Y
INPUT B+
INPUT B-
OUTPUT B
VDD
1
2
3
4
5
6
7
8
-367
-367
-367
35
232
15
x
x
x
x
x
x
x
x
70
70
70
70
70
70
70
70
70
-232
-232
-232
15
70
155
70
OUTPUT A
INPUT A-
INPUT A+
GND
367
367
367
68
70
232
232
70
155
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18
LM4908 MDC MWC
Dual 120MW Headphone Amplifier (Continued)
IN U.S.A
Tel #:
Fax:
1 877 Dial Die 1 877 342 5343
1 207 541 6140
IN EUROPE
Tel:
49 (0) 8141 351492 / 1495
49 (0) 8141 351470
Fax:
IN ASIA PACIFIC
Tel:
(852) 27371701
81 043 299 2308
IN JAPAN
Tel:
19
www.national.com
Physical Dimensions inches (millimeters)
unless otherwise noted
Order Number LM4908LQ
NS Package Number LQB08A
Order Number LM4908MA
NS Package Number M08A
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20
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Order Number LM4908MM
NS Package Number MUA08A
LIFE SUPPORT POLICY
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.
BANNED SUBSTANCE COMPLIANCE
National Semiconductor certifies that the products and packing materials meet the provisions of the Customer Products
Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification
(CSP-9-111S2) and contain no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
National Semiconductor
Americas Customer
Support Center
National Semiconductor
Europe Customer Support Center
Fax: +49 (0) 180-530 85 86
National Semiconductor
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Support Center
National Semiconductor
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Fax: 81-3-5639-7507
Email: new.feedback@nsc.com
Tel: 1-800-272-9959
Email: europe.support@nsc.com
Deutsch Tel: +49 (0) 69 9508 6208
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Email: ap.support@nsc.com
Email: jpn.feedback@nsc.com
Tel: 81-3-5639-7560
www.national.com
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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