MICROSEMI LX1704CLQ

LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
The LX1704 family represents a
new generation of a fully integrated
audio stereo Class-D amplifier from
Microsemi. This CMOS stereo ClassD amplifier series is optimized for low
voltage, low power operation and
minimum system cost. The products
are ideal for use in battery powered
applications where low power consumption
is desirable such as: portable speakers,
DVDs, PMP, and other low power
systems.
The LX1704 family provides very
low quiescent current consumption
through the use of a proprietary output
modulation scheme. This technology
enables filterless operation in many
applications. The part features on board,
low Rdson, complementary output
MOSFET’s that reduces the need for
external components.
The LX1704 is offered in a small
footprint, low profile, 4mm x 4mm 16pin MLPQ.
IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com
PRODUCT HIGHLIGHT
Speaker Out 1
PVDD
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
ƒ
VDD
PVDD
OUT2+
Speaker Out 2
ƒ
ƒ
ƒ
ƒ
Portable Speakers
Portable DVD
PMP / PMC
Notebook PC
PVSS2
EN
IN1VSS
IN1-
Part
LX1704
IN2+
IN1+
APPLICATIONS
OUT2-
PVDD2
IN2-
IN1+
PVSS3
OUT1-
VDD
PVDD1
OUT1+
PVSS1
No Output Filter Required
Low EMI Design
Low Quiescent Current: 4mA
Low Shutdown Current: 1µA
Wide Supply Voltage Range:
2.5 - 5.5 Volt
2W Output Power into 4Ω Load
with THD<1% @ 5.0V
THD+N as Low as 0.1%
Small Form Factor...16 pin
MLP Package Only 4 x 4mm
Built-in Clock Frequency
Built-in Feedback Loop, Keep
High Audio Fidelity
Fixed 20dB Gain
Full 20 - 20kHz Audio
Bandwidth
Shut-down Function
Internal Thermal Shutdown
High Efficiency: over 85%
through Modulation Scheme
and Class-D Operation
Built-in De-Pop Circuit
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KEY FEATURES
DESCRIPTION
IN2ENABLE
IN2+
PACKAGE ORDER INFO
TA (°C)
LQ
Plastic MLPQ 4mm x 4mm
16-Pin
0 to 70
LX1704
RoHS Compliant / Pb-free
LX1704CLQ
Note: Available in Tape & Reel. Append the letters “TR” to the
part number. (i.e. LX1704CLQ-TR)
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 1
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
OUT1-
PVSS3
15
14
13
OUT2-
VDD
2
11
PVDD2
IN1+
3
e10
OUT2+
IN1-
4
9
PVSS2
5
LQ
IN2-
THERMAL DATA
Plastic MLPQ 16-Pin 4mm x 4mm
6
7
8
EN
12
VSS
1
IN2+
Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to
Ground. Currents are positive into, negative out of specified terminal.
16
PVSS1
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Positive Supply Voltage (VDD, PVDD) ........................................................... -0.3 to 6.5V
Analog Input Voltage (IN1+, IN1-, IN2+, IN2-).................................. -0.3 to VDD + 0.3V
Digital Input Voltage(EN, MUTE) ...................................................... -0.3 to VDD + 0.3V
Operating Temperature Range (TA) ................................................................0°C to +70°C
Maximum Operating Junction Temperature (TJ) ....................................................... 150°C
Storage Temperature Range.........................................................................-65°C to 150°C
Package Peak Temp. for Solder Reflow (40 seconds maximum exposure) ... 260°C (+0 -5)
PVDD1
PACKAGE PIN OUT
OUT1+
ABSOLUTE MAXIMUM RATINGS
LQ PACKAGE
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA
24.6°C/W
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.
(Top View)
RoHS / Pb-free 100% matte Tin Lead Finish
FUNCTIONAL PIN DESCRIPTION
Name
Description
VSS
Negative Supply to Analog Stage (ground)
IN1-
Negative Audio Input Channel 1
IN1+
Positive Audio Input Channel 1
EN
Enable Pin, Active High
IN2-
Negative Audio Input Channel 2
IN2+
Positive Audio Input Channel 2
VDD
Analog Positive Power Supply
PVSS1
PVSS2
PVSS3
Negative Supply to Negative Output Stage (ground) for Channel1
OUT1+
Positive Audio (PWM) Output for Channel 1
Positive supply to Positive Output Stage for Channel 1
OUT1-
Negative Audio (PWM) Output for Channel 1
OUT2+
Positive Audio (PWM) Output Channel 2
OUT2-
Negative Audio (PWM) Output Channel 2
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
PACKAGE DATA
PVDD1 &
PVDD2
Page 2
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
SYSTEM CHARACTERISTICS
Parameter
Symbol
Supply Current: Quiescent
Supply Current: Shutdown Mode
IQQ
IQQSD
Output Power @ 4 Ohms
Power Efficiency
Total Harmonic Distortion @ 50% of
Maxim Power
Signal To Noise Ratio
LX1704
Typ
Η
VDD = PVDD = 5V, Fin = 1kHz, RL = 4Ω
0.1
%
90
dB
VN
VDD = PVDD = 5V, F = 1kHz, PO = 1W, Aweighted
Input Grounded A-weighted 20 to 20kHz
FLO
3dB relative to 1kHz
20
VDD = PVDD = 2.5 to 5.5V, RL = 4Ω,
PO = 200mW @ 20 to 80kHz, Filter less
Input Reffered, VDD = PVDD = 2.5V to 5.5V
VDD = PVDD = 2.5V to 5.5V
55
55
PSRR
CMRR
GSYS
5
1
Units
THD_N
PQ
2.5
Max
2.4
3.3
0.9
1.2
85
Frequency Response
Power Supply Rejection Ratio
Common Mode Rejection Ratio
Gain
Min
No Load
Disable Pin Active
VDD = PVDD = 5V, Fin THD+N = 1%
= 1kHz
THD+N = 10%
THD+N = 1%
VDD = PVDD = 3.3V,
Fin = 1kHz
THD+N = 10%
VDD = PVDD = 5V, Fin = 1kHz
SNR
Output Noise Floor
Frequency Response Lower Corner
Frequency
Test Conditions
W
%
100
µVRMS
20K
3
60
60
20
mA
µA
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The following specifications apply over the operating ambient temperature 0 < TA < 70°C except where otherwise noted and the following
test conditions: PVDD = VDD = 5.0V, PVSS = VSS = 0V, RL = 4Ω
Hz
dB
dB
dB
dB
ELECTRICALS
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 3
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
ELECTRICAL CHARACTERISTICS
Parameter
Supply Voltage
Oscillator Frequency
Supply Current: Quiescent
Supply Current: Shutdown Mode
Power Supply Rejection Ratio
Input Resistance
Output DC Offset
Static Drain-to-Source ONResistance
Stage Gain
Thermal Indicator Junction
Under Voltage Threshold Level
Enable Threshold
Symbol
Test Conditions
VDD PVDD
fSW
VDD = PVDD = 2.5 to 5.5V
VDD = PVDD = 5V
IQQ
No Load
VDD = PVDD = 3.3V
IQQSD
Disable Pin Active
PSRR
VDD = PVDD = 2.5V to 5.5V
RIN
VDD = PVDD = 2.5V to 5.5V Single Ended
VOFF
Input Shorted to GND
P Channel
VDD = PVDD = 5V
N Channel
P Channel
VDD = PVDD = 3.3V
RDSON
N Channel
P Channel
VDD = PVDD = 2.5V
N Channel
GH
VDD = PVDD = 2.5V to 5.5V
TJ
VDD
EN
Min
LX1704
Typ
2.5
5.5
200
2.5
2
55
Max
5
4
1
60
18
-50
+50
350
350
470
470
9
1.8
2.10
10
150
2.0
2.25
Units
V
kHz
mA
µA
dB
KΩ
mV
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The following specifications apply over the operating ambient temperature 0 < TA < 70°C except where otherwise noted and the following
test conditions: PVDD = VDD = 5.0V, PVSS = VSS = 0V, RL = 4Ω
mΩ
600
600
11
2.2
2.40
V/V
°C
V
V
ELECTRICALS
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 4
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
SIMPLIFIED BLOCK DIAGRAM
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LX1704
Triangle
Wave
Generator
PVDD2
PVDD1
DRIVER
VINP
OUTP
Dynamic
Pulse
Generation
VINN
OUTN
DRIVER
PVSS1
VDD
VSS
De-pop signal
ground
Generation
LP
LP
PVSS2
EN
Figure 1 – LX1704 Simplified Block Diagram (Half Circuit)
BLOCK DIAGRAM
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 5
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
SYSTEM TEST SETUP
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Output1Audio
Precision
System One
IN1-
Output1+
IN1+
Output2-
IN2-
Output2+
GND
VBAT
+
Power
Supply
-
2nd Order
RC LPF
C1
TP1OUT1-
OUT1+
LX1704
Input1Audio
Precision
System One
2nd Order
RC LPF
TP1+
GND
Input1+
2nd Order
RC LPF
TP2-
Input2-
OUT2IN2+
OUT2+
2nd Order
RC LPF
TP2+
Input2+
LX1704 Evaluation Kit
Figure 2 – Typical Evaluation Test Setup Circuit
Default Settings:
Equipments: Audio Precision SYSTEM 1
Oscilloscope,
Power Supply ~ +5V;
Supply Voltage: 2.5V / 3.3V / 5.0V 3 corner voltages
On-Board passive LPF: 40kHz cut off frequency ( -6dB)
AP settings: 10Hz ~ 22KHz BPF
APPLICATIONS
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 6
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
APPLICATION CIRCUITS
WWW . Microsemi .C OM
R1 470
TP9
R2 470
C11
2200pF
C12
4700pF
For Test
Purposes Only
TB2
OUTR+
OUTR-
R3 470
TB1
C19
4700pF
VIN
C1
47µF
INR-
PVSS3
TP7
R5 470
PVDD2
VIN
OUT2+
For Test
Purposes Only
TP8
TB3
J2
C5
0.47µF
JP2
C13
2200pF
C14
4700pF
C8 1µF
PVSS2
IN1-
TP11
R6 470
EN
C4
0.47µF
IN1+
For Test
Purposes Only
OUT2-
LX1704
Part
VSS
JP1
VDD
IN2+
C3
0.47µF
OUT1-
PVSS1
J1
INR+
PVDD1
OUT1+
C2
1µF
C10
2200pF
TP6
C7
1µF
TP2
IN2-
RTN
TP10
TP5
TP1
+VIN
R4 470
TP1
C6
0.47µF
OUTLVIN
ENABLE
INL+
OUTL+
TP4
INL-
C15
4700pF
R8 470
APPLICATIONS
R7 470
TP12
C16
2200pF
For Test
Purposes Only
Figure 3 – Typical LX1704 Application
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 7
LX1704
TM
®
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
FUNCTIONAL DESCRIPTION
FILTERLESS 3-LEVEL CLASS-D MODULATION
The LX1704 output stage is configured as a full H-bridge
push-pull driver. The speaker must be driven differentially
from the OUTP and OUTN pins. Each side of the speaker
is driven by a 200KHz switching signal that transitions
between VDD and GND. With zero input voltage, the duty
cycle at each output is around 50% and the signals are inphase with each other. In this case, there is basically no
differential voltage across the speaker.
When the input
signal goes positive, the duty cycle at OUTP increases
above 50% and the duty cycle at OUTN decreases below
50%. This causes a net positive current to flow into the
speaker. A negative input voltage causes the OUTN duty
cycle to increase and the OUTP duty cycle to decrease
which causes a net negative current to flow into the
speaker. The differential voltage across the speaker has a
fundamental frequency of twice the 200KHz switching
frequency. The speaker itself serves as the low pass filter
which then recreates the audio signal. This type of
modulation can be described as driving +VDD, -VDD, and 0V
across the speaker which is why it is referred to as 3-Level
modulation.
Classical, 2-Level modulation drives either +VDD or –VDD
across the speaker at all times. This scheme requires an LC filter between the amplifier’s outputs and the speaker in
order to keep the output current low.
LOW-EMI OUTPUT STAGE WITH SLEW RATE LIMITING
AND ACTIVE OVERSHOOT CLAMPING
With 3-Level modulation, the carrier frequency drives a
full amplitude common-mode signal to the speaker wires.
This can cause high EMI radiation. One way to combat
this would be to filter the outputs with LC filters or ferrite
beads located close to the amplifier. In the LX1704, the
output stage has been carefully designed to minimize EMI
radiation so that these types of filters are not required.
Slew rate limiting is used to keep the outputs from
switching too quickly. Active overshoot clamping is used
to minimize the inductive overshoot which occurs at each
transition. These two techniques allow the LX1704 to
easily meet FCC standards for radiated emissions when
driving up to 3 meters of speaker wire.
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GENERAL DESCRIPTION
The LX1704 is a filterless, low-EMI, class-D audio
power amplifier. It offers high performance (THD+N is
just 0.1% @ 2W), high efficiency (>85% @ 1.2W), and
best in class EMI radiation (just 20dBµV/m). The internal
signal path is completely differential to minimize commonmode noise pickup. The inputs may be driven single-ended
or differentially and they may be direct or AC coupled. The
LX1704 may be operated with just a single decoupling
capacitor.
DIFFERENTIAL SIGNAL PATH, WIDE DYNAMIC RANGE,
AND BUILT-IN THERMAL OVERLOAD PROTECTION
The fully differential signal path uses Pulse Width
Modulation and multiple feedback loops to provide high
performance and low distortion. This is all fully-integrated
to eliminate the need for any external feedback
components or filters. The gain is fixed by internal
resistors at 20dB. The differential signal path and internal
voltage boosters allow for wide dynamic range. In fact, the
LX1704 can be operated from supplies as low as 2.5V and
as high as 5.5V. The output power will be limited by the
available supply voltage.
An internal thermal sensing
circuit shuts down the outputs when the junction
temperature exceeds about 150°C to provide thermal
overload protection.
APPLICATIONS
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 8
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
THD+N VS. FREQUENCY
GAIN RESPONSE
NOISE FLOOR
WWW . Microsemi .C OM
THD+N VS. POWER
CHANNEL CROSSTALK
IQQ VS. SUPPLY VOLTAGE
3.5
3
IQQ (mA)
2.5
2
1.5
GRAPHS
1
0.5
0
2.5
3
3.5
4
4.5
5
5.5
Supply Voltage (V)
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 9
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
PSRR
WWW . Microsemi .C OM
POWER SUPPLY VS OUTPUT POWER
900
800
700
Current (mA)
600
500
400
300
200
100
0
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Output Power (mW)
POWER VS SUPPLY VOLTAGE
3500
3000
Power/CH (mW)
2500
2000
1500
1000
500
0
2.5
3
3.5
4
4.5
5
5.5
Supply Voltage (V)
GRAPHS
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 10
LX1704
®
TM
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
PACKAGE DIMENSIONS
16-Pin MLPQ Plastic (4mm x 4mm EP / 114x114Cu Exposed Pad)
D
b
E2
L
D2
E
e
A
A1
A3
K
or
Pin 1 Indicator
Dim
A
A1
A3
b
D
E
e
D2
E2
K
L
MILLIMETERS
MIN
MAX
0.80
1.00
0
0.05
0.18
0.30
0.23
0.38
4.00 BSC
4.00 BSC
0.65 BSC
2.55
2.80
2.55
2.80
0.20
0.30
0.50
INCHES
MIN
MAX
0.031 0.039
0
0.002
0.007 0.012
0.009 0.015
0.157 BSC
0.157 BSC
0.026 BSC
0.100 0.110
0.100 0.110
0.008
0.012 0.020
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LQ
Note:
1. Dimensions do not include mold flash or protrusions; these
shall not exceed 0.155mm(.006”) on any side. Lead
dimension shall not include solder coverage.
MECHANICALS
Copyright © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 11
LX1704
TM
®
2W Filter less Stereo Class-D Amplifier
P RODUCTION D ATA S HEET
NOTES
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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 © 2005
Rev. 1.2, 2006-10-11
Microsemi
Integrated Products Division
11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570
Page 12