WM2002 Product Brief

WM2002
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Stereo Headphone Driver with Wolfson
Ambient Noise Cancellation
DESCRIPTION
FEATURES
The WM2002 is a low power, high quality stereo headphone
driver, delivering Wolfson’s patented ambient noise cancellation.
The WM2002 supports analogue playback or voice input, and
analogue microphones for noise cancellation.

Wolfson Ambient Noise Cancellation (ANC)
- >30dB (peak), 25dB (typical) ambient noise reduction*
- Wide noise cancellation bandwidth (40Hz to 4kHz)*
- * depending on acoustic configuration
- Up to 3 banks of ANC coefficients can be programmed to
support different operating conditions

Audio inputs
- Up to 10 analogue noise cancellation microphones
- 2 single-ended or 1 differential line input per channel

Headphone driver (LDO4VOUT = 1.8V)
- 45mW per channel into 16 load
- 22mW per channel into 32 load
- Single-ended or differential (BTL) drive configuration
- -82dB THD+N for differential (BTL) drive

Integration
- On-chip DC-DC boost converter, charge-pump and LDOs
- Flexible power supply options, including single cell battery
(1 x AAA battery)
- Internal crystal oscillator

Miscellaneous
- Monitor pin to select mute / talk-through modes
- LED driver
- Tone generator for audible status indication
- Pop and click noise protection circuit
- RFI suppression
- 48-pin QFN package (7 x 7 x 0.75mm, 0.5mm pitch)
Designed for incorporation within a stand-alone headset or
headphone, the Wolfson ANC noise cancellation engine
performs ambient noise cancellation during a voice call or during
music playback.
The WM2002 provides integrated power management,
comprising a DC-DC converter, Charge Pump and LDO
Regulators. Different power supply configurations can be
supported, including operation from a single cell AAA or AA
battery, and other configurations using externally regulated
supplies.
System clocking is achieved using a crystal-controlled on-chip
oscillator. An external clock can be connected directly, if
available.
The WM2002 is configured using programmable settings stored
in an integrated non-volatile memory. The configuration stored in
the OTP memory is enabled automatically at start-up. If
required, the WM2002 can also be configured using register
control accessed using a 2-wire serial control interface.
APPLICATIONS
WOLFSON MICROELECTRONICS plc

“Pod-style” stereo ear-buds, headsets, headphones with
ANC

“Supra-Aural” stereo headphones with ANC

Mono/Stereo Bluetooth headsets with ANC
Product Brief, September 2013, Rev 4.1
Copyright 2013 Wolfson Microelectronics plc
WM2002
Product Brief
BLOCK DIAGRAM
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WM2002
Product Brief
PIN CONFIGURATION
ORDERING INFORMATION
DEVICE
TEMPERATURE
RANGE
WM2002GEFL/V
-40 C to +85 C
WM2002GEFL/RV
-40 C to +85 C
o
o
o
o
MOISTURE
PACKAGE
SENSITIVITY
LEVEL
PEAK SOLDERING
TEMPERATURE
48-pin QFN
(Pb-free)
MSL3
260 C
48-pin QFN
(Pb-free, tape and reel)
MSL3
260 C
o
o
Note:
Reel quantity = 2,200
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WM2002
Product Brief
PIN DESCRIPTION
A description of each pin on the WM2002 is provided below.
Note that, where multiple pins share a common name (eg. DGND), these pins should be tied together on the PCB.
PIN
NAME
TYPE
DESCRIPTION
1
LED
Analogue Output
Status LED output
2
DGND
Supply
Digital supplies ground
3
MON
Digital Input
Digital control input (changes ANC filter characteristics, selects mute
or talk-through mode)
4
ADDR
Digital Input
Control interface address select
5
SDA
Digital Input/Output
Control interface data input / output
6
SCLK
Digital Input
Control interface clock input
7
LDO1VDD
Supply
LDO1 supply input
8
LDO1VOUT
Analogue Output /
Supply
LDO1 output / Digital core supply
9
MICVDD
Supply
MICBIAS supply input
10
MICBIAS
Analogue Output
Bias supply for external microphones
11
LDO3VOUT
Analogue Output /
Supply
LDO3 output / Analogue supply
12
AGND
Supply
Analogue supplies ground
13
MICLN
Analogue Input
Left channel inverting analogue noise cancelling mic input
14
MICLP
Analogue Input
Left channel non-inverting analogue noise cancelling mic input
15
MICRP
Analogue Input
Right channel non-inverting analogue noise cancelling mic input
16
MICRN
Analogue Input
Right channel inverting analogue noise cancelling mic input
17
INLP
Analogue Input
Left channel non-inverting differential line input
18
INLN
Analogue Input
Left channel inverting differential line input
(can be grounded for single-ended operation)
19
INRN
Analogue Input
Right channel inverting differential line input
(can be grounded for single-ended operation)
20
INRP
Analogue Input
Right channel non-inverting differential line input
21
VMIDC
Analogue I/O
Midrail voltage capacitor connection point
22
LDO4VOUT
Analogue Output /
Supply
LDO4 output / Headphone driver supply
23
HPOUTLP
Analogue Output
Left headphone non-inverting output
24
HPOUTLN
Analogue Output
Left headphone inverting output
25
HPGND
Supply
Headphone driver ground
26
HPOUTRN
Analogue Output
Right headphone inverting output
27
HPOUTRP
Analogue Output
Right headphone non-inverting output
28
CPVOUT
Analogue Output
Charge pump output
29
BATTVDD
Supply
DC1 boost converter supply input / Battery supply
30
CFB2
Analogue I/O
Charge pump flyback capacitor connection
31
CFB1
Analogue I/O
Charge pump flyback capacitor connection
32
CPGND
Supply
Charge pump ground
33
DC1LX
Analogue I/O
DC1 boost converter inductor connection pin
34
DC1VOUT
Analogue Output
DC1 boost converter output
35
SYSVDD
Supply
System supply input
36
XTO
Analogue Output
Crystal drive output
37
XTI
Analogue Input
Crystal drive input or CMOS clock input
38
DGND
Supply
Digital supplies ground
39
PROGVDD
Supply
OTP Memory programming supply - normally tied to DGND
40
LDO2VOUT
Analogue Output /
Supply
LDO2 output / OTP memory supply
41
VREFC
Analogue I/O
Voltage reference capacitor connection
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WM2002
Product Brief
PIN
NAME
TYPE
DESCRIPTION
42
IREFR
Analogue
Input/Output
Current reference resistor connection
43
DBVDD
Supply
Digital buffer supply
44
DNC
n/a
Do Not Connect
45
DGND
Supply
Digital supplies ground
46
DGND
Supply
Digital supplies ground
47
DGND
Supply
Digital supplies ground
48
DGND
Supply
Digital supplies ground
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are stress ratings only. Permanent damage to the device may be caused by continuously
operating at or beyond these limits. Device functional operating limits and guaranteed performance specifications are
given under Electrical Characteristics at the test conditions specified.
ESD Sensitive Device. This device is manufactured on a CMOS process. It is therefore generically
susceptible to damage from excessive static voltages. Proper ESD precautions must be taken
during handling and storage of this device.
Wolfson tests its package types according to IPC/JEDEC J-STD-020 for Moisture Sensitivity to determine acceptable
storage conditions prior to surface mount assembly. These levels are:
MSL1 = unlimited floor life at <30C / 85% Relative Humidity. Not normally stored in moisture barrier bag.
MSL2 = out of bag storage for 1 year at <30C / 60% Relative Humidity. Supplied in moisture barrier bag.
MSL3 = out of bag storage for 168 hours at <30C / 60% Relative Humidity. Supplied in moisture barrier bag.
The Moisture Sensitivity Level for each package type is specified in “Ordering Information”.
CONDITION
MIN
MAX
BATTVDD
-0.3V
+1.8V
SYSVDD, MICVDD, LDO1VDD, DBVDD
-0.3V
+3.6V
PROGVDD
-0.3V
+6.75V
Voltage range digital inputs
DGND - 0.3V
DBVDD + 0.3V
Voltage range analogue inputs
AGND - 0.3V
LDO3VOUT + 0.25V
Operating temperature range, TA
-40ºC
+85ºC
Storage temperature after soldering
-65ºC
+150ºC
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WM2002
Product Brief
RECOMMENDED OPERATING CONDITIONS
PARAMETER
SYMBOL
MIN
MAX
UNIT
DC Boost converter input
(see Note 5)
BATTVDD
0.9
1.6
V
Digital buffer supply
DBVDD
1.4
2.5
V
MICBIAS supply
(see Note 4)
MICVDD
2.3
2.8
3.6
V
Digital core supply (LDO1)
TYP
LDO1VDD
1.2
3.3
V
SYSVDD
2.1
2.1
3.3
V
PROGVDD
6.25
6.5
6.75
V
System supply
(LDO2, LDO3 and LDO4)
OTP Memory programming
supply (see Note 3)
Ground
DGND, AGND, CPGND,
HPGND
0
V
Notes:
1.
Analogue and digital grounds must always be within 0.3V of each other.
2.
All supplies are completely independent from each other (i.e. not internally connected).
3.
The OTP Memory programming supply (PROGVDD) should only be present when programming the OTP. At other
times, this pin should be tied to DGND.
4.
MICVDD must be at least 300mV higher than the selected MICBIAS output voltage.
5.
When the Charge Pump is enabled, the maximum BATTVDD voltage will depend on the programmable voltage
DC1VOUT. The combined voltage BATTVDD + DC1VOUT must not exceed 3.6V.
TYPICAL APPLICATIONS
A typical application circuit is illustrated in Figure 1, showing the line inputs, ANC microphone inputs,
and stereo headphone output.
Figure 1 Typical Application
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WM2002
Product Brief
WOLFSON AMBIENT NOISE CANCELLATION (ANC)
The Wolfson (ANC) engine within the WM2002 improves the intelligibility of a voice call by using
destructive interference to reduce the acoustic energy of the ambient sound.
The ANC engine is configured using parameters that are determined during product development and
programmed on integrated OTP memory. The configuration settings are specific to the acoustic
properties of the target application. The primary acoustic elements in an application are typically the
microphones and the speaker, but other components such as the plastics and the PCBs also have
significant importance to the acoustic coefficient data.
Note that the WM2002 configuration parameters are determined during development and are
programmed in the OTP memory during production calibration. These parameters are applicationspecific, and must be recalculated following any change in the design of the acoustic elements of that
application. Any mismatch between the acoustic coefficient data and the target application will give
inferior ANC performance.
The ANC engine employs digital circuits to process the ambient noise (microphone) signals; these
inputs are digitized by two Analogue to Digital Converters (ADCs), then filtered and processed in
accordance with the acoustic parameters programmed into the WM2002. The noise cancellation
signals are then output via two Digital to Analogue Converters (DACs) and mixed with the received
voice or audio playback (line) signals.
The ANC engine can support multiple noise cancellation filter coefficients, to enable best
performance under different ambient noise conditions and different audio playback conditions. Other
user-selectable options are also available, such as mute or talk-through modes.
A high pass filter provides rejection of wind noise and other low frequency signals .Noise cancellation
is applied selectively to different audio frequency bands. A configurable low frequency limiter protects
the loudspeaker from excessive signal levels, and ensures that the ANC algorithms deliver noise
reduction in the most sensitive frequency bands, without introducing distortion in other frequency
bands.
The ANC engine is adaptive to different ambient noise levels in order to provide the most natural
sound at the headphone audio output. The integrated noise gate automatically mutes the noise
cancelling input at low ambient noise levels; this ensures that the noise cancellation performance is
optimised across a wide range of input signal conditions. The noise gate threshold level, attack time
and decay time are all configurable.
The various functions of ANC engine, as described above, combine to form a comprehensive, standalone noise-cancelling product.
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WM2002
Product Brief
RECOMMENDED EXTERNAL COMPONENTS
External
2.1V supply
SYSVDD
DC1VOUT
DBVDD
DC1LX
LDO1VDD
2.2 F
BATTVDD
2.2 F
2.2 F
CFB1
CFB2
CPGND
External
2.8V supply
DBVDD
CPVOUT
MICVDD
300
2.2 F
LDO1VOUT
LDO2VOUT
LED
LDO3VOUT
LDO4VOUT
2.2 F
2.2 F
2.2 F
DMICBVDD
2.2 F
10k
MON
PROGVDD
1 F
100k
100k
DBVDD
IREFR
1k
VMIDC
4.7 F
SDA
VREFC
100nF
1k
Control
Interface
SCLK
WM2002
4.7 F
ADDR
10k
27pF
Stereo
Headphone
MICBIAS
3.3k
4.7 F
MICLP
PreAmp*
ANC
Microphone
Inputs
HPOUTLP
4.7 F
MICLN
HPOUTLN
HPOUTRN
3.3k
4.7 F
MICRP
PreAmp*
HPOUTRP
100nF
4.7 F
MICRN
* see reference schematics for full pre-amp details
2.2 F
33
HPGND
INLP
AGND
DGND
INLN
Line Inputs
2.2 F
INRP
INRN
18pF
XTI
18pF
XTO
12.288MHz
Figure 2 External Components Diagram
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WM2002
Product Brief
The recommended external components are illustrated in Figure 2. This shows the external
connections to the audio inputs/outputs, clocking crystal and power management circuits.
Note that Figure 2 shows the recommended device configuration for use with a 2.5V external supply.
In this example, the DC1 boost converter and the Charge Pump are not used.
In other cases where the DC1 boost converter and Charge Pump circuits are used (for example,
when the WM2002 is powered from a single AAA battery), some additional external components are
required, as shown in Figure 3.
SYSVDD
DC1VOUT
DBVDD
LDO1VDD
4.7 F
2.2 F
1.5 H
DC1LX
1.2V Battery
Supply
BATTVDD
2.2 F
100nF
CFB1
CFB2
CPGND
CPVOUT
LDO1VOUT
MICVDD
LDO2VOUT
2.2 F
LDO3VOUT
LDO4VOUT
2.2 F
2.2 F
2.2 F
2.2 F
WM2002
PROGVDD
1 F
100k
100k
IREFR
4.7 F
100nF
HPGND
VMIDC
AGND
VREFC
DGND
Figure 3 External Components - DC1 Boost Converter and Charge Pump
Note that an external pre-amp is recommended for microphone input (instead of the direct connection
shown in Figure 2). Additional options for noise improvement, battery control, and for different input or
output component configurations are noted in the typical application circuit schematics. Please
contact your local Wolfson representative for details.
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WM2002
Product Brief
PACKAGE DIMENSIONS
DM079.A
FL: 48 PIN QFN PLASTIC PACKAGE 7 X 7 X 0.75 mm BODY, 0.50 mm LEAD PITCH
PIN 1
D2
D
D2/2
48
37
L
INDEX AREA
(D/2 X E/2)
1
36
EXPOSED
6
GND
PADDLE
E2/2
E2
E
12
25
24
b
aaa C
2X
13
aaa C
2X
e
(A3)
TOP VIEW
ccc C
A2
A
A1
C
SEATING PLANE
bbb C
Symbols
A
A1
A2
A3
b
D
D2
E
E2
e
L
aaa
bbb
ccc
REF
MIN
0.7
0
0.20
5.55
5.55
0.35
Dimensions (mm)
NOM
MAX
0.75
0.8
0.05
0.035
0.55
0.57
0.203 REF
0.25
0.30
7.00 BSC
5.65
5.75
7.00 BSC
5.65
5.75
0.5 BSC
0.45
0.4
NOTE
1
Tolerances of Form and Position
0.10
0.08
0.10
JEDEC, MO-220
NOTES:
1. DIMENSION b APPLIED TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.15 mm AND 0.30 mm FROM TERMINAL TIP.
2. ALL DIMENSIONS ARE IN MILLIMETRES
3. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO JESD 95-1 SPP-002.
4. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.
5. THIS DRAWING IS SUBJECT TO CHANGE WITHOUT NOTICE.
6. REFER TO APPLICATIONS NOTE WAN_0118 FOR FURTHER INFORMATION.
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Product Brief
WM2002
IMPORTANT NOTICE
Wolfson Microelectronics plc (“Wolfson”) products and services are sold subject to Wolfson’s terms and conditions of sale,
delivery and payment supplied at the time of order acknowledgement.
Wolfson warrants performance of its products to the specifications in effect at the date of shipment. Wolfson reserves the
right to make changes to its products and specifications or to discontinue any product or service without notice. Customers
should therefore obtain the latest version of relevant information from Wolfson to verify that the information is current.
Testing and other quality control techniques are utilised to the extent Wolfson deems necessary to support its warranty.
Specific testing of all parameters of each device is not necessarily performed unless required by law or regulation.
In order to minimise risks associated with customer applications, the customer must use adequate design and operating
safeguards to minimise inherent or procedural hazards. Wolfson is not liable for applications assistance or customer
product design. The customer is solely responsible for its selection and use of Wolfson products. Wolfson is not liable for
such selection or use nor for use of any circuitry other than circuitry entirely embodied in a Wolfson product.
Wolfson’s products are not intended for use in life support systems, appliances, nuclear systems or systems where
malfunction can reasonably be expected to result in personal injury, death or severe property or environmental damage.
Any use of products by the customer for such purposes is at the customer’s own risk.
Wolfson does not grant any licence (express or implied) under any patent right, copyright, mask work right or other
intellectual property right of Wolfson covering or relating to any combination, machine, or process in which its products or
services might be or are used. Any provision or publication of any third party’s products or services does not constitute
Wolfson’s approval, licence, warranty or endorsement thereof. Any third party trade marks contained in this document
belong to the respective third party owner.
Reproduction of information from Wolfson datasheets is permissible only if reproduction is without alteration and is
accompanied by all associated copyright, proprietary and other notices (including this notice) and conditions. Wolfson is
not liable for any unauthorised alteration of such information or for any reliance placed thereon.
Any representations made, warranties given, and/or liabilities accepted by any person which differ from those contained in
this datasheet or in Wolfson’s standard terms and conditions of sale, delivery and payment are made, given and/or
accepted at that person’s own risk. Wolfson is not liable for any such representations, warranties or liabilities or for any
reliance placed thereon by any person.
ADDRESS
Wolfson Microelectronics plc
Westfield House
26 Westfield Road
Edinburgh
EH11 2QB
Tel :: +44 (0)131 272 7000
Fax :: +44 (0)131 272 7001
Email :: [email protected]
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WM2002
Product Brief
REVISION HISTORY
DATE
REV
28/05/10
1.0
DESCRIPTION OF CHANGES
04/08/10
1.1
19/01/12
4.0
Updates to all sections
10/09/13
4.1
Block Diagram corrected: ADC L changed to ADC R
01/10/13
4.1
Initial version
External components drawings updated.
Ambient noise reduction and bandwidth figures updated.
Microphone pre-amp added to diagrams,
Recommended mic input capacitor changed to 4.7uF.
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CHANGED BY
PH
PH
PH
JMacD
JMacD
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