Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsLinear ICsLinear IC - Audio amplifier Headphones (2-channel, stereo) Class AB TQFN 16 EP (3x3)

General Description

The MAX9722A/MAX9722B stereo headphone amplifiers

are designed for portable equipment where board space

is at a premium. The MAX9722A/MAX9722B use a

unique DirectDrive architecture to produce a ground-ref-

erenced output from a single supply, eliminating the

need for large DC-blocking capacitors, which saves

cost, board space, and component height. Additionally,

the gain of the amplifier is set internally

(-2V/V, MAX9722B) or adjusted externally (MAX9722A).

The MAX9722A/MAX9722B deliver up to 70mW per

channel into a 16Ω load or 130mW into a 32Ω load and

have low 0.009% THD+N. An 80dB at 217Hz power-sup-

ply rejection ratio (PSRR) allows these devices to operate

from noisy digital supplies without an additional linear

regulator. The MAX9722A/MAX9722B include ±8kV ESD

protection on the headphone outputs. Comprehensive

anticlick-and-pop circuitry suppresses audible clicks

and pops on startup and shutdown. A low-power shut-

down mode reduces the supply current to 0.1µA.

The MAX9722A/MAX9722B operate from a single 2.4V

to 5.5V supply, consume only 5.5mA of supply current,

feature short-circuit and thermal-overload protection,

and are specified over the extended -40°C to +85°C

temperature range. The devices are available in tiny

16-pin thin QFN (3mm ✕ 3mm ✕ 0.8mm) and 16-pin

TSSOP packages.

Applications

Features

♦ 2.4V to 5.5V Single-Supply Operation

♦ High PSRR (80dB at 217Hz) Eliminates LDO

♦ No Bulky DC-Blocking Capacitors Required

♦ Ground-Referenced Outputs Eliminate DC Bias

Voltage on Headphone Ground Pin

♦ No Degradation of Low-Frequency Response Due

to Output Capacitors

♦ Differential Inputs for Enhanced Noise

Cancellation

♦ Adjustable Gain (MAX9722A) or Fixed -2V/V Gain

(MAX9722B)

♦ 130mW per Channel into 32Ω

♦ Low 0.009% THD+N

♦ Integrated Click-and-Pop Suppression

♦ Low Quiescent Current (5.5mA)

♦ Short-Circuit and Thermal-Overload Protection

♦ ±8kV ESD-Protected Amplifier Outputs (Human

Body Model)

♦ Available in a Space-Saving 16-Pin Thin QFN

(3mm

✕ 3mm ✕ 0.8mm) Package

MAX9722A/MAX9722B

5V, Differential Input, DirectDrive, 130mW

Stereo Headphone Amplifiers with Shutdown

________________________________________________________________ Maxim Integrated Products 1

Ordering Information

LEFT

AUDIO

INPUT

DirectDrive OUTPUTS

ELIMINATE DC-BLOCKING

CAPACITORS.

FIXED GAIN ELIMINATES

EXTERNAL RESISTOR

NETWORK.

RIGHT

AUDIO

INPUT

SHDN

MAX9722B

Simplified Diagram

19-3049; Rev 2; 10/07

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.

Note: All devices are specified over the -40°C to +85°C operating

temperature range.

*EP = Exposed paddle.

Pin Configurations and Typical Application Circuit appear at

end of data sheet.

PART PIN-PACKAGE

TOP

MARK

PKG

CODE

MAX9722AETE

16 Thin QFN-EP* (3mm

3mm

0.8mm)

AAX

T1633-5

MAX9722AEUE

16 TSSOP —

U16-1

MAX9722BETE

16 Thin QFN-EP* (3mm

3mm

0.8mm)

AAY

T1633-5

MAX9722BEUE

16 TSSOP —

U16-1

Notebook and

Desktop PCs

MP3 Players

Flat-Panel Monitors

Cellular Phones

Smart Phones

PDAs

Portable Audio

Equipment

EVALUATION KIT

AVAILABLE

Summary of content (21 pages)

PAGE 1
9-3049; Rev 2; 10/07 KIT ATION EVALU LE B A IL A AV 5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown The MAX9722A/MAX9722B stereo headphone amplifiers are designed for portable equipment where board space is at a premium. The MAX9722A/MAX9722B use a unique DirectDrive architecture to produce a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, which saves cost, board space, and component height.
PAGE 2
MAX9722A/MAX9722B 5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown ABSOLUTE MAXIMUM RATINGS PVSS to SVSS ............................................................................0V Output Short Circuit to GND.......................................Continuous Continuous Power Dissipation (TA = +70°C) 16-Pin Thin QFN (derate 14.7mW/°C above +70°C)....1176mW 16-Pin TSSOP (derate 9.4mW/°C above +70°C) .........755mW Junction Temperature ....................................
PAGE 3
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown (PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1µF, RL = ∞, resistive load referenced to ground, for MAX9722A gain = -1V/V (RIN = RF = 10kΩ), for MAX9722B gain = -2V/V (internally set), TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C, unless otherwise noted.
PAGE 4
Typical Operating Characteristics (continued) (MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1µF, RL = ∞, gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.) 0.01 VDD = 5V AV = -1V/V RL = 32Ω 1 THD+N (%) POUT = 20mW 10 1 POUT = 5mW 0.1 POUT = 20mW 0.01 POUT = 5mW 0.1 POUT = 20mW 0.01 POUT = 40mW 0.001 0.0001 100 1k 10k 100k 0.0001 10 100 1k 10k 100k 10 TOTAL HARMONIC DISTORTION PLUS NOISE vs.
PAGE 5
V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown (MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1µF, RL = ∞, gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.) 1 f = 1kHz THD+N (%) 0.1 0.01 90 80 RL = 16Ω 0.1 0.01 RL = 32Ω 0.001 20 30 40 50 60 -0.5 -0.1 0.1 0.3 2.4 0.5 2.6 2.8 3.0 3.
PAGE 6
Typical Operating Characteristics (continued) (MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1µF, RL = ∞, gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.) CROSSTALK vs. FREQUENCY -20 -40 -50 -60 -70 -40 -50 -60 -20 RIGHT TO LEFT -70 RIGHT -80 -80 -90 -90 LEFT 10k 100 1k 100k 10k FREQUENCY (Hz) GAIN FLATNESS vs. FREQUENCY CHARGE-PUMP OUTPUT RESISTANCE vs.
PAGE 7
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown (MAX9722A, PVDD = SVDD = +5V, PGND = SGND = 0V, SHDN = SVDD, C1 = C2 = 1µF, RL = ∞, gain = -1V/V, single-ended input, THD+N measurement bandwidth = 22Hz to 22kHz, TA = +25°C, unless otherwise noted.
PAGE 8
MAX9722A/MAX9722B 5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown Detailed Description The MAX9722A/MAX9722B stereo headphone amplifiers feature Maxim’s DirectDrive architecture, eliminating the large output-coupling capacitors required by conventional single-supply headphone amplifiers.
PAGE 9
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown • When using the headphone jack as a line out to other equipment, the bias voltage on the sleeve may conflict with the ground potential from other equipment, resulting in possible damage to the amplifiers. • When using a combination microphone and speaker headset, the microphone typically requires a GND reference. The amplifier DC bias on the sleeve conflicts with the microphone requirements (Figure 3).
PAGE 10
ADDITIONAL THD+N DUE TO DC-BLOCKING CAPACITORS LOW-FREQUENCY ROLLOFF (RL = 16Ω) 0 10 -3 DirectDrive -6 -9 1 330μF -12 THD+N (%) ATTENUATION (dB) MAX9722A/MAX9722B 5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown 220μF -15 100μF -18 0.1 TANTALUM 0.01 33μF -21 -24 0.001 ALUM/ELEC -27 -30 0.0001 10 100 1k 10k 100k FREQUENCY (Hz) Figure 4.
PAGE 11
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown Power Dissipation Under normal operating conditions, linear power amplifiers can dissipate a significant amount of power.
PAGE 12
MAX9722A/MAX9722B 5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown Component Selection Input Filtering The input capacitor (CIN), in conjunction with the input resistor (RIN), forms a highpass filter that removes the DC bias from an incoming signal (see the Typical Application Circuit). The AC-coupling capacitor allows the device to bias the signal to an optimum DC level.
PAGE 13
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A LEFT AUDIO INPUT SHDN R1 RIGHT AUDIO INPUT R2 Common-Mode Noise Rejection Figure 9 shows a theoretical connection between two devices, for example, a notebook computer (transmitter, on the left) and an amplifier (receiver, on the right), Figure 8. Common-Mode Sense Input Eliminates Ground-Loop Noise EXAMPLE CONNECTION: VIN = VAUDIO VAUDIO GND NOISE COMPONENT IN OUTPUT = VNOISE/2 0.1Ω VNOISE 0.
PAGE 14
It allows the MAX9722A/MAX9722B differential sensing to reduce the GND noise seen by the receiver (amplifier). The other side effect is that the differential headphone jack sensing corrects the headphone crosstalk (from introducing the resistance on the jack GND return). Only one channel is depicted in Figure 9. Figure 9 has some example numbers for resistance, but the audio designer has control over only one series resistance applied to the headphone jack return.
PAGE 15
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY MAX9722 fig12 10 THD+N (%) VDD = 5V AV = -1V/V 1 VOUT(P-P) = 2V OUTPUTS DRIVING PIEZOELECTRIC SPEAKER A 0.1 500mV/div 0.01 0.001 4μs/div 0.0001 10 100 1k 10k 100k FREQUENCY (Hz) Figure 12. MAX9722 THD+N vs.
PAGE 16
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown MAX9722A/MAX9722B System Diagram VDD 0.1μF 15kΩ 0.1μF 15kΩ INR VDD PVDD 0.1μF 1μF OUTR- MAX9710 BIAS AUX_IN OUTR+ 1μF SHDN OUT OUTL- 0.1μF 15kΩ MAX4060 BIAS OUTL+ INL VDD 15kΩ CODEC VDD 2.2kΩ 10kΩ 0.1μF IN- IN+ VDD 10kΩ Q IN0.1μF MAX961 Q 100kΩ 100kΩ IN+ 0.
PAGE 17
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown CIN 1μF 2.4V TO 5.
PAGE 18
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown 3 C1N 4 C1N 6 11 SVDD PVSS 7 10 INR- SGND 8 9 INR+ TSSOP INL- SVDD 14 13 8 PGND 12 OUTR MAX9722A MAX9722B INR- PGND 5 13 SVSS 7 2 MAX9722A MAX9722B INR+ C1P C1P 4 INL+ 1 15 PVDD 14 OUTL 6 15 SVDD PVDD 3 SGND SHDN 2 SHDN 16 INL- 16 INL+ 1 5 TOP VIEW PVSS MAX9722A/MAX9722B Pin Configurations THIN QFN Chip Information TRANSISTOR COUNT: 1100 PROCESS: BiCMOS 18 ___________________
PAGE 19
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown TSSOP4.40mm.EPS PACKAGE OUTLINE, TSSOP 4.40mm BODY 21-0066 I 1 1 ______________________________________________________________________________________ 19 MAX9722A/MAX9722B 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
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.) (NE - 1) X e E MARKING 12x16L QFN THIN.EPS MAX9722A/MAX9722B 5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown E/2 D2/2 (ND - 1) X e D/2 AAAA e CL D D2 k CL b 0.10 M C A B E2/2 L E2 0.10 C C L C L 0.
PAGE 21
5V, Differential Input, DirectDrive, 130mW Stereo Headphone Amplifiers with Shutdown PKG 8L 3x3 12L 3x3 16L 3x3 REF. MIN. NOM. MAX. MIN. NOM. MAX. MIN. NOM. MAX. A 0.70 0.75 0.80 0.70 0.75 0.80 0.70 0.75 0.80 b 0.25 0.30 0.35 0.20 0.25 0.30 0.20 0.25 0.30 D 2.90 3.00 3.10 2.90 3.00 3.10 2.90 3.00 3.10 E 2.90 3.00 3.10 2.90 3.00 3.10 2.90 3.00 3.10 e L 0.65 BSC. 0.35 N 0.55 0.50 BSC. 0.75 0.45 0.55 0.50 BSC. 0.65 0.30 12 8 0.