NSC LM4908LQ 10kv esd rated, dual 120 mw headphone amplifier Datasheet

LM4908
10kV ESD Rated, Dual 120 mW Headphone Amplifier
General Description
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.
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 snubber networks, it is optimally suited for low-power portable
systems.
The unity-gain stable LM4908 can be configured by external
gain-setting resistors.
j Output power at 0.1% THD+N
at 1kHz into 32Ω
75mW (typ)
Features
n
n
n
n
n
n
Up to 10kV ESD protection on all pins
MSOP, SOP, and LLP surface mount packaging
Switch on/off click suppression
Excellent power supply ripple rejection
Unity-gain stable
Minimum external components
Applications
Key Specifications
j THD+N at 1kHz at 120mW
continuous average output power
into 16Ω
n Headphone Amplifier
n Personal Computers
n Portable electronic devices
0.1% (typ)
j THD+N at 1kHz at 75mW
continuous average output power
into 32Ω
0.1% (typ)
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
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10kV ESD Rated, Dual 120 mW Headphone Amplifier
February 2004
LM4908
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
θJC (MSOP)
56˚C/W
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
θJA (MSOP)
210˚C/W
θJC (SOP)
35˚C/W
θJA (SOP)
170˚C/W
θJC (LLP)
15˚C/W
Supply Voltage
6.0V
Storage Temperature
Input Voltage
−65˚C to +150˚C
θJA (LLP)
117˚C/W (Note 9)
−0.3V to VDD + 0.3V
θJA (LLP)
150˚C/W (Note 10)
Power Dissipation (Note 4)
Internally limited
ESD Susceptibility (Note 5)
10.0kV
ESD Susceptibility (Note 6)
500V
Junction Temperature
Operating Ratings
Temperature Range
150˚C
TMIN ≤ TA ≤ TMAX
Soldering Information (Note 1)
−40˚C ≤ T
Small Outline Package
Vapor Phase (60 seconds)
215˚C
Infrared (15 seconds)
220˚C
A
≤ 85˚C
2.0V ≤ VDD ≤ 5.5V
Supply Voltage
Note 1: See AN-450 “Surface Mounting and their Effects on Product Reliability” for other methods of soldering surface mount devices.
Thermal Resistance
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
Typ
(Note 7)
VDD
Supply Voltage
Limit
(Note 8)
Units
(Limits)
2.0
V (min)
5.5
V (max)
IDD
Supply Current
VIN = 0V, IO = 0A
1.6
3.0
mA (max)
Ptot
Total Power Dissipation
VIN = 0V, IO = 0A
8
16.5
mW (max)
VOS
Input Offset Voltage
VIN = 0V
5
50
mV (max)
Ibias
Input Bias Current
VCM
Common Mode Voltage
GV
Open-Loop Voltage Gain
RL = 5kΩ
Io
Max Output Current
THD+N < 0.1 %
RO
Output Resistance
VO
Output Swing
10
pA
0
V
4.3
V
67
dB
70
mA
0.1
Ω
RL = 32Ω, 0.1% THD+N, Min
.3
RL = 32Ω, 0.1% THD+N, Max
4.7
V
PSRR
Power Supply Rejection Ratio
Cb = 1.0µF, Vripple = 100mVPP,
f = 40Hz
90
dB
Crosstalk
Channel Separation
RL = 32Ω, f = 1kHz
82
dB
THD+N
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
Signal-to-Noise Ratio
VO = 3.5Vpp (at 0 dB)
100
dB
fG
Unity Gain Frequency
Open Loop, RL = 5kΩ
25
MHz
Po
Output Power
THD+N = 0.1%, f = 1 kHz
RL = 16Ω
120
RL = 32Ω
75
mW
60
mW
THD+N = 10%, f = 1 kHz
CI
RL = 16Ω
157
mW
RL = 32Ω
99
mW
3
pF
Input Capacitance
3
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LM4908
Absolute Maximum Ratings (Note 3)
LM4908
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
Typ
(Note 7)
CL
Load Capacitance
SR
Slew Rate
Limit
(Note 8)
200
Unity Gain Inverting
3
Units
(Limits)
pF
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
Typ
(Note 7)
IDD
Supply Current
VIN = 0V, IO = 0A
VOS
Input Offset Voltage
VIN = 0V
Po
Output Power
THD+N = 0.1%, f = 1 kHz
Limit
(Note 8)
Units
(Limits)
1.4
mA (max)
5
mV (max)
RL = 16Ω
43
mW
RL = 32Ω
30
mW
RL = 16Ω
61
mW
RL = 32Ω
41
mW
THD+N = 10%, f = 1 kHz
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
Typ
(Note 7)
IDD
Supply Current
VIN = 0V, IO = 0A
VOS
Input Offset Voltage
VIN = 0V
Po
Output Power
THD+N = 0.1%, f = 1 kHz
Limit
(Note 8)
Units
(Limits)
1.3
mA (max)
5
mV (max)
RL = 16Ω
20
mW
RL = 32Ω
16
mW
RL = 16Ω
34
mW
RL = 32Ω
24
mW
THD+N = 10%, f = 1 kHz
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 TJMAX, θJA, and the ambient temperature TA. The maximum
allowable power dissipation is PDMAX = (TJMAX − TA) / θJA. For the LM4908, TJMAX = 150˚C, and the typical junction-to-ambient thermal resistance, when board
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 θJA 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
that of the Exposed-DAP itself.
Note 10: The given θJA is for an LM4908 packaged in an LQB08A with the Exposed-DAP not soldered to any printed circuit board copper.
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LM4908
External Components Description
(Figure 1)
Components
Functional Description
1. Ri
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).
2. Ci
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.
3. Rf
The feedback resistance, along with Ri, set closed-loop gain.
4. CS
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.
5. CB
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.
6. CO
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)
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 = 16Ω
THD+N vs Frequency
VDD = 2.6V, PWR = 15mW, RL = 8Ω
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LM4908
Typical Performance Characteristics
(Continued)
THD+N vs Frequency
VDD = 2.6V, PWR = 15mW, RL = 32Ω
THD+N vs Frequency
VDD = 3.3V, PWR = 25mW, RL = 8Ω
20075269
20075270
THD+N vs Frequency
VDD = 3.3V, PWR = 25mW, RL = 32Ω
THD+N vs Frequency
VDD = 3.3V, PWR = 25mW, RL = 16Ω
20075271
20075272
THD+N vs Frequency
VDD = 5V, PWR = 50mW, RL = 16Ω
THD+N vs Frequency
VDD = 5V, PWR = 50mW, RL = 8Ω
20075273
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20075274
6
LM4908
Typical Performance Characteristics
(Continued)
THD+N vs Frequency
VDD = 5V, PWR = 50mW, RL = 32Ω
THD+N vs Frequency
VDD = 5V, VOUT = 3.5Vpp, RL = 5kΩ
20075275
20075276
THD+N vs Output Power
VDD = 2.6V, RL = 16Ω, f = 1kHz
THD+N vs Output Power
VDD = 2.6V, RL = 8Ω, f = 1kHz
20075277
20075278
THD+N vs Output Power
VDD = 3.3V, RL = 8Ω, f = 1kHz
THD+N vs Output Power
VDD = 2.6V, RL = 32Ω, f = 1kHz
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LM4908
Typical Performance Characteristics
(Continued)
THD+N vs Output Power
VDD = 3.3V, RL = 16Ω, f = 1kHz
THD+N vs Output Power
VDD = 3.3V, RL = 32Ω, f = 1kHz
20075281
20075282
THD+N vs Output Power
VDD = 5V, RL = 16Ω, f = 1kHz
THD+N vs Output Power
VDD = 5V, RL = 8Ω, f = 1kHz
20075283
20075284
Output Power vs Load Resistance
VDD = 2.6V, f = 1kHz
THD+N vs Output Power
VDD = 5V, RL = 32Ω, f = 1kHz
20075286
20075285
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LM4908
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
RL = 16Ω, f = 1kHz
Output Power vs Supply Voltage
RL = 8Ω, f = 1kHz
20075289
20075290
Clipping Voltage vs
Supply Voltage
Output Power vs Supply Voltage
RL = 32Ω, f = 1kHz
20075292
20075291
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LM4908
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
Output Noise vs Frequency
VDD = 5V, RL = 32Ω
Crosstalk vs Frequency
VDD = 5V, RL = 32Ω
20075294
20075295
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(Continued)
PSRR vs Frequency
VDD = 5V, RL = 32Ω, VRIPPLE = 100mVpp
Inputs Terminated
PSRR vs Frequency
VDD = 5V, RL = 32Ω, VRIPPLE = 100mVpp
Pins 3 and 5 directly driven, Inputs Floating
20075297
20075296
Open Loop Frequency Response
VDD = 5V, RL = 32Ω
Open Loop Frequency Response
VDD = 5V, RL = 8Ω
20075298
20075299
Supply Current vs
Supply Voltage (no Load)
Open Loop Frequency Response
VDD = 5V, RL = 5kΩ
200752A0
200752A1
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LM4908
Typical Performance Characteristics
LM4908
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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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 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 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. Connecting 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 connected 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 applications, 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 Characteristics 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 Engineering Group under application note AN1187.
SELECTING PROPER EXTERNAL COMPONENTS
Optimizing the LM4908’s performance requires properly selecting external components. Though the LM4908 operates
well when using external components with wide tolerances,
best performance is achieved by optimizing component values.
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 ratio. 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 information on selecting the proper gain.
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.
PDMAX = (VDD)
2
/ (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 temperature. 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:
PDMAX = (TJMAX − TA) / θJA
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 compromise 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.
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 frequency 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).
(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 decreased, 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 Performance Characteristics curves for power dissipation information for lower output powers.
13
fI-3db=1/2πRICI
(3)
fO-3db=1/2πRLCO
(4)
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LM4908
POWER SUPPLY BYPASSING
Application Information
LM4908
Application Information
package. Once the power dissipation equations have been
addressed, the required gain can be determined from Equation (7).
(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 perfromance. For this example, let AV = 1.5.
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).
Bypass Capacitor Value
Besides minimizing the input capacitor size, careful consideration 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 minimize clicks and pops.
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
70mW
Load Impedance
Input Level
32Ω
1Vrms (max)
Input Impedance
20kΩ
Bandwidth
100Hz–20kHz ± 0.50dB
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 Characteristics 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 account for the amplifier’s dropout voltage, two additional voltages, 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 singleended application, the result is Equation (6).
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 highpass filters. Thus to obtain the desired low frequency response 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.
(6)
Ci ≥ 1 / (2π * 20 kΩ * 20 Hz) = 0.397µF; use 0.39µF.
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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(9)
and a
(5)
VDD ≥ (2VOPEAK + (VODTOP + VODBOT))
fL = 100Hz/5 = 20Hz
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.
14
LM4908
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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LM4908
Demonstration Board Layout
(Continued)
200752B1
Recommended LQ Board Layout:
Top Overlay
200752B0
Recommended LQ Board Layout:
Top Layer
200752A9
Recommended LQ Board Layout:
Bottom Layer
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LM4908
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
LM4908 MDC MWC
Dual 120MW Headphone Amplifier
20075263
Die Layout (A - Step)
DIE/WAFER CHARACTERISTICS
Fabrication Attributes
General Die Information
Physical Die Identification
LM4908A
Bond Pad Opening Size (min)
70µm x 70µm
Die Step
A
Bond Pad Metalization
ALUMINUM
Passivation
NITRIDE
Wafer Diameter
150mm
Back Side Metal
BARE BACK
Dise Size (Drawn)
889µm x 622µm
35.0mils x 24.5mils
Back Side Connection
Floating
Thickness
216µm Nominal
Min Pitch
216µm Nominal
Physical Attributes
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
SIGNAL NAME
INPUT B+
PAD# NUMBER
1
X/Y COORDINATES
PAD SIZE
X
Y
X
-367
232
70
x
70
Y
INPUT B-
2
-367
15
70
x
70
OUTPUT B
3
-367
-232
70
x
70
VDD
4
35
-232
155
x
70
OUTPUT A
5
367
-232
70
x
70
INPUT A-
6
367
15
70
x
70
INPUT A+
7
367
232
70
x
70
GND
8
68
232
155
x
70
www.national.com
18
LM4908
LM4908 MDC MWC
Dual 120MW Headphone Amplifier
(Continued)
IN U.S.A
Tel #:
1 877 Dial Die 1 877 342 5343
Fax:
1 207 541 6140
IN EUROPE
Tel:
49 (0) 8141 351492 / 1495
Fax:
49 (0) 8141 351470
IN ASIA PACIFIC
Tel:
(852) 27371701
IN JAPAN
Tel:
81 043 299 2308
19
www.national.com
LM4908
Physical Dimensions
inches (millimeters)
unless otherwise noted
Order Number LM4908LQ
NS Package Number LQB08A
Order Number LM4908MA
NS Package Number M08A
www.national.com
20
10kV ESD Rated, Dual 120 mW Headphone Amplifier
Physical Dimensions
inches (millimeters) unless otherwise noted (Continued)
Order Number LM4908MM
NS Package Number MUA08A
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NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
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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
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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
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can be reasonably expected to cause the failure of
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