CD326x Audio Interface Transmitter for Specially Enabled Headsets

1 Features

• Compatible with specially enabled audio interfaces

(iPhone® and iPad®)

• Low quiescent current

– Button mode (microphone not in use): 3µA

– Tone mode (microphone in use): 110µA

• Miniature DSBGA (YZP) package

• ESD performance

– Human body model: 2000V

– Charged device model: 500V

2 Applications

• Wired headset signaling transmitter compatible

with systems including a specially enabled audio

interface

• See Chapter 54: Headset Remote and Microphone

Transmitter in Accessory Design Guidelines for

Apple Devices from the Apple Development Page

3 Description

The CD326x supports two operating modes; button

mode and tone mode. Button mode offers no

microphone support. Button mode passes the DC

voltage from an external switch-resistor network (tied

to the REM pin) to the MIC pin to measure the

voltage externally. Tone mode offers microphone

support and senses button presses based on an

external switch-resistor network (tied to the REM

pin). Tone mode generates corresponding ultrasonic

signals that are superimposed (via a driver output on

the TONE pin) on the system MICBIAS line. These

signals control audio functions when connected to

a specially enabled audio interface. The input DC

bias level provided on the MIC pin controls button or

tone mode selection. During tone mode, the CD326x

also provides functionality to control or bias an

external MEMS (micro-electrical-mechanical systems)

technology microphone module.

Package Information

PART NUMBER

PACKAGE(1)

PACKAGE SIZE(2)

CD3268

YZP (DSBGA, 6) 1.45mm × 0.95mm × 0.5mm

CD3269

YZP (DSBGA, 6) 1.45mm × 0.95mm × 0.5mm

(1)

For all available packages, see the orderable addendum in

Section 11

(2)

The package size (length × width × height) is a nominal value

and includes pins, where applicable

Device Information

PART NUMBER

TX ACK TONE

FREQUENCY (kHz) (TYP)

EQUIVALENT

BUTTON

CD3268

130

1

CD3269

165

2

VSHUNT

MIC

TONE

MICPWR

GND

REM

CD326x

RTONE

CTONE

S0

RVSHUNT

CVSHUNT

S1

R2

R3

R4

S2

S3

S4

Microphone

module

VMIC

Host system

(including

specially-enabled

audio interface)

INT

MICBIAS

GND

R1

Simplified Application

CD3268A, CD3269A

SCHS463 – MAY 2025

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.