TI1 LM4665 Lm4665 filterless high efficiency 1w switching audio amplifier Datasheet

LM4665
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LM4665
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Filterless High Efficiency 1W Switching Audio
Amplifier
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FEATURES
DESCRIPTION
•
The LM4665 is a fully integrated single-supply high
efficiency switching audio amplifier. It features an
innovative modulator that eliminates the LC output
filter used with typical switching amplifiers.
Eliminating the output filter reduces parts count,
simplifies circuit design, and reduces board area. The
LM4665 processes analog inputs with a delta-sigma
modulation technique that lowers output noise and
THD when compared to conventional pulse width
modulators.
1
2
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•
•
•
•
•
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No Output Filter Required for Inductive
Transducers
Selectable Gain of 6dB (2V/V) or 12dB (4V/V)
Very Fast Turn On Time: 5ms (typ)
User Selectable Shutdown High or Low Logic
Level
Minimum External Components
"Click and Pop" Suppression Circuitry
Micro-Power Shutdown Mode
Short Circuit Protection
DSBGA, WSON, and VSSOP Packages (No
Heat Sink Required)
APPLICATIONS
•
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Mobile Phones
PDAs
Portable Electronic Devices
KEY SPECIFICATIONS
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Efficiency at 100mW into 8Ω Transducer
75%(typ)
Efficiency at 400mW into 8Ω Transducer
80%(typ)
Total Quiescent Power Supply Current (3V)
3mA(typ)
Total Shutdown Power Supply Current (3V)
0.01µA(typ)
Single Supply Range (VSSOP & WSON) 2.7V to
5.5V
Single Supply Range (DSBGA) (Note 11) 2.7V
to 3.8V
The LM4665 is designed to meet the demands of
mobile phones and other portable communication
devices. Operating on a single 3V supply, it is
capable of driving 8Ω transducer loads at a
continuous average output of 400mW with less than
2%THD+N.
The LM4665 has high efficiency with an 8Ω
transducer load compared to a typical Class AB
amplifier. With a 3V supply, the IC's efficiency for a
100mW power level is 75%, reaching 80% at 400mW
output power.
The LM4665 features a low-power consumption
shutdown mode. Shutdown may be enabled by either
a logic high or low depending on the mode selection.
Connecting the Shutdown Mode pin to either VDD
(high) or GND (low) enables the Shutdown pin to be
driven in a likewise manner to activate shutdown.
The LM4665 has fixed selectable gain of either 6dB
or 12dB. The LM4665 has short circuit protection
against a short from the outputs to VDD, GND or
across the outputs.
1
2
Please 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.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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LM4665
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Typical Application
Figure 1. Typical Audio Amplifier Application Circuit
Connection Diagram
Figure 2. VSSOP Package – Top View
See Package Number DGS
Figure 3. 9 Bump DSBGA Package – Top View
See Package Number YZR0009
Figure 4. WSON Package – Top View
See Package Number NGZ
2
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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.
Absolute Maximum Ratings (1) (2) (3)
Supply Voltage (1)
6.0V
−65°C to +150°C
Storage Temperature
VDD + 0.3V ≥ V ≥ GND - 0.3V
Voltage at Any Input Pin
(4)
Internally Limited
ESD Susceptibility (5)
2.0kV
ESD Susceptibility (6)
200V
Power Dissipation
Junction Temperature (TJ)
Thermal Resistance
150°C
θJA (VSSOP)
190°C/W
θJC (VSSOP)
56°C/W
θJA (DSBGA)
180°C/W
θJA (WSON) (7)
θJC (WSON) (7)
Soldering Information
(1)
(2)
(3)
(4)
(5)
(6)
(7)
63°C/W
12°C/W
See the AN-1112 Application Report
All voltages are measured with respect to the ground pin, unless otherwise specified.
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.
If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.
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 LM4665, TJMAX = 150°C. See the Efficiency and Power Dissipation versus Output Power curves for more information.
Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Machine Model, 220 pF–240 pF discharged through all pins.
The exposed-DAP of the LDA10B package should be electrically connected to GND.
Operating Ratings (1)
Temperature Range TMIN ≤ TA ≤ TMAX
−40°C ≤ TA ≤ 85°C
Supply Voltage (DGS & NGZ)
2.7V ≤ VDD ≤ 5.5V
Supply Voltage (YZR0009) (Note11)
2.7V ≤ VDD ≤ 3.8V
(1)
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.
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Electrical Characteristics VDD = 5V (1) (2) (3)
The following specifications apply for VDD = 5V, RL = 8Ω + 33µH, measurement bandwidth is <10Hz - 22kHz unless otherwise
specified. Limits apply for TA = 25°C.
Symbol
Parameter
Conditions
LM4665
Typical (4)
Limit (5) (6)
Units
(Limits)
IDD
Quiescent Power Supply Current
VIN = 0V, No Load
VIN = 0V, 8Ω + 22µH Load
14
14.5
mA
mA
ISD
Shutdown Current
VSD = VSD Mode (7)
0.1
5.0
µA (max)
VSDIH
Shutdown Voltage Input High
VSD Mode = VDD
1.2
1.4
V (min)
VSDIL
Shutdown Voltage Input Low
VSD Mode = VDD
1.1
0.4
V (max)
VSDIH
Shutdown Voltage Input High
VSD Mode = GND
1.2
1.4
V (min)
VSDIL
Shutdown Voltage Input Low
VSD Mode = GND
1.1
0.4
V (max)
VGSIH
Gain Select Input High
1.2
1.4
V (min)
VGSIL
Gain Select Input Low
1.1
0.4
V (max)
AV
Closed Loop Gain
VGain Select = VDD
6
5.5
6.5
dB (min)
dB (max)
AV
Closed Loop Gain
VGain Select = GND
12
11.5
12.5
dB (min)
dB (max)
VOS
Output Offset Voltage
TWU
Wake-up Time
Po
Output Power
THD+N = 3% (max), fIN = 1kHz
THD+N
Total Harmonic Distortion+Noise
PO = 400mWRMS, fIN = 1kHz
0.8
%
RIN
Differential Input Resistance
VGain Select = VDD, Gain = 6dB
100
kΩ
VGain Select = GND, Gain = 12dB
65
kΩ
PSRR
Power Supply Rejection Ratio
VRipple = 100mVRMS,
fRipple = 217Hz, AV = 6dB
Inputs Terminated
52
dB
10
mV
5
ms
1.4
W
CMRR
Common Mode Rejection Ratio
VRipple = 100mVRMS,
fRipple = 217Hz, AV = 6dB
43
dB
eN
Output Noise Voltage
A-Weighted filter, VIN = 0V
350
µV
(1)
(2)
(3)
(4)
(5)
(6)
(7)
4
All voltages are measured with respect to the ground pin, unless otherwise specified.
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.
The LM4665 in the DSBGA package (NGZ) has an operating range of 2.7V - 3.8V for 8Ω speaker loads. The supply range may be
increased as speaker impedance is increased. It is not recommended that 4Ω loads be used with the DSBGA package. To increase the
supply voltage operating range, see Figure 31 and INCREASING SUPPLY VOLTAGE RANGE in the Application Information section for
more information.
Typical specifications are specified at 25°C and represent the parametric norm.
Tested limits are specified to TI's AOQL (Average Outgoing Quality Level).
Datasheet min/max specification limits are ensured by design, test, or statistical analysis.
Shutdown current is measured in a normal room environment. Exposure to direct sunlight will increase ISD by a maximum of 2µA. The
Shutdown Mode pin should be connected to VDD or GND and the Shutdown pin should be driven as close as possible to VDD or GND for
minimum shutdown current and the best THD performance in PLAY mode. See the Application Information section under SHUTDOWN
FUNCTION for more information.
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Electrical Characteristics VDD = 3V (1) (2)
The following specifications apply for VDD = 3V, and RL = 8Ω + 33µH, measurement bandwidth is <10Hz - 22kHz unless
otherwise specified. Limits apply for TA = 25°C.
Symbol
Parameter
Conditions
LM4665
Typical (3)
Limit (4) (5)
Units
(Limits)
IDD
Quiescent Power Supply Current
VIN = 0V, No Load
VIN = 0V, 8Ω + 22µH Load
3.0
3.5
7.0
mA (max)
mA
ISD
Shutdown Current
VSD = VSD Mode (6)
0.01
5.0
µA (max)
VSDIH
Shutdown Voltage Input High
VSD Mode = VDD
1.0
1.4
V (min)
VSDIL
Shutdown Voltage Input Low
VSD Mode = VDD
0.8
0.4
V (max)
VSDIH
Shutdown Voltage Input High
VSD Mode = GND
1.0
1.4
V (min)
VSDIL
Shutdown Voltage Input Low
VSD Mode = GND
0.8
0.4
V (max)
VGSIH
Gain Select Input High
1.0
1.4
V (min)
VGSIL
Gain Select Input Low
0.8
0.4
V (max)
AV
Closed Loop Gain
VGain Select = VDD
6
5.5
6.5
dB (min)
dB (max)
AV
Closed Loop Gain
VGain Select = GND
12
11.5
12.5
dB (min)
dB (max)
VOS
Output Offset Voltage
TWU
Wake-up Time
Po
Output Power
THD+N = 2% (max), fIN = 1kHz
400
THD+N
Total Harmonic Distortion+Noise
PO = 100mWRMS, fIN = 1kHz
0.4
% (max)
RIN
Differential Input Resistance
VGain Select = VDD, Gain = 6dB
100
kΩ
VGain Select = GND, Gain = 12dB
65
kΩ
52
dB
10
mV
5
ms
350
mW (min)
PSRR
Power Supply Rejection Ratio
VRipple = 100mVRMS,
fRipple = 217Hz, AV = 6dB,
Inputs Terminated
CMRR
Common Mode Rejection Ratio
VRipple = 100mVRMS,
fRipple = 217Hz, AV = 6dB
39
dB
eN
Output Noise Voltage
A-Weighted filter, VIN = 0V
350
µV
(1)
(2)
(3)
(4)
(5)
(6)
All voltages are measured with respect to the ground pin, unless otherwise specified.
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.
Typical specifications are specified at 25°C and represent the parametric norm.
Tested limits are specified to TI's AOQL (Average Outgoing Quality Level).
Datasheet min/max specification limits are ensured by design, test, or statistical analysis.
Shutdown current is measured in a normal room environment. Exposure to direct sunlight will increase ISD by a maximum of 2µA. The
Shutdown Mode pin should be connected to VDD or GND and the Shutdown pin should be driven as close as possible to VDD or GND for
minimum shutdown current and the best THD performance in PLAY mode. See the Application Information section under SHUTDOWN
FUNCTION for more information.
External Components Description
(Figure 1)
Components
1.
CS
Functional Description
Supply 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.
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Typical Performance Characteristics
6
THD+N vs Frequency
VDD = 5V, RL = 8Ω + 33µH
POUT = 400mW, 30kHz BW
THD+N vs Frequency
VDD = 3V, RL = 8Ω + 33µH
POUT = 100mW, 30kHz BW
Figure 5.
Figure 6.
THD+N vs Frequency
VDD = 3.3V, RL = 4Ω + 33µH
POUT = 300mW, 30kHz BW
THD+N vs Power Out
VDD = 5V, RL = 8Ω + 33µH
f = 1kHz, 22kHz BW
Figure 7.
Figure 8.
THD+N vs Power Out
VDD = 3V, RL = 8Ω + 33µH
f = 1kHz, 22kHz BW
THD+N vs Power Out
VDD = 3.3V, RL = 4Ω + 33µH
f = 1kHz, 22kHz BW
Figure 9.
Figure 10.
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Typical Performance Characteristics (continued)
THD+N vs Common-Mode Voltage
VDD = 5V, RL = 8Ω + 33µH, f = 1kHz
POUT = 400mW, 22kHz BW
THD+N vs Common-Mode Voltage
VDD = 3V, RL = 8Ω + 33µH, f = 1kHz
POUT = 100mW, 22kHz BW
Figure 11.
Figure 12.
CMRR vs Frequency
VDD = 5V, RL = 8Ω + 33µH
VCM = 100mVRMS Sine Wave, 80kHz BW
CMRR vs Frequency
VDD = 3V, RL = 8Ω + 33µH
VCM = 100mVRMS Sine Wave, 80kHz BW
Figure 13.
Figure 14.
PSRR vs DC Common-Mode Voltage
VDD = 5V, RL = 8Ω + 33µH
VRipple = 100mVRMS, fRipple = 217Hz Sine Wave
PSRR vs DC Common-Mode Voltage
VDD = 3V, RL = 8Ω + 33µH
VRipple = 100mVRMS, fRipple = 217Hz Sine Wave
Figure 15.
Figure 16.
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Typical Performance Characteristics (continued)
8
PSRR vs Frequency
VDD = 5V, RL = 8Ω + 33µH
VCM = 100mVRMSSine Wave, 22kHz BW
PSRR vs Frequency
VDD = 3V, RL = 8Ω + 33µH
VCM = 100mVRMSSine Wave, 22kHz BW
Figure 17.
Figure 18.
Efficiency (top trace) and
Power Dissipation (bottom trace) vs Output Power
VDD = 5V, RL = 8Ω + 33µH, f = 1kHz, THD < 3%
Efficiency (top trace) and
Power Dissipation (bottom trace) vs Output Power
VDD = 3V, RL = 8Ω + 33µH, f = 1kHz, THD < 2%
Figure 19.
Figure 20.
Efficiency (top trace) and
Power Dissipation (bottom trace) vs Output Power
VDD = 3.3V, RL = 4Ω + 33µH, f = 1kHz, THD < 2%
Gain Threshold Voltages
VDD = 3V - 5V
Figure 21.
Figure 22.
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Typical Performance Characteristics (continued)
Output Power vs Supply Voltage
RL = 16Ω + 33µH, f = 1kHz
Output Power vs Supply Voltage
RL = 8Ω + 33µH, f = 1kHz
Figure 23.
Figure 24.
Output Power vs Supply Voltage
RL = 4Ω + 33µH, f = 1kHz
Shutdown Hysteresis Voltage
VDD = 5V, SD Mode = GND (SD Low)
Figure 25.
Figure 26.
Shutdown Hysteresis Voltage
VDD = 3V, SD Mode = GND (SD Low)
Shutdown Hysteresis Voltage
VDD = 5V, SD Mode = GND (SD High)
Figure 27.
Figure 28.
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Typical Performance Characteristics (continued)
10
Shutdown Hysteresis Voltage
VDD = 3V, SD Mode = GND (SD High)
Supply Current vs Supply Voltage
RL = 8Ω + 33µH
Figure 29.
Figure 30.
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APPLICATION INFORMATION
GENERAL AMPLIFIER FUNCTION
The output signals generated by the LM4665 consist of two, BTL connected, output signals that pulse
momentarily from near ground potential to VDD. The two outputs can pulse independently with the exception that
they both may never pulse simultaneously as this would result in zero volts across the BTL load. The minimum
width of each pulse is approximately 160ns. However, pulses on the same output can occur sequentially, in
which case they are concatenated and appear as a single wider pulse to achieve an effective 100% duty cycle.
This results in maximum audio output power for a given supply voltage and load impedance. The LM4665 can
achieve much higher efficiencies than class AB amplifiers while maintaining acceptable THD performance.
The short (160ns) drive pulses emitted at the LM4665 outputs means that good efficiency can be obtained with
minimal load inductance. The typical transducer load on an audio amplifier is quite reactive (inductive). For this
reason, the load can act as it's own filter, so to speak. This "filter-less" switching amplifier/transducer load
combination is much more attractive economically due to savings in board space and external component cost
by eliminating the need for a filter.
POWER DISSIPATION AND EFFICIENCY
In general terms, efficiency is considered to be the ratio of useful work output divided by the total energy required
to produce it with the difference being the power dissipated, typically, in the IC. The key here is “useful” work. For
audio systems, the energy delivered in the audible bands is considered useful including the distortion products of
the input signal. Sub-sonic (DC) and super-sonic components (>22kHz) are not useful. The difference between
the power flowing from the power supply and the audio band power being transduced is dissipated in the
LM4665 and in the transducer load. The amount of power dissipation in the LM4665 is very low. This is because
the ON resistance of the switches used to form the output waveforms is typically less than 0.25Ω. This leaves
only the transducer load as a potential "sink" for the small excess of input power over audio band output power.
The LM4665 dissipates only a fraction of the excess power requiring no additional PCB area or copper plane to
act as a heat sink.
DIFFERENTIAL AMPLIFIER EXPLANATION
As logic supply voltages continue to shrink, designers are increasingly turning to differential analog signal
handling to preserve signal to noise ratios with restricted voltage swing. The LM4665 is a fully differential
amplifier that features differential input and output stages. A differential amplifier amplifies the difference between
the two input signals. Traditional audio power amplifiers have typically offered only single-ended inputs resulting
in a 6dB reduction in signal to noise ratio relative to differential inputs. The LM4665 also offers the possibility of
DC input coupling which eliminates the two external AC coupling, DC blocking capacitors. The LM4665 can be
used, however, as a single ended input amplifier while still retaining it's fully differential benefits. In fact,
completely unrelated signals may be placed on the input pins. The LM4665 simply amplifies the difference
between the signals. A major benefit of a differential amplifier is the improved common mode rejection ratio
(CMRR) over single input amplifiers. The common-mode rejection characteristic of the differential amplifier
reduces sensitivity to ground offset related noise injection, especially important in high noise applications.
PCB LAYOUT CONSIDERATIONS
As output power increases, interconnect resistance (PCB traces and wires) between the amplifier, load and
power supply create a voltage drop. The voltage loss on the traces between the LM4665 and the load results is
lower output power and decreased efficiency. Higher trace resistance between the supply and the LM4665 has
the same effect as a poorly regulated supply, increase ripple on the supply line also reducing the peak output
power. The effects of residual trace resistance increases as output current increases due to higher output power,
decreased load impedance or both. To maintain the highest output voltage swing and corresponding peak output
power, the PCB traces that connect the output pins to the load and the supply pins to the power supply should
be as wide as possible to minimize trace resistance.
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The rising and falling edges are necessarily short in relation to the minimum pulse width (160ns), having
approximately 2ns rise and fall times, typical, depending on parasitic output capacitance. The inductive nature of
the transducer load can also result in overshoot on one or both edges, clamped by the parasitic diodes to GND
and VDD in each case. From an EMI standpoint, this is an aggressive waveform that can radiate or conduct to
other components in the system and cause interference. It is essential to keep the power and output traces short
and well shielded if possible. Use of ground planes, beads, and micro-strip layout techniques are all useful in
preventing unwanted interference.
POWER SUPPLY BYPASSING
As with any power amplifier, proper supply bypassing is critical for low noise performance and high power supply
rejection ratio (PSRR). The capacitor (CS) location should be as close as possible to the LM4665. Typical
applications employ a voltage regulator with a 10µF and a 0.1µF bypass capacitors that increase supply stability.
These capacitors do not eliminate the need for bypassing on the supply pin of the LM4665. A 1µF tantalum
capacitor is recommended.
SHUTDOWN FUNCTION
In order to reduce power consumption while not in use, the LM4665 contains shutdown circuitry that reduces
current draw to less than 0.01µA. In addition, the LM4665 contains a Shutdown Mode pin allowing the designer
to designate whether the shutdown circuitry is activated by either a High level logic signal or a Low level logic
signal. The Shutdown Mode pin should be permanently connected to either GND (Low) or VDD (High). The
LM4665 may then be placed into shutdown by toggling the Shutdown pin to the same state as the Shutdown
Mode pin. For simplicity's sake, this is called "Shutdown same", as the LM4665 enters into a shutdown state
whenever the two pins are in the same logic state. The trigger point for either shutdown high or shutdown low is
shown as a typical value in the Electrical Characteristics Tables and in the Shutdown Hysteresis Voltage graphs
found in the Typical Performance Characteristics section. It is best to switch between ground and supply for
minimum current usage while in the shutdown state. While the LM4665 may be disabled with shutdown voltages
in between ground and supply, the idle current will be greater than the typical 0.01µA value. Increased THD may
also be observed with voltages greater than GND and less than VDD on the Shutdown pin when in PLAY mode.
The LM4665 has an internal resistor connected between the Shutdown Mode and Shutdown pins. The purpose
of this resistor is to eliminate any unwanted state changes when the Shutdown pin is floating, as long as the
Shutdown Mode pin is connected to GND or VDD. When the Shutdown Mode pin is properly connected, the
LM4665 will enter the shutdown state when the Shutdown pin is left floating or if not floating, when the shutdown
voltage has crossed the corresponding threshold for the logic level assigned by the Shutdown Mode pin voltage.
To minimize the supply current while in the shutdown state, the Shutdown pin should be driven to the same
potential as the Shutdown Mode pin or left floating. The amount of additional current due to the internal shutdown
resistor can be found by Equation 1 below.
(VSD MODE - VSD) / 60kΩ
(1)
With only a 0.5V difference between the Shutdown Mode voltage and the Shutdown voltage an additional 8.3µA
of current will be drawn while in the shutdown state.
GAIN SELECTION FUNCTION
The LM4665 has fixed selectable gain to minimize external components, increase flexibility and simplify design.
For a differential gain of 6dB (2V/V), the Gain Select pin should be permanently connected to VDD or driven to a
logic high level. For a differential gain of 12dB (4V/V), the Gain Select pin should be permanently connected to
GND or driven to a logic low level. The gain of the LM4665 can be switched while the amplifier is in PLAY mode
driving a load with a signal without damage to the IC. The voltage on the Gain Select pin should be switched
quickly between GND (logic low) and VDD (logic high) to eliminate any possible audible artifacts from appearing at
the output. For typical threshold voltages for the Gain Select function, refer to the Gain Threshold Voltages graph
in the Typical Performance Characteristics section.
INCREASING SUPPLY VOLTAGE RANGE
When using the DSBGA package (YZR0009), the operating supply voltage range is 2.7V - 3.8V with an 8Ω
speaker load. To increase the operating supply voltage range, four Schottky diodes (D1 - D4) can be used to
control the over and undershoot of the output pulse waveform (See Figure 31 below). To reduce THD+N, small
value capacitors in the range of 10pF - 33pF (CN1 & CN2) can also be added as needed. The diodes should be
placed as close to the DSBGA package as possible.
12
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Figure 31. Increased Supply Voltage Operating Range for the DSBGA Package
SINGLE-ENDED CIRCUIT CONFIGURATIONS
Figure 32. Single-Ended Input, Shutdown High and Gain of 6dB Configuration
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Figure 33. Single-Ended Input, Shutdown High and Gain of 12dB Configuration
Figure 34. Single-Ended Input, Shutdown Low and Gain of 6dB Configuration
14
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Figure 35. Single-Ended Input, Shutdown Low and Gain of 12dB Configuration
REFERENCE DESIGN BOARD SCHEMATIC
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In addition to the minimal parts required for the application circuit, a measurement filter is provided on the
evaluation circuit board so that conventional audio measurements can be conveniently made without additional
equipment. This is a balanced input / grounded differential output low pass filter with a 3dB frequency of
approximately 35kHz and an on board termination resistor of 300Ω (see schematic). Note that the capacitive load
elements are returned to ground. This is not optimal for common mode rejection purposes, but due to the
independent pulse format at each output there is a significant amount of high frequency common mode
component on the outputs. The grounded capacitive filter elements attenuate this component at the board to
reduce the high frequency CMRR requirement placed on the analysis instruments.
Even with the grounded filter the audio signal is still differential, necessitating a differential input on any analysis
instrument connected to it. Most lab instruments that feature BNC connectors on their inputs are NOT differential
responding because the ring of the BNC is usually grounded.
The commonly used Audio Precision analyzer is differential, but its ability to accurately reject fast pulses of
160nS width is questionable necessitating the on board measurement filter. When in doubt or when the signal
needs to be single-ended, use an audio signal transformer to convert the differential output to a single ended
output. Depending on the audio transformer's characteristics, there may be some attenuation of the audio signal
which needs to be taken into account for correct measurement of performance.
Measurements made at the output of the measurement filter suffer attenuation relative to the primary, unfiltered
outputs even at audio frequencies. This is due to the resistance of the inductors interacting with the termination
resistor (300Ω) and is typically about -0.35dB (4%). In other words, the voltage levels (and corresponding power
levels) indicated through the measurement filter are slightly lower than those that actually occur at the load
placed on the unfiltered outputs. This small loss in the filter for measurement gives a lower output power reading
than what is really occurring on the unfiltered outputs and its load.
16
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LM4665 VSSOP BOARD ARTWORK
Figure 36. Composite View
Figure 37. Silk Screen
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Figure 38. Top Layer
Figure 39. Bottom Layer
18
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LM4665 WSON BOARD ARTWORK
Figure 40. Composite View
Figure 41. Silk Screen
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Figure 42. Top Layer
Figure 43. Bottom Layer
20
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LM4665 DSBGA BOARD ARTWORK
Figure 44. Composite View
Figure 45. Silk Screen
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Figure 46. Top Layer
Figure 47. Bottom Layer
22
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SNAS146E – FEBRUARY 2002 – REVISED MAY 2013
REVISION HISTORY
Changes from Revision D (May 2013) to Revision E
•
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 22
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PACKAGE OPTION ADDENDUM
www.ti.com
2-May-2013
PACKAGING INFORMATION
Orderable Device
Status
(1)
LM4665ITL/NOPB
ACTIVE
Package Type Package Pins Package
Drawing
Qty
DSBGA
YZR
9
250
Eco Plan
Lead/Ball Finish
(2)
Green (RoHS
& no Sb/Br)
MSL Peak Temp
Op Temp (°C)
Top-Side Markings
(3)
SNAGCU
Level-1-260C-UNLIM
(4)
-40 to 85
G
A2
(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)
Multiple Top-Side Markings will be inside parentheses. Only one Top-Side 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 Top-Side 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.
Addendum-Page 1
Samples
PACKAGE MATERIALS INFORMATION
www.ti.com
8-May-2013
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
LM4665ITL/NOPB
Package Package Pins
Type Drawing
SPQ
DSBGA
250
YZR
9
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
178.0
8.4
Pack Materials-Page 1
1.7
B0
(mm)
K0
(mm)
P1
(mm)
1.7
0.76
4.0
W
Pin1
(mm) Quadrant
8.0
Q1
PACKAGE MATERIALS INFORMATION
www.ti.com
8-May-2013
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
LM4665ITL/NOPB
DSBGA
YZR
9
250
210.0
185.0
35.0
Pack Materials-Page 2
MECHANICAL DATA
YZR0009xxx
D
0.600±0.075
E
TLA09XXX (Rev C)
D: Max = 1.545 mm, Min =1.484 mm
E: Max = 1.545 mm, Min =1.484 mm
4215046/A
NOTES:
A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994.
B. This drawing is subject to change without notice.
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12/12
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