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AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
KEY FEATURES
DESCRIPTION
ƒ Integrated Switching Class-D
Stereo Controller IC
ƒ Full 20Hz-20kHz Audio
Bandwidth
ƒ High Fidelity (LX1721) Or
High Power (LX1722)
Versions Available
ƒ Single Supply Operation
ƒ THD+N <0.06% Typical
(1Wrms, 1kHz, 4Ω)
ƒ Maximum Efficiency 80%85%
ƒ Output Power >60Wrms per
Channel (LX1722, 4Ω, 1%
THD+N)
ƒ PSRR –70dB Typical
ƒ Differential Input To Minimize
Noise Effects
ƒ Supports Multi-Channel
Systems
ƒ Complete LXE1721or
LXE1722 Amplifier Evaluation
Module Available
ƒ 44-Pin QSOP Package
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A complete audio amplifier module is
available to quickly evaluate the LX1721
or LX1722 stereo controller. Simply
connect the amplifier to the power source,
audio signal, and speakers. Reference
designs support a variety of requirements
including
multi
channel
systems,
subwoofers, satellite / subwoofer combinations and various speaker loads (2Ω,
4Ω, 8Ω). The versatile amplifier solution
can easily be adjusted for frequency
response, optimized for efficiency and
performance, or designed to minimize
PCB area and component count. The
LX1721/1722 is available in a space
saving 44-pin QSOP package.
(Continued Next Page)
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
WWW . Microsemi .C OM
The LX1721/1722 is a monolithic high
performance Class-D stereo controller IC
designed for high efficiency or space
constrained audio requirements such as
portable or battery operated products,
automotive amplifiers, and multi-channel
multimedia computer and video game
applications. This high frequency, full
audio bandwidth switching power
amplifier controller offers dramatically
improved performance over Linfinity’s
previous generation amplifier products.
Enhancements include higher output
power, better SNR, lower noise floor, and
reduced THD. Combined with output
power MOSFET’s and an output filter, the
LX1721/1722 is a complete Class-D audio
solution.
7V - 25V
Channel
1
Output Power vs. Supply Voltage
1kHz, 4Ω, THD+N=1%
IN +
IN -
FETs
Left
FETs
Right
LX1722
Stereo
Channel 2
IN +
IN -
2Ω, 4Ω, 8Ω
CLOCK
LX1711
Channel 3
Mono
FETs
IN +
IN -
2.1 Audio Amplifier
Configuration
ƒ Multimedia Speakers
ƒ Surround Sound Game
Systems
ƒ Notebook Computers
ƒ Desktop Computers
ƒ Automotive Amplifiers And
Head units
ƒ Battery Operated Equipment
(Megaphone, Public Address
System)
ƒ Portable Audio (Boom Box)
ƒ Wireless Speakers
ƒ High Power Subwoofer
ƒ Automotive Audio Systems
ƒ Home Theatre
LX1721 / 22
O
Subwoofer
APPLICATIONS
PACKAGE ORDER INFO
TJ (°C)
VDD
-20 to 70
-20 to 70
7V – 15V
7V – 25V
DB
Plastic QSOP
44-Pin
LX1721CDB
LX1722CDB
Note: Available in Tape & Reel.
Append the letters “TR” to the part number. (i.e. LX1722CDBTR)
Copyright © 2001
Rev. 1.2a,2004-06-10
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
AudioMAX™
I N T E G R A T E D
P R O D U C T S
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P RODUCTION
PACKAGE PIN OUT
DB 44-PIN QSSOP PACKAGE
LFAOUT
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
50°C/W
44
LFBKLFBK+
RPWM
LISN
LMUTE
VDD
LEAOUT
CN
LEAIN
PVDD
VREF
PGND
CLOCK
LN+
GND
LP+
V25
LP-
LIN+
LN-
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Junction Temperature Calculation: TJ = TA + (PD x θJA).
The θJA numbers are guidelines for the thermal performance of the device/pc-board
system. All of the above assume no ambient airflow.
1
CPWM
LIN-
RN-
LAMPOUT
RP-
RIN+
RP+
RIN-
RN+
RAMPOUT
SLEEP
STATUS
RMUTE
REAIN
REAOUT
RFAOUT
22
23
PGND
WWW . Microsemi .C OM
THERMAL DATA
CP
PVDD
NC
RISN
RFBK+
RFBK-
DB PACKAGE
(Top View)
DESCRIPTION (CONTINUTED)
THD+N levels of 0.06%(1kHz, 1Wrms). Efficiency is
greater than 80% typical, which eliminates the need for
heatsinks in most applications. The AudioMAX™ solution
requires a single supply voltage, simplifying input power
requirements where a dual supply may not be available. To
minimize potential environmental noise issues and ease the
integration of the amplifier into a variety of applications,
features such as a balanced/differential audio input and a high
power supply rejection ratio help reduce the effects of noise
from the audio signal or power supply.
Copyright © 2001
Rev. 1.2a,2004-06-10
PACKAGE DATA
O
The stereo output controller is available in either an
LX1722 high power version (>65Wrms, 4Ω) with a supply
voltage range of 7V-25V or an LX1721 high fidelity
version (better SNR performance) with a supply voltage
range of 7V-15V. The current rating of the external
MOSFET’s, the available supply voltage, and speaker load
primarily limits the maximum output power. The amplifier
provides high fidelity performance and is designed to
operate over the full 20Hz to 20kHz audio band. Signal
distortion measurements yield.
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 2
AudioMAX™
I N T E G R A T E D
P R O D U C T S
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P RODUCTION
PIN NAME
DESCRIPTION
PIN NAME
Left Feedback Amplifier Output
LFBK-
PWM Capacitor Connection
LFBK+
RPWM
LMUTE
LEAOUT
LEAIN
VREF
PWM Resistor Connection
Left Mute Input (Active High)
Left Error Amplifier Output
Left Inverting Input of Error Amplifier
5V Reference
LISN
VDD
CN
PVDD
PGND
CLOCK
Input / Output Clock for Synch Operation
LN+
Low Current Ground
LP+
2.5V Reference
LP-
Left Positive Audio Input
LN-
Left Negative Audio Input
RN-
LAMPOUT
Left Input Amplifier Output
RP-
RIN+
Right Positive Audio Input
RP+
Right Negative Audio Input
RN+
LFAOUT
GND
V25
LIN+
LIN-
RIN-
DESCRIPTION
Left Feedback Amplifier Inverting Input
Left Feedback Amplifier Non-Inverting
Input
Left Current Limit Sense Input
Analog Supply Voltage
Supply Decoupling for NFET Drivers
Output Driver Supply Voltage
Output Driver High Current Ground
Left Drive for NFET on Positive Half of
Bridge
Left Drive for PFET on Positive Half of
Bridge
Left Drive for PFET on Negative Half of
Bridge
Left Drive for NFET on Negative Half of
Bridge
Right Drive for NFET on Negative Half of
Bridge
Right Drive for PFET on Negative Half of
Bridge
Right Drive for PFET on Positive Half of
Bridge
Right Drive for NFET on Positive Half of
Bridge
Output Driver High Current Ground
Supply Decoupling for PFET Drivers
Output Driver Supply Voltage
No Connect
Right Current Limit Sense Input
Left Feedback Amplifier Non-Inverting
Input
Right Feedback Amplifier Inverting Input
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CPWM
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FUNCTIONAL PIN DESCRIPTION
SLEEP
STATUS
RMUTE
REAIN
Right Input Amplifier Output
Sleep Input (active low)
UVLO Indicator (Open Collector Output)
Right Mute Input (Active High)
Right Inverting Input of Error Amplifier
PGND
CP
PVDD
NC
RISN
REAOUT
Right Error Amplifier Output
RFBK+
RFAOUT
Right Feedback Amplifier Output
RFBK-
RAMPOUT
ABSOLUTE MAXIMUM RATINGS
O
Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into negative out of the
specified terminal.
Copyright © 2001
Rev. 1.2a,2004-06-10
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
PACKAGE DATA
Supply Voltage (PVDD, VDD) ............................................................................................................................. -0.3V to 30V
SLEEP , STATUS, R/LFBK+, R/LFBK- .................................................................................................-0.3V to VDD +0.3V
R/LISN .........................................................................................................................................PVDD –2 to PVDD to +0.3V
RPWM, CPWM, R/LMUTE ................................................................................................................... -0.3V to VREF +0.3V
R/LIN+, R/LIN-, R/LAMPOUT.............................................................................................................. -0.3V to VREF +0.3V
R/LEAIN, R/LEAOUT, R/LFAOUT ..................................................................................................... -0.3V to VREF + 0.3V
CLOCK ........................................................................................................................................................-0.3V to CN +0.3V
Operating Junction Temperature Plastic........................................................................................................................... 125°C
Storage Temperature Range ...............................................................................................................................-65°C to 150°C
Lead Temperature (Soldering, 10 seconds) ...................................................................................................................... 300°C
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
Parameter
Symbol
Test Conditions
Min
LX1721 / 1722
Typ
Max
Units
Evaluation Module (See LXE1721)
Supply Voltage
LX1721
Power Supply Rejection Ratio
Output Power (Per Channel)
Efficiency
VDD
7
15
7
25
bs
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LX1722
Total Harmonic Distortion Plus Noise
Signal-To-Noise Ratio
PSRR
PO
THD+N
SNR
VIN = 15V, VRIPPLE = 1VRMS, 20Hz
to 20kHz
VIN = 15V, RL=4Ω, THD+N=1%,
10Hz to 22kHz
VIN = 25V, RL=4Ω, THD+N=1%,
10Hz to 22kHz
VIN = 15V, fIN = 1kHz, PO = 10W
-70
V
dB
25
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ELECTRICAL CHARACTERISTICS
Unless otherwise specified, the following specifications apply over the operating ambient temperature -20°C < TA < 70°C (NOTE 2).
Test conditions: RPWM = 34.8k, CPWM = 100pF, VDD = PVDD = 15V
W
60
82
VIN = 15V, fIN = 1kHz, PO = 20W
85
fIN = 1kHz, PO = 1W
.06
fIN = 20Hz to 20kHz, PO = 1W
.2
RL = 4Ω, PO = 1W
%
%
81
dBr
450
kHz
Oscillator Section
Oscillator Frequency
FOSC
Charge Current
ICHG
(varies with VDD pin voltage)
-225
µA
Discharge Current
IDIS
(varies with VDD pin voltage)
225
µA
Oscillator Peak Voltage
VPK
(varies with VDD pin voltage)
3.6
V
Oscillator Valley Voltage
VVAL
(varies with VDD pin voltage)
1.4
Voltage Stability
VDD = 8V to 25V
0.6
2
%
Temperature Stability
TA = 0 C to 70 C
1.0
2
%
O
O
V
Error Amplifier
Input Offset Voltage
VIO
5
DC Open Loop Gain
AOL
60
dB
Unity Gain Bandwidth
UGBW
7
‘MHz
VOH
IOUT = -100µA
Low Output Voltage
VOL
IOUT = +100µA
IIN
VIN = 1V to 4V
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High Output Voltage
Input Bias Current
3.5
100
1
‘mV
V
‘mV
µA
Input Amplifier
Stage Gain
3.465
3.85
Output Voltage, High
VOH
IOUT = -100µA
Output Voltage, Low
VOL
IOUT = +100µA
3.5
3.535
V
1.3
Input Impedance
V/V
180
V
‘kΩ
Feedback Amplifier
Stage Gain
Input Impedance
Copyright © 2001
Rev. 1.2a,2004-06-10
LX1721
Set by Internal Resistors
89
91
93
‘mV/V
LX1722
Set by Internal Resistors
56
57
58
‘mV/V
LX1721
250
kΩ
LX1722
400
kΩ
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
ELECTRICALS
Set by Internal Resistors
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
Parameter
Symbol
Test Conditions
Min
LX1721 / 1722
Typ
Max
Units
Current Limit Comparator
Voltage Sense Threshold
190
210
Blanking Pulse Delay
Response Time
IUM Pulses required to Current Limit
Latch
Consecutive Clear Pulses required to
reset IUM counter
Reference Voltage Section
Excluding blanking pulse
‘ns
‘ns
4
2
4
‘cycles
2
2
‘cycles
± 100
‘mV
± 25
± 50
mV
5
‘mV
Initial Accuracy
Voltage Stability
(VREF)
(VREF)
5.0
± 50
Initial Accuracy
(V25)
2.5
Voltage Stability
(V25)
O
mV
250
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4
230
500
O
Temperature Stability
TA = 0 C to 70 C
2
Line Regulation
VDD = 9V to 15V
0.5
‘mV
Load Regulation
IOUT = 0 to 10mA
5
‘mV
6
250
V
mV
62,500
clkcyc
µA
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ELECTRICAL CHARACTERISTICS (CONTINUED)
Under Voltage Lockout Section
Start Threshold Voltage
UV Lockout Hysteresis
UVLO Delay To Output Enable
Supply Current
O
Sleep Current
SLEEP Input = 0V, TA = 25 C
30
Operating Current
SLEEP Input = 2V, VIN = 15V,
No MOSFETs connected
8
Sleep to Output Enable
11
62,500
Sleep Threshold
‘mA
clkcyc
1.45
1.6
1.75
V
1.2
1.35
1.5
V
ISINK = 3mA
ISINK = 100mA
ISOURCE = 3mA, CN = 5.2V
applied externally
ISOURCE = 100mA, CN = 5.2V
applied externally
30
0.3
100
1.0
‘mV
V
30
100
‘mV
0.3
1.0
V
ISINK = 3mA
30
100
‘mV
Mute Section
Mute Threshold
Output Drivers For N-Channel MOSFETs
O
NFET Drivers, Low Level Voltage
NFET Drivers, High Level Voltage
VOL
VOH
Output Drives For P-Channel MOSFETs
VOL
ISINK = 100mA
0.5
1.0
V
ISOURCE = 3mA, CP = 5.2V
30
100
‘mV
(applied externally)
PFET Drivers, High Level Voltage
VOH
ISOURCE = 100mA, CP = 5.2V
0.5
1.0
V
(applied externally)
Note 2: The LX1721 / 22CDB is guaranteed to meet performance specifications from 0° to 70°C. Specifications over the -20° to 0°C operation temperature
range are assured by design, characterization, and statistical process control.
Copyright © 2001
Rev. 1.2a,2004-06-10
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
ELECTRICALS
PFET Drivers, Low Level Voltage
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
17 SLEEP
VDD 41
7
PVDD
LISN 42
RPW M
CPW M
8
+
-
SYNC
UVLO
&
REFERENCE
10 V25
5V
Reference
220m V
3
OSC
40 CN
CLK
27,39 PVDD
2
5V
Reference
CURRENT SENSE
LEAOUT
VREF
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CLOCK
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BLOCK DIAGRAM
28 CP
5
36 LP+
LEAIN
6
FAULT
TIMER
OUTPUT
DRIVERS
&
LOGIC
ERROR AMP
LAMPOUT 13
CLK
LIN- 12
S
Q
R
Q
34 LN35 LP-
1
MUTE
LIN+ 11
37 LN+
LFAOUT
MUX
INPUT AMP
44 LFBK-
MUTE
43 LFBK+
2.5V
FEEDBACK AMP
LMUTE
4
2.5V
Copyright © 2001
Rev. 1.2a,2004-06-10
BLOCK DIAGRAM
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FIGURE 1 – LX1721 / 22 SIMPLIFIED BLOCK DIAGRAM (LEFT CHANNEL CIRCUIT SHOWN)
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 6
AudioMAX™
I N T E G R A T E D
P R O D U C T S
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P RODUCTION
Frequency Synchronization
Oscillator Configuration (RPWM and CPWM selection)
The oscillator is programmed by the external timing components
RPWM and CPWM. For a nominal frequency of 333kHz, RPWM and
CPWM should be set to 49.9kOhms and 100pF respectively. Note that
in order to keep the slope of the PWM ramp voltage proportional to
the supply voltage, both the ramp peak and valley voltages, and the
charge and discharge currents are proportional to the supply voltage.
This keeps the frequency relatively constant while keeping the slope
of the PWM ramp proportional to the voltage on the VDD pin. For
operating frequencies other than 333kHz, the frequency can be
approximated by the following equation:
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Two or more LX1721 / LX1722 oscillators can be configured for
synchronous operation. One unit, the master, is programmed for
the desired frequency with the RPWM and CPWM as usual.
Additional units will be slave units, and their oscillators will be
disabled by leaving the RPWM pin disconnected. The CLOCK pin
and the CPWM pin of the slave units should be tied to the CLOCK
pin and the CPWM pin of the master unit respectively. In this
configuration, the CLOCK pins of the slave units begin receiving
instead of transmitting clock pulses. Also, the CPWM pins quit
driving the PWM capacitor in the slave units. Note that for
optimum performance, all slave units should be located within a
few inches of the master unit.
1
(0.577)( RPWM )(CPWM ) + 320ns
Copyright © 2001
Rev. 1.2a,2004-06-10
APPLICATION
O
Frequency =
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APPLICATION INFORMATION
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
100
dx=-18.20 W
dy=-0.17812 %
FIGURE 2 – THD+N VS. OUTPUT POWER
50
20
10
5
VIN = 15V
fIN = 1kHz
RL = 4Ω
2
1
0.1
bs
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THD+N (%)
0.5
0.24563
0.2
0.06751
0.05
0.02
0.01
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CHARACTERISTIC CURVES
0.005
0.002
0.001
100m
200m
500m
.91611
2
5
10
19.12
20
50
100
Output Power (W)
100
dx=58.73
W
dy=0.47633 %
FIGURE 3 – THD+N VS. OUTPUT POWER
50
20
10
5
VIN = 25V
fIN = 1kHz
RL = 4Ω
2
1
THD+N (%)
0.5
0.53924
0.2
0.1
0.0629
0.05
0.02
0.01
0.005
0.002
0.001
100m
200m
500m
1 1.225
2
5
10
5059.95
20
100
Output Power (W)
100
dx=-36.99 W
dy=-0.22386 %
FIGURE 4 – THD+N VS. OUTPUT POWER
50
O
20
10
5
2
VIN = 15V
fIN = 1kHz
RL = 2Ω
1
THD+N (%)
0.5
0.26783
0.2
0.1
GRAPHS
0.05
0.04397
0.02
0.01
0.005
0.002
0.001
100m
Copyright © 2001
Rev. 1.2a,2004-06-10
200m
500m
1 1.252
2
5
Output Power (W)
10
20
38.24
50
100
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
dx=108.8
100
W
dy=0.48800 %
FIGURE 5 – THD+N VS. OUTPUT POWER
50
20
10
5
2
VIN = 25V
fIN = 1kHz
RL = 2Ω
0.2
0.1
bs
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THD+N(%)
1
0.5
0.53924
0.05
0.05123
0.02
0.01
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CHARACTERISTIC CURVES (CONTINUED)
0.005
0.002
0.001
100m
200m
500m
1.136
1
2
5
10
20
50
109.9
100
200 300
Output Power (W)
100
dx=-4.8988 kHz
dy=-0.17080 %
FIGURE 6 – THD+N VS. FREQUENCY
50
20
10
5
2
VIN = 15V
RL = 4Ω
PO = 1WRMS
1
THD+N (%)
0.5
0.2
0.19402
0.1
0.05
0.02322
0.02
0.01
0.005
0.002
0.001
20
50
100126.2
200
500
1k
2k
5.025k
5k
10k
20k
Frequency (Hz)
100
dx=-4.8988 kHz
dy=-0.11937 %
FIGURE 7 – THD+N VS. FREQUENCY
50
20
O
10
5
2
VIN = 25V
RL = 4Ω
PO = 1WRMS
1
THD+N (%)
0.5
0.2
0.1798
0.1
0.06044
0.05
GRAPHS
0.02
0.01
0.005
0.002
0.001
20
50
100126.2
200
500
1k
2k
5.025k
5k
10k
20k
Frequency (Hz)
Copyright © 2001
Rev. 1.2a,2004-06-10
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 9
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
+10
dx=-17.869 kHz
dy=-0.155 dB
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CHARACTERISTIC CURVES (CONTINUED)
FIGURE 8 – FREQUENCY RESPONSE
+8
+6
VIN = 15V
RL = 4Ω
PO = 1WRMS
+2
+0
-0.965
-1.119
-2
bs
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Voltage Amplification (dBr)
+4
-4
-6
-8
-10
10
18.220
50
dx=-17.869 kHz
+10
100
200
500
1k
2k
Frequency (Hz)
5k
10k
17.8875k
20k
50k
80k
dy=+0.170 dB
FIGURE 9 – FREQUENCY RESPONSE
+8
+6
Voltage Amplification (dBr)
+4
VIN = 25V
RL = 4Ω
PO = 1WRMS
+2
+0
-1.436
-1.606
-2
-4
-6
-8
-10
10
18.220
50
100
200
500
1k
2k
5k
10k
17.8875k
20k
50k
80k
Frequency (Hz)
+10
dx=-2.9880 kHz
dy=+3.205 dB
FIGURE 10 – NOISE FLOOR FFT
+0
-10
O
-20
-30
-40
VIN = 15V
RL = 4Ω
10Hz – 22kHz Bandwidth
A-weighted
dBV
-50
-60
-70
-80
-90
-94.916
-100
-98.12
GRAPHS
-110
-120
-130
-140
-150
20
50
100
200
500
.973932k
1k
2k
3.96192k 5k
10k
20k
Frequency (Hz)
Copyright © 2001
Rev. 1.2a,2004-06-10
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 10
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
CHARACTERISTIC CURVES (CONTINUED)
dx=-2.9880 kHz
dy=-1.969 dB
WWW . Microsemi .C OM
+10
FIGURE 11 – NOISE FLOOR FFT
+0
-10
-20
-30
-40
-50
VIN = 25V
RL = 4Ω
10Hz – 22kHz Bandwidth
A-Weighted
dBV
-60
-70
-80
bs
ol
et
e
-90
-94.11
-96.079
-100
-110
-120
-130
-140
-150
20
50
100
200
.973932k
1k
500
2k
3.96192k5k
10k
20k
Frequency (Hz)
FIGURE 12 – EFFICIENCY VS. OUTPUT
POWER
90%
85%
Efficency (%)
80%
75%
70%
VIN = 15V
fIN = 1kHz
65%
60%
55%
50%
45%
0
5
10
15
20
25
30
Output Power (W)
8Ω
4Ω
2Ω
FIGURE 13 – POWER SUPPLY REJECTION
RATIO (PSSR)
O
Power Supply Rejection Ratio (PSRR)
0
-10
-30
PO = 1WRMS
RL = 4Ω
-40
-50
GRAPHS
Amplitude (dB)
-20
-60
-70
-80
-90
-100
10
100
1000
10000
100000
Frequency (Hz)
15V+1,Left
Copyright © 2001
Rev. 1.2a,2004-06-10
15V+1,Right
15V-1,Left
15V-1,Right
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 11
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
LISN
R16
Q1
LFBK+
R8
24.3K 1%
C25
220pF
5.1/1W
JP1
Vcc
2
1
PGND
Teminal 2
Vcc Vcc
+ C1
1000µF
25V
PGND
L1
Vcc
R6
0.020/1W
C2
0.1uF/25V
OUTL+
LISN
R9
15uH
Q2
C29
0.68uF/50V
5.1/1W
LFBKLFBK+
PGND
R10
U1
C7
1
100pF
2
3
GND
C9
18pF
R5 34.8k 1%
4
5
R2 56.2k 1%
C10 150pF
6
7
+
C13 1uF/10V,TANT
8
9
C14 0.1uF/25V
LIN-
RIN+
RIN-
C3
LIN+
0.47uF
11
LIN-
12
C4 0.47uF
C5 0.47uF
RIN+
13
RIN-
15
C6
14
0.47uF
16
17
18
_MUTE
19
R4 56.2k 1%
C12150pF
20
21
22
LFBK-
CPWM
LFBK+
RPWM
LISN
_LMUTE
LEAOUT
VDD
CN
LEAIN
PVDD
VREF
PGND
CLOCK
LN+
GND
LP+
V25
LP-
LIN+
LN-
LIN-
RN-
LAMPOUT
RP-
RIN+
RP+
RIN-
RN+
RAMPOUT
SLEEP
PGND
CP
STATUS
PVDD
_RMUTE
NC
REAIN
RISN
REAOUT
RFBK+
RFAOUT
RFBK-
44
43
42
41
40
39
38
C16
0.1uF/25V
LN+
36
LP+
35
LP-
34
LN-
33
RN-
32
RP-
31
RP+
30
RN+
28
27
26
25
C30
0.68uF/50V
5.1/1W
R11
5.1/1W
LFBK-
Q4
24.3K 1%
R18
RFBK-
R12
24.3K 1%
PGND
C20 4.7uF/25V,TANT
C22
0.1uF/25V
L3
R13
5.1/1W
23
Q6
C32
0.68uF/50V
PGND
RFBK+
RFBK-
C33
0.68uF/50V
5.1/1W
C34
0.47uF/50V
L4
OUTR+
15uH
R19
R15
APPLICATION
O
R21
15/1W
Q7
Vcc
R7
0.020/1W
OUTR-
15uH
Vcc
24
C27
220pF
5.1/1W
C21
47uF/25V
R14
Vcc
C26
220pF
Q5
LX1721-01CDB
10k
OUTL-
15uH
R17
C11 18pF
R3
C31
0.47uF/50V
L2
PGND
C17 4.7uF/25V,TANT
Vcc
C18
+47uF/25V
C19
PGND
0.1uF/25V
37
29
C15
10uF/25V
+
+
SLEEP
10
Q3
Vcc
LFAOUT
+
10k
+
R1
LIN+
R20
15/1W
bs
ol
et
e
Vcc
RFBK+
RISN
Q8
24.3K 1%
5.1/1W
C28
220pF
RISN
GND
PGND
FIGURE 14 – TYPICAL CLASS-D STEREO SWITCHING AMPLIFIER CIRCUIT APPLICATION
Copyright © 2001
Rev. 1.2a,2004-06-10
WWW . Microsemi .C OM
APPLICATION
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 12
AudioMAX™
I N T E G R A T E D
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P R O D U C T S
P RODUCTION
DB
WWW . Microsemi .C OM
MECHANICAL DIMENSIONS
44-Pin Quarter Size Outline Package (QSOP)
44
bs
ol
et
e
23
R
E
1
P
22
B
F
ZD
D
E
A
G
A
B
C
D
E
F
G
L
M
P
R
ZD
*LC
M
MILLIMETERS
INCHES
MIN
MAX
2.44
2.64
0.28
0.51
0.23
0.32
17.73
17.93
7.40
7.60
0.80 BSC
0.10
0.30
0.40
1.27
0°
8°
10.11
10.51
0.63
0.89
0.51 REF
0.10
MIN
MAX
0.096
0.104
0.011
0.020
0.091
0.0125
0.698
0.706
0.291
0.299
0.0315 BSC
0.004
0.012
0.016
0.050
0°
8°
0.396
0.414
0.025
0.035
0.020 REF
0.004
L
* Lead Coplanarity
Note:
Dimensions do not include mold flash or protrusions; these shall not exceed 0.15mm (.006”) on any side. Lead dimension shall not include
solder coverage.
Copyright © 2001
Rev. 1.2a,2004-06-10
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 13
MECHANICALS
O
Dim
C
AudioMAX™
I N T E G R A T E D
P R O D U C T S
LX1721 / 1722
Class-D Stereo Power Amplifier Controller
P RODUCTION
O
bs
ol
et
e
WWW . Microsemi .C OM
NOTES
NOTES
PRODUCTION DATA – Information contained in this document is proprietary to Microsemi and
is current as of publication date. This document may not be modified in any way without the
express written consent of Microsemi. Product processing does not necessarily include testing of
all parameters. Microsemi reserves the right to change the configuration and performance of the
product and to discontinue product at any time.
Copyright © 2001
Rev. 1.2a,2004-06-10
Microsemi
Linfinity Microelectronics Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 14