Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Audio amplifier 2-channel (stereo) Class D TQFN 24 (4x4)

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Stereo, High-Power, Class D Amplifiers

MAX98400A/MAX98400B

General Description

The MAX98400A/MAX98400B Class D amplifiers provide

high-performance, thermally efficient amplifier solutions. The

MAX98400A delivers 2x20W into 8I loads or 1x40W into a

4I load. The MAX98400B delivers 2x12W into 8I loads.

An integrated limiting circuit prevents output clipping

distortion, protects small speakers from transient volt-

ages, and reduces power dissipation.

A thermal-foldback feature can be enabled to automati-

cally reduce the output power at above a junction tem-

perature of +120NC. Traditional thermal protection is also

available in addition to robust overcurrent protection.

The ICs operate from a single 8V to 28V supply and

provide a high 67dB PSRR, eliminating the need for a

regulated power supply. They offer up to 90% efficiency

from a 12V supply.

Filterless modulation allows the ICs to pass EN55022B

EMI limits with 1m cables using only a low-cost ferrite

bead and small-value capacitor on each output.

Both devices feature eight digitally controlled gain settings.

Comprehensive click-and-pop reduction circuitry mini-

mizes noise coming into and out of shutdown.

The MAX98400A/MAX98400B are available in 36-pin

and 24-pin TQFN packages, respectively, and are speci-

fied over the -40NC to +85NC temperature range.

Features

S Wide 8V to 28V Supply Voltage Range

S Single-Supply Operation

S Low EMI: Active Emissions Limiting

S Clipping Limiter

S Low Quiescent Current

S Thermal Foldback

S Thermal and Overcurrent Protection

Applications

LCD/PDP Televisions

LCD Monitors

MP3 Docking Stations

Notebook PCs

Ordering Information

19-5286; Rev 0; 6/10

Simplified Block Diagram

Note: Devices operate over the -40°C to +85°C temperature

range.

*EP = Exposed pad.

EVALUATION KIT

AVAILABLE

PART PIN-PACKAGE SPEC

MAX98400AETX+ 36 TQFN-EP* 2x20W

MAX98400BETG+ 24 TQFN-EP* 2x12W

INR-

INR+

OUTR-

OUTR+

PGA

CLIPPING

LIMITER

CLASS D

MODULATOR

AND H-BRIDGE

INL-

INL+

OUTL-

OUTL+

MONO*

PGA

CLIPPING

LIMITER

CLASS D

MODULATOR

AND H-BRIDGE

*MAX98400A ONLY

MAX98400A/B

Summary of content (26 pages)

PAGE 1
9-5286; Rev 0; 6/10 TION KIT EVALUA BLE AVAILA Stereo, High-Power, Class D Amplifiers The MAX98400A/MAX98400B Class D amplifiers provide high-performance, thermally efficient amplifier solutions. The MAX98400A delivers 2x20W into 8I loads or 1x40W into a 4I load. The MAX98400B delivers 2x12W into 8I loads. An integrated limiting circuit prevents output clipping distortion, protects small speakers from transient voltages, and reduces power dissipation.
PAGE 2
MAX98400A/MAX98400B Stereo, High-Power, Class D Amplifiers Table of Contents Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Typical Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PAGE 3
Stereo, High-Power, Class D Amplifiers Figure 1. MAX98400B EMI Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 2. MAX98400A Efficiency vs. Class AB Effifciency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 3. Limiter Control, Mode3 Configuration (Table 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 4.
PAGE 4
MAX98400A/MAX98400B Stereo, High-Power, Class D Amplifiers Absolute Maximum Ratings PVDD to PGND.......................................................-0.3V to +30V VS to GND................................................................-0.3V to +6V SHDN, MONO to GND.............................................-0.3V to +6V IN_ to GND...............................................................-0.3V to +6V G1, G2, RELEASE, TEMPLOCK, LIM_TH to GND......................................... -0.3V to (VS + 0.
PAGE 5
Stereo, High-Power, Class D Amplifiers (VPVDD = 18V, CIN = 1FF, VSHDN = 5V, LIM_TH = VS, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20.1dB), CREL = 1FF, C1 = C2 = 1FF, RL = J, AC measurement bandwidth 20Hz to 20kHz, differential input signal, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25NC.) (Notes 2, 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 11 ms Q0.
PAGE 6
MAX98400A/MAX98400B Stereo, High-Power, Class D Amplifiers Electrical Characteristics (continued) (VPVDD = 18V, CIN = 1FF, VSHDN = 5V, LIM_TH = VS, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20.1dB), CREL = 1FF, C1 = C2 = 1FF, RL = J, AC measurement bandwidth 20Hz to 20kHz, differential input signal, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25NC.
PAGE 7
Stereo, High-Power, Class D Amplifiers (MAX98400A, VPVDD = 18V, VSHDN = 5V, LIM_TH = VS, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20.1dB), CIN = CREL = C1 = C2 = 1FF, typical values are at TA = +25NC, unless otherwise noted.) POUT = 4W MAX98400 toc02 1 0.1 POUT = 0.5W THD+N (%) 0.1 THD+N (%) THD+N (%) 0.1 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 1 MAX98400 toc01 1 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY POUT = 7W 0.
PAGE 8
Typical Operating Characteristics (continued) (MAX98400A, VPVDD = 18V, VSHDN = 5V, LIM_TH = VS, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20.1dB), CIN = CREL = C1 = C2 = 1FF, typical values are at TA = +25NC, unless otherwise noted.
PAGE 9
Stereo, High-Power, Class D Amplifiers (MAX98400A, VPVDD = 18V, VSHDN = 5V, LIM_TH = VS, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20.1dB), CIN = CREL = C1 = C2 = 1FF, typical values are at TA = +25NC, unless otherwise noted.) WIDEBAND OUTPUT SPECTRUM -40 -60 -80 SHDN 2V/div -40 -60 -80 OUTPUT 2V/div -100 -120 -120 20 0.1 1 10 100 FREQUENCY (kHz) FREQUENCY (MHz) SUPPLY CURRENT vs. PVDD SUPPLY VOLTAGE SUPPLY CURRENT vs.
PAGE 10
Typical Operating Characteristics (continued) (MAX98400A, VPVDD = 18V, VSHDN = 5V, LIM_TH = VS, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20.1dB), CIN = CREL = C1 = C2 = 1FF, typical values are at TA = +25NC, unless otherwise noted.) f = 1kHz 0.01 0.1 f = 1kHz 0.01 VPVDD = 12V, 4I LOAD 0 4 8 12 16 20 8 0 16 OUTPUT POWER (W) EFFICIENCY vs. OUTPUT POWER (MONO) 60 50 40 0.
PAGE 11
Stereo, High-Power, Class D Amplifiers (MAX98400A, VPVDD = 18V, VSHDN = 5V, LIM_TH = VS, TEMPLOCK = unconnected; G1 = GND, G2 = open (gain = 20.1dB), CIN = CREL = C1 = C2 = 1FF, typical values are at TA = +25NC, unless otherwise noted.) SUPPLY CURRENT vs. PVDD SUPPLY VOLTAGE (MONO) OUTPUT POWER vs. LOAD (MONO) 12 SUPPLY CURRENT (mA) 50 40 30 20 10% THD+N 8 6 IVS 4 2 10 1% THD+N VS = 5V 0 0 10 20 30 40 50 60 70 80 90 100 0 8 16 20 24 28 PVDD SUPPLY VOLTAGE (V) SUPPLY CURRENT vs.
PAGE 12
MAX98400A/MAX98400B Stereo, High-Power, Class D Amplifiers 17 INR+ 30 16 INR- PVDD 31 15 GND PVDD 32 14 MAX98400A PVDD 33 13 GND MONO PGND 34 12 INL- PGND 35 11 INL+ N.C. 36 10 LIM_TH EP 1 2 3 4 5 6 7 8 9 OUTL- OUTL- N.C. OUTL+ OUTL+ VS N.C. G1 G2 + SHDN RELEASE TEMPLOCK 16 15 14 13 PGND 19 12 INR+ PGND 20 11 INR- PVDD 21 10 GND MAX98400B PVDD 22 PGND 23 PGND 24 EP + 1 2 3 4 5 6 G2 29 17 G1 PGND PGND 18 VS N.C.
PAGE 13
Stereo, High-Power, Class D Amplifiers PIN MAX98400A MAX98400B NAME 11 8 INL+ 12 9 INL- 13 FUNCTION Left-Channel Positive Analog Input Left-Channel Negative Analog Input Mono Operation. Connect MONO to GND for stereo operation. Connect MONO to VS for mono operation.
PAGE 14
Stereo, High-Power, Class D Amplifiers MAX98400A/MAX98400B Stereo Configuration for MAX98400A 8V TO 28V C1 1.0µF C2 1.0µF VS PVDD 6 MONO CIN 1.0µF LEFT INPUT CIN 1.0µF CBULK 200µF 31, 32, 33 13 REGULATOR MAX98400A INL+ 11 INL- 12 4, 5 OUTL+ CLIPPING LIMITER PGA 1, 2 OUTL- TEMPLOCK 19 CIN 1.0µF RIGHT INPUT CIN 1.
PAGE 15
Stereo, High-Power, Class D Amplifiers 8V TO 28V C2 1.0µF CBULK 200µF C1 1.0µF PVDD VS MONO CIN 1µF LEFT INPUT REGULATOR CIN 1µF RIGHT INPUT MAX98400A 13 INL+ 11 INL- 12 CIN 1µF 31, 32, 33 6 VS TEMPLOCK 4, 5 OUTL+ CLIPPING LIMITER PGA 19 1, 2 OUTL- POWER STAGE THERMAL FOLDBACK 23, 24 OUTR+ INR+ 17 INR- 16 CLIPPING LIMITER WITH THERMAL AND OVERCURRENT PROTECTION PGA 26, 27 OUTR- CIN 1µF LIMITER CONTROL 10 LIM_TH GAIN SELECTION 20 RELEASE CREL 1.
PAGE 16
The MAX98400A/MAX98400B are available in 36-pin and 24-pin TQFN packages, respectively, and are specified over the -40NC to +85NC temperature range. Efficiency The high efficiency of a Class D amplifier is due to the switching operation of the output stage transistors. In a Class D amplifier, the output transistors act as switches and consume negligible power.
PAGE 17
Stereo, High-Power, Class D Amplifiers In Mode1, the limiter is disabled. The output clips when output peak voltage reaches the voltage on PVDD, VPVDD. In Mode2, the limiter threshold (VTHRESH) tracks supply voltage, VPVDD. The peak output voltage is limited to approximately VTHRESH = VPVDD x 0.95. In Mode3, the limiter threshold, VTHRESH, is programmable. VLIM_TH can be set to a voltage proportional to the desired output threshold. The limiter threshold can be set down to 0.5 x VPVDD and up to 1.
PAGE 18
MAX98400A/MAX98400B Stereo, High-Power, Class D Amplifiers Preamplifier Gain Setting sequence. The shutdown and recovering sequence is repeated until the output fault is removed. The ICs offer eight pin-selectable gain settings, selectable through the G1 and G2 pins. Applications Information Protection Filterless Class D Operation The ICs feature overcurrent protection and two types of thermal protection: thermal foldback and overtemperature protection.
PAGE 19
Stereo, High-Power, Class D Amplifiers The load impedance of the speaker determines the filter component selection (Table 3). Inductors L1 and L2 and capacitor C1 form the primary output filter. Capacitors C2 and C3 provide commonmode filtering to reduce radiated emissions. Capacitors C4 and C5, plus resistors R1 and R2, form a Zobel at the output. A Zobel corrects the output loading to compensate for the rising impedance of the loudspeaker.
PAGE 20
Stereo, High-Power, Class D Amplifiers MAX98400A/MAX98400B Functional Diagrams PVDD VS 31, 32, 33 6 MONO 13 MAX98400A REGULATOR INL+ 11 INL- 12 4, 5 OUTL+ CLIPPING LIMITER PGA 1, 2 OUTL- TEMPLOCK 19 POWER STAGE THERMAL FOLDBACK 23, 24 OUTR+ INR+ 17 INR- 16 CLIPPING LIMITER LIMITER CONTROL 10 LIM_TH 20 WITH THERMAL AND OVERCURRENT PROTECTION PGA GAIN SELECTION 20 RELEASE 8 9 G1 G2 26, 27 OUTR- BIAS AND OSCILLATOR 21 SHDN 14, 15 GND 29, 30, 34, 35 PGND
PAGE 21
Stereo, High-Power, Class D Amplifiers VS PVDD 4 21, 22 REGULATOR MAX98400B INL+ 8 INL- 9 3 OUTL+ CLIPPING LIMITER PGA 1, 2 OUTL- TEMPLOCK 13 POWER STAGE THERMAL FOLDBACK 16 OUTR+ INR+ 12 INR- 11 CLIPPING LIMITER LIMITER CONTROL 7 LIM_TH WITH THERMAL AND OVERCURRENT PROTECTION PGA GAIN SELECTION 14 RELEASE 5 6 G1 G2 17, 18 OUTR- BIAS AND OSCILLATOR 15 SHDN 10 GND 19, 20, 23, 24 PGND 21 MAX98400A/MAX98400B Functional Diagrams (continued)
PAGE 22
MAX98400A/MAX98400B Stereo, High-Power, Class D Amplifiers Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. 22 PACKAGE TYPE PACKAGE CODE OUTLINE No. LAND PATTERN NO.
PAGE 23
Stereo, High-Power, Class D Amplifiers 23 MAX98400A/MAX98400B Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PAGE 24
MAX98400A/MAX98400B Stereo, High-Power, Class D Amplifiers Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PAGE 25
Stereo, High-Power, Class D Amplifiers 25 MAX98400A/MAX98400B Package Information (continued) For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.
PAGE 26
Stereo, High-Power, Class D Amplifiers MAX98400A/MAX98400B Revision History REVISION NUMBER REVISION DATE 0 6/10 DESCRIPTION Initial release PAGES CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.