LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
LM4954 Boomer™ Audio Power Amplifier Series High Voltage 3 Watt Audio Power
Amplifier
Check for Samples: LM4954
1FEATURES DESCRIPTION
The LM4954 is an audio power amplifier primarily
23• No Output Coupling Capacitors, Snubber designed for demanding applications in mobile
Networks or Bootstrap Capacitors Required phones and other portable communication device
• Unity Gain Stable applications. It is capable of delivering 2.4 Watts of
• Externally Configurable Gain continuous average power to an 8ΩBTL load with
less than 1% THD+N from a 7VDC power supply.
• Ultra Low Current Active Low Shutdown Mode Boomer audio power amplifiers are designed
• BTL Output can Drive Capacitive Loads Up to specifically to provide high quality output power with a
100pF minimal number of external components. The
• “Click and Pop” Suppression Circuitry LM4954 does not require output coupling capacitors
• 2.7V - 9.0V Operation or bootstrap capacitors, and therefore is ideally suited
for lower-power portable applications where minimal
• Available in Space-Saving DSBGA Package space and power consumption are primary
requirements.
APPLICATIONS The LM4954 features a low-power consumption
• Mobile Phones global shutdown mode which is achieved by driving
• PDAs the shutdown pin with logic low. Additionally, the
LM4954 features an internal thermal shutdown
KEY SPECIFICATIONS protection mechanism.
• Wide Power Supply Voltage Range, 2.7 ≤VDD ≤The LM4954 contains advanced pop & click circuitry
9V which eliminates noises that would otherwise occur
• Output Power: VDD = 7V, 1% THD+N, 2.4W during turn-on and turn-off transitions.
(Typ) The LM4954 is unity-gain stable and can be
• Quiescent Power Supply Current, 3mA (Typ) configured by external gain-setting resistors.
• PSRR: VDD = 5V and 3V at 217Hz, 80dB (Typ)
• Shutdown Power Supply Current, 0.01µA (Typ)
1Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2Boomer is a trademark of Texas Instruments.
3All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Copyright © 2005–2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
Typical Application
Figure 1. Typical Audio Amplifier Application Circuit
Connection Diagram
Figure 2. 9 Bump DSBGA
Top View
See Package Number YZR0009
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
2Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
Absolute Maximum Ratings(1)(2)(3)
Supply Voltage(1) 9.5V
Storage Temperature −65°C to +150°C
Input Voltage −0.3V to VDD +0.3V
Power Dissipation(4) Internally Limited
ESD Susceptibility(5) 2000V
ESD Susceptibility(6) 200V
Junction Temperature 150°C
Thermal Resistance θJA (DSBGA)(7) 180°C/W
Soldering Information See AN-112 (SNAA002) “DSBGA Wafers Level Chip Scale Package.”
(1) All voltages are measured with respect to the ground pin, unless otherwise specified.
(2) 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 ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
(3) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
(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 or the number given in Absolute Maximum Ratings,
whichever is lower. For the LM4954, see power derating curves for additional information.
(5) Human body model, 100pF discharged through a 1.5kΩresistor.
(6) Machine Model, 220pF – 240pF discharged through all pins.
(7) All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The θJA given in the
Absolute Maximum Ratings section under Thermal Resistance is for the ITL package without any heat spreading planes on the PCB.
Operating Ratings(1)(2)
Temperature Range TMIN ≤TA≤TMAX −40°C ≤TA≤85°C
Supply Voltage 2.7V ≤VDD ≤9V
(1) All voltages are measured with respect to the ground pin, unless otherwise specified.
(2) 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 ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
Copyright © 2005–2013, Texas Instruments Incorporated Submit Documentation Feedback 3
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
Electrical Characteristics VDD = 7V(1)(2)
The following specifications apply for VDD = 7V, AV-BTL = 6dB, and RL= 8Ωunless otherwise specified. Limits apply for TA=
25°C. LM4954 Units
Symbol Parameter Conditions (Limits)
Typical(3) Limit(4)(5)
IDD Quiescent Power Supply Current VIN = 0V, RL= 8ΩBTL 3 5 mA (max)
ISD Shutdown Current VSD = GND(6) 0.01 1 µA (max)
VOS Output Offset Voltage 10 25 mV (max)
THD+N = 1% (max); f = 1kHz 2.4 2.2 W (min)
PoOutput Power(7) THD+N = 10% (max); f = 1kHz 3.0 W
PO= 1Wrms; f = 1kHz 0.1 %
AV-BTL = 6dB
THD+N Total Harmonic Distortion + Noise PO= 1Wrms; f = 1kHz 0.4 %
AV-BTL = 26dB
VRipple = 200mVsine p-p,
CB= 2.2µF, Input terminated 71 54 dB (min)
with 10Ωto GND
fRipple = 217Hz, Input Referred
PSRR Power Supply Rejection Ratio VRipple = 200mVsine p-p,
CB= 2.2µF, Input terminated 71 55 dB (min)
with 10Ωto ground
fRipple = 1kHz, Input Referred
VSDIH Shutdown High Input Voltage 1.2 V (min)
VSDIL Shutdown Low Input Voltage 0.4 V (max)
TWU Wake-up Time CB= 2.2µF 130 ms
A-Wtg, AV-BTL = 6dB
Input terminated with 10Ωto GND, 20 µVRMS
Output Referred
∈OUT Output Noise A-Wtg, AV-BTL = 26dB
Input terminated with 10Ωto GND, 100 µVRMS
Output Referred
RPD Pull Down Resistor on Shutdown 75 kΩ
(1) All voltages are measured with respect to the ground pin, unless otherwise specified.
(2) 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 ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
(3) Typical specifications are specified at 25°C and represent the parametric norm.
(4) Tested limits are specified to Texas Instruments' AOQL (Average Outgoing Quality Level).
(5) Datasheet min/max specification limits are specified by design, test, or statistical analysis.
(6) Shutdown current is measured in a normal room environment. Exposure to direct sunlight in the TL package will increase ISD by a
minimum of 2μA.
(7) The demo board shown has 1.1in2(710mm2) heat spreading planes on the two internal layers and the bottom layer. The bottom internal
layer is electrically VDD while the top internal and bottom layers are electrically GND. Thermal performance for the demo board is found
on the Power Derating graph in the Typical Performance Characteristics section. 7V operation requires heat spreading planes for the
thermal stability.
4Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
Electrical Characteristics VDD = 5V(1)(2)
The following specifications apply for VDD = 5V, AV-BTL = 6dB, and RL= 8Ωunless otherwise specified. Limits apply for TA=
25°C. LM4954 Units
Symbol Parameter Conditions (Limits)
Typical(3) Limit(4)(5)
IDD Quiescent Power Supply Current VIN = 0V, RL= 8ΩBTL 2.7 5 mA (max)
ISD Shutdown Current VSD = GND(6) 0.01 1 µA (max)
VOS Output Offset Voltage 8 25 mV (max)
PoOutput Power THD+N = 1% (max); f = 1kHz 1.2 1.1 W (min)
THD+N Total Harmonic Distortion + Noise PO= 600mWrms; f = 1kHz 0.1 %
Vripple = 200mVsine p-p,
CB= 2.2µF, Input terminated 80 63 dB (min)
with 10Ωto GND
fRipple = 217Hz, Input Referred
PSRR Power Supply Rejection Ratio Vripple = 200mVsine p-p,
CB= 2.2µF, Input terminated 80 dB
with 10Ωto GND
fRipple = 1kHz, Input Referred
VSDIH Shutdown High Input Voltage 1.2 V (min)
VSDIL Shutdown Low Input Voltage 0.4 V (max)
TWU Wake-up Time CB= 2.2µF 130 ms
A-Wtg, Input terminated with 10Ωto
∈OUT Output Noise GND, 20 µVRMS
Output referred
RPD Pul Down Resistor on Shutdown 75 kΩ
(1) All voltages are measured with respect to the ground pin, unless otherwise specified.
(2) 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 ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
(3) Typical specifications are specified at 25°C and represent the parametric norm.
(4) Tested limits are specified to Texas Instruments' AOQL (Average Outgoing Quality Level).
(5) Datasheet min/max specification limits are specified by design, test, or statistical analysis.
(6) Shutdown current is measured in a normal room environment. Exposure to direct sunlight in the TL package will increase ISD by a
minimum of 2μA.
Copyright © 2005–2013, Texas Instruments Incorporated Submit Documentation Feedback 5
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
Electrical Characteristics VDD = 3V(1)(2)
The following specifications apply for VDD = 3V, AV-BTL = 6dB, and RL= 8Ωunless otherwise specified. Limits apply for TA=
25°C. LM4954 Units
Symbol Parameter Conditions (Limits)
Typical(3) Limit(4)(5)
IDD Quiescent Power Supply Current VIN = 0V, RL= 8ΩBTL 2.5 5 mA (max)
ISD Shutdown Current VSD = GND(6) 0.01 1 µA (max)
VOS Output Offset Voltage 5 25 mV (max)
PoOutput Power THD+N = 1% (max); f = 1kHz 380 360 mW (min)
THD+N Total Harmonic Distortion + Noise Po= 100mWrms; f = 1kHz 0.18 %
Vripple = 200mVsine p-p,
CB= 2.2µF, Input teiminated 80 63 dB (min)
with 10Ωto GND,
fRipple = 217Hz, Input referred
PSRR Power Supply Rejection Ratio Vripple = 200mVsine p-p,
CB= 2.2µF, Input teiminated 80 dB
with 10Ωto GND,
fRipple = 1kHz, Input referred
VSDIH Shutdown High Input Voltage 1.2 V (min)
VSDIL Shutdown Low Input Voltage 0.4 V (max)
TWU Wake-Up Time CB= 2.2μF 130 ms
A-Wtg, Input terminated with 10Ωto
∈OUT Output Noise GND, 20 μVRMS
Output referred
RPD Pull Down Resistor on Shutdown 75 kΩ
(1) All voltages are measured with respect to the ground pin, unless otherwise specified.
(2) 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 ensure specific performance limits. Electrical Characteristics state DC and AC electrical
specifications under particular test conditions which ensure specific performance limits. This assumes that the device is within the
Operating Ratings. Specifications are not ensured for parameters where no limit is given, however, the typical value is a good indication
of device performance.
(3) Typical specifications are specified at 25°C and represent the parametric norm.
(4) Tested limits are specified to Texas Instruments' AOQL (Average Outgoing Quality Level).
(5) Datasheet min/max specification limits are specified by design, test, or statistical analysis.
(6) Shutdown current is measured in a normal room environment. Exposure to direct sunlight in the TL package will increase ISD by a
minimum of 2μA.
External Components Description
(See Figure 1)
Components Functional Description
1. RiInverting input resistance which sets the closed-loop gain in conjunction with Rf. This resistor also forms a high pass
filter with Ciat fC= 1/(2πRiCi).
2. CiInput coupling capacitor which blocks the DC voltage at the amplifiers input terminals. Also creates a highpass filter with
Riat fc= 1/(2πRiCi). Refer to the section, PROPER SELECTION OF EXTERNAL COMPONENTS, for an explanation
of how to determine the value of Ci.
3. RfFeedback resistance which sets the closed-loop gain in conjunction with Ri. AVD = 2 * (Rf/Ri).
4. CSSupply bypass capacitor which provides power supply filtering. Refer to the POWER SUPPLY BYPASSING section for
information concerning proper placement and selection of the supply bypass capacitor.
5. CBBypass pin capacitor which provides half-supply filtering. Refer to the section, PROPER SELECTION OF EXTERNAL
COMPONENTS, for information concerning proper placement and selection of CB.
6Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
Typical Performance Characteristics
THD+N vs Output Power THD+N vs Frequency
VDD = 7V, RL= 8Ω, AV= 6dB, VDD = 7V, RL= 8Ω, AV= 6dB,
f = 1kHz, 80kHz BW POUT = 600mW, 80kHz BW
Figure 3. Figure 4.
THD+N vs Output Power THD+N vs Frequency
VDD = 7V, RL= 8Ω, AV= 26dB, VDD = 7V, RL= 8Ω, AV= 26dB,
f = 1kHz, 80kHz BW POUT = 600mW, 80kHz BW
Figure 5. Figure 6.
THD+N vs Output Power THD+N vs Frequency
VDD = 5V, RL= 4Ω, AV= 6dB, VDD = 5V, RL= 4Ω, AV= 6dB,
f = 1kHz, 80kHz BW POUT = 100mW, 80kHz BW
Figure 7. Figure 8.
Copyright © 2005–2013, Texas Instruments Incorporated Submit Documentation Feedback 7
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
Typical Performance Characteristics (continued)
THD+N vs Output Power THD+N vs Frequency
VDD = 5V, RL= 8Ω, AV= 6dB, VDD = 5V, RL= 8Ω, AV= 6dB,
f = 1kHz, 80kHz BW POUT = 100mW, 80kHz BW
Figure 9. Figure 10.
THD+N vs Output Power THD+N vs Frequency
VDD = 3V, RL= 4Ω, AV= 6dB, VDD = 3V, RL= 4Ω, AV= 6dB,
f = 1kHz, 80kHz BW POUT = 100mW, 80kHz BW
Figure 11. Figure 12.
THD+N vs Output Power THD+N vs Frequency
VDD = 3V, RL= 8Ω, AV= 6dB, VDD = 3V, RL= 8Ω, AV= 6dB,
f = 1kHz, 80kHz BW POUT = 100mW, 80kHz BW
Figure 13. Figure 14.
8Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
Typical Performance Characteristics (continued)
THD+N vs Differential Gain PSRR vs Frequency
VDD = 7V, RL= 8Ω, VDD = 7V, VRIPPLE = 200mVP-P
POUT = 600mW, 80kHz BW Input Terminated, 80kHz BW
Figure 15. Figure 16.
PSRR vs Frequency PSRR vs Frequency
VDD = 5V, VRIPPLE = 200mVP-P VDD = 3V, VRIPPLE = 200mVP-P
Input Terminated, 80kHz BW Input Terminated, 80kHz BW
Figure 17. Figure 18.
Output Power vs Supply Voltage Output Power vs Supply Voltage
RL= 4Ω, AV= 6dB, 80kHz BW RL= 8Ω, AV= 6dB, 80kHz BW
Figure 19. Figure 20.
Copyright © 2005–2013, Texas Instruments Incorporated Submit Documentation Feedback 9
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
Typical Performance Characteristics (continued)
Power Dissipation vs Output Power Power Dissipation vs Output Power
VDD = 7V, AV= 6dB, VDD = 5V, AV= 6dB,
THD+N ≤1%, 80kHz BW THD+N ≤1%, 80kHz BW
Figure 21. Figure 22.
Power Dissipation vs Output Power Power Derating – 9 bump DSBGA
VDD = 3V, AV= 6dB, PDMAX = 1.26W, VDD = 7V,
THD+N ≤1%, 80kHz BW RL= 8Ω(1)(2)
Figure 23. Figure 24.
(1) All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The θJA given in the
Absolute Maximum Ratings section under Thermal Resistance is for the ITL package without any heat spreading planes on the PCB.
(2) The demo board shown has 1.1in2(710mm2) heat spreading planes on the two internal layers and the bottom layer. The bottom internal
layer is electrically VDD while the top internal and bottom layers are electrically GND. Thermal performance for the demo board is found
on the Power Derating graph in the Typical Performance Characteristics section. 7V operation requires heat spreading planes for the
thermal stability.
10 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
Typical Performance Characteristics (continued)
Shutdown Threshold vs Supply Voltage Supply Current vs Supply Voltage
RL= 8Ω, AV= 6dB, 80kHz BW RL= 8Ω
Figure 25. Figure 26.
Copyright © 2005–2013, Texas Instruments Incorporated Submit Documentation Feedback 11
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
APPLICATION INFORMATION
BRIDGE CONFIGURATION EXPLANATION
As shown in Figure 1, the LM4954 has two operational amplifiers internally, allowing for a few different amplifier
configurations. The first amplifier's gain is externally configurable, while the second amplifier is internally fixed in
a unity-gain, inverting configuration. The closed-loop gain of the first amplifier is set by selecting the ratio of Rfto
Riwhile the second amplifier's gain is fixed by the two internal 20kΩresistors. Figure 1 shows that the output of
amplifier one serves as the input to amplifier two which results in both amplifiers producing signals identical in
magnitude, but out of phase by 180°. Consequently, the differential gain for the IC is
AVD = 2 *(Rf/Ri) (1)
By driving the load differentially through outputs Vo1 and Vo2, an amplifier configuration commonly referred to as
“bridged mode” is established. Bridged mode operation is different from the classical single-ended amplifier
configuration where one side of the load is connected to ground.
A bridge amplifier design has a few distinct advantages over the single-ended configuration, as it provides
differential drive to the load, thus doubling output swing for a specified supply voltage. Four times the output
power is possible as 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 clipped. In order to choose an amplifier's closed-
loop gain without causing excessive clipping, please refer to the AUDIO POWER AMPLIFIER DESIGN section.
A bridge configuration, such as the one used in LM4954, also creates a second advantage over single-ended
amplifiers. Since the differential outputs, Vo1 and Vo2, are biased at half-supply, no net DC voltage exists across
the load. This eliminates the need for an output coupling capacitor which is required in a single supply, single-
ended amplifier configuration. Without an output coupling capacitor, the half-supply bias across the load would
result in both increased internal IC power dissipation and also possible loudspeaker damage.
POWER DISSIPATION
Power dissipation is a major concern when designing a successful amplifier, whether the amplifier is bridged or
single-ended. A direct consequence of the increased power delivered to the load by a bridge amplifier is an
increase in internal power dissipation. Since the LM4954 has two operational amplifiers in one package, the
maximum internal power dissipation is four times that of a single-ended amplifier. The maximum power
dissipation for a given application can be derived from the power dissipation graphs or from Equation 2.
PDMAX = 4*(VDD)2/(2π2RL) (2)
It is critical that the maximum junction temperature (TJMAX) of 150°C is not exceeded. TJMAX can be determined
from the power derating curves by using PDMAX and the PC board foil area. By adding additional copper foil, the
thermal resistance of the application can be reduced from the free air value, resulting in higher PDMAX. Additional
copper foil can be added to any of the leads connected to the LM4954. It is especially effective when connected
to VDD, GND, and the output pins. Refer to the application information on the LM4954 reference design board for
an example of good heat sinking. If TJMAX still exceeds 150°C, then additional changes must be made. These
changes can include reduced supply voltage, higher load impedance, or reduced ambient temperature. Internal
power dissipation is a function of output power. Refer to the Typical Performance Characteristics curves for
power dissipation information for different output powers and output loading.
POWER SUPPLY BYPASSING
As with any amplifier, proper supply bypassing is critical for low noise performance and high power supply
rejection. The capacitor location on both the bypass and power supply pins should be as close to the device as
possible. Typical applications employ a 5V regulator with 10µF tantalum or electrolytic capacitor and a ceramic
bypass capacitor which aid in supply stability. This does not eliminate the need for bypassing the supply nodes of
the LM4954. The selection of a bypass capacitor, especially CB, is dependent upon PSRR requirements, click
and pop performance (as explained in the section, PROPER SELECTION OF EXTERNAL COMPONENTS),
system cost, and size constraints.
12 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
SHUTDOWN FUNCTION
In order to reduce power consumption while not in use, the LM4954 contains a shutdown pin to externally turn off
the amplifier's bias circuitry. This shutdown feature turns the amplifier off when a logic low is placed on the
shutdown pin. By switching the shutdown pin to ground, the LM4954 supply current draw will be minimized in idle
mode. While the device will be disabled with shutdown pin voltages less than 0.4VDC, the idle current may be
greater than the typical value of 0.01µA. (Idle current is measured with the shutdown pin tied to ground). The
LM4954 has an internal 75kΩpull-down resistor. If the shutdown pin is left floating the IC will automatically enter
shutdown mode.
PROPER SELECTION OF EXTERNAL COMPONENTS
Proper selection of external components in applications using integrated power amplifiers is critical to optimize
device and system performance. While the LM4954 is tolerant of external component combinations,
consideration to component values must be used to maximize overall system quality.
The LM4954 is unity-gain stable which gives the designer maximum system flexibility. The LM4954 should be
used in low gain configurations to minimize THD+N values, and maximize the signal to noise ratio. Low gain
configurations require large input signals to obtain a given output power. Input signals equal to or greater than 1
Vrms are available from sources such as audio codecs. Please refer to the section, AUDIO POWER AMPLIFIER
DESIGN, for a more complete explanation of proper gain selection.
Besides gain, one of the major considerations is the closed-loop bandwidth of the amplifier. To a large extent, the
bandwidth is dictated by the choice of external components shown in Figure 1. The input coupling capacitor, Ci,
forms a first order high pass filter which limits low frequency response. This value should be chosen based on
needed frequency response for a few distinct reasons.
Selection Of Input Capacitor Size
Large input capacitors are both expensive and space hungry for portable designs. Clearly, a certain sized
capacitor is needed to couple in low frequencies without severe attenuation. But in many cases the speakers
used in portable systems, whether internal or external, have little ability to reproduce signals below 100Hz to
150Hz. Thus, using a large input capacitor may not increase actual system performance.
In addition to system cost and size, click and pop performance is affected by the size of the input coupling
capacitor, Ci. A larger input coupling capacitor requires more charge to reach its quiescent DC voltage (nominally
1/2VDD). This charge comes from the output via the feedback and is apt to create pops upon device enable.
Thus, by minimizing the capacitor size based on necessary low frequency response, turn-on pops can be
minimized.
Besides minimizing the input capacitor size, careful consideration should be paid to the bypass capacitor value.
Choosing CBequal to 2.2µF along with a small value of Ci(in the range of 0.1µF to 0.39µF), should produce a
virtually clickless and popless shutdown function. While the device will function properly, (no oscillations or
motorboating), with CBequal to 0.1µF.
AUDIO POWER AMPLIFIER DESIGN
A designer must first determine the minimum supply rail to obtain the specified output power. By extrapolating
from the Output Power vs Supply Voltage graphs in the Typical Performance Characteristics section, the supply
rail can be easily found.
At this time, the designer must make sure that the power supply choice along with the output impedance does
not violate the conditions explained in the POWER DISSIPATION section.
Once the power dissipation equations have been addressed, the required differential gain can be determined
from Equation 3 and Equation 4.
(3)
AVD = (Rf/Ri) 2 (4)
Copyright © 2005–2013, Texas Instruments Incorporated Submit Documentation Feedback 13
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
Figure 27. HIGHER GAIN AUDIO AMPLIFIER
The LM4954 is unity-gain stable and requires no external components besides gain-setting resistors, an input
coupling capacitor, and proper supply bypassing in the typical application. However, if a closed-loop differential
gain of greater than 10 is required, a feedback capacitor (CF) may be needed as shown in Figure 27 to
bandwidth limit the amplifier. This feedback capacitor creates a low pass filter that eliminates possible high
frequency oscillations. Care should be taken when calculating the -3dB frequency in that an incorrect
combination of RFand CFwill cause rolloff before 20kHz. A typical combination of feedback resistor and
capacitor that will not produce audio band high frequency rolloff is RF= 20kΩand CF= 25pf. These components
result in a -3dB point of approximately 320 kHz. To calculate the value of the capacitor for a given -3dB point,
use Equation 5 below:
CF= 1/(2πf3dBRF) (F) (5)
Figure 28. DIFFERENTIAL AMPLIFIER CONFIGURATION FOR LM4954
14 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
LM4954 DSBGA BOARD ARTWORK(3)
Figure 30. Composite View Figure 31. Silk Screen
Figure 32. Top Layer Figure 33. Internal Layer 1, GND
Figure 34. Internal Layer 2, VDD Figure 35. Bottom Layer
(3) All bumps have the same thermal resistance and contribute equally when used to lower thermal resistance. The θJA given in the
Absolute Maximum Ratings section under Thermal Resistance is for the ITL package without any heat spreading planes on the PCB.
16 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
LM4954
www.ti.com
SNAS292B –JUNE 2005–REVISED APRIL 2013
Table 1. Mono LM4954 Reference Design Boards Bill of Materials
Designator Value Tolerance Part Description Comment
Ri20kΩ1% 1/10W, 1% 0805 Resistor
RF20kΩ1% 1/10W, 1% 0805 Resistor
Ci0.39μF 10% Ceramic 1206 Capacitor, 10%
CFPart not used
CS2.2μF 10% 16V Tantalum 1210 Capacitor
CB2.2μF 10% 16V Tantalum 1210 Capacitor
J1, J3, J40.100” 1x2 header, vertical mount Input, Output, Vdd/GND
J20.100” 1x3 header, vertical mount Shutdown control
PCB LAYOUT GUIDELINES
This section provides practical guidelines for mixed signal PCB layout that involves various digital/analog power
and ground traces. Designers should note that these are only "rule-of-thumb" recommendations and the actual
results will depend heavily on the final layout.
GENERAL MIXED SIGNAL LAYOUT RECOMMENDATIONS
Power and Ground Circuits
For a two layer mixed signal design, it is important to isolate the digital power and ground trace paths from the
analog power and ground trace paths. Star trace routing techniques (bringing individual traces back to a central
point rather than daisy chaining traces together in a serial manner) can have a major impact on low level signal
performance. Star trace routing refers to using individual traces to feed power and ground to each circuit or even
device. This technique requires a greater amount of design time but will not increase the final price of the board.
The only extra parts required may be some jumpers.
Single-Point Power / Ground Connections
The analog power traces should be connected to the digital traces through a single point (link). A "Pi-filter" can
be helpful in minimizing high frequency noise coupling between the analog and digital sections. It is further
recommended to put digital and analog power traces over the corresponding digital and analog ground traces to
minimize noise coupling.
Placement of Digital and Analog Components
All digital components and high-speed digital signals traces should be located as far away as possible from
analog components and circuit traces.
Avoiding Typical Design / Layout Problems
Avoid ground loops or running digital and analog traces parallel to each other (side-by-side) on the same PCB
layer. When traces must cross over each other do it at 90 degrees. Running digital and analog traces at 90
degrees to each other from the top to the bottom side as much as possible will minimize capacitive noise
coupling and cross talk.
Copyright © 2005–2013, Texas Instruments Incorporated Submit Documentation Feedback 17
Product Folder Links: LM4954
LM4954
SNAS292B –JUNE 2005–REVISED APRIL 2013
www.ti.com
REVISION HISTORY
Rev Date Description
1.1 4/29/05 Added curves 71 and 72. Edited Note 10. Changed Av =
26dB to 6dB under 7V EC table. Edited SHUTDOWN
FUNCTION under the Application section.
1.2 6/08/05 Removed all the LLP pkg references. Changed TLA09XXX
into YZR0009. Changed X1 and X2 measurements.
1.3 6/15/05 Fixed some typos.
Initial WEB release.
1.4 6/20/05 Replaced curve 20129170 with 20129192.
1.5 6/22/05 Split Note 10 and added Note 11. Re-released to the WEB.
Changes from Revision A (April 2013) to Revision B Page
• Changed layout of National Data Sheet to TI format .......................................................................................................... 17
18 Submit Documentation Feedback Copyright © 2005–2013, Texas Instruments Incorporated
Product Folder Links: LM4954
PACKAGE OPTION ADDENDUM
www.ti.com 9-Aug-2013
Addendum-Page 1
PACKAGING INFORMATION
Orderable Device Status
(1)
Package Type Package
Drawing Pins Package
Qty Eco Plan
(2)
Lead/Ball Finish MSL Peak Temp
(3)
Op Temp (°C) Device Marking
(4/5)
Samples
LM4954TL/NOPB ACTIVE DSBGA YZR 9 250 Green (RoHS
& no Sb/Br) SNAGCU Level-1-260C-UNLIM G
F2
(1) The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device Package
Type Package
Drawing Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0
(mm) B0
(mm) K0
(mm) P1
(mm) W
(mm) Pin1
Quadrant
LM4954TL/NOPB DSBGA YZR 9 250 178.0 8.4 1.7 1.7 0.76 4.0 8.0 Q1
PACKAGE MATERIALS INFORMATION
www.ti.com 12-Aug-2013
Pack Materials-Page 1
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
LM4954TL/NOPB DSBGA YZR 9 250 210.0 185.0 35.0
PACKAGE MATERIALS INFORMATION
www.ti.com 12-Aug-2013
Pack Materials-Page 2
MECHANICAL DATA
YZR0009xxx
www.ti.com
TLA09XXX (Rev C)
0.600±0.075 D
E
A
. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994.
B. This drawing is subject to change without notice.
4215046/A 12/12
NOTES:
D: Max =
E: Max =
1.51 mm, Min =
1.51 mm, Min =
1.45 mm
1.45 mm
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other
changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest
issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and
complete. All semiconductor products (also referred to herein as “components”) are sold subject to TI’s terms and conditions of sale
supplied at the time of order acknowledgment.
TI warrants performance of its components to the specifications applicable at the time of sale, in accordance with the warranty in TI’s terms
and conditions of sale of semiconductor products. Testing and other quality control techniques are used to the extent TI deems necessary
to support this warranty. Except where mandated by applicable law, testing of all parameters of each component is not necessarily
performed.
TI assumes no liability for applications assistance or the design of Buyers’ products. Buyers are responsible for their products and
applications using TI components. To minimize the risks associated with Buyers’ products and applications, Buyers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any patent right, copyright, mask work right, or
other intellectual property right relating to any combination, machine, or process in which TI components or services are used. Information
published by TI regarding third-party products or services does not constitute a license to use such products or services or a warranty or
endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual property of the
third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of significant portions of TI information in TI data books or data sheets is permissible only if reproduction is without alteration
and is accompanied by all associated warranties, conditions, limitations, and notices. TI is not responsible or liable for such altered
documentation. Information of third parties may be subject to additional restrictions.
Resale of TI components or services with statements different from or beyond the parameters stated by TI for that component or service
voids all express and any implied warranties for the associated TI component or service and is an unfair and deceptive business practice.
TI is not responsible or liable for any such statements.
Buyer acknowledges and agrees that it is solely responsible for compliance with all legal, regulatory and safety-related requirements
concerning its products, and any use of TI components in its applications, notwithstanding any applications-related information or support
that may be provided by TI. Buyer represents and agrees that it has all the necessary expertise to create and implement safeguards which
anticipate dangerous consequences of failures, monitor failures and their consequences, lessen the likelihood of failures that might cause
harm and take appropriate remedial actions. Buyer will fully indemnify TI and its representatives against any damages arising out of the use
of any TI components in safety-critical applications.
In some cases, TI components may be promoted specifically to facilitate safety-related applications. With such components, TI’s goal is to
help enable customers to design and create their own end-product solutions that meet applicable functional safety standards and
requirements. Nonetheless, such components are subject to these terms.
No TI components are authorized for use in FDA Class III (or similar life-critical medical equipment) unless authorized officers of the parties
have executed a special agreement specifically governing such use.
Only those TI components which TI has specifically designated as military grade or “enhanced plastic” are designed and intended for use in
military/aerospace applications or environments. Buyer acknowledges and agrees that any military or aerospace use of TI components
which have not been so designated is solely at the Buyer's risk, and that Buyer is solely responsible for compliance with all legal and
regulatory requirements in connection with such use.
TI has specifically designated certain components as meeting ISO/TS16949 requirements, mainly for automotive use. In any case of use of
non-designated products, TI will not be responsible for any failure to meet ISO/TS16949.
Products Applications
Audio www.ti.com/audio Automotive and Transportation www.ti.com/automotive
Amplifiers amplifier.ti.com Communications and Telecom www.ti.com/communications
Data Converters dataconverter.ti.com Computers and Peripherals www.ti.com/computers
DLP® Products www.dlp.com Consumer Electronics www.ti.com/consumer-apps
DSP dsp.ti.com Energy and Lighting www.ti.com/energy
Clocks and Timers www.ti.com/clocks Industrial www.ti.com/industrial
Interface interface.ti.com Medical www.ti.com/medical
Logic logic.ti.com Security www.ti.com/security
Power Mgmt power.ti.com Space, Avionics and Defense www.ti.com/space-avionics-defense
Microcontrollers microcontroller.ti.com Video and Imaging www.ti.com/video
RFID www.ti-rfid.com
OMAP Applications Processors www.ti.com/omap TI E2E Community e2e.ti.com
Wireless Connectivity www.ti.com/wirelessconnectivity
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2013, Texas Instruments Incorporated
