Rainbow Electronics MAX9768 User Manual

General Description

The MAX9768 mono 10W Class D speaker amplifier provides high-quality, efficient audio power with an integrated volume control function.

The MAX9768 features a 64-step dual-mode (analog or digitally programmable) volume control and mute function. The audio amplifier operates from a 4.5V to 14V single supply and can deliver up to 10W into an 8Ω speaker with a 14V supply.

A selectable spread-spectrum mode reduces EMI-radiated emissions, allowing the device to pass EMC testing with ferrite bead filters and cable lengths up to 1m. The MAX9768 can be synchronized to an external clock, allowing synchronization of multiple Class D amplifiers.

The MAX9768 features high 77dB PSRR, low 0.08% THD+N, and SNR up to 97dB. Robust short-circuit and thermal-overload protection prevent device damage during a fault condition. The MAX9768 is available in a 24-pin thin QFN-EP (4mm x 4mm x 0.8mm) package and is specified over the extended -40°C to +85°C temperature range.

Applications

Features

♦ 10W Output (8Ω, PVDD= 14V, THD+N = 10%)

♦ Patented Spread-Spectrum Modulation

♦ Meets EN55022B EMC with Ferrite Bead Filters

♦ Amplifier Operation from 4.5V to 14V Supply

♦ 64-Step Integrated Volume Control (I

2

C or Analog)

♦ Low 0.08% THD+N (R

L

= 8Ω, P

OUT

= 6W)

♦ High 77dB PSRR

♦ Two t

ON

Times Offered MAX9768—220ms MAX9768B—15ms

♦ Low-Power Shutdown Mode (0.5µA)

♦ Short-Circuit and Thermal-Overload Protection

MAX9768

10W Mono Class D Speaker

Amplifier with Volume Control

________________________________________________________________

Maxim Integrated Products

1

19-0854; Rev 0; 9/07

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

Pin Configuration located at end of data sheet.

Ordering Information

Note: All devices are specified over the -40°C to +85°C operating temperature range.

+

Denotes lead-free package.

*

EP = Exposed pad.

Simplified Block Diagram

Notebook Computers

Flat-Panel Displays

Multimedia Monitors

GPS Navigation Systems

Security/Personal Mobile Radio

PART PIN-PACKAGE tON (ms)

MAX9768ETG+ 24 TQFN-EP* 220 T2444+4

MAX9768BETG+ 24 TQFN-EP* 15 T2444+4

PKG

CODE

3.3V 4.5V TO 14V

SPEAKER

AUDIO

INPUT

SHDN

MUTE

ANALOG OR

2

C VOLUME

I

CONTROL

MAX9768

FILTERLESS CLASS D SPEAKER OUTPUT

MAX9768 EMI WITH FERRITE BEAD FILTERS

40

35

30

25

20

15

AMPLITUDE (dBμV/m)

10

5

0

= 12V, 1m CABLE, 8Ω LOAD)

(V

DD

OVER 20dB MARGIN TO EN55022B LIMIT

0 1000

FREQUENCY (MHz)

800100 200 300 500 600400 700

900

MAX9768

10W Mono Class D Speaker Amplifier with Volume Control

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(PVDD= 12V, VDD= 3.3V, GND = PGND = 0V, V

SHDN

= VDD, V

MUTE

= 0V; Max volume setting; speaker load resistor connected

between OUT+ and OUT-, R

L

= ∞, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RF= 30kΩ,

SSM mode. Filterless modulation mode (see the

Functional Diagram/Typical Application Circuit

). TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.) (Note 1)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

PVDDto PGND........................................................-0.3V to +16V

V

DD

to GND..............................................................-0.3V to +4V

SCLK, SDA/VOL to GND ..........................................-0.3V to +4V

FB, SYNCOUT ............................................-0.3V to (V

DD

+ 0.3V)

BOOT_ to OUT_........................................................-0.3V to +4V

OUT_ to GND ...........................................-0.3V to (PV

DD

+ 0.3V)

PGND to GND ......................................................-0.3V to +0.3V

Any Other Pin to GND ..............................................-0.3V to +4V

OUT_ Short-Circuit Duration.......................................Continuous

Continuous Current (PV

DD

, PGND, OUT_) ..........................2.2A

Continuous Input Current (Any Other Pin) .......................±20mA

Continuous Input Current (FB_) .......................................±60mA

Continuous Power Dissipation (T

A

= +70°C)

Single-Layer Board:

24-Pin Thin QFN 4mm x 4mm,

(derate 20.8mW/°C above +70°C).................................1.67W

Multilayer Board:

24-Pin Thin QFN 4mm x 4mm,

(derate 27.8mW/°C above +70°C).................................2.22W

θ

JA

, Single-Layer Board…...........................................….48°C/W

θ

JA

, Multilayer Board ...................................................….36°C/W

Operating Temperature Range ...........................-40°C to +85°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) ................................+300°C

,

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

GENERAL

Speaker Supply Voltage Range

Supply Voltage Range V

Shutdown Current I

Output Offset V

Turn-On Time t

Common-Mode Bias Voltage V

Input Amplifier OutputVoltage Swing High

Input Amplifier OutputVoltage Swing Low

Input Amplifier Output Short-Circuit Current Limit

Input Amplifier GainBandwidth Product

SPEAKER AMPLIFIERS

Internal Gain A

PV

I

VDD

I

PVDD

SHDNISHDN

ON

BIAS

V

GBW 1.8 MHz

VMAX

Inferred from PSRR test 4.5 14.0 V

DD

Inferred from PSRR and UVLO test 2.7 3.6 V

DD

Filterless modulation 4 7.6Quiescent Current

Classic PWM modulation 4 7.6

Filterless modulation, V

OS

Filterless modulation, V

MAX9768 220

MAX9768B 15

Specified as

OH

V

DD

Specified as

OL

V

OL

Max volume setting; from FB to amplifier outputs |(OUT+) - (OUT-)|; excludes external gain resistors

= I

- V

OH

- GND

+ IDD, SHDN = GND 0.5 50 µA

PVDD

= V

MUTE

= 0V, TA = +25°C ±2 ±14

MUTE

RL = 2kΩ connect to 1.5V 3.6 100 mV

R

= 2kΩ connect to 1.5V 6 50 mV

L

= +25°C ±2 ±12.5

T

DD

A

29.27 30.1 31.00 dB

714.2

1.5 V

±60 mA

mA

mV

ms

MAX9768

10W Mono Class D Speaker

Amplifier with Volume Control

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(PVDD= 12V, VDD= 3.3V, GND = PGND = 0V, V

SHDN

= VDD, V

MUTE

= 0V; Max volume setting; speaker load resistor connected

between OUT+ and OUT-, R

L

= ∞, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RF= 30kΩ,

SSM mode. Filterless modulation mode (see the

Functional Diagram/Typical Application Circuit

). TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Efficiency (Note 2) η

Output Power (Note 2) P

Soft Output Current Limit I

Hard Output Current Limit I

Total Harmonic Distortion Plus Noise (Note 2)

Signal-to-Noise Ratio (Note 2)

MUTE Attenuation (Note 3) 0dB = 8W, f = 1kHz 115 dB

Power-Supply Rejection Ratio

Oscillator Frequency f

P

OUT

1kHz, R

PVDD = 5V

OUT

LIM

SC

THD+N

SNR

PSRR

OCS

PVDD = 12V

PVDD = 14V

f = 1kHz, RL = 8Ω, P

OUT

0dB = 8W, RL = 8Ω, BW = 22Hz to 22kHz, filterless modulation mode

0dB = 8W, R 8Ω, BW = 22Hz to 22kHz, classic PWM modulation

VDD = 2.7V to 3.6V, filterless modulation T

= +25°C

A

PVDD = 4.5V to 14V, filterless modulation T

= +25°C

A

f = 1kHz, V

SYNC = GND 1060 1200 1320

SYNC = unconnected 1296 1440 1584

SYNC = VDD (spread-spectrum modulation mode)

= 8W, fIN =

= 8Ω

L

= 5W

=

L

RIPPLE

Filterless modulation 87

Classic PWM modulation 85

RL = 8Ω, THD+N = 1%, filterless modulation

= 8Ω, THD+N = 10%,

R

L

filterless modulation

RL = 8Ω, THD+N = 10%, classic PWM modulation

= 8Ω, THD+N = 10%,

R

L

filterless modulation

RL = 8Ω, THD+N = 10%, classic PWM modulation

R

= 8Ω, THD+N = 10%,

L

filterless modulation

Filterless modulation 0.09

Classic PWM modulation 0.08

Unweighted

A-weighted

Unweighted

A-weighted

= 200mV

= 100mV

P-P

FFM 94

SSM 93

FFM 97

SSM 97

FFM 93

SSM 89

FFM 97

SSM 91

,

on PV

DD

on V

DD

1.75 2 A

52 68

67 84

1200

1.3

1.7

9

10

2.5 A

77

60

±30

%

W

%

dB

kHz

MAX9768

10W Mono Class D Speaker Amplifier with Volume Control

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(PVDD= 12V, VDD= 3.3V, GND = PGND = 0V, V

SHDN

= VDD, V

MUTE

= 0V; Max volume setting; speaker load resistor connected

between OUT+ and OUT-, R

L

= ∞, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RF= 30kΩ,

SSM mode. Filterless modulation mode (see the

Functional Diagram/Typical Application Circuit

). TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Class D Switching Frequency

SYNC Frequency Lock Range

Minimum SYNC Frequency Lock Duty Cycle

Maximum SYNC Frequency Lock Duty Cycle

Gain Matching Full volume (ideal matching for RIN and RF)2%

Click-and-Pop Level (Note 2) K

Input Impedance DC volume control mode (SDA/VOL) 100 MΩ

Input Hysteresis DC volume control mode (SDA/VOL) 11 mV

9.5dB Gain Voltage DC volume control mode (SDA/VOL) 0.1 x V

Full Mute Voltage DC volume control mode (SDA/VOL) 0.9 x V

DIGITAL INPUTS (SHDN, MUTE, ADDR1, ADDR2, SYNC)

Input-Voltage High V

Input-Voltage Low V

Input Leakage Current

DIGITAL OUTPUT (SYNCOUT)

Output-Voltage High Load = 1mA VDD - 0.3 V

Output-Voltage Low Load = 1mA 0.3 V

Rise/Fall Time CL = 10pF 5 ns

SYNC = GND 265 300 330

SYNC = unconnected 324 360 396

SYNC = V mode)

Peak voltage, 32 samples per second, A-weighted, R

CP

x C

IN

clickless/popless operation

SYNC 2.33

IH

All other pins 0.7 x V

SYNC 0.8

IL

All other pins 0.3 x V

I

SYNC

I

All other digital inputs ±1

LK

(spread-spectrum modulation

DD

≤ 10ms to guarantee

IN

1000 1600 kHz

Into shutdown 52.6

Out of shutdown 48

Into mute 67

Out of mute 57

300

±7.5

DD

±7.5 ±13

40 %

60 %

DD

kHz

dBV

V

DD

µA

MAX9768

10W Mono Class D Speaker

Amplifier with Volume Control

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(PVDD= 12V, VDD= 3.3V, GND = PGND = 0V, V

SHDN

= VDD, V

MUTE

= 0V; Max volume setting; speaker load resistor connected

between OUT+ and OUT-, R

L

= ∞, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RF= 30kΩ,

SSM mode. Filterless modulation mode (see the

Functional Diagram/Typical Application Circuit

). TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

THERMAL PROTECTION

Thermal Shutdown Threshold

Thermal Shutdown Hysteresis

DIGITAL INPUTS (SCLK, SDA/VOL)

Input-Voltage High V

Input-Voltage Low V

Input High Leakage Current I

Input Low Leakage Current I

Input Hysteresis 0.1 x V

Input Capacitance C

DIGITAL OUTPUTS (SDA/VOL)

Output High Current I

Output Low Voltage V

I2C TIMING CHARACTERISTICS (Figure 3)

Serial Clock f

Bus Free Time Between a STOP and START Condition

IH

IL

VIN = V

IH

VIN = GND ±1 µA

IL

IN

OH

SCL

t

BUF

VOH = V

IOL = 3mA 0.4 V

OL

DD

0.7 x V

DD

1.3 µs

150 °C

15 °C

V

0.3 x V

DD

±1 µA

DD

5pF

1µA

400 kHz

V

Hold Time (Repeated) START Condition

Repeated START Condition Setup Time

STOP Condition Setup Time t

Data Hold Time t

Data Setup Time t

SCL Clock Low Period t

SCL Clock High Period t

Rise Time of SDA and SCL, Receiving

Fall Time of SDA and SCL, Receiving

t

HD,STA

t

SU,STA

SU,STO

HD,DAT

SU,DAT

LOW

HIGH

t

R

t

F

(Note 4)

0.6 µs

00.9µs

100 ns

1.3 µs

0.6 µs

20 +

0.1Cb

20 +

0.1Cb

300 ns

MAX9768

10W Mono Class D Speaker Amplifier with Volume Control

6 _______________________________________________________________________________________

Note 1: All devices are 100% production tested at TA= +25°C. All temperature limits are guaranteed by design. Note 2: Testing performed with a resistive load in series with an inductor to simulate an actual speaker load. For R

L

= 8Ω, L = 68µH.

Note 3: Device muted by either asserting MUTE or minimum V

OL

setting.

Note 4: C

b

= total capacitance of one bus line in pF.

ELECTRICAL CHARACTERISTICS (continued)

(PVDD= 12V, VDD= 3.3V, GND = PGND = 0V, V

SHDN

= VDD, V

MUTE

= 0V; Max volume setting; speaker load resistor connected

between OUT+ and OUT-, R

L

= ∞, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RF= 30kΩ,

SSM mode. Filterless modulation mode (see the

Functional Diagram/Typical Application Circuit

). TA= T

MIN

to T

MAX

, unless otherwise

noted. Typical values are at T

A

= +25°C.) (Note 1)

Typical Operating Characteristics

(PVDD= 12V, VDD= 3.3V = GND = PGND = 0V, V

MUTE

= 0V; 0dB volume setting; all speaker load resistors connected between

OUT+ and OUT-, R

L

= 8Ω, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RFB= 30kΩ,

spread-spectrum modulation mode.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Fall Time of SDA, Transmitting

Pulse Width of Spike Suppressed

Capacitive Load for Each Bus Line

t

SP

C

(Note 4)

F

b

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

PVDD = 12V

Ω

= 8

R

L

FILTERLESS MODULATION

1

THD+N (%)

0.1

OUTPUT POWER = 6W

MAX9768 toc01

THD+N (%)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

PVDD = 12V

Ω

= 8

R

L

PWM MODE

1

OUTPUT POWER = 5W

0.1

20 +

0.1Cb

050ns

TOTAL HARMONIC DISTORTION

10

PVDD = 5V

= 8

R

L

MAX9768 toc02

FILTERLESS MODULATION

1

0.1

THD+N (%)

OUTPUT POWER = 300mW

0.01

OUTPUT POWER = 1W

250 ns

400 pF

PLUS NOISE vs. FREQUENCY

Ω

MAX9768 toc03

OUTPUT POWER = 2W

0.01 10 100k

FREQUENCY (Hz)

10k1k100

0.01 10 100k

OUTPUT POWER = 2W

FREQUENCY (Hz)

0.001

10k1k100

10 100k

10k1k100

FREQUENCY (Hz)

MAX9768

10W Mono Class D Speaker

Amplifier with Volume Control

_______________________________________________________________________________________

7

Typical Operating Characteristics (continued)

(PVDD= 12V, VDD= 3.3V = GND = PGND = 0V, V

MUTE

= 0V; 0dB volume setting; all speaker load resistors connected between

OUT+ and OUT-, R

L

= 8Ω, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RFB= 30kΩ,

spread-spectrum modulation mode.)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

PVDD = 5V

Ω

= 8

R

L

PWM MODE

1

OUTPUT POWER = 300mW

0.1

THD+N (%)

0.01 OUTPUT POWER = 800mW

0.001 10 100k

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

PVDD = 12V

Ω

= 8

R

L

FILTERLESS MODULATION

10

1

MAX9768 toc04

10k1k100

FREQUENCY (Hz)

MAX9768 toc07

fIN = 10kHz

10

1

0.1

THD+N (%)

0.01

0.001

100

10

1

PVDD = 12V R FILTERLESS MODULATION

P

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

Ω

= 8

L

= 4W

OUT

FIXED-FREQUENCY MODULATION

SPREAD-SPECTRUM MODULATION

10k1k10010 100k

FREQUENCY (Hz)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

PVDD = 12V

Ω

= 8

R

L

PWM MODE

fIN = 10kHz

MAX9768 toc05

THD+N (%)

0.001

MAX9768 toc08

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

= 12V

PV

DD

Ω

= 8

R

L

PWM MODE

1

= 4W

P

OUT

FIXED-FREQUENCY

0.1

0.01

MODULATION

SPREAD-SPECTRUM MODULATION

FREQUENCY (Hz)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

PVDD = 5V

Ω

= 8

R

L

FILTERLESS MODULATION

10

1

fIN = 10kHz

MAX9768 toc06

10k1k10010 100k

MAX9768 toc09

THD+N (%)

0.1

0.01 fIN = 100Hz

0.001 012

fIN = 1kHz

108462

OUTPUT POWER (W)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

PVDD = 5V

Ω

= 8

R

L

PWM MODE

10

0

fIN = 10kHz

fIN = 100Hz

fIN = 1kHz

OUTPUT POWER (W)

1

THD+N (%)

0.1

0.01

0.001

2.00.8 1.2 1.60.4

MAX9768 toc10

THD+N (%)

0.1

0.01 fIN = 100Hz

0.001 0

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

PV

DD

= 8

R

L

f

= 1kHz

IN

10

FILTERLESS MODULATION

1

THD+N (%)

0.1

0.01 0

= 12V

Ω

FIXED-FREQUENCY MODULATION

fIN = 1kHz

OUTPUT POWER (W)

SPREAD-SPECTRUM MODULATION

OUTPUT POWER (W)

108462

MAX9768 toc11

104682

THD+N (%)

0.1

0.01

0.001 0

100

10

1

THD+N (%)

0.1

0.01 0

fIN = 100Hz

fIN = 1kHz

OUTPUT POWER (W)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

PVDD = 12V

Ω

= 8

R

L

f

= 1kHz

IN

PWM MODE

FIXED-FREQUENCY MODULATION

SPREAD-SPECTRUM MODULATION

OUTPUT POWER (W)

2.01.0 1.50.5

MAX9768 toc12

104682

MAX9768

10W Mono Class D Speaker Amplifier with Volume Control

8 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(PVDD= 12V, VDD= 3.3V = GND = PGND = 0V, V

MUTE

= 0V; 0dB volume setting; all speaker load resistors connected between

OUT+ and OUT-, R

L

= 8Ω, unless otherwise noted. C

BIAS

= 2.2µF, C1 = C2 = 0.1µF, CIN= 0.47µF, RIN= 20kΩ, RFB= 30kΩ,

spread-spectrum modulation mode.)

CASE TEMPERATURE vs. OUTPUT POWER

MAX9768 toc21

OUTPUT POWER (W)

CASE TEMPERATURE (°C)

1246 1082

10

30

20

40

50

70

60

90

80

0

fIN = 1kHz R

L

= 8

Ω

PVDD = 14V

PVDD = 12V

EFFICIENCY vs. OUTPUT POWER

100

0

FILTERLESS MODULATION

PWM MODE

OUTPUT POWER (W)

PVDD = 12V

= 1kHz

f

IN

Ω

= 8

R

L

104682

90

80

70

60

50

40

EFFICIENCY (%)

30

20

10

0

MAX9768 toc13

100

90

80

70

60

50

40

EFFICIENCY (%)

30

20

10

0

EFFICIENCY vs. OUTPUT POWER

FILTERLESS MODULATION

PWM MODE

0

OUTPUT POWER (W)

PVDD = 5V

= 1kHz

f

IN

Ω

= 8

R

L

2.01.0 1.50.5

MAX9768 toc14

EFFICIENCY vs. SUPPLY VOLTAGE

95

fIN = 1kHz

Ω

= 8

R

L

FILTERLESS MODULATION

92

89

86

EFFICIENCY (%)

83

80

4.5

THD+N = 10%

THD+N = 1%

SUPPLY VOLTAGE (V)

MAX9768 toc15

14.58.5 10.5 12.56.5

EFFICIENCY vs. SUPPLY VOLTAGE

95

fIN = 1kHz

Ω

= 8

R

L

PWM MODULATION

92

89

86

EFFICIENCY (%)

83

80

4.5

OUTPUT POWER vs. LOAD RESISTANCE

12

10

8

6

4

OUTPUT POWER (W)

2

0

THD+N = 1%

0

THD+N = 10%

THD+N = 1%

SUPPLY VOLTAGE (V)

THD+N = 10%

LOAD RESISTANCE (Ω)

PVDD = 12V

f = 1kHz

PWM MODE

MAX9768 toc16

14.58.5 10.5 12.56.5

MAX9768 toc19

3010 15 25205

OUTPUT POWER vs. SUPPLY VOLTAGE

14

Ω

RL = 8

= 1kHz

f

IN

12

PWM MODE

10

8

6

OUTPUT POWER (W)

4

2

0

4

THD+N = 10%

SUPPLY VOLTAGE (V)

OUTPUT POWER vs. LOAD RESISTANCE

3.5

3.0

2.5

2.0

1.5

OUTPUT POWER (W)

1.0

0.5

0

THD+N = 10%

THD+N = 1%

LOAD RESISTANCE (Ω)

THD+N = 1%

PVDD = 5V

f = 1kHz

PWM MODE

MAX9768 toc17

14810126

MAX9768 toc20

3010 15 25205

OUTPUT POWER vs. SUPPLY VOLTAGE

12

Ω

RL = 4 f

= 1kHz

IN

10

PWM MODE

THD+N = 10%

8

6

4

OUTPUT POWER (W)

2

0

4

THD+N = 1%

SUPPLY VOLTAGE (V)

MAX9768 toc18

14810126