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19-0627; Rev 0; 9/06
DirectDrive, Headphone Amplifier with BassMax, I2C, Volume and Gain Control
General Description
The MAX9726 stereo, DirectDrive™, headphone amplifier with BassMax and volume control is ideal for portable audio applications where space is at a premium and performance is essential. The MAX9726 operates from a single 2.7V to 5.5V power supply and includes features that reduce external component count, system cost, board space, and offer improved audio reproduction. High 85dB PSRR makes the MAX9726 ideal for direct connection to a battery-powered supply and eliminates the need for a dedicated LDO. The MAX9726 features Maxim’s industry-leading click-and-pop suppression circuitry, which reduces/eliminates audible transients during power-up and power-down. The headphone amplifier uses Maxim’s patented † DirectDrive architecture that produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors. The headphone amplifiers deliver 105mW into a 32Ω load and feature low 0.02% THD+N. The BassMax feature boosts the bass response of the amplifier, improving audio reproduction when using inexpensive headphones. The integrated volume control features 64 discrete volume levels, eliminating the need for an external potentiometer. External resistors set the MAX9726’s overall gain allowing for custom gain settings. BassMax and the volume control are enabled through the I2C/SMBus™-compatible interface. Shutdown can be controlled through the hardware or software interface. The MAX9726 consumes only 5.5mA of supply current, provides short-circuit and thermal-overload protection, and is specified over the -40°C to +85°C extended temperature range. The MAX9726 is available in a tiny (2mm x 2.5mm x 0.62mm) 20-bump chip-scale package (UCSP™) and a 20-pin TQFN package (4mm x 4mm x 0.75mm).
Features
♦ 105mW DirectDrive Headphone Amplifier Eliminates Bulky DC-Blocking Capacitors ♦ 2.7V to 5.5V Single-Supply Operation ♦ Integrated 64-Level Volume Control ♦ High 85dB PSRR at 1kHz ♦ Software-Enabled Bass Boost (BassMax) ♦ Industry-Leading Click-and-Pop Suppression ♦ ±7.5kV HBM ESD-Protected Headphone Outputs ♦ Short-Circuit and Thermal-Overload Protection ♦ Low-Power Shutdown Mode (8µ A) ♦ Low 0.02% THD+N ♦ I2C/SMBus-Compatible Interface ♦ Available in Space-Saving, Thermally Efficient Packages 20-Bump UCSP (2mm x 2.5mm x 0.62mm) 20-Pin TQFN (4mm x 4mm x 0.75mm)
MAX9726
Ordering Information
PART MAX9726AEBP+T* MAX9726AETP+ MAX9726BEBP+T* MAX9726BETP+ PIN-PACKAGE 20 UCSP-20 20 TQFN-EP** 20 UCSP-20 20 TQFN-EP** SLAVE ADDRESS 1001100 1001100 1001101 1001101 PKG CODE B20-1 T2044-3 B20-1 T2044-3
Note: All devices specified over the -40°C to +85°C operating range. +Denotes lead-free package. *Future product—contact factory for availability. **EP = Exposed pad.
Simplified Block Diagram
2.7V TO 5.5V SUPPLY
Applications
Cell Phones MP3/PMP Players Flat-Panel TVs
†U.S. Patent # 7,061,327
INR FBR
Automotive Rear-Seat Entertainment (RSE) Portable CD/DVD/MD Players
SCL SDA FBL INL
BML I2C INTERFACE
BassMax
VOLUME CONTROL
Σ Σ
OUTL OUTR
MAX9726
BMR BassMax
SMBus is a trademark of Intel Corp. UCSP is a trademark of Maxim Integrated Products, Inc. Pin Configurations appear at end of data sheet. 1
________________________________________________________________ Maxim Integrated Products
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.
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DirectDrive, Headphone Amplifier with BassMax, I2C, Volume and Gain Control MAX9726
ABSOLUTE MAXIMUM RATINGS
VDD to PGND............................................................-0.3V to +6V PVSS to SVSS .........................................................-0.3V to +0.3V SGND to PGND .....................................................-0.3V to +0.3V C1P to PGND..............................................-0.3V to (VDD + 0.3V) C1N to PGND............................................(PVSS - 0.3V) to +0.3V PVSS, SVSS to PGND ................................................+0.3V to -6V IN_ to SGND...................................(SVSS - 0.3V) to (VDD + 0.3V) FB_ to SGND..................................(SVSS - 0.3V) to (VDD + 0.3V) SDA, SCL to PGND ....................................-0.3V to (VDD + 0.3V) SHDN to PGND ..........................................-0.3V to (VDD + 0.3V) OUT_ to SGND ............................................................-3V to +3V BM_ to SGND ..............................................................-3V to +3V Duration of OUT_ Short Circuit to PGND....................Continuous Continuous Current Into/Out of: VDD, C1P, PGND, C1N, PVSS, SVSS, or OUT_ ...........±850mA Any Other Pin................................................................±20mA Continuous Power Dissipation (TA = +70°C, multilayer board) 20-Bump UCSP (derate 10mW/°C abo.