MAXIM MAX9701 Technical data

General Description

The MAX9701 stereo Class D audio power amplifier pro­vides Class AB amplifier audio performance with the
benefits of Class D efficiency, eliminating the need for a
heatsink while extending battery life. The MAX9701
delivers up to 1.3W per channel into an 8Ω load while
offering 87% efficiency. Maxim’s next-generation, low­EMI modulation scheme allows the amplifier to operate
without an external LC filter while still meeting FCC EMI
emission levels.

The MAX9701 offers two modulation schemes: a fixed-fre­quency (FFM) mode, and a spread-spectrum (SSM)
mode that reduces EMI-radiated emissions. The
MAX9701 oscillator can be synchronized to an external
clock through the SYNC input, allowing synchronization of
multiple Maxim Class D amplifiers. The sync output
(SYNC_OUT) can be used for a master-slave application
where more channels are required. The MAX9701 fea­tures a fully differential architecture, a full bridge-tied load
(BTL) output, and comprehensive click-and-pop suppres­sion. The device features internally set gains of 0dB, 6dB,
12dB, and 18dB selected through two gain-select inputs,
further reducing external component count.

The MAX9701 features high 80dB PSRR, less than 0.1%
THD+N, and SNR in excess of 88dB. Short-circuit and
thermal-overload protection prevent the device from
being damaged during a fault condition. The MAX9701 is
available in 24-pin thin QFN-EP (4mm x 4mm x 0.8mm),
and 20-bump UCSP™ (2mm x 2.5mm x 0.6mm) pack­ages. The MAX9701 is specified over the extended

-40°C to +85°C temperature range.

Applications

Cellular Phones

Notebooks

Handheld Gaming Consoles

Docking Stations

MP3 Players

Features

♦ Patented Spread-Spectrum Modulation Lowers

Radiated Emissions

♦ Single-Supply Operation (2.5V to 5.5V)

♦ 1.3W Stereo Output (8Ω, V

DD

= 5V, THD+N = 1%)

♦ No LC Output Filter Required

♦ 87% Efficiency (R

L

= 8Ω, P

OUT

= 1000mW)

♦ Less Than 0.1% THD+N

♦ High 80dB PSRR

♦ Fully Differential Inputs

♦ Integrated Click-and-Pop Suppression

♦ Typical Low Quiescent Current (9mA)

♦ Typical Low-Power Shutdown Mode (0.1µA)

♦ Short-Circuit and Thermal-Overload Protection

♦ Available in Thermally Efficient, Space-Saving

Packages

24-Pin Thin QFN-EP (4mm x 4mm x 0.8mm)
20-Bump UCSP (2mm x 2.5mm x 0.6mm)

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

________________________________________________________________ Maxim Integrated Products 1

MAX9701

GAIN2

GAIN1

V

DD

GAIN

RIGHT

MODULATOR

AND H-BRIDGE

SYNC

OSCILLATOR

LEFT

MODULATOR

AND H-BRIDGE

INR+

INR-

INL+

INL-

SYNC_OUT

Block Diagram

Ordering Information

19-3457; Rev 2; 2/07

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

PART

TEMP RANGE

PIN­PACKAGE

PKG

CODE

MAX9701EBP-T

B20-1

MAX9701ETG+

T2444-4

Pin Configurations appear at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

+Denotes lead-free package.
*EP = Exposed paddle.

-40°C to +85°C

-40°C to +85°C

20 UCSP-20

24 TQFN-EP*

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VDD= PVDD= SHDN = 3.3V, GND = PGND = 0V, SYNC = 0V (FFM), gain = 6dB (GAIN1 = 0, GAIN2 = 1), RLconnected between

OUT+ and OUT-, R

L

= ∞, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)

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.

VDDto GND..............................................................................6V

V

DD

to PVDD..........................................................-0.3V to +0.3V

PV

DD

to PGND .........................................................................6V

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

All Other Pins to GND.................................-0.3V to (V

DD

+ 0.3V)

Continuous Current In/Out of PV

DD

, PGND, OUT_.........±800mA

Continuous Input Current (all other pins)..........................±20mA

Duration of OUT_ Short Circuit to GND or PV

DD

........Continuous

Duration of Short Circuit Between OUT+ and OUT- ......Continuous

Continuous Power Dissipation (TA= +70°C)

20-Bump UCSP (derate 10mW/°C above +70°C) ...........800mW

24-Pin Thin QFN (derate 20.8mW/°C above +70°C) ..1666.7mW

Junction Temperature......................................................+150°C

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

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

Bump Temperature (soldering) Reflow............................+235°C

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

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

GENERAL

Supply Voltage Range V

DD

Inferred from PSRR test 2.5 5.5 V

VDD = 3.3V, per channel 4.5 8

Quiescent Current I

DD

VDD = 5V, per channel 6.3 10

mA

Shutdown Current I

SHDN

0.1 10 µA

Common-Mode Rejection Ratio CMRR fIN = 1kHz 66 dB

Input Bias Voltage V

BIAS

V

Turn-On Time t

ON

40 ms

TA = +25oC

Output Offset Voltage V

OS

T

MIN

< TA < T

MAX

mV

VDD = 2.5V to 5.5V, VIN = 0V 60 80

f

RIPPLE

= 217Hz 72Power-Supply Rejection Ratio PSRR

100mV

P-P

ripple,

V

IN

= 0V

f

RIPPLE

= 20kHz 50

dB

Output Power (Note 3) P

OUT

THD+N = 1%,
T

A

= +25oC

V

DD

= 5V

mW

RL = 8Ω (P

OUT

= 300mW), f = 1kHz

Total Harmonic Distortion Plus
Noise (Note 3)

RL = 4Ω (P

OUT

= 400mW), f = 1kHz

%

FFM 86

BW = 22Hz
to 22kHz

SSM 86

FFM

Signal-to-Noise Ratio SNR V

OUT

= 1V

RMS

SSM

dB

SYNC = GND
SYNC = unconnected

Oscillator Frequency f

OSC

SYNC = V

DD

kHz

Minimum On-Time t

MIN

ns

SYNC Frequency Lock Range f

SYNC

kHz

THD+N

VDD = 3.3V

A-weighted

RL = 8Ω 460

= 4Ω 750

R

L

RL = 8Ω 1300

RL = 4Ω 2200

1.125 1.25 1.375

±10 ±30

0.08

0.15

88.5

88.5

950 1100 1250

1200 1400 1600

1000 1600

1200

±60

200

±55

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

_______________________________________________________________________________________ 3

Note 1: All devices are 100% production tested at +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

= 4Ω, L = 33µH.

For R

L

= 8Ω, L = 68µH.

Note 3: When driving speakers below 4Ω with large signals, exercise care to avoid violating the absolute maximum rating for continuous

output current.

Note 4: Testing performed with 8Ω resistive load in series with 68µH inductive load connected across the BTL output. Mode transi-

tions are controlled by SHDN. K

CP

level is calculated as: 20 x log[(peak voltage under normal operation at rated power

level) / (peak voltage during mode transition, no input signal)]. Units are expressed in dB.

ELECTRICAL CHARACTERISTICS (continued)

(VDD= PVDD= SHDN = 3.3V, GND = PGND = 0V, SYNC = 0V (FFM), gain = 6dB (GAIN1 = 0, GAIN2 = 1), RLconnected between
OUT+ and OUT-, R

L

= ∞, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C.) (Notes 1, 2)

PARAMETER

CONDITIONS

UNITS

SYNC_OUT Capacitance Drive

pF

Bridge-tied capacitance

Capacitive Drive C

L

Single ended

pF

Click-and-Pop Level K

CP

A-weighted, 32 samples
per second (Note 4)

Out of
shutdown

dB

VDD = 3.3V, P

OUT

= 500mW per channel,

f

IN

= 1kHz, RL = 8Ω

87

Efficiency η

V

DD

= 5V, P

OUT

= 1000mW per channel,

f

IN

= 1kHz, RL = 8Ω

%

GAIN1 = 0, GAIN2 = 0

15

GAIN1 = 1, GAIN2 = 0 25

GAIN1 = 0, GAIN2 = 1

Input Resistance R

IN

GAIN1 = 1, GAIN2 = 1 50

kΩ

GAIN1 = 0, GAIN2 = 0 18

GAIN1 = 1, GAIN2 = 0 12

GAIN1 = 0, GAIN2 = 1 6

Gain A

V

GAIN1 = 1, GAIN2 = 1 0

dB

Channel-to-Channel Gain
Tracking

1%

Crosstalk

L to R, R to L, f = 10kHz, R

L

= 8Ω,

P

OUT

= 300mW

70 dB

DIGITAL INPUTS (SHDN, SYNC, GAIN1, GAIN2)

Input-Voltage High V

INH

2V

Input-Voltage Low V

INL

0.8 V

Input Leakage Current
(SHDN, GAIN1, GAIN2)

±1µA

VIN = GND, normal operation -15 -7

Input Leakage Current (SYNC)

V

IN

= VDD, normal operation 12 25

µA

DIGITAL OUTPUTS (SYNC_OUT)

Output-Voltage High V

OH

IOH = 3mA, VDD = 3.3V 2.4 V

Output-Voltage Low V

OL

IOL = 3mA

V

SYMBOL

C

SYNC_OUT

Peak reading, TH D + N = 1%

Into shutdown 66.16

MIN TYP MAX

100

200

400

66.26

87.4

10.5

37.4

0.08

19.5

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

4 _______________________________________________________________________________________

Typical Operating Characteristics

(VDD= PVDD= SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), gain = 6dB (GAIN1 = 0, GAIN2 = 1)).

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

MAX9701 toc01

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.1

1

10

0.01
10 100k

VDD = 5V
R

L

= 4

Ω

OUTPUT POWER = 300mW

OUTPUT POWER = 100mW

OUTPUT POWER = 600mW

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

MAX9701 toc02

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.1

1

10

0.01
10 100k

VDD = 5V
R

L

= 8

Ω

OUTPUT POWER = 250mW

OUTPUT POWER = 100mW

OUTPUT POWER = 500mW

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

MAX9701 toc03

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.1

1

10

0.01
10 100k

VDD = 3.3V
R

L

= 4

Ω

OUTPUT POWER = 300mW

OUTPUT POWER = 100mW

OUTPUT POWER = 600mW

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

MAX9701 toc04

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.1

1

10

0.01
10 100k

VDD = 3.3V
R

L

= 8

Ω

OUTPUT POWER = 100mW

OUTPUT POWER = 400mW

OUTPUT POWER = 250mW

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

MAX9701 toc05

FREQUENCY (Hz)

THD+N (%)

10k1k100

0.1

1

10

0.01
10 100k

VDD = 5V
R

L

= 8

Ω

P

OUT

= 800mW

FFM

SSM

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

MAX9701 toc06

OUTPUT POWER (W)

THD+N (%)

2.52.01.51.00.5

0.1

1

10

100

0.01

03.0

VDD = 5V
R

L

= 4Ω

fIN = 10kHz

fIN = 20kHz

fIN = 1kHz

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

MAX9701 toc07

OUTPUT POWER (W)

THD+N (%)

1.51.00.5

0.01

0.1

1

10

100

0.001

02.0

VDD = 5V
R

L

= 8Ω

fIN = 10kHz

fIN = 20kHz

fIN = 1kHz

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

MAX9701 toc08

OUTPUT POWER (W)

THD+N (%)

1.00.80.60.40.2

0.1

1

10

100

0.01
0 1.2

VDD = 3.3V
R

L

= 4Ω

fIN = 10kHz

fIN = 20kHz

fIN = 1kHz

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

MAX9701 toc09

OUTPUT POWER (mW)

THD+N (%)

600500400300200100

0.1

1

10

100

0.01
0700

VDD = 3.3V
R

L

= 8Ω

fIN = 10kHz

fIN = 20kHz

fIN = 1kHz

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

_______________________________________________________________________________________ 5

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

MAX9701 toc10

OUTPUT POWER (W)

THD+N (%)

1.61.20.80.4

0.01

0.1

1

10

100

0.001

02.0

VDD = 5V
R

L

= 8Ω

f

IN

= 1kHz

SSM

FFM

EFFICIENCY vs. OUTPUT POWER

MAX9701 toc11

OUTPUT POWER (W)

EFFICIENCY (%)

2.01.51.00.5

10

20

30

40

50

60

70

80

90

100

0

02.5

RL = 8Ω

RL = 4Ω

VDD = 5V
f

IN

= 1kHz

EFFICIENCY vs. OUTPUT POWER

MAX9701 toc12

OUTPUT POWER (W)

EFFICIENCY (%)

1.00.80.60.40.2

10

20

30

40

50

60

70

80

90

100

0

01.2

RL = 8Ω

RL = 4Ω

VDD = 3.3V
f

IN

= 1kHz

OUTPUT POWER vs. SUPPLY VOLTAGE

MAX9701 toc13

SUPPLY VOLTAGE (V)

OUTPUT POWER (W)

5.04.54.03.53.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0

2.5 5.5

RL = 4Ω
A

V

= 12dB

f

IN

= 1kHz

THD+N = 10%

THD+N = 1%

OUTPUT POWER vs. SUPPLY VOLTAGE

MAX9701 toc14

SUPPLY VOLTAGE (V)

OUTPUT POWER (W)

5.04.54.03.53.0

0.4

0.8

1.2

1.6

2.0

0

2.5 5.5

RL = 8Ω
A

V

= 12dB

f

IN

= 1kHz

THD+N = 10%

THD+N = 1%

OUTPUT POWER vs. LOAD RESISTANCE

MAX9701 toc15

LOAD RESISTANCE (Ω)

OUTPUT POWER (W)

80604020

0.5

1.0

1.5

2.0

2.5

3.0

0

0100

VDD = 5V

f

IN

= 1kHz

THD+N = 10%

THD+N = 1%

OUTPUT POWER vs. LOAD RESISTANCE

MAX9701 toc16

LOAD RESISTANCE (Ω)

OUTPUT POWER (W)

80604020

0.4

0.8

1.2

1.6

2.0

0

0 100

fIN = 1kHz

THD+N = 10%

THD+N = 1%

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

MAX9701 toc17

FREQUENCY (Hz)

PSRR (dB)

10k1k100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

-100
10 100k

V

RIPPLE

= 100mV

P-P

RL = 8Ω

COMMON-MODE REJECTION RATIO

vs. FREQUENCY

MAX9701 toc18

FREQUENCY (Hz)

CMRR (dB)

10k1k100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

-100
10 100k

VCM = 100mV

P-P

RL = 8Ω

VDD = 5V

VDD = 3.3V

Typical Operating Characteristics (continued)

(VDD= PVDD= SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), gain = 6dB (GAIN1 = 0, GAIN2 = 1)).

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(VDD= PVDD= SHDN = 3.3V, GND = PGND = 0V, SYNC = VDD(SSM), gain = 6dB (GAIN1 = 0, GAIN2 = 1)).

CROSSTALK vs. FREQUENCY

MAX9701 toc19

FREQUENCY (Hz)

CROSSTALK (dB)

10k1k100

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-130
10 100k

RIGHT TO LEFT

LEFT TO RIGHT

P

OUT

= 300mW

R

L

= 8Ω

CROSSTALK vs. INPUT AMPLITUDE

MAX9701 toc20

INPUT AMPLITUDE (dB)

CROSSTALK (dB)

-14-34-54-74

-120

-110

-100

-90

-80

-70

-60

-50

-40

-30

-130

-94 6

RL = 8Ω
f

IN

= 1kHz

RIGHT TO LEFT

LEFT TO RIGHT

OUTPUT FREQUENCY SPECTRUM

MAX9701 toc21

FREQUENCY (Hz)

OUTPUT MAGNITUDE (dBV)

15k10k5k

-120

-100

-80

-60

-40

-20

0

-140

0 20k

FFM MODE
V

OUT

= -60dBV
f = 1kHz
R

L

= 8Ω

UNWEIGHTED

OUTPUT FREQUENCY SPECTRUM

MAX9701 toc22

FREQUENCY (Hz)

OUTPUT MAGNITUDE (dBV)

15k10k5k

-120

-100

-80

-60

-40

-20

0

-140
020k

FFM MODE
V

OUT

= -60dBV
f = 1kHz
R

L

= 8Ω

A-WEIGHTED

OUTPUT FREQUENCY SPECTRUM

MAX9701 toc23

FREQUENCY (Hz)

OUTPUT MAGNITUDE (dBV)

15k10k5k

-120

-100

-80

-60

-40

-20

0

-140
0 20k

SSM MODE
V

OUT

= -60dBV
f = 1kHz
R

L

= 8Ω

UNWEIGHTED

OUTPUT FREQUENCY SPECTRUM

MAX9701 toc24

FREQUENCY (Hz)

OUTPUT MAGNITUDE (dBV)

15k10k5k

-120

-100

-80

-60

-40

-20

0

-140
020k

SSM MODE
V

OUT

= -60dBV
f = 1kHz
R

L

= 8Ω

A-WEIGHTED