MAX9721 Datasheet, PDF (1/14 Pages) Maxim Integrated Products – 1V, Fixed-Gain, DirectDrive, Stereo Headphone Amplifier with Shutdown

19-3167; Rev 0; 1/04
1V, Fixed-Gain, DirectDrive, Stereo Headphone
Amplifier with Shutdown
General Description
The MAX9721 fixed-gain, stereo headphone amplifier
is ideal for portable equipment where board space is at a
premium. The MAX9721 uses a unique, patented
DirectDrive 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 (MAX9721A),
-1.5V/V (MAX9721B), and -1V/V (MAX9721C) further
reduce external component count.
The MAX9721 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
MAX9721 to operate from noisy digital supplies without
an additional linear regulator. The MAX9721 includes
±8kV ESD protection 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
1.0µA (typ).
The MAX9721 operates from a single 0.9V to 1.8V sup-
ply allowing the device to be powered directly from a
single AA or AAA battery. The MAX9721 consumes only
2.2mA of supply current, provides short-circuit protection,
and is specified over the extended -40°C to +85°C tem-
perature range. The MAX9721 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
Cellular Phones
PDAs
Smart Phones
Portable Audio Equipment
Ordering Information
PA RT
TEMP RANGE
PIN-
PA CK A G E
TOP GAIN
MARK (V/V)
MAX9721AEBC-T* -40°C to +85°C 12 UCSP-12 ABP -2
MAX9721AETC -40°C to +85°C 12 TQFN-EP** AADZ -2
MAX9721BEBC-T* -40°C to +85°C 12 UCSP-12 ABQ -1.5
MAX9721BETC -40°C to +85°C 12 TQFN-EP** AAEA -1.5
MAX9721CEBC-T* -40°C to +85°C 12 UCSP-12 ABR -1
MAX9721CETC -40°C to +85°C 12 TQFN-EP** AAEB -1
*Future product—contact factory for availability.
**EP = Exposed paddle.
Features
♦ Single Cell, 0.9V to 1.8V Single-Supply Operation
♦ Fixed Gain Eliminates External Feedback Network
MAX9721A: -2V/V
MAX9721B: -1.5V/V
MAX9721C: -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 Quiescent Current (2.2mA)
♦ 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
MAX9721
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
UCSP is a trademark of Maxim Integrated Products, Inc.
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.