MAX4409 Datasheet, PDF (1/19 Pages) Maxim Integrated Products – 80mW, DirectDrive Stereo Headphone Amplifier with Common-Mode Sense

19-2842; Rev 1; 6/04
80mW, DirectDrive, Stereo Headphone
Amplifier with Common-Mode Sense
General Description
The MAX4409 stereo headphone amplifier combines
Maxim’s DirectDrive architecture and a common-mode
sense input, which allows the amplifier to reject com-
mon-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, elimi-
nating 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 connec-
tion to other grounded equipment, for example, a PC
connected to a home hi-fi system.
The MAX4409 draws only 5mA of supply current, deliv-
ers up to 80mW per channel into a 16Ω load, and has a
low 0.002% THD+N. A high 86dB power-supply rejec-
tion 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 cir-
cuitry eliminates audible clicks and pops on startup
and shutdown. A low-power shutdown mode reduces
supply current draw to only 6µA.
The MAX4409 operates from a single 1.8V to 3.6V sup-
ply, has short-circuit and thermal overload protection,
and is specified over the extended -40°C to +85°C tem-
perature range. The MAX4409 is available in tiny 20-pin
thin QFN (4mm x 4mm x 0.8mm) and 14-pin TSSOP
packages.
Applications
Notebooks
Desktop PCs
Cellular Phones
PDAs
MP3 Players
Tablet PCs
Portable Audio Equipment
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 16Ω
♦ 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 QFN (4mm x 4mm x 0.8mm)
Ordering Information
PART
TEMP RANGE
MAX4409ETP
MAX4409EUD
-40°C to +85°C
-40°C to +85°C
*EP = Exposed paddle.
PIN-PACKAGE
20 Thin QFN-EP*
14 TSSOP
Functional Diagram
LEFT
AUDIO
INPUT
MAX4409
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS
SHDN
COM
RIGHT
AUDIO
INPUT
Pin Configurations and Typical Application Circuit appear
at end of data sheet.
COMMON-MODE
SENSE INPUT ELIMINATES
GROUND-LOOP NOISE
________________________________________________________________ Maxim Integrated Products 1
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.