MAX9725_07 Datasheet, PDF (1/19 Pages) Maxim Integrated Products – 1V, Low-Power, DirectDrive, Stereo Headphone Amplifier with Shutdown

19-3465; Rev 2; 11/07
1V, Low-Power, DirectDrive, Stereo Headphone
Amplifier with Shutdown
General Description
The MAX9725A–MAX9725D fixed-gain, stereo head-
phone amplifiers are ideal for portable equipment where
board space is at a premium. The MAX9725E offers the
flexibility to adjust the gain with external input and feed-
back resistors. The MAX9725A–MAX9725E use a unique,
patented DirectDrive^TM architecture to produce a ground-
referenced output from a single supply, eliminating the
need for large DC-blocking capacitors, saving cost,
board space, and component height. Fixed gains of
-2V/V (MAX9725A), -1.5V/V (MAX9725B), -1V/V
(MAX9725C), and -4V/V (MAX9725D) further reduce
external component count. The adjustable gain of the
MAX9725E DirectDrive headphone amplifier allows for
any gain down to -1V/V using external resistors.
The MAX9725 delivers up to 20mW per channel into a
32Ω load and achieves 0.006% THD+N. An 80dB at 1kHz
power-supply rejection ratio (PSRR) allows the MAX9725
to operate from noisy digital supplies without an additional
linear regulator. The MAX9725 includes ±8kV ESD protec-
tion on the headphone output. Comprehensive click-and-
pop circuitry suppresses audible clicks and pops at
startup and shutdown. A low-power shutdown mode
reduces supply current to 0.6µA (typ).
The MAX9725 operates from a single 0.9V to 1.8V supply,
allowing the device to be powered directly from a single
AA or AAA battery. The MAX9725 consumes only
2.1mA of supply current, provides short-circuit protection,
and is specified over the extended -40°C to +85°C tem-
perature range. The MAX9725 is available in a tiny
(1.54mm x 2.02mm x 0.6mm) 12-bump chip-scale
package (UCSP™) and a 12-pin thin QFN package
(4mm x 4mm x 0.8mm).
Applications
MP3 Players
Smart Phones
Cellular Phones
Portable Audio Equipment
PDAs
Ordering Information
PA RT
PIN-
PA CK A G E
PKG TOP GAIN
CODE MARK (V/V)
MAX9725AEBC+T 12 UCSP-12 B12-1 +ACK
-2
MAX9725AETC+ 12 TQFN-EP* T1244-4 +AAEW -2
MAX9725BEBC+T 12 UCSP-12 B12-1 +ACL -1.5
Ordering Information continued at end of data sheet.
Note: All devices are specified over the -40°C to +85°C operating
temperature range.
+Denotes a lead-free package. T = Tape and reel.
*EP = Exposed pad.
UCSP is a trademark of Maxim Integrated Products, Inc.
Features
♦ Low Quiescent Current:
2.1mA (MAX9725A–MAX9725D)
2.3mA (MAX9725E)
♦ Single-Cell, 0.9V to 1.8V Single-Supply Operation
♦ Fixed Gain Eliminates External Feedback Network
MAX9725A: -2V/V
MAX9725B: -1.5V/V
MAX9725C: -1V/V
MAX9725D: -4V/V
♦ Adjustable Gain with External Input and Feedback
Resistors
MAX9725E: Minimum Stable Gain of -1V/V
♦ Ground-Referenced Outputs Eliminate DC Bias
♦ No Degradation of Low-Frequency Response Due
to Output Capacitors
♦ 20mW per Channel into 32Ω
♦ Low 0.006% THD+N
♦ High PSRR (80dB at 1kHz)
♦ Integrated Click-and-Pop Suppression
♦ Low-Power Shutdown Control
♦ Short-Circuit Protection
♦ ±8kV ESD-Protected Amplifier Outputs
♦ Available in Space-Saving Packages
12-Bump UCSP (1.54mm x 2.02mm x 0.6mm)
12-Pin Thin QFN (4mm x 4mm x 0.8mm)
Block Diagrams
V_DD
MAX9725A–MAX9725D
C3
SINGLE
1.5V CELL
AA OR AAA
BATTERY
INL
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS.
OUTL
C1P
INVERTING
PV_SS
CHARGE PUMP
C1N
C2
V_SS
INR
OUTR
SGND PGND
Block Diagrams continued at end of data sheet.
Pin Configurations appear at end of data sheet.
________________________________________________________________ Maxim Integrated Products 1
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.