D E S C R I P T I O N

K E Y F E A T U R E S

s Integrated Switching (Class-D) Stereo

Power Amplifier Controller IC

s Delivers >10W

RMS

Across 8

/Channel

(20W

RMS

stereo)

s Output Power Limited Only By External

FETs And Available Supply Voltage

s Will Drive A Wide Range Of Speakers
s

s High Efficiency (>92%)
s

s Due To High Efficiency, Power FETs Do Not

Require Heatsinking

s Audio Bandwidth Of 20Hz to 20kHz
s

s Wide Input Voltage Range Of 7V-15V
s

s Low Output Signal Distortion <1%
s

s High Operating Frequency (350kHz) Helps

To Reduce Output Filter Size

s Compact Design Minimizes EMI / RFI

The LX1720 is a highly-integrated,
Switching Class-D Stereo Power Am-
plifier Controller IC with power and
size features that make it ideal for multi-
media computer applications, as well as
other applications where high fidelity
sound is required.

With input voltage ranging from 7V-

15V, 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).

P R O D U C T H I G H L I G H T

WITCHING

LASS

-D, S

TEREO

OWER

MPLIFIER

ONTROLLER

R O D U C T I O N

A T A

H E E T

H E

N F I N I T E

O W E R

O F

N N O V A T I O N

LX1720

Its high efficiency (>92%) eliminates the
need for heat sinks -- even while deliv-
ering more than 10W

RMS

across 8 ohms

per channel (20W

RMS

stereo) with 0.1 ohm

SO-8 power FETs.

The LX1720's output power is limited

only by external FETs and available sup-
ply voltage.

While offering breakthrough perfor-

mance capabilities for notebooks, the
LX1720 is equally attractive for multime-
dia systems or to drive full-size home
theatre speakers.

Rev. 1.0 9/99

11861 W

ESTERN

VENUE

, G

ARDEN

ROVE

, CA. 92841, 714-898-8121, F

: 714-893-2570

I N

I N I T Y

I C R O E L E C T R O N I C S

N C

APPLICATIONS / BENEFITS

Notebook Computers:

s Replaces existing internal low power linear

amplifier with a high efficiency Class-D
amplifier

s Enables the use of virtually any external

speaker without amplification

s Precious battery life is extended
s

s Fully protected power topology can

withstand shorts or external speaker
failures without damage, overheating or
posing fire hazard

Desktop Computers:

s Output power capability of up to 20W

RMS

per channel in an area less than 3"x3",
without using expensive heatsinks

s Greatly reduced power supply

requirements when compared to a linear
solution of same power capabilities

s Any speakers can be used including

conventional home stereo speakers

s Very light weight circuitry will not add to

the overall weight of the system

s Multimedia amplifier can be directly

incorporated on the motherboard using
surface mount components

0 to 70

15V

LX1720-01CDB

PA C K A G E O R D E R I N F O

(°C)

Plastic SSOP
44-pin

Note: Available in Tape & Reel.

Append the letter "T" to part number. (i.e. LX1720-01CDBT)

Seconds

Efficiency (%)

100

Highly Integrated

Linear Amplifier

Linfinity's LX1720

Class-D Amplifier

- Average Power Out for 20sec. approx. 512mW
- Across 8.6 Ohm Load

Audio sample from "Hold On Tight"
by Electric Light Orchestra

F F I C I E N C Y

O M PA R I S O N

O F

T H E

L A S S

-D A

M P L F I E R

Maximum

VDD

IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.

APPLICATION NOTE AN-11

available on our web site

or call 1-800-LMI-7011

AudioMAX

WITCHING

LASS

-D, S

TEREO

OWER

MPLIFIER

ONTROLLER

LX1720

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

Rev. 1.0 9/99

R O D U C T I O N

A T A

H E E T

AudioMAX

A B S O L U T E M A X I M U M R A T I N G S

(Note 1)

Supply Voltage (PVDD, VDD) ...................................................................... -0.3V to 18V
RPWM .................................................................................................... -0.3V to V

+0.3V

INPUT (R), INPUT (L) .......................................................................... -0.3V to V

+0.3V

FBK+(R), FBK-(R), FBK+(L), FBK-(L), SLEEP .............................................. -0.3V to V

MUTE (R), MUTE (L) .................................................................................... -0.3V to 6.0V
EAOUT (R), EAOUT (L) ....................................................................... -0.3V to V

+0.3V

CPWM, CT ............................................................................................. -0.3V to V

+0.3V

IS+, LIS-, RIS+ ................................................................................................ V

-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

PACKAGE PIN OUTS

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.

DB PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

65°C/W

Junction Temperature Calculation: T

= T

+ (P

The

numbers are guidelines for the thermal performance of the device/pc-board

system. All of the above assume no ambient airflow.

T H E R M A L D A TA

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)

RIS-

LIS-

IS+

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)

RIS-

LIS-

IS+

RPWM
CPWM

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

F U N C T I O N A L P I N D E S C R I P T I O N

FAOUT (R)

EAOUT (L)

EAIN (L)

FAOUT (L)

FBK+(R), FBK-(R)

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)

Pin Name

Description

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

WITCHING

LASS

-D, S

TEREO

OWER

MPLIFIER

ONTROLLER

LX1720

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

Rev. 1.0 9/99

R O D U C T I O N

A T A

H E E T

AudioMAX

E L E C T R I C A L C H A R A C T E R I S T I C S

(Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C

70°C.

Test conditions: RT = 30k, CT = 100pF, VDD = PVDD = 15V.)

Parameter

Symbol

Test Conditions

Input Offset Voltage

DC Open Loop Gain

Unity Gain Bandwidth

High Output Voltage

OUT

= -100µA

Low Output Voltage

OUT

= +100µA

Input Common Mode Range

Input Bias Current

Oscillator Section

Oscillator Frequency

Oscillator Peak Voltage

Oscillator Valley Voltage

Oscillator Max. Frequency

Voltage Stability

Temperature Stability

Input Amplifiers

Stage Gain

Set by Internal Resistors

Input Impedance

Units

LX1720

Min.

Typ.

Max.

280

330

380

kHz

2.5

200

MHz

µA

3.465

3.5

3.535

V/V

Error Amplifiers

Current Limit Comparators

Voltage Sense Threshold

Comparator Response Time

200

220

240

500

nsec

PWM Comparators

CPWM Delay To Output

250

nsec

PWM Current Generator

CPWM Charge Current

RPWM = 75k

Impedance of Internal Discharge FET

µA

Feedback Amplifiers

High Output Voltage

OUT

= -250µA

Low Output Voltage

OUT

= +250µA

Common Mode Rejection

Input Common Mode Range

Input Impedance

Stage Gain

LX1720-01

Set by Internal Resistors

388

mV/V

Output Drivers For The N-Channel MOSFETs

Ext. NFET Drivers, Low Level Voltage

SINK

= 3mA

SINK

= 75mA

Ext. NFET Drivers, High Level Voltage

SOURCE

= 3mA

SOURCE

= 75mA, CN = 5.2V (applied externally)

100

1.5

100

1.5

Output Drivers For The P-Channel MOSFETs

Ext. PFET Drivers, Low Level Voltage

SINK

= 3mA

SINK

= 75mA

Ext. PFET Drivers, High Level Voltage

SOURCE

= 3mA

SOURCE

= 75mA, CP = 5.2V (applied externally)

100

1.5

100

1.5

WITCHING

LASS

-D, S

TEREO

OWER

MPLIFIER

ONTROLLER

LX1720

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

Rev. 1.0 9/99

R O D U C T I O N

A T A

H E E T

AudioMAX

E L E C T R I C A L C H A R A C T E R I S T I C S

(Continued)

Parameter

Symbol

Test Conditions

Units

LX1720

Min.

Typ.

Max.

Undervoltage Lockout Section

Start Threshold Voltage

UV Lockout Hysteresis

UVLO Delay To Output Enable

6.3

6.5

6.7

500

976

clkcyc

Supply Current

Sleep Current

SLEEP Input = 0V, T

= 25°C

Operating Current

SLEEP Input = 2V, V

= 15V, No MOSFETs Connected

Sleep To Output Enable

Sleep Threshold

µA

976

clkcyc

1.2

1.45

1.6

Mute Section

Mute Threshold

1.6

1.7

1.8

WITCHING

LASS

-D, S

TEREO

OWER

MPLIFIER

ONTROLLER

LX1720

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

Rev. 1.0 9/99

R O D U C T I O N

A T A

H E E T

AudioMAX

B L O C K D I A G R A M

U V L O

V R E F

B I A S

O S C

C T

P - ( R )

N - ( R )

P + ( R )

N + ( R )

C L K

O U T P U T

D R I V E R S

A N D

P R O T E C T I O N

C I R C U I T R Y

C N

V D D

E r r o r A m p

P - ( L )

N - ( L )

P + ( L )

N + ( L )

V D D

S L E E P

R P W M

C P W M

I N P U T ( L )

F B K + ( L )

F B K - ( L )

E A O U T ( L )

P V D D

P G N D

C L K

V D D

R T

C P

R E G

F A O U T ( L )

E A I N ( L )

R B I A S

F e e d b a c k

A m p

M U T E ( L )

I n p u t A m p

E r r o r A m p

I N P U T ( R )

F B K + ( R )

F B K - ( R )

E A O U T ( R )

F A O U T ( R )

E A I N ( R )

F e e d b a c k

A m p

M U T E ( R )

I n p u t A m p

FIGURE 1 -- LX1720 Block Diagram

WITCHING

LASS

-D, S

TEREO

OWER

MPLIFIER

ONTROLLER

LX1720

P R O D U C T D A T A B O O K 1 9 9 6 / 1 9 9 7

Rev. 1.0 9/99

R O D U C T I O N

A T A

H E E T

AudioMAX

T Y P I C A L A P P L I C A T I O N

1 7

1 6

I N

= 7 V T O 1 5 V

F B K - ( R )

F B K + ( R )

1 0

F B K - ( L )

1 1

L 7

L 8

F B K + ( L )

1 2

A G N D

1 8

1 9

F B K - ( R )
F B K + ( R )
F B K - ( L )
F B K + ( L )

F B K - ( R )

2 0

2 1

F A O U T ( R )

S L E E P

I N P U T ( L )

I N P U T ( R )

S L E E P

L E F T I N

R I G H T I N

2 4

2 5

R I S -

L I S -

I S +

L
X

1720

P - ( R )

N - ( R )

P + ( R )

N + ( R )

P - ( L )

P + ( L )

N + ( L )

N - ( L )

P V D D
V D D

R P W M

P W M

C P

R T

R M U T E

L M U T E

R M U T E

L M U T E

E A O U T ( R )

2 2

2 3

F A O U T ( L )

E A O U T ( L )

1 0

E A I N ( R )

E A I N ( L )

F B K + ( R )

F B K - ( L )

F B K + ( L )

FIGURE 2 -- Typical Class-D Stereo Switching Amplifier Circuit Application

For detailed application

information please refer to

APPLICATION NOTE AN-11

available on our web site

or call 1-800-LMI-7011

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.

Ð­Ð»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LX1720-01CDB

ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: LX1720-01CDB