MAXIM MAX9701 User Manual

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

♦ 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

Block Diagram

Ordering Information

19-3457; Rev 3; 3/09

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.

Pin Configurations appear at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

+

Denotes lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed pad.

PART TEMP RANGE PIN-PACKAGE

MAX9701EBP+TG45 -40°C to +85°C

MAX9701ETG+ -40°C to +85°C

20 UCSP

24 TQFN-EP*

V

DD

INR+

INR-

MAX9701

RIGHT

MODULATOR

AND H-BRIDGE

GAIN1
GAIN2

INL+

SYNC

INL-

GAIN

LEFT

MODULATOR

AND H-BRIDGE

OSCILLATOR

SYNC_OUT

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

Quiescent Current I

Shutdown Current I

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

Input Bias Voltage V

Turn-On Time t

Output Offset Voltage V

Output Power (Note 3) P

Total Harmonic Distortion Plus
Noise (Note 3)

Signal-to-Noise Ratio SNR V

Oscillator Frequency f

Minimum On-Time t

SYNC Frequency Lock Range f

DD

DD

SHDN

BIAS

ON

Inferred from PSRR test 2.5 5.5 V

VDD = 3.3V, per channel 4.5 8

VDD = 5V, per channel 6.3 10

TA = +25oC ±10 ±30

OS

T

MIN

< TA < T

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

OUT

THD+N

100mV
V

IN

THD+N = 1%,
T

A

RL = 8Ω (P

R

L

OUT

P-P

= 0V

= +25oC

= 4Ω (P

= 1V

ripple,

RMS

SYNC = GND 950 1100 1250
SYNC = unconnected 1200 1400 1600

OSC

SYNC = V

MIN

SYNC

DD

0.1 10 μA

1.125 1.25 1.375 V

40 ms

MAX

f

= 217Hz 72Power-Supply Rejection Ratio PSRR

RIPPLE

f

= 20kHz 50

RIPPLE

VDD = 3.3V

V

= 5V

DD

= 300mW), f = 1kHz 0.08

OUT

= 400mW), f = 1kHz 0.15

OUT

BW = 22Hz

to 22kHz

A-weighted

RL = 8Ω 460

= 4Ω 750

R

L

RL = 8Ω 1300

R

= 4Ω 2200

L

FFM 86

SSM 86

FFM 88.5

SSM 88.5

1200

±60

200 ns

1000 1600 kHz

±55

mA

mV

dB

mW

%

dB

kHz

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 SYMBOL CONDITIONS MIN TYP MAX UNITS

SYNC_OUT Capacitance Drive C

Capacitive Drive C

Click-and-Pop Level K

Efficiency η

Input Resistance R

Gain A

Channel-to-Channel Gain
Tracking

Crosstalk

DIGITAL INPUTS (SHDN, SYNC, GAIN1, GAIN2)

Input-Voltage High V

Input-Voltage Low V

Input Leakage Current
(SHDN, GAIN1, GAIN2)

Input Leakage Current (SYNC)

DIGITAL OUTPUTS (SYNC_OUT)

Output-Voltage High V

Output-Voltage Low V

SYNC_OUT

Bridge-tied capacitance 200

L

Single ended 400

Into shutdown 66.16

Out of
shutdown

= 8Ω,

L

CP

IN

INH

INL

OH

OL

Peak reading, TH D + N = 1%
A-weighted, 32 samples
per second (Note 4)

VDD = 3.3V, P
f

= 1kHz, RL = 8Ω

IN

V

= 5V, P

DD

f

= 1kHz, RL = 8Ω

IN

GAIN1 = 0, GAIN2 = 0 10.5 15 19.5

GAIN1 = 1, GAIN2 = 0 25

GAIN1 = 0, GAIN2 = 1 37.4

GAIN1 = 1, GAIN2 = 1 50

GAIN1 = 0, GAIN2 = 0 18

GAIN1 = 1, GAIN2 = 0 12

V

GAIN1 = 0, GAIN2 = 1 6

GAIN1 = 1, GAIN2 = 1 0

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

= 300mW

P

OUT

VIN = GND, normal operation -15 -7

V

= VDD, normal operation 12 25

IN

IOH = 3mA, VDD = 3.3V 2.4 V

IOL = 3mA 0.08 V

= 500mW per channel,

OUT

= 1000mW per channel,

OUT

100 pF

pF

dB

66.26

87

%

87.4

kΩ

dB

1%

70 dB

2V

0.8 V

±1μA

μA

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

10

VDD = 5V

= 4Ω

R

L

1

OUTPUT POWER = 600mW

THD+N (%)

0.1

OUTPUT POWER = 100mW

0.01
10 100k

FREQUENCY (Hz)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

VDD = 3.3V

= 8Ω

R

L

1

OUTPUT POWER = 400mW

THD+N (%)

0.1

OUTPUT POWER = 100mW

0.01
10 100k

FREQUENCY (Hz)

OUTPUT POWER = 300mW

10k1k100

OUTPUT POWER = 250mW

10k1k100

MAX9701 toc01

MAX9701 toc04

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

VDD = 5V

= 8Ω

R

L

1

OUTPUT POWER = 500mW

THD+N (%)

0.1

OUTPUT POWER = 100mW

0.01
10 100k

OUTPUT POWER = 250mW

FREQUENCY (Hz)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

VDD = 5V

= 8Ω

R

L

= 800mW

P

OUT

1

THD+N (%)

0.1

0.01
10 100k

FFM

SSM

FREQUENCY (Hz)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. FREQUENCY

10

VDD = 3.3V

= 4Ω

R

MAX9701 toc02

10k1k100

L

1

OUTPUT POWER = 600mW

THD+N (%)

0.1

OUTPUT POWER = 100mW

OUTPUT POWER = 300mW

0.01
10 100k

FREQUENCY (Hz)

MAX9701 toc03

10k1k100

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

VDD = 5V

= 4Ω

R

MAX9701 toc05

10k1k100

L

10

1

THD+N (%)

0.1

0.01

0 3.0

fIN = 10kHz

fIN = 20kHz

OUTPUT POWER (W)

fIN = 1kHz

MAX9701 toc06

2.52.01.51.00.5

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

VDD = 5V

= 8Ω

R

L

10

1

THD+N (%)

0.1

0.01

0.001

fIN = 10kHz

fIN = 20kHz

0 2.0

OUTPUT POWER (W)

fIN = 1kHz

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

VDD = 3.3V

= 4Ω

R

MAX9701 toc07

THD+N (%)

1.51.00.5

L

10

1

fIN = 10kHz

0.1

0.01
0 1.2

OUTPUT POWER (W)

fIN = 20kHz

fIN = 1kHz

1.00.80.60.40.2

MAX9701 toc08

THD+N (%)

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

VDD = 3.3V

= 8Ω

R

L

10

1

0.1

0.01

fIN = 10kHz

fIN = 20kHz

0 700

OUTPUT POWER (mW)

MAX9701 toc09

fIN = 1kHz

600500400300200100

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

_______________________________________________________________________________________

5

Typical Operating Characteristics (continued)

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

TOTAL HARMONIC DISTORTION

PLUS NOISE vs. OUTPUT POWER

100

VDD = 5V

= 8Ω

R

L

= 1kHz

f

IN

10

1

SSM

THD+N (%)

0.1

0.01

0.001
0 2.0

FFM

OUTPUT POWER (W)

OUTPUT POWER vs. SUPPLY VOLTAGE

3.5
RL = 4Ω

= 12dB

A

V

3.0

= 1kHz

f

IN

2.5

2.0

1.5

OUTPUT POWER (W)

1.0

0.5

THD+N = 10%

THD+N = 1%

EFFICIENCY vs. OUTPUT POWER

100

RL = 8Ω

90

MAX9701 toc10

80

70

60

50

40

EFFICIENCY (%)

30

20

10

0

1.61.20.80.4

0 2.5

RL = 4Ω

OUTPUT POWER (W)

VDD = 5V
f

IN

2.01.51.00.5

MAX9701 toc11

EFFICIENCY (%)

= 1kHz

OUTPUT POWER vs. SUPPLY VOLTAGE

2.0
RL = 8Ω

= 12dB

A

V

= 1kHz

MAX9701 toc13

f

IN

1.6

1.2

THD+N = 10%

0.8

OUTPUT POWER (W)

0.4

MAX9701 toc14

OUTPUT POWER (W)

THD+N = 1%

EFFICIENCY vs. OUTPUT POWER

100

RL = 8Ω

90

80

70

60

50

40

30

20

10

0

RL = 4Ω

0 1.2

OUTPUT POWER vs. LOAD RESISTANCE

3.0

2.5

2.0

1.5

1.0

0.5

THD+N = 10%

THD+N = 1%

OUTPUT POWER (W)

VDD = 3.3V

= 1kHz

f

IN

1.00.80.60.40.2

VDD = 5V

= 1kHz

f

IN

MAX9701 toc12

MAX9701 toc15

0

2.5 5.5
SUPPLY VOLTAGE (V)

OUTPUT POWER vs. LOAD RESISTANCE

2.0

1.6

1.2

0.8

OUTPUT POWER (W)

0.4

THD+N = 10%

THD+N = 1%

0

0 100

LOAD RESISTANCE (Ω)

5.04.54.03.53.0

fIN = 1kHz

80604020

MAX9701 toc16

0

2.5 5.5
SUPPLY VOLTAGE (V)

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

0

V

= 100mV

RIPPLE

-10
RL = 8Ω

-20

-30

-40

-50

PSRR (dB)

-60

-70

-80

-90

-100
10 100k

P-P

FREQUENCY (Hz)

0

5.04.54.03.53.0

0 100

LOAD RESISTANCE (Ω)

80604020

COMMON-MODE REJECTION RATIO

vs. FREQUENCY

0

VCM = 100mV

-10

MAX9701 toc17

10k1k100

RL = 8Ω

-20

-30

-40

-50

CMRR (dB)

-60

-70

-80

-90

-100
10 100k

P-P

MAX9701 toc18

VDD = 5V

VDD = 3.3V

10k1k100

FREQUENCY (Hz)

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 (dB)

-100

-110

-120

-130

-100

OUTPUT MAGNITUDE (dBV)

-120

-30
P

= 300mW

OUT

-40

= 8Ω

R

L

-50

-60

-70

-80

-90

10 100k

LEFT TO RIGHT

RIGHT TO LEFT

10k1k100

FREQUENCY (Hz)

OUTPUT FREQUENCY SPECTRUM

0

FFM MODE

= -60dBV

V

OUT

-20

f = 1kHz

= 8Ω

R

L

-40

UNWEIGHTED

-60

-80

CROSSTALK vs. FREQUENCY

MAX9701 toc19

MAX9701 toc21

CROSSTALK vs. INPUT AMPLITUDE

-30
RL = 8Ω

-40

= 1kHz

f

IN

-50

-60

-70

-80

-90

CROSSTALK (dB)

-100

-110

-120

-130

-94 6
INPUT AMPLITUDE (dB)

LEFT TO RIGHT

RIGHT TO LEFT

OUTPUT FREQUENCY SPECTRUM

0

FFM MODE

= -60dBV

V

OUT

-20
f = 1kHz

= 8Ω

R

L

-40
A-WEIGHTED

-60

-80

-100

OUTPUT MAGNITUDE (dBV)

-120

MAX9701 toc20

-14-34-54-74

MAX9701 toc22

-140
0 20k

FREQUENCY (Hz)

OUTPUT FREQUENCY SPECTRUM

0

SSM MODE

= -60dBV

V

OUT

-20
f = 1kHz

= 8Ω

R

L

-40
UNWEIGHTED

-60

-80

-100

OUTPUT MAGNITUDE (dBV)

-120

-140
0 20k

FREQUENCY (Hz)

15k10k5k

MAX9701 toc23

15k10k5k

-140
0 20k

FREQUENCY (Hz)

OUTPUT FREQUENCY SPECTRUM

0

SSM MODE

= -60dBV

V

OUT

-20
f = 1kHz

= 8Ω

R

L

-40
A-WEIGHTED

-60

-80

-100

OUTPUT MAGNITUDE (dBV)

-120

-140
0 20k

FREQUENCY (Hz)

15k10k5k

15k10k5k

MAX9701 toc24

MAX9701

1.3W, Filterless, Stereo Class D Audio
Power Amplifier

_______________________________________________________________________________________

7

Typical Operating Characteristics (continued)

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

WIDEBAND OUTPUT SPECTRUM

(FFM MODE)

0

RBW = 10kHz

-10
INPUT AC GROUNDED

-20

-30

-40

-50

-60

-70

OUTPUT MAGNITUDE (dB)

-80

-90

-100
1k 1M

FREQUENCY (Hz)

TURN-ON/TURN-OFF RESPONSE

SHDN

MAX9701

OUTPUT

MAX9701 toc25

OUTPUT MAGNITUDE (dB)

100k10k

MAX9701 toc27

2V/div

0V

250mV/div

SUPPLY CURRENT (mA)

WIDEBAND OUTPUT SPECTRUM

(SSM MODE)

0

RBW = 10kHz

-10
INPUT AC GROUNDED

-20

-30

-40

-50

-60

-70

-80

-90

-100
1k 1M

FREQUENCY (Hz)

100k10k

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

20

BOTH CHANNELS

17

14

11

8

SSM

FFM

MAX9701 toc26

MAX9701 toc28

10ms/div

2.5 5.5
SUPPLY VOLTAGE (V)

5.04.54.03.53.0

5

SHUTDOWN CURRENT
vs. SUPPLY VOLTAGE

5

BOTH CHANNELS

4

3

2

SHUTDOWN CURRENT (μA)

1

0

2.5 5.5
SUPPLY VOLTAGE (V)

MAX9701 toc29

5.04.54.03.53.0