Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Audio amplifier 1-channel (mono) Class D uMAX 10

General Description

The MAX9700 mono class D audio power amplifier pro-

vides class AB amplifier performance with class D effi-

ciency, conserving board space and extending battery

life. Using a class D architecture, the MAX9700 delivers

1.2W into an 8Ω load while offering efficiencies above

90%. A low-EMI modulation scheme renders the tradi-

tional class D output filter unnecessary.

The MAX9700 offers two modulation schemes: a fixed-

frequency (FFM) mode, and a spread-spectrum (SSM)

mode that reduces EMI-radiated emissions due to the

modulation frequency. Furthermore, the MAX9700 oscil-

lator can be synchronized to an external clock through

the SYNC input, allowing the switching frequency to be

user defined. The SYNC input also allows multiple

MAX9700s to be cascaded and frequency locked, mini-

mizing interference due to clock intermodulation. The

device utilizes a fully differential architecture, a full-

bridged output, and comprehensive click-and-pop sup-

pression. The gain of the MAX9700 is set internally

(MAX9700A: 6dB, MAX9700B: 12dB, MAX9700C:

15.6dB, MAX9700D: 20dB), further reducing external

component count.

The MAX9700 features high 72dB PSRR, a low 0.01%

THD+N, and SNR in excess of 90dB. Short-circuit and

thermal-overload protection prevent the device from

damage during a fault condition. The MAX9700 is avail-

able in 10-pin TDFN (3mm

3mm

0.8mm), 10-pin

µMAX

, and 12-bump UCSP™ (1.5mm

2mm

0.6mm)

packages. The MAX9700 is specified over the extended

-40°C to +85°C temperature range.

Applications

Features

♦ Filterless Amplifier Passes FCC Radiated

Emissions Standards with 100mm of Cable

♦ Unique Spread-Spectrum Mode Offers 5dB

Emissions Improvement Over Conventional

Methods

♦ Optional External SYNC Input

♦ Simple Master-Slave Setup for Stereo Operation

♦ 94% Efficiency

♦ 1.2W into 8Ω

♦ Low 0.01% THD+N

♦ High PSRR (72dB at 217Hz)

♦ Integrated Click-and-Pop Suppression

♦ Low Quiescent Current (4mA)

♦ Low-Power Shutdown Mode (0.1µA)

♦ Short-Circuit and Thermal-Overload Protection

♦ Available in Thermally Efficient, Space-Saving

Packages

10-Pin TDFN (3mm x 3mm x 0.8mm)

10-Pin µMAX

12-Bump UCSP (1.5mm x 2mm x 0.6mm)

MAX9700

1.2W, Low-EMI, Filterless,

Class D Audio Amplifier

________________________________________________________________

Maxim Integrated Products

OUT-

OUT+

PGNDGND

IN-

IN+

MAX9700

TDFN/μMAX

TOP VIEW

SYNCSHDN

Pin Configurations

Ordering Information

MAX9700

DIFFERENTIAL

AUDIO INPUT

SYNC

INPUT

OSCILLATOR

MODULATOR

AND H-BRIDGE

Block Diagram

19-3030; Rev 2; 10/08

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.

Cellular Phones

PDAs

MP3 Players

Portable Audio

PART

TEMP RANGE

PIN-

PACKAGE

TOP

MARK

MAX9700AETB

-40

C to +85

C 10 TDFN-EP*

ACM

MAX9700AEUB

-40

C to +85

10 µMAX —

MAX9700AEBC-T

-40

C to +85

12 UCSP —

MAX9700BETB

-40

C to +85

C 10 TDFN-EP*

ACI

MAX9700BEUB

-40

C to +85

10 µMAX —

MAX9700BEBC-T

-40

C to +85

12 UCSP —

Pin Configurations continued at end of data sheet.

Ordering Information continued and Selector Guide appears

at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

*EP = Exposed pad.

Summary of content (20 pages)

PAGE 1
9-3030; Rev 2; 10/08 1.2W, Low-EMI, Filterless, Class D Audio Amplifier The MAX9700 mono class D audio power amplifier provides class AB amplifier performance with class D efficiency, conserving board space and extending battery life. Using a class D architecture, the MAX9700 delivers 1.2W into an 8Ω load while offering efficiencies above 90%. A low-EMI modulation scheme renders the traditional class D output filter unnecessary.
PAGE 2
MAX9700 1.2W, Low-EMI, Filterless, Class D Audio Amplifier ABSOLUTE MAXIMUM RATINGS VDD to GND..............................................................................6V PVDD to PGND .........................................................................6V GND to PGND .......................................................-0.3V to +0.3V All Other Pins to GND.................................-0.3V to (VDD + 0.3V) Continuous Current Into/Out of PVDD/PGND/OUT_........
PAGE 3
1.2W, Low-EMI, Filterless, Class D Audio Amplifier (VDD = PVDD = V SHDN = 3.3V, VGND = VPGND = 0V, SYNC = GND (FFM), RL = 8Ω, RL connected between OUT+ and OUT-, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
Typical Operating Characteristics (VDD = 3.3V, SYNC = GND (SSM), TA = +25°C, unless otherwise noted.) 1 1 1 VDD = +3.3V RL = 8Ω 0.1 POUT = 300mW POUT = 125mW 0.001 FFM MODE 0.001 0.001 10 100 SSM MODE 0.01 0.01 POUT = 125mW 1k 10k 100k 10 100 1k 10k 10 100k 100 1k 10k 100k FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs.
PAGE 5
1.2W, Low-EMI, Filterless, Class D Audio Amplifier TOTAL HARMONIC DISTORTION PLUS NOISE vs. COMMON-MODE VOLTAGE 80 RL = 8Ω RL = 4Ω 90 80 60 50 40 VDD = 3.3V f = 1kHz 10 1.5 2.0 2.5 3.0 0.3 0.6 COMMON-MODE VOLTAGE (V) EFFICIENCY vs. SUPPLY VOLTAGE EFFICIENCY (%) RL = 4Ω 60 50 40 40 20 f = 1kHz POUT = MAX (THD+N = 1%) 10 0 2.5 3.0 3.5 4.0 4.5 5.0 VDD = 3.3V f = 1kHz POUT = 300mW RL = 8Ω 10 0 5.5 800 1000 1200 1400 1600 1800 f = 1kHz RL = 4Ω THD+N = 10% 3.
PAGE 6
Typical Operating Characteristics (continued) (VDD = 3.3V, SYNC = GND (SSM), TA = +25°C, unless otherwise noted.
PAGE 7
1.2W, Low-EMI, Filterless, Class D Audio Amplifier TA = +85°C 5.0 TA = +25°C 4.5 TA = -40°C 4.0 TA = +85°C 0.14 SUPPLY CURRENT (μA) SUPPLY CURRENT (mA) 5.5 0.16 MAX9700 toc26 6.0 MAX9700 toc27 SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT vs. SUPPLY VOLTAGE 0.12 0.10 TA = +25°C 0.08 0.06 0.04 3.5 TA = -40°C 0.02 0 3.0 2.5 3.0 3.5 4.0 4.5 SUPPLY VOLTAGE (V) 5.0 2.5 5.5 3.0 3.5 4.0 4.5 5.0 5.
PAGE 8
1.2W, Low-EMI, Filterless, Class D Audio Amplifier MAX9700 Pin Description PIN BUMP TDFN/µMAX UCSP 1 NAME FUNCTION A1 VDD Analog Power Supply. Connect to an external power supply. Bypass to GND with a 1µF capacitor. 2 B1 IN+ Noninverting Audio Input 3 C1 IN- Inverting Audio Input 4 C2 GND 5 B2 SHDN Active-Low Shutdown Input. Connect to VDD for normal operation. Analog Ground 6 A3 SYNC Frequency Select and External Clock Input. SYNC = GND: Fixed-frequency mode with fS = 1100kHz.
PAGE 9
1.2W, Low-EMI, Filterless, Class D Audio Amplifier MAX9700 tSW VIN- VIN+ OUT- OUT+ tON(MIN) VOUT+ - VOUT- Figure 1. MAX9700 Outputs with an Input Signal Applied Table 1. Operating Modes SYNC INPUT MODE GND FFM with fS = 1100kHz UNCONNECTED FFM with fS = 1450kHz VDD Clocked SSM with fS = 1220kHz ±120kHz FFM with fS = external clock frequency scheme remains the same, but the period of the sawtooth waveform changes from cycle to cycle (Figure 2).
PAGE 10
MAX9700 1.2W, Low-EMI, Filterless, Class D Audio Amplifier tSW tSW tSW tSW VIN- VIN+ OUT- OUT+ tON(MIN) VOUT+ - VOUT- Figure 2. MAX9700 Output with an Input Signal Applied (SSM Mode) output a 50% duty cycle square wave when no signal is present. With no filter, the square wave appears across the load as a DC voltage, resulting in finite load current, increasing power consumption. When no signal is present at the input of the MAX9700, the outputs switch as shown in Figure 4.
PAGE 11
1.2W, Low-EMI, Filterless, Class D Audio Amplifier MAX9700 VIN = 0V 50.0 AMPLITUDE (dBμV/m) 45.0 40.0 35.0 30.0 OUT- 25.0 20.0 15.0 10.0 30.0 OUT+ 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 220.0 240.0 260.0 280.0 300.0 FREQUENCY (MHz) VOUT+ - VOUT- = 0V Figure 4. MAX9700 Outputs with No Input Signal Figure 3. MAX9700 EMI Spectrum Shutdown The MAX9700 has a shutdown mode that reduces power consumption and extends battery life. Driving SHDN low places the MAX9700 in a low-power (0.
PAGE 12
MAX9700 1.2W, Low-EMI, Filterless, Class D Audio Amplifier the power conversion of the class D amplifier. For example, an 8mV DC offset across an 8Ω load results in 1mA extra current consumption in a class AB device. In the class D case, an 8mV offset into 8Ω equates to an additional power drain of 8µW. Due to the high efficiency of the class D amplifier, this represents an additional quiescent-current draw of 8µW/(VDD/100η), which is on the order of a few microamps.
PAGE 13
1.2W, Low-EMI, Filterless, Class D Audio Amplifier 1μF RIGHT-CHANNEL DIFFERENTIAL AUDIO INPUT VDD PVDD IN+ MAX9700 OUT+ IN- OUTSYNC Designing with Volume Control The MAX9700 can easily be driven by single-ended sources (Figure 6), but extra care is needed if the source impedance “seen” by each differential input is unbalanced, such as the case in Figure 10a, where the MAX9700 is used with an audio taper potentiometer acting as a volume control.
PAGE 14
MAX9700 1.2W, Low-EMI, Filterless, Class D Audio Amplifier One solution is the configuration shown in Figure 10b. The potentiometer is connected between the differential inputs, and these “see” identical RC paths when the device powers up. The variable resistive element appears between the two inputs, meaning the setting affects both inputs the same way. The potentiometer is audio taper, as in Figure 10a. This significantly improves transient performance on power-up or release from SHDN.
PAGE 15
1.2W, Low-EMI, Filterless, Class D Audio Amplifier VDD 1μF VDD VDD 0.1μF AUX_IN PVDD IN+ OUT 2.2kΩ OUT+ IN- OUT- SHDN SYNC CODEC/ BASEBAND PROCESSOR OUT BIAS MAX9700 2.2kΩ MAX4063 0.1μF IN+ VDD IN0.
PAGE 16
Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 12 UCSP B12-11 21-0104 10 TDFN-EP T1033-1 21-0137 10 µMAX U10-2 21-0061 12L, UCSP 4x3.EPS MAX9700 1.
PAGE 17
1.2W, Low-EMI, Filterless, Class D Audio Amplifier 6, 8, &10L, DFN THIN.EPS ______________________________________________________________________________________ 17 MAX9700 Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
PAGE 18
MAX9700 1.2W, Low-EMI, Filterless, Class D Audio Amplifier Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. 18 COMMON DIMENSIONS PACKAGE VARIATIONS SYMBOL MIN. MAX. PKG. CODE N D2 E2 e JEDEC SPEC b [(N/2)-1] x e A 0.70 0.80 T633-2 6 1.50–0.10 2.30–0.10 0.95 BSC MO229 / WEEA 0.40–0.05 1.90 REF D 2.90 3.10 T833-2 8 1.50–0.10 2.30–0.10 0.65 BSC MO229 / WEEC 0.30–0.05 1.95 REF E 2.90 3.
PAGE 19
1.2W, Low-EMI, Filterless, Class D Audio Amplifier 10LUMAX.EPS α α ______________________________________________________________________________________ 19 MAX9700 Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.
PAGE 20
MAX9700 1.2W, Low-EMI, Filterless, Class D Audio Amplifier Revision History REVISION NUMBER REVISION DATE 0 10/03 Initial release 1 6/04 Changes made to TOCs and specs 2 10/08 Addition of EP information to pin description table DESCRIPTION PAGES CHANGED — 3–8, 14, 15 1, 2, 3, 8, 14 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.