AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 1
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
Data Sheet
Part number(s)
AKU240, AKU241, AKU242
Package type
8-pin LGA top port
Data sheet revision
1.01
Release date
23 December 2014
Document number
DS45-1.01 AKU240 Family Data Sheet
Notes
Specifications are subject to change without notice.
Product photos and pictures are for illustration purposes only and may differ
from the real product’s appearance.
Data Sheet
AKU240 Family
Top port, Digital Silicon MEMS Microphones
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 2
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
AKU240 Family
Digital, HD Voice Silicon MEMS Microphones
General Description
AKU240 family consists of HD Voice quality,
top port, digital output silicon MEMS IC
microphones. They are microphones consisting
of a MEMS acoustic sensor, and an integrated
circuit (IC) with a pre-amplifier, analog-to-digital
converter, charge pump and supporting circuitry
in a small 4.0 x 3.0 x 1.0 mm3 package.
The robust digital output stream from the
AKU240 family is virtually immune to all forms
of Radio Frequency Interference (RFI) and
Electromagnetic Interference (EMI), allowing
designers the flexibility to integrate the
component anywhere on the platform and
obtain consistent SNR regardless of proximity
to displays, Wi-Fi antennae, or other sources of
interference that would degrade the signal of
conventional analog microphones.
The devices in this family provide a pulse
density modulated (PDM), single-bit digital
stream designed to enable the multiplexing of
stereo microphone data onto a single wire.
With a user selectable L/R channel option, it is
ideal for use in multiple microphone
applications.
Key Features
Digital PDM output
Omni-directional audio sensor
Excellent acoustic performance: 63dB SNR
Sensitivity: -26dBFS
Tightly controlled sensitivity tolerances:
o AKU240: ± 2dB
o AKU241: ± 1dB
o AKU242: ± 1.5dB
Compatible with Microsoft® Windows®,
LYNC® & Skype® logo certifications, Intel®
UltrabookTM and Google® ChromebookTM
requirements for digital microphones
Robust digital-output & Faraday-cage
constructed package immune to RF/EM
interference
Matched microphones in frequency and
phase response for array applications
Output supports dual-microphone, single-
wire multiplexing
Industry standard microphone interface
compatible with multiple codecs
Low current power-down mode
Lead-free surface-mountable and RoHS2
compliant
Halogen-free compliance, IEC61249-2-21
Thin profile, SMT packaging
Industry std. package: 4.00x3.00x1.00mm3
Typical Applications
Ultrabooks
Mobile phones
Media tablets
eReaders
Microphone arrays
Webcams and camera modules
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 3
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
Index of Contents
1. ABSOLUTE MAXIMUM RATINGS ........................................................................................................... 4
2. STANDARD OPERATING CONDITIONS ................................................................................................ 4
3. ELECTRICAL AND ELECTRO-ACOUSTIC SPECIFICATIONS ............................................................. 4
3.1 Timing Characteristics
3.2 Digital Logic Characteristics
3.3 Sleep Mode, and Active Mode
3.4 Radio Frequency Interference (RFI) Immunity
4. DEVICE CHARACTERISTICS .............................................................................................................. 7-8
4.1 Typical Frequency Response
4.2 IDD vs. VDD
4.3 Sensitivity vs. VDD
4.4 IDD vs. Clock Frequency
4.5 Sensitivity vs. Temperature
4.6 PSR vs. Frequency
6. PIN-OUT AND CONNECTION DIAGRAMS ............................................................................................. 9
6.1 Pin Out
6.2 Schematic
7. MANUFACTURING NOTES ..............................................................................................................10-12
7.1 Solder Reflow
7.2 Part Handling
7.3 PCB Land Pattern & Stencil Pattern
8. RELIABILITY SPECIFICATIONS ........................................................................................................... 13
9. PART MARKING INFORMATION .......................................................................................................... 13
10. PACKAGING INFORMATION .............................................................................................................. 14
11. ORDERING INFORMATION ................................................................................................................ 15
12. DOCUMENT REVISIONS ..................................................................................................................... 15
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 4
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
1. ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VDD to GND 5.5V
ESD Tolerance
Human Body Model 2000V
Machine Model 200V
Storage Temperature Range -40°C to 105°C
2. STANDARD OPERATING CONDITIONS
Operating Temperature Range -40°C to 85°C
Supply Voltage (VDD) 1.62V to 3.6V
Clock Frequency 1.00MHz to 3.25MHz
3. ELECTRICAL AND ELECTRO-ACOUSTIC SPECIFICATIONS
Unless otherwise noted, test conditions are:
VDD = 1.8V Ta = 25°C RH = 50% CLK = 2.4MHz
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
Directivity
Omni-directional
Signal to Noise Ratio (SNR)
fin = 1kHz, A-weighted, 20Hz-
10kHz
63
dB
Low Frequency Corner1
-3dB from 1kHz sensitivity value
50
100
Hz
High Frequency Corner
+3dB from 1kHz sensitivity value
11
kHz
Sensitivity1
AKU240
1kHz, 94dB SPL,
full-scale = 100% 1’s density at
PDM output of microphone
-28
-26
-24
dBFS
AKU241
-27
-26
-25
AKU242
-27.5
-26
-24.5
Total Harmonic Distortion1
(THD)
@ 100dB SPL, fin = 1kHz
1
%
@ 110dB SPL, fin = 1kHz
5
Acoustic Overload Point (AOP)
< 10% THD, fin = 1 kHz
116
dBSPL
Power Supply Rejection (PSR)
Signal on VDD = 217Hz, 100mVpp
-73
dBFS
Part-to-part phase matching
from nominal
fin = 1kHz
+ 10
Current
Consumption1
(with no load)
AKU240/242
Clock on (CLK = 2.8MHz)
800
930
A
AKU241
865
1020
A
Clock off
5
7
A
Power-up initialization
Data invalid time from clock on
28
ms
Polarity
Increasing sound pressure
Increasing 1’s density
Note 1: Max. value of parameter 100% tested
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 5
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
3.1 Timing Characteristics
(Typical performance with load capacitance <20pF and a clock frequency of 2.4MHz)
Typical Mode
Data Valid
Data Sampled
L/R SELECT Connected to
DATAL
Left
Falling clock
Rising clock
GND
DATAR
Right
Rising clock
Falling clock
VDD
Output
Parameter
Typical Value
Description
DATAR
t1
6ns
Time from falling edge of clock until
data becomes high impedance
DATAL
t2
61ns
Time from falling edge of clock until
data becomes valid
DATAL
t3
6ns
Time from rising edge of clock until data
becomes high impedance
DATAR
t4
53ns
Time from rising edge of clock until data
becomes valid
Clock
DATAL
DATAR
Left
Data
Valid
Left
Data
Valid
Right
Data
Valid
High
Impedance
High
Impedance
t1
t2
t1
t2
t3
t4
Multiplexed
Data Line
Left
Data
Valid
Left
Data
Valid
Right
Data
Valid
Z
Z
Z
High
Impedance
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 6
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
3.2 Digital Logic Characteristics
(Typical performance with load capacitance <20pF and a clock frequency of 2.4MHz)
Symbol
Parameter
Min
Max
Units
VIL MAX
Maximum level
considered a logic 0
0.4*VDD
V
VIH MIN
Minimum level
considered a logic 1
0.5*VDD
V
VOL MAX
Maximum level a driven
output logic 0 can be
0.05*VDD
V
VOH MIN
Minimum level a driven
output logic 1 can be
0.95*VDD
V
3.3 Sleep Mode, and Active Mode
The AKU24X enters Sleep Mode within 5µS of the clock signal becoming inactive (i.e. clock
frequency = 0Hz).
In Sleep Mode the microphone PDM Data output pin is in high impedance state.
The microphone returns from Sleep Mode to Active Mode 65,536 cycles after the clock becomes
active (i.e. clock frequency ≥ 1.0MHz). With a 3.072MHz clock, the microphone start-up time is
21.4ms; for a 2.4MHz clock the microphone start-up time is 27.4ms.
3.4 Radio Frequency Interference (RFI) Immunity
The AKU240 family is virtually immune to all forms of Radio Frequency Interference (RFI) and
Electromagnetic Interference (EMI). Select devices in the family have additional built-in RF
filter(s), as shown in the microphone block diagram below.
Please refer to the ordering information table in section 11, for available device options.
See ordering information table
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 7
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
4. DEVICE CHARACTERISTICS
4.1 Frequency Response
(Measured frequency response normalized to
1kHz)
4.2 IDD vs. VDD
(Measured current consumption relative to supply
voltage)
4.3 Sensitivity vs. VDD
(Measured sensitivity changes relative to supply
voltage)
4.4 IDD vs. Clock Frequency
(Measured current consumption relative to clock
frequency)
4.5 Sensitivity vs. Temperature
(Typical sensitivity changes relative to
temperature)
4.6 PSR vs. Frequency
(Typical PSR relative to frequency)
-10
-5
0
5
10
15
10 100 1000 10000
Normalized Microphone Output re:1kHz Mo
Frequency (Hz)
AKU24X
700
800
900
1000
1100
1200
1300
1 1.5 2 2.5 3 3.5 4 4.5
IDD (µA)
VDD (V)
AKU241
AKU240/242
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
1 1.5 2 2.5 3 3.5 4 4.5 5
Output (dB) VDD = 1.8V
VDD (V)
AKU24X
600
650
700
750
800
850
900
950
0.75 1.25 1.75 2.25 2.75 3.25 3.75 4.25
IDD (uA)
Clock Frequency (MHz)
AKU240/242
AKU241
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
-60 -40 -20 020 40 60 80 100
Change in Sensitivity (dB) re: 25C
Temperature (ºC)
AKU24X
-75
-73
-71
-69
-67
-65
100 1000 10000
PSR (dB)
Frequency (Hz)
AKU24X
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 8
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
5. MECHANICAL SPECIFICATIONS
Bottom View Top View Side View
Item
Dimension
Tolerance
Units
Length (L)
4.00
± 0.10
mm
Width (W)
3.00
± 0.10
mm
Height (H)
1.00
± 0.10
mm
Acoustic Port (AP)
0.400
± 0.10
mm
Solder Mask (SRO)
0.700
± 0.05
mm
Planarity
Top/Bottom
± 0.10
mm
All dimensions in mm
Tolerance ± 0.05mm unless otherwise specified
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 9
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
6. PIN-OUT AND CONNECTION DIAGRAMS
6.1 Pin-Out
(As viewed from bottom of package)
6.2 Typical Application Schematic
Pin
Name
Function
1
VDD
Power
2
L/R*
Left / Right Select
3
CLK
Clock
4
DATA
PDM Data output
5, 6,
7, 8
GND
Ground
AKU24X (LEFT)
DATA (4)
GND (5,6,7,8)
L/R SEL (2)
CLK
(3)
VDD (1)
0.1u
F
VDD
AKU24X (RIGHT)
DATA (4)
GND (5,6,7,8)
L/R SEL (2)
CLK
(3)
VDD (1)
0.1u
F
VDD
VDD
DMIC CLK
VDD
DMIC IN
GND
Audio codec
VDD
RT
Value of termination resistor
(RT) is dependent on system
design and location of resistor
(near codec or near mic).
Contact support@akustica.com
for more information.
Pin 1
Indicator
4
2
6
7
8
*Must be electrically connected to either
ground or VDD.
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 10
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
7. MANUFACTURING NOTES
7.1 Solder Reflow
Typical solder reflow profile
Average ramp-up rate
max. 3°C/s
Time ts between Tsmin (150°C) and Tsmax (200°C)
60s – 120s
Time tL above liquidous temperature TL (217°C)
60s – 90s
Peak temperature TP
max. 260°C
Time tP at TP
max. 20s
Average ramp-down rate
max. 6°C/s
Note: It is recommended to fine-tune the reflow process to optimize for variations in materials,
environment, handling, PCB board size and thickness, etc.
Please refer to AN60-Handling, Soldering, and Mounting Instructions for more detailed information
and precautions.
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 11
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
7.2. Microphone Handling
Although the microphone may not appear damaged immediately due to inappropriate handling,
there can be long term effects that affect the lifetime of the component.
Rule of thumb: The microphone is an artificial ear so treat it like your own ear.
Do not blow air into the acoustic port of the microphone for any reason. Do not subject it to
pressurized air
- e.g. when cleaning the board or other components on the same board
Do not apply vacuum to acoustic port of the microphone
- See section 5.0 for pick & place location
Do not insert liquids
- If populated circuit boards are washed, the microphone must be protected
Do not insert dust
- The production facilities must be clean
- e.g. if PCB routing/sawing is done close to the microphone after SMT assembly and
reflow
Do not insert any objects
- If assembly or rework is done manually, care must be taken that the tools cannot enter
the microphone sound port
- It is best to choose tool size so that it does not fit through the sound port of the
microphone
Do not cover the acoustic port with tape when heating during assembly or reflow
Do not apply extreme mechanical stresses on the microphone, including mechanical
shocks above 10kG or compression of the microphone package.
After a bottom port microphone has been assembled on a circuit board, protect the sound
port (now on the other side of the board) from dust, liquids, and other foreign materials as
well as any tools and pressurized air.
ESD Handling Procedures
Follow CMOS handling procedures with Akustica MEMS microphones. Handle the
microphone with proper workplace grounding to include wrist straps and ionized
airflow over open trays and reels of microphones. Do not hot-swap/hot-plug during
testing. Device pins have ESD ratings of 2kV/200V for HBM/MM respectively.
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 12
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
7.3 PCB Land Pattern & Stencil Pattern
Note: Stencil printer settings will likely require minor optimizations when transferring this stencil
pattern to a high volume production printer.
Please refer to AN60-Handling, Soldering, and Mounting Instructions for more detailed information
and precautions.
PCB Land
Pattern Layout
Suggested Solder Paste
Stencil Pattern Layout
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 13
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
8. RELIABILITY SPECIFICATIONS
The microphone sensitivity after stress must deviate by no more than 3dB from the initial value.
Test
Test Condition
1
Cold Temp Operation
Temperature = -40°C, 1000 hours (with bias)
2
Hot Temp Operation
Temperature = 105°C, 1000 hours (with bias)
3
Humidity Operation
Temperature = 85°C, RH = 85%, 1000 hours (with bias)
4
Cold Temp Storage
Temperature = -40°C, 1000 hours (without bias)
5
Hot Temp Storage
Temperature = 105°C, 1000 hours (without bias)
6
Humidity Storage
Temperature = 85°C, RH = 85%, 1000 hours (without bias)
7
Thermal Cycle
100 Cycles, -40°C to +125°C, 15min soaks, <30sec ramps
8
Vibration
Sinusoidal Vibration, 20Hz-2000Hz, 4min sweeps, 16min along each
of 3 axis, amplitude 3 limits of 20G and 0.06”
9
Mechanical Shock
10,000G shocks, 5 impacts along each of 6 axes
10
Drop Test
Using 150gm aluminum fixture, 3 drops along each of 6 axes (total 18
drops) from 1.5m height onto concrete drop surface.
11
ESD (HBM)
+/- 2000V, 1 discharge for each polarity, 11 pin combinations, 22 total
discharges per microphone
12
ESD (MM)
+/- 200V, 1 discharge for each polarity, 11 pin combinations, 22 total
discharges per microphone
13
ESD
+/- 8kV, contact discharge to lid with DUT grounded
14
Moisture Sensitivity
Level
24 hour bake at 125°C, followed by 168 hours at 85°C, 85%RH,
followed by 3 passes solder reflow (MSL Level 1)
9. PART MARKING INFORMATION
Line 1: A24XF (A = Akustica | 24X = Part Num | X = 0, 1, 2 | F = Assembly Facility)
Line 2: WWYLL (WW = Work Week | Y = Year | LL = Lot Number Processed During
Work Week)
Pin 1
A24XF
WWYLL
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 14
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
10. PACKAGING INFORMATION
10.1 Tape Specification
Notes:
1. 10 sprocket hole pitch cumulative tolerance +/- 0.2
2. Camber in compliance with EIA-481
3. Pocket position relative to sprocket hole measured as true position of pocket, not pocket
hole
10.2 Component Orientation
Ao = 4.30
Bo = 3.20
Ko = 1.30
Pin 1
A24XF
WWYLL
AKU240 Family
Digital Silicon MEMS Microphones
Data Sheet
DS45-1.01
Page 15
23Dec2014
© Akustica, Inc. reserves all rights even in the event of industrial property rights. We reserve all rights of disposal such
as copying and passing on to third parties. Bosch Group and the symbol are registered trademarks of Robert Bosch
GmbH, Germany. Note: Specifications within this document are subject to change without notice.
11. ORDERING INFORMATION
Order Number
Sensitivity
Tolerance (dB)
RF
Filter
Part
Marking
Package
Shipping
Method
Standard
Quantity
02730A0006*
02730A0007*
+/- 2
No
A240
8-Pad LGA
13” Reel
5,700
02730A0029
+/- 1
Yes
A241
02730A0019
+/- 1.5
No
A242
*Not recommended for new designs
12. DOCUMENT REVISIONS
Rev. No
Description of modification/changes
Date
0.75
Released 0.75.
26-Aug-14
0.76
Updated first page description
25-Sep-14
0.77
Updated sensitivity tolerance
06-Oct-14
0.78
Updated current consumption
20-Oct-14
1.0
Released 1.0
06-Nov-14
1.01
Updated section 4
23-Dec-14
Akustica, Inc.
2835 E Carson St. Suite 301
Pittsburgh, PA / USA 15203
sales@akustica.com
www.akustica.com
Modifications reserved | Printed in USA
Specifications subject to change without notice
