Detailed Description

The MAX4060/MAX4061/MAX4062 are differential micro-

phone preamplifiers providing high-quality audio, opti-

mized for use in computer and mobile applications. These

devices feature rail-to-rail outputs, very high power-supply

rejection, and common-mode rejection, making them

ideal for low-noise applications. The MAX4060/MAX4061/

MAX4062 are particularly effective when layout con-

straints force the microphone amplifier to be physically

remote from the ECM microphone and/or the rest of the

audio circuitry.

The MAX4060/MAX4062 are capable of switching their

output between the differential input and an inverting

single-ended input. INT/AUX selects either the differ-

ential input or single-ended auxiliary input. In addition,

the MAX4060 has an internal bias generator to bias the

microphone in either differential or single-ended modes.

The MAX4061 includes a complete 0.3μA shutdown

mode for ultimate power savings. The differential gain of

the MAX4061/MAX4062 is set with a single resistor con-

nected between the G1 and G2 pins. The MAX4060 has

a fixed gain of 10V/V.

Differential Input

The main microphone input is a low-noise, differential

input structure. This is an almost essential element when

faced with amplification of low-amplitude analog signals

in digitally intense environments such as notebook PCs

or PDAs. Used correctly, the advantages over a single-

ended solution are:

● Better power-supply noise rejection.

● Less degradation from noise in PC board ground

planes.

● The microphone and preamplifier can be placed

physically further apart, easing PC board layout

restrictions.

PIN

NAME

FUNCTION

MAX4060 MAX4061 MAX4062

1

—

2

INT

/AUX Internal (Differential) or Auxiliary (Single-Ended) Input Select. Drive INT/AUX low

to select internal or high to select auxiliary microphone input.

2

3

3

OUT

Amplifier Output. OUT is high impedance when in shutdown mode.

3

—

—

BIAS

External Electret Microphone Capsule Bias Output. BIAS has a greater than 2kΩ

output impedance.

4

4

5

VCC

Power Supply. Bypass the VCC to GND with a 0.1µF capacitor.

5

5

6

IN+

Noninverting Differential Amplifier Input. AC-couple the audio signal into IN+.

6

6

7

IN-

Inverting Differential Amplifier Input. AC-couple the audio signal into IN-.

7

7

8

GND

Ground

8

—

9

AUX_IN

Single-Ended Input for Auxiliary Microphone. AC-couple the audio signal into

AUX_IN.

—

1

1

G2

Gain-Selectable Input. Connect an external resistor between G1 and G2 to set

the gain for the differential amplifier. (See Adjustable Differential-Gain Setting

section.)

—

2

—

SHDN

Shutdown Input. Drive SHDN high for normal operation. Drive SHDN low for

shutdown mode.

—

—

4

BIAS

External Electret Microphone Capsule Bias Output. Bypass BIAS with 1µF

capacitor to ground.

—

8

10

G1

Gain-Selectable Input. Connect an external resistor between G1 and G2 to set

the gain for the differential amplifier.

—

—

—

EP

Exposed Pad (TDFN Only). Internally connected to GND. Connect to a large

ground plane to minimize thermal performance. Not intended as an electrical

connection point.

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Analog Devices │ 8

MAX4060/MAX4061/

MAX4062

Differential Microphone Preamplifiers with

Internal Bias and Complete Shutdown

Pin Description