MAX9725 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – 1V, Low-Power, DirectDrive, Stereo Headphone Amplifier with Shutdown

19-3465; Rev 0; 11/04
1V, Low-Power, DirectDrive, Stereo Headphone
Amplifier with Shutdown
General Description
The MAX9725 fixed-gain, stereo headphone amplifier
is ideal for portable equipment where board space is at a
premium. The MAX9725 uses 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 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
TEMP RANGE
PIN-
PA CK A G E
TOP GAIN
MARK (V/V)
MAX9725AEBC-T* -40°C to +85°C 12 UCSP-12 ACK -2
MAX9725AETC -40°C to +85°C 12 TQFN-EP** AAEW -2
MAX9725BEBC-T* -40°C to +85°C 12 UCSP-12 ACL -1.5
MAX9725BETC -40°C to +85°C 12 TQFN-EP** AAEX -1.5
MAX9725CEBC-T* -40°C to +85°C 12 UCSP-12 ACM -1
MAX9725CETC -40°C to +85°C 12 TQFN-EP** AAEY -1
MAX9725DEBC-T* -40°C to +85°C 12 UCSP-12 ACN -4
MAX9725DETC -40°C to +85°C 12 TQFN-EP** AAEZ -4
*Future product—contact factory for availability.
**EP = Exposed paddle.
UCSP is a trademark of Maxim Integrated Products, Inc.
Features
♦ Low Quiescent Current (2.1mA)
♦ 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
♦ 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 Diagram
V_DD
MAX9725
INL
SINGLE
1.5V CELL
AA OR AAA
BATTERY
DirectDrive OUTPUTS
ELIMINATE DC-BLOCKING
CAPACITORS.
OUTL
C1P
INVERTING
PV_SS
CHARGE PUMP
C1N
V_SS
INR
OUTR
SGND PGND
Pin Configurations appear at end of data sheet.
________________________________________________________________ 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.