Features: ` No Bulky DC-Blocking Capacitors Required
` Ground-Referenced Outputs Eliminate DC-Bias Voltages on Headphone Ground Pin
` Common-Mode Voltage Sensing Eliminates Ground-Loop Noise
` 96dB CMRR
` No Degradation of Low-Frequency Response Due to Output Capacitors
` 80mW per Channel into 16
` Low 0.002% THD+N
` High 86dB PSRR
` Integrated Click-and-Pop Suppression
` 1.8V to 3.6V Single-Supply Operation
` Low Quiescent Current
` Low-Power Shutdown Mode
` Short-Circuit and Thermal-Overload Protection
` ±8kV ESD-Protected Amplifier Outputs
` Available in Space-Saving Packages
14-Pin TSSOP
20-Pin Thin QFNApplication·Notebooks
·Desktop PCs
·Cellular Phones
·PDAs
·MP3 Players
·Tablet PCs
·Portable Audio EquipmentPinout
SpecificationsPGND to SGND ...................................................-0.3V to +0.3V
PVDD to SVDD .....................................................-0.3V to +0.3V
PVSS to SVSS ......................................................-0.3V to +0.3V
PVDD and SVDD to PGND or SGND .........................-0.3V to +4V
PVSS and SVSS to PGND or SGND ..........................-4V to +0.3V
IN_ and COM to SGND.................................SVSS to (SVDD - 1V)
IN_ to COM ....................................(COM + 2V) to (COM - 0.3V)
SHDN_ to SGND.........................(SGND - 0.3V) to (SVDD + 0.3V)
OUT_ to SGND ............................(SVSS - 0.3V) to (SVDD + 0.3V)
C1P to PGND..............................(PGND - 0.3V) to (PVDD + 0.3V)
C1N to PGND .............................(PVSS - 0.3V) to (PGND + 0.3V)
Output Short Circuit to GND or VDD..........................Continuous
Continuous Power Dissipation (TA = +70°C)
14-Pin TSSOP (derate 9.1mW/°C above +70°C) ........727mW
20-Pin Thin QFN (derate 16.9mW/°C above +70°C) .1349mW
Junction Temperature...................................................+150°C
Operating Temperature Range ......................-40°C to +85°C
Storage Temperature Range .......................-65°C to +150°C
Lead Temperature (soldering, 10s) ............................+300°C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DescriptionThe MAX4409 stereo headphone amplifier combines Maxim's DirectDrive architecture and a common-mode sense input, which allows the amplifier to reject common-mode noise. Conventional headphone amplifiers require a bulky DC-blocking capacitor between the headphone and the amplifier. DirectDrive produces a ground-referenced output from a single supply, eliminating the need for large DC-blocking capacitors, which saves cost, board space, and component height. The common-mode voltage sensing corrects for any difference between SGND of the amplifier and the headphone return. This feature minimizes ground-loop noise when the HP socket is used as a line out connection to other grounded equipment, for example, a PC connected to a home hi-fi system.
The MAX4409 draws only 5mA of supply current, delivers up to 80mW per channel into a 16 load, and has a low 0.002% THD+N. A high 86dB power-supply rejection ratio allows this device to operate from noisy digital supplies without additional power-supply conditioning. The MAX4409 includes ±8kV ESD protection on the headphone outputs. Comprehensive click-and-pop circuitry eliminates audible clicks and pops on startup and shutdown. A low-power shutdown mode reduces supply current draw to only 6A.
The MAX4409 operates from a single 1.8V to 3.6V supply, has short-circuit and thermal overload protection, and is specified over the extended -40°C to +85°C temperature range. The MAX4409 is available in tiny 20-pin thin QFN and 14-pin TSSOP packages.
MAX4409 Data Sheet
