19-3049; Rev 2; 10/07
KIT
ATION
EVALU
E
AILABL
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, patented 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.
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-supply 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 shutdown 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
Notebook and
Desktop PCs
♦ 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
Smart Phones
MP3 Players
Features
Portable Audio
Equipment
Simplified Diagram
PDAs
Flat-Panel Monitors
Cellular Phones
Ordering Information
PART
PIN-PACKAGE
TOP
MARK
PKG
CODE
SHDN
MAX9722AETE
16 Thin QFN-EP* (3mm
✕ 3mm ✕ 0.8mm)
MAX9722AEUE
16 TSSOP
MAX9722BETE
16 Thin QFN-EP* (3mm
✕ 3mm ✕ 0.8mm)
MAX9722BEUE
16 TSSOP
AAX
T1633-5
—
AAY
T1633-5
—
MAX9722B
U16-1
U16-1
Note: All devices are specified over the -40°C to +85°C operating
temperature range.
*EP = Exposed paddle.
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS.
LEFT
AUDIO
INPUT
RIGHT
AUDIO
INPUT
FIXED GAIN ELIMINATES
EXTERNAL RESISTOR
NETWORK.
Pin Configurations and Typical Application Circuit appear at
end of data sheet.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX9722A/MAX9722B
General Description
