MAX9725 1V, Low-Power, DirectDrive, Stereo Headphone Amplifier with Shutdown

Description

The MAX9725A–MAX9725D fixed-gain, stereo headphone 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 feedback resistors. The MAX9725A–MAX9725E use 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 (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 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 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 temperature 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).

An evaluation kit is available: MAX9725EEVKIT

Key Features

Applications/Uses

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)

	Cell Phones
	MP3 Players
	PDAs
	Portable Audio Equipment
	Smartphones

Key Specifications: Headphone Amplifiers

Part Number

Hdph. Amp. V_CC
(V)

Hdph. Amp. I_CC
(mA)

Hdph. Amp. P_OUT into 32Ω
(mW)

Hdph. Amp. Half Pwr. THD+N
(%)

SNR
(dB)

PSRR
(dB)

Hdph. Amp. Ext. Gain

Hdph. Amp. Fxd. Gain
(|V/V|)

Package/Pins

Smallest Available Pckg.
(mm²)

Price

min

max

typ

@ 1% THD+N

A- Weighted

min

max

max w/pins

See Notes

MAX9725

0.9

1.8

2.1

0.02

TQFN/12

UCSP/12

3.3

$0.49 @1k

See All Headphone Amplifiers (15)

Ordering Information

Notes:

Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
* Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.

Devices: 1-21 of 21

MAX9725

Free
Sample

Buy

Status

Package:	TYPE PINS FOOTPRINT
	DRAWING CODE/VAR *

Temp

RoHS/Lead-Free?
Materials Analysis

MAX9725BETC+

Active