Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Audio amplifier 1-channel (mono) Class D TQFN 16 (4x4)

General Description

The MAX9759 mono Class D, audio power amplifier

provides Class AB amplifier audio performance with the

benefits of Class D efficiency, eliminating the need for a

heatsink and extending battery life. The MAX9759 deliv-

ers up to 3.2W of continuous power into a 4Ω load while

offering greater than 90% efficiency. Maxim’s next-gen-

eration, low-EMI modulation scheme allows the amplifi-

er to operate without an external LC filter while still

meeting FCC EMI-radiated emission levels.

The MAX9759 offers two modulation schemes: a fixed-

frequency modulation (FFM) mode and a spread-spec-

trum modulation (SSM) mode. The SSM mode flattens

the wideband spectral components, reducing EMI-radi-

ated emissions due to the modulation frequency.

Furthermore, the MAX9759 oscillator can be synchro-

nized to an external clock through the SYNC input,

allowing the switching frequency to range from

1000kHz to 1600kHz. The SYNC input and SYNC_OUT

output of the MAX9759 allow multiple Maxim Class D

amplifiers to be cascaded and frequency locked, mini-

mizing interference due to clock intermodulation. The

MAX9759 utilizes fully differential input amplifiers, a full-

bridged output, comprehensive click-and-pop suppres-

sion, and features four selectable gain settings (6dB,

12dB, 18dB, 24dB).

The MAX9759 features high 81dB PSRR, low 0.02%

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

thermal-overload protection prevents damage to the

device during a fault condition. The MAX9759 operates

from a single 5V supply, consumes 8.4mA of supply

current, and is available in a 16-pin thin QFN package

(4mm x 4mm x 0.8mm). The MAX9759 is fully specified

over the extended -40°C to +85°C temperature range.

Applications

Cell Phones/PDAs

Notebook PCs

Portable DVD Players

Flat-Panel PC Monitors

LCD TVs

LCD Projectors

Features

♦ 3.2W into 4Ω Load (THD+N = 10%)

♦ Filterless Amplifier Passes FCC Radiated

Emissions Standards with 7.6cm of Cable

♦ 92% Efficiency

♦ High PSRR (81dB at 1kHz)

♦ Low 0.02% THD+N

♦ External Clock Synchronization for Multiple,

Cascaded Maxim Class D Amplifiers

♦ 3.0V to 5.5V Single-Supply Operation

♦ Pin-Selectable Gain (6dB, 12dB, 18dB, 24dB)

♦ Integrated Click-and-Pop Suppression

♦ Low Quiescent Current (8.4mA)

♦ Low-Power Shutdown Mode (10µA)

♦ Mute Function

♦ Short-Circuit and Thermal-Overload Protection

♦ Available in Thermally Efficient Package

16-Pin TQFN (4mm x 4mm x 0.8mm)

MAX9759

3.2W, High-Efficiency, Low-EMI,

Filterless, Class D Audio Amplifier

________________________________________________________________ Maxim Integrated Products 1

MAX9759

DIFFERENTIAL

AUDIO INPUT

SYNC

INPUT

SYNC

OUTPUT

OSCILLATOR

MODULATOR

AND H-BRIDGE

MONO SPEAKER

OUTPUT

GAIN

CONTROL

MUTE

CONTROL

SHDN

CONTROL

SHDN

MUTE

Simplified Block Diagram

Ordering Information

19-3691; Rev 1; 10/05

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.

EVALUATION KIT

AVAILABLE

PART

TEMP RANGE

PIN-

PACKAGE

PKG

CODE

MAX9759ETE+

-40°C to +85°C 16 TQFN-EP*

T1644-4

Pin Configurations appear at end of data sheet.

+Denotes lead-free package.

*EP = Exposed paddle.

Summary of content (20 pages)

PAGE 1
9-3691; Rev 1; 10/05 KIT ATION EVALU E L B AVAILA 3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier The MAX9759 mono Class D, audio power amplifier provides Class AB amplifier audio performance with the benefits of Class D efficiency, eliminating the need for a heatsink and extending battery life. The MAX9759 delivers up to 3.2W of continuous power into a 4Ω load while offering greater than 90% efficiency.
PAGE 2
MAX9759 3.2W, High-Efficiency, 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+/OUT-....1.
PAGE 3
.2W, High Efficiency, Low-EMI, Filterless, Class D Audio Amplifier (VDD = PVDD = SHDN = MUTE = 5V, GND = PGND = 0V, SYNC = 0V (FFM). Gain = 12dB (G1 = 0, G2 = 1). Speaker load resistor (RL) connected between OUT+ and OUT-, unless otherwise noted, RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 4
MAX9759 3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier ELECTRICAL CHARACTERISTICS (VDD = 3.3V) (VDD = PVDD = SHDN = MUTE = 3.3V, GND = PGND = 0V, SYNC = GND (FFM). Gain = 12dB (G1 = 0, G2 = 1). Speaker load resistor (RL) connected between OUT+ and OUT-, unless otherwise noted. RL = ∞, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.
PAGE 5
3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier (VDD = PVDD = SHDN = MUTE = 5V, GND = PGND = 0V, SYNC = VDD (SSM), unless otherwise noted. Gain = 12dB (G1 = 0, G2 = 1). THD+N measurement bandwidth: 22Hz to 22kHz. Typical values are at TA = +25°C.) (See Typical Operating Circuit) TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY VDD = 5V RL = 3Ω VDD = 3.3V RL = 3Ω 0.1 POUT = 2.6W 0.01 1 POUT = 500mW THD+N (%) THD+N (%) 0.1 0.01 10 100 1k 10k POUT = 2.2W 0.01 0.
PAGE 6
Typical Operating Characteristics (continued) (VDD = PVDD = SHDN = MUTE = 5V, GND = PGND = 0V, SYNC = VDD (SSM), unless otherwise noted. Gain = 12dB (G1 = 0, G2 = 1). THD+N measurement bandwidth: 22Hz to 22kHz. Typical values are at TA = +25°C.) (See Typical Operating Circuit) TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER 1 fIN = 200Hz, 1kHz 0.1 1 fIN = 200Hz, 1kHz 0.1 fIN = 10kHz 0 2 1 3 0.5 TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER TOTAL HARMONIC DISTORTION PLUS NOISE vs.
PAGE 7
3.2W, High Efficiency, Low-EMI, Filterless, Class D Audio Amplifier (VDD = PVDD = SHDN = MUTE = 5V, GND = PGND = 0V, SYNC = VDD (SSM), unless otherwise noted. Gain = 12dB (G1 = 0, G2 = 1). THD+N measurement bandwidth: 22Hz to 22kHz. Typical values are at TA = +25°C.) (See Typical Operating Circuit) OUTPUT POWER vs. SUPPLY VOLTAGE 2.0 OUTPUT POWER (W) OUTPUT POWER (W) RL = 8Ω fIN = 1kHz 3.0 THD+N = 10% 2.5 2.0 1.5 THD+N = 1% MAX9759 toc20 RL = 4Ω fIN = 1kHz 3.5 2.5 MAX9759 toc19 4.
PAGE 8
Typical Operating Characteristics (continued) (VDD = PVDD = SHDN = MUTE = 5V, GND = PGND = 0V, SYNC = VDD (SSM), unless otherwise noted. Gain = 12dB (G1 = 0, G2 = 1). THD+N measurement bandwidth: 22Hz to 22kHz. Typical values are at TA = +25°C.
PAGE 9
3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier (VDD = PVDD = SHDN = MUTE = 5V, GND = PGND = 0V, SYNC = VDD (SSM), unless otherwise noted. Gain = 12dB (G1 = 0, G2 = 1). THD+N measurement bandwidth: 22Hz to 22kHz. Typical values are at TA = +25°C.) (See Typical Operating Circuit) SHUTDOWN SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT (mA) TA = +25°C 7.5 7.0 TA = -40°C 6.5 6.0 FFM 0.18 TA = +85°C 0.16 0.14 0.12 TA = +25°C 0.10 0.08 0.06 5.5 0.04 5.0 0.02 TA = -40°C 3.
PAGE 10
3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier MAX9759 Pin Description PIN NAME 1 VDD Analog Power Supply. Bypass to GND with a 1µF ceramic capacitor. FUNCTION 2 IN+ Noninverting Audio Input 3 IN- Inverting Audio Input 4 GND Analog Ground 5 SHDN Active-Low Shutdown Input. Drive SHDN low to shut down the MAX9759. Connect to VDD for normal operation.
PAGE 11
3.2W, High Efficiency, Low-EMI, Filterless, Class D Audio Amplifier MAX9759 tSW VIN- VIN+ OUT- OUT+ tON(MIN) VOUT+ - VOUT- Figure 1. MAX9759 Outputs with an Input Signal Applied Table 1.
PAGE 12
MAX9759 3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier tSW tSW tSW tSW VIN- VIN+ OUT- OUT+ tON(MIN) VOUT+ - VOUT- Figure 2. MAX9759 Outputs with an Input Signal Applied (SSM Mode) External Synchronization The SYNC function allows the MAX9759 to allocate spectral components of the switching harmonics to insensitive frequency bands and facilitates synchronization to a system clock (allowing for a fully synchronous system).
PAGE 13
3.2W, High Efficiency, Low-EMI, Filterless, Class D Audio Amplifier MAX9759 VIN = 0V 50 FCC LIMIT AMPLITUDE (dBµV/m) 45 40 35 OUT- 30 MAX9759 OUTPUT SPECTRUM 25 20 OUT+ 15 30 60 80 100 120 140 160 180 200 220 240 260 280 300 FREQUENCY (MHz) VOUT+ - VOUT- = 0V Figure 3. MAX9759 EMI Spectrum Figure 4. MAX9759 Outputs with No Input Signal sent at the input of the MAX9759, the outputs switch as shown in Figure 4.
PAGE 14
MAX9759 3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier Mute The MAX9759 features a mute function that disables the H-bridge outputs of the switching amplifier. The mute function only affects the power amplifiers of the MAX9759; it does not shut down the device. Driving MUTE low places the MAX9759 in a disabled output mode. Drive MUTE high for normal operation.
PAGE 15
3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier MAX9759 VDD TOTAL HARMONIC DISTORTION PLUS NOISE vs. OUTPUT POWER 100 VDD U1 PVDD VDD = 5.0V f = 1kHz RL = 8Ω SLAVE DEVICE 10 RIGHT-CHANNEL DIFFERENTIAL AUDIO INPUT OUT+ IN- OUT- THD+N (%) MAX9759 SYNC IN+ 1 0.1 SYNC_OUT 0.01 0.001 0 VDD U2 MAX9759 SYNC LEFT-CHANNEL DIFFERENTIAL AUDIO INPUT IN+ 0.5 1.0 1.5 2.0 OUTPUT POWER (W) PVDD Figure 8. Total Harmonic Distortion Plus Noise vs.
PAGE 16
MAX9759 3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier 1µF 22kΩ CW IN- 50kΩ 1µF 22kΩ MAX9759 IN+ Use wide, low-resistance output traces. As load impedance decreases, the current drawn from the device outputs increase. At higher current, the resistance of the output traces decrease the power delivered to the load. Wide output, supply, and GND traces also improve the power dissipation of the device. The MAX9759 thin QFN package features an exposed thermal pad on its underside.
PAGE 17
3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier AVDD VDD 1µF OUT-R 2.
PAGE 18
3.
PAGE 19
3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier 24L QFN THIN.EPS PACKAGE OUTLINE, 12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm 21-0139 E 1 2 ______________________________________________________________________________________ 19 MAX9759 Package Information (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.
PAGE 20
MAX9759 3.2W, High-Efficiency, Low-EMI, Filterless, Class D Audio Amplifier Package Information (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.) PACKAGE OUTLINE, 12, 16, 20, 24, 28L THIN QFN, 4x4x0.8mm 21-0139 E 2 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product.