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TM
AudioMAX
LX1720
SWITCHING CLASS-D, STEREO POWER AMPLIFIER CONTROLLER IC
T HE I NFINITE P OWER OF I NNOVATION
DESCRIPTION KEY FEATURES
The LX1720 is a highly-integrated,
Switching Class-D Stereo Power Amplifier Controller IC with power and
size features that make it ideal for multimedia computer applications, as well as
other applications where high fidelity
sound is required.
With input voltage ranging from 7V15V, the LX1720 is designed to operate
over the full 20Hz to 20kHz audio range.
Signal distortion measurements using
industry standard 1kHz signal yields THD
+ noise levels < 1% (10 watts output).
IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.
Its high efficiency (>92%) eliminates the
need for heat sinks — even while delivering more than 10W
per channel (20W
SO-8 power FETs.
across 8 ohms
RMS
stereo) with 0.1 ohm
RMS
The LX1720's output power is limited
only by external FETs and available supply voltage.
While offering breakthrough performance capabilities for notebooks, the
LX1720 is equally attractive for multimedia systems or to drive full-size home
theatre speakers.
PRODUCT HIGHLIGHT
EFFICIENCY COMPARISON OF THE CLASS-D AMPLFIER
100
- Average Power Out for 20sec. approx. 512mW
- Across 8.6 Ohm Load
80
Linfinity's LX1720
Class-D Amplifier
60
40
Efficiency (%)
Highly Integrated
20
0
0
Audio sample from "Hold On Tight"
by Electric Light Orchestra
5
10
Seconds
Linear Amplifier
15 20
P RODUCTION DATA SHEET
■■
■ Integrated Switching (Class-D) Stereo
■■
Power Amplifier Controller IC
■■
■ Delivers >10W
■■
■■
■ Output Power Limited Only By External
■■
■■
■ Will Drive A Wide Range Of Speakers
■■
■■
■ High Efficiency (>92%)
■■
■■
■ Due To High Efficiency, Power FETs Do Not
■■
■■
■ Audio Bandwidth Of 20Hz to 20kHz
■■
■■
■ Wide Input Voltage Range Of 7V-15V
■■
■■
■ Low Output Signal Distortion <1%
■■
■■
■ High Operating Frequency (350kHz) Helps
■■
■■
■ Compact Design Minimizes EMI / RFI
■■
stereo)
(20W
RMS
FETs And Available Supply Voltage
Require Heatsinking
To Reduce Output Filter Size
APPLICATIONS / BENEFITS
Notebook Computers:
■■
■ Replaces existing internal low power linear
■■
amplifier with a high efficiency Class-D
amplifier
■■
■ Enables the use of virtually any external
■■
speaker without amplification
■■
■ Precious battery life is extended
■■
■■
■ Fully protected power topology can
■■
withstand shorts or external speaker
failures without damage, overheating or
posing fire hazard
Desktop Computers:
■■
■ Output power capability of up to 20W
■■
per channel in an area less than 3"x3",
without using expensive heatsinks
■■
■ Greatly reduced power supply
■■
requirements when compared to a linear
solution of same power capabilities
■■
■ Any speakers can be used including
■■
conventional home stereo speakers
■■
■ Very light weight circuitry will not add to
■■
the overall weight of the system
■■
■ Multimedia amplifier can be directly
■■
incorporated on the motherboard using
surface mount components
APPLICATION NOTE AN-11
available on our web site
or call 1-800-LMI-7011
Across 8Ω /Channel
RMS
RMS
Copyright © 1999
Rev. 1.0 9/99
PACKAGE ORDER INFO
T
(°C)
J
Maximum
VDD
Plastic SSOP
DB
44-pin
0 to 70 15V LX1720-01CDB
Append the letter "T" to part number. (i.e. LX1720-01CDBT)
Note: Available in Tape & Reel.
L INF INITY MICROELECTRONICS INC.
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570
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LX1720
PRODUCT DATABOOK 1996/1997
TM
AudioMAX
SWITCHING CLASS-D, STEREO POWER AMPLIFIER CONTROLLER IC
P RODUCTION DATA SHEET
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage (PVDD, VDD) ...................................................................... -0.3V to 18V
RPWM .................................................................................................... -0.3V to VCN+0.3V
INPUT (R), INPUT (L) .......................................................................... -0.3V to V
FBK+(R), FBK-(R), FBK+(L), FBK-(L), SLEEP .............................................. -0.3V to V
+0.3V
CN
MUTE (R), MUTE (L) .................................................................................... -0.3V to 6.0V
EAOUT (R), EAOUT (L) ....................................................................... -0.3V to VCN+0.3V
CPWM, CT ............................................................................................. -0.3V to VCN+0.3V
IS+, LIS-, RIS+ ................................................................................................ VDD-2 to V
Operating Junction Temperature
Plastic (DB Package) ............................................................................................ 125ºC
Storage Temperature Range ...................................................................... -65°C to 150°C
Lead Temperature (Soldering, 10 seconds) ............................................................ 300°C
Note 1. 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.
THERMAL DATA
DB PACKAGE:
D
x θ
θθ
θ
θθ
JA
).
JA
65°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
Junction Temperature Calculation: TJ = TA + (P
The θ
numbers are guidelines for the thermal performance of the device/pc-board
JA
system. All of the above assume no ambient airflow.
FUNCTIONAL PIN DESCRIPTION
PACKAGE PIN OUTS
RIS-
DD
DD
RPWM
CPWM
N.C.
RBIAS
GND
AGND
INPUT (R)
INPUT (L)
SLEEP
EAIN (R)
N.C.
EAOUT (R)
FAOUT (R)
EAOUT (L)
EAIN (L)
FAOUT (L)
144
243
LIS-
342
IS+
441
540
639
CN
738
837
CT
936
RT
10 35
11 34
12 33
13 32
14 31
15 30
16 29
17 28
18 27
19 26
20 25
21 24
22 23
DB PACKAGE
(Top View)
FBK- (R)
FBK+ (R)
N.C.
VDD
CP
PVDD
PGND
P- (R)
N- (R)
N+ (R)
P+ (R)
P- (L)
N- (L)
N+ (L)
P+ (L)
PGND
PVDD
FBK- (L)
FBK+ (L)
GND
MUTE (L)
MUTE (R)
Pin Name Description
RISLIS-
IS+
RPWM
CPWM
CN
CT
RT
RBIAS
GND
AGND
INPUT (R)
INPUT (L)
SLEEP
EAIN (R)
EAOUT (R)
Right Channel Current Sense Input
Left Channel Current Sense Input
Positive Current Sense Input
PWM Resistor Connection
PWM Capacitor Connection
Supply Decoupling for NFET Drivers
Oscillator Timing Capacitor Connection
Oscillator Timing Resistor
Bias Setting Resistor for Error Amps
Ground (2-pins)
Audio Input Ground
Right Channel Input
Left Channel Input
Sleep Input
Inverting Input of Right Channel Error Amp
Right Channel Error Amplifier Output
Pin Name Description
FAOUT (R)
EAOUT (L)
EAIN (L)
FAOUT (L)
FBK+(R), FBK-(R)
CP
PVDD
VDD
PGND
P+(R), N+(R),
P-(R), N-(R)
P+(L), N+(L),
P-(L), N-(L)
FBK+(L), FBK-(L)
MUTE (R),
MUTE (L)
Output of Right Feedback Amp
Left Channel Error Amplifier Output
Inverting Input of Left Channel Error Amp
Output of Left Feedback Amp
Right Channel Feedback Inputs
Supply Decoupling for PFET Drivers
Output Driver Supply Voltage (2-pins)
Analog Supply Voltage
IC Power Ground for the Output Drivers (2-pins)
Right Channel Gate Drive Outputs
Left Channel Gate Drive Outputs
Left Channel Feedback Inputs
Mute Inputs
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Copyright © 1999
Rev. 1.0 9/99
Page 3
PRODUCT DATABOOK 1996/1997
TM
AudioMAX
SWITCHING CLASS-D, STEREO POWER AMPLIFIER CONTROLLER IC
P RODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS
(
Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 70°C.
Test conditions: RT = 30k, CT = 100pF, VDD = PVDD = 15V.)
Parameter
Symbol
Test Conditions
Oscillator Section
Oscillator Frequency
Oscillator Peak Voltage
Oscillator Valley Voltage
Oscillator Max. Frequency
Voltage Stability
Temperature Stability
Error Amplifiers
Input Offset Voltage
DC Open Loop Gain
Unity Gain Bandwidth
High Output Voltage I
Low Output Voltage I
Input Common Mode Range
Input Bias Current
= -100µA
OUT
= +100µA
OUT
Input Amplifiers
Stage Gain Set by Internal Resistors
Input Impedance
Feedback Amplifiers
High Output Voltage I
Low Output Voltage I
Common Mode Rejection
Input Common Mode Range
Input Impedance
Stage Gain LX1720-01 Set by Internal Resistors
= -250µA
OUT
= +250µA
OUT
Current Limit Comparators
Voltage Sense Threshold
Comparator Response Time
PWM Comparators
CPWM Delay To Output 250 nsec
PWM Current Generator
CPWM Charge Current RPWM = 75k
Impedance of Internal Discharge FET
LX1720
Min. Typ. Max.
280 330 380 kHz
2.5 V
200 mV
1MHz
12%
2%
5mV
60 dB
7MHz
4V
15V
3.465 3.5 3.535 V/V
42 kΩ
4V
70 dB
0V
388 kΩ
89 91 93 mV/V
200 220 240 mV
500 nsec
75 µA
20 Ω
LX1720
Units
50 mV
1µA
50 mV
DD
V
Output Drivers For The N-Channel MOSFETs
Ext. NFET Drivers, Low Level Voltage V
Ext. NFET Drivers, High Level Voltage V
Output Drivers For The P-Channel MOSFETs
Ext. PFET Drivers, Low Level Voltage V
Ext. PFET Drivers, High Level Voltage V
Copyright © 1999
Rev. 1.0 9/99
OLISINK
I
SINK
OHISOURCE
I
SOURCE
OLISINK
I
SINK
OHISOURCE
I
SOURCE
= 3mA
= 75mA
= 3mA
= 75mA, CN = 5.2V (applied externally)
= 3mA
= 75mA
= 3mA
= 75mA, CP = 5.2V (applied externally)
30 100 mV
11.5 V
30 100 mV
11.5 V
30 100 mV
11.5 V
30 100 mV
11.5 V
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LX1720
PRODUCT DATABOOK 1996/1997
TM
AudioMAX
SWITCHING CLASS-D, STEREO POWER AMPLIFIER CONTROLLER IC
P RODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS (Continued)
Parameter
Undervoltage Lockout Section
Start Threshold Voltage
UV Lockout Hysteresis
UVLO Delay To Output Enable
Supply Current
Sleep Current SLEEP Input = 0V, TA = 25°C
Operating Current SLEEP Input = 2V, VIN = 15V, No MOSFETs Connected
Sleep To Output Enable
Sleep Threshold
Mute Section
Mute Threshold 1.6 1.7 1.8 V
Symbol
Test Conditions Units
LX1720
Min. Typ. Max.
6.3 6.5 6.7 V
500 mV
976 clkcyc
20 µA
57mA
976 clkcyc
1.2 1.45 1.6 V
4
Copyright © 1999
Rev. 1.0 9/99
Page 5
AudioMAX
PRODUCT DATABOOK 1996/1997
TM
LX1720
SWITCHING CLASS-D, STEREO POWER AMPLIFIER CONTROLLER IC
P RODUCTION DATA SHEET
BLOCK DIAGRAM
RT
CT
SLEEP
RBIAS
VDD
CN
EAOUT (R)
EAIN (R)
FBK+ (R)
FBK- (R)
FAO U T (R)
IN P U T (R )
MUTE (R)
RPW M
CPW M
VDD
UVLO
VREF
BIAS
Feedback
Am p
Input Am p
OSC
CLK
E rro r A m p
VDD
CLK
CLK
PGND
PVDD
V
REG
S
Q
Q
R
OUTPUT
CP
P- (R)
N- (R)
P+ (R)
N+ (R)
DRIVERS
AND
PRO TECTIO N
CIRCUITRY
S
Q
P- (L)
N- (L)
P+ (L)
EAOUT (L)
EAIN (L)
FBK+ (L)
FBK- (L)
FAO U T (L)
IN P U T (L )
MUTE (L)
Copyright © 1999
Rev. 1.0 9/99
Feedback
Am p
Input Am p
E rro r A m p
CLK
FIGURE 1 — LX1720 Block Diagram
Q
R
IS +
LIS -
RIS-
N+ (L)
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LX1720
VIN = 7 V T O 1 5 V
PRODUCT DATABOOK 1996/1997
SWITCHING CLASS-D, STEREO POWER AMPLIFIER CONTROLLER IC
P RODUCTION DATA SHEET
TYPICAL APPLICATION
R
6
R
5
TM
AudioMAX
C
19
RIGHT IN
LEFT IN
SLEEP
RMUTE
LM U TE
C
C
17C16
18
PVDD
RIS-LIS-IS +
P- (R )
Q
1
L
1
L
2
VDD
C
C
C
24
25
R
PW M
R
C
20
R
C
21
R
8
C
22
R
C
23
R
10
FBK- (R)
FBK+ (R)
FBK- (L)
FBK+ (L)
P
T
7
9
CP
RPW M
RT
IN P U T (R )
IN P U T (L )
SLEEP
RMUTE
LM U TE
EAO UT (R)
EAIN (R)
FAO U T (R )
EAO UT (L)
E A IN (L )
FAO U T (L)
FBK- (R )
FBK+ (R )
FBK- (L)
FBK+ (L)
LX 1720
N- (R)
P+ (R)
N+ (R)
P- (L)
N- (L)
P+ (L)
N+ (L)
AGND
Q
2
R
1
C
1
C
2
FBK-(R )
C
9
Q
3
Q
4
L
3
R
2
L
4
C
3
C
4
RIGHTLEFT
FBK+(R )
C
10
Q
5
Q
6
L
5
R
3
L
6
C
5
C
6
FBK-(L)
C
11
Q
7
Q
8
L7 L8
R
4
C
7
C
8
FBK+(L)
C
12
CT
CN
CPW M
PGND
GND
For detailed application
information please refer to
APPLICATION NOTE AN-11
PW M
C
N
T
C
C
FIGURE 2 — Typical Class-D Stereo Switching Amplifier Circuit Application
PRODUCTION DATA - Information contained in this document is proprietary to LinFinity, and is current as of publication date. This document
may not be modified in any way without the express written consent of LinFinity. Product processing does not necessarily include testing of
all parameters. Linfinity reserves the right to change the configuration and performance of the product and to discontinue product at any time.
6
available on our web site
or call 1-800-LMI-7011
Copyright © 1999
Rev. 1.0 9/99
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