Anaren A8520E24A91 User manual

Anaren Integrated Radio
A8520E24A91 Users
Manual
Release Date Dec 27
th
2010

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iii
Users Manual
Model A8520E24A91
Contents
1.  Overview ..........................................................................................................................................................5 
1.1.  Features.......................................................................................................................................................6 
2.  Theory of Operation........................................................................................................................................6 
2.1.  Network Topology and Nomenclature..................................................................................................9 
2.2.  Adaptive Frequency Hopping...............................................................................................................10 
2.3.  Applications.............................................................................................................................................13 
3.  Product Approvals........................................................................................................................................13 
3.1.  USA (Federal Communications Commission, FCC, ) ..................................................................13 
3.1.1.  FCC Labeling Requirements .............................................................................................................14 
3.1.2.  End User Manual..............................................................................................................................14 
3.1.3.  RF Exposure......................................................................................................................................15 
3.2.  Canada (Industry Canada, IC)...............................................................................................................15 
3.3.  Potential Interference Sources ...............................................................................................................17 
4.  Electrical Characteristics ..............................................................................................................................18 
4.1.  Absolute Maximum Ratings..................................................................................................................18 
4.2.  Operating Conditions .............................................................................................................................19 
4.3.  Pin Out......................................................................................................................................................19 
4.4.  Recommended Layout............................................................................................................................22 
4.5.  Power Supply Considerations...............................................................................................................23 
5.  Configuration and Programming ...............................................................................................................24 
5.1.  Calibrating Transmit Power ..................................................................................................................24 
5.2.  Programming...........................................................................................................................................25 

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A8520E24A91 – Users Manual Page 5 of 28
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1. Overview
The A8520E24A91 series modules are surface mount modules integrating a CC85xx
PurePath™ wireless audio transceiver with the CC2591 PA/LNA device for increased range
and an integral antenna. The module incorporates a crystal, the required RF matching and
filtering for FCC compliance as well as filtering on all digital lines for noise reduction and
sensitivity. The modules operate in the global non-licensed 2.4GHz ISM/SRD frequency band.
These radio modules are ideal for achieving low power, long range wireless connectivity without
having to deal with extensive Protocol, RF, antenna design and regulatory compliance, allowing
quick time to market. The modules are 100% tested to provide consistent performance.
The A8520E24A91 series modules have received regulatory approvals for modular devices in
the United States (FCC) and Canada (IC). The modular approval allows the end user to place
an A8520E24A91 module inside a finished product without having to perform costly regulatory
testing for an intentional RF radiator. Section 3 has information on the requirements for the end
user/integrator must fulfill to use the modules without intentional radiator regulatory testing.
The A85xxE91A91 is based on the CC85xx series chips and the CC2591 chip, both from Texas
Instruments. All control lines are provided at module level for full control of its operation. Please
see the CC85xx and CC2591 data sheet (www.ti.com) for how to operate, program and control
the module. The PurePath™ protocol is developed, by Texas Instruments, specifically for the
CC85xx series chips and specifically for digital audio distribution. At the extremes of its range,
the protocol provides graceful degradation of the audio signal usign algorithms like interpolation,
to make intermittent connectivity inaudible. Thus the A8520E24A91 series modules are not
suitable for strict data transport.
The module/protocol is configured and programmed by the OEM/Integrator to setup the specific
Codec chip used for audio conversion and to setup control buttons and manufacturer/network
addresses. This is described in detail in the CC85xx datasheet, users guide and PurePath™
documentation on Texas Instruments web (www.ti.com). Specifics pertaining to calibrating the
transmit power from the module is covered in section 5.1.
The A8520E24A91 module measures 11x19x2mm and are footprint compatible with other
family members:
A85xxE24A90 – ETSI compliant version similar to the A8520E24A91.
A85xxR24A00 – Lower power consumption, shorter range modulens.

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1.1. Features
Features:
Un-Compressed Wireless Audio
Connectivity
Pre-defined protocol
Configurable human interface
Autonomous or Hosted mode
Benefits Summary:
Operating temperature -40 to +85C
100% RF Tested in production for
repeatable performance
Common footprint for multiple family
members
No RF engineering experience
necessary
No protocol experience necessary
Only requires a 2 layer Host PCB
implementation
FCC & IC certified
No regulatory “Intentional radiator”
testing required to integrate module
into end product. Simple certification
labeling replaces testing.
2. Theory of Operation
The A8520E24A91 interfaces directly to a audio Codec chip through the I2S for audio data and
though I2C fro volume control and other Codec chip settings.
Below a block diagram is given for the A8520E24A91 module.
Antenna
oThe antenna couples energy between the air and the module. The integral
antenna provides a near omni-directional antenna pattern with high efficiency;
such that the application will work equally well in any direction. Note that the end
radiation pattern depend not only on the antenna, but also the ground plane,
enclosure and installation environment.
Filtering
oFiltering removes spurious signals to comply with regulatory intentional radiator
requirements as well as provide reduced susceptibility to power supply and
digital noise, as well as filter out RF and high frequency noise from the digital
audio and control link (I2S, I2C).
Matching
oThe matching provides the correct loading of the transmit amplifier to achieve the
highest output power as well as the correct loading for the receive LNA to
achieve the best sensitivity.
Protocol

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oThe protocol implements an entire wireless audio transport mechanism with
adaptive frequency usage, retransmission of lost packets as well as a low data
rate link for remote control purposes.

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Figure 1 the functionality of the A8520E24A91, using an integral antenna
CC259x
CC85xx
Bias RF
RF
AVdd
HGM
PAEN EN
XPAEN/GIO14
XLNAEN/GIO15
AVdd
AVdd
DVdd
IOVdd
AD1
AD2/GIO9
AD0
WCLK
BCLK
MCLK
RSTN
GIO3 GIO2 GIO1
MOSI
SCLK
CS_N
MISO
XANTP/USBP XANTN/USBM
GIO13
GIO12
SDA
SCL
VBAT
100k
29
32
33
4
28
27
26
25
24
23
21
9
20
19 18 17
16 15
14
13
8
7
6
5
11
10
2
3
1
22
12
30
34
100k
DNC (AVdd_CC259x)
VBAT
SCL
SDA
GIO12
GIO13
XLNAEN/GIO15
XPAEN/GIO14
GND
DNC (RF-Test)
GND
GND
GND
GND
GND 31 HGM
Vdd
IOVdd
AD2/GIO9
AD1
AD0
WCLK
BCLK
MCLK
RSTN
GIO3
GIO2
GIO1
MISO
MOSI
SCLK
CS_N
XANTP/USBP
XANTN/USBM
X1
X0
48MHz
100k

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2.1. Network Topology and Nomenclature
A A8520E24A91 network consists of one Protocol Master (PM) and one or two Protocol
Slave(s) (PS). The PM provides the audio reference clock and controls network association.
The PS regenerate the audio reference clock based on the packets received. Audio can be
transmitted from the PM to a PS. The device receiving the audio is called an Audio Sink, the
device sending the audio is called an Audio Source. A device can be both Audio Sink and Audio
Source at the same time (bidirectional audio will be supported in future revisions of the
firmware). The CC8520 network also includes a Data Side-Channel which is a bi-directional
data link between the PM and all PS in the network. This is further described in chapter 8.
Error! Reference source not found. Illustrates the different network topologies that can be
formed with CC8520 using the different firmware versions.

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Figure 2 A8520E24A91 topologies supported for different A8520E24A91 FW revisions
2.2. Adaptive Frequency Hopping
The purpose of using frequency hopping in a radio system is to provide diversity that allows
data throughput to be maintained even if interfering radio systems or the physical environment
(e.g. multipath fading) renders some RF channels unusable. In the 2.4 GHz ISM band, the
sheer amount of radio systems and the severity and dynamic nature of indoor fading
phenomena in typical operating environments require the use of this kind of diversity if a

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minimum data throughput is to be guaranteed (as audio streaming requires). Frequency
hopping systems can either implement a fixed sequence of channel hops or adapt its hopping
sequence dynamically to the changing environment it operates in. In order to maximize its own
chances of delivering audio data in time and to co-exist amicably with other fixed-frequency or
adaptive frequency hopping systems, PurePath Wireless uses an adaptive frequency hopping
(AFH) scheme that adapts to changing conditions within tens of milliseconds. PurePath
Wireless divides the 2.4 GHz band into 18 RF channels with 4 MHz bandwidth. A protocol
master, which controls the adaptive frequency hopping scheme for the audio network, maintains
a table with an entry for each RF channel and an associated quality-of-service (QoS) estimate
for each. Each time an RF channel is used the QoS estimate is updated based on what
happens during the timeslot. The frequency hopping algorithm separates the 18 RF channels
into two sets:
A set of 4 active channels
A set of 14 trial channels
The active channel set contains the preferred RF channels that have proven that they provide
sufficiently good quality-of-service. The trial channel set contains the remaining RF channels
that are only evaluated occasionally in order to be able to maintain an accurate picture of their
quality-of-service. If the QoS estimate of an RF channel in the active set goes beyond a
minimum threshold this channel is swapped out with the RF channel in the trial channel set that
has the best QoS estimate. Other factors play in when selecting a new RF channel to the active
channel set, such as trying to maintain a certain minimum distance in frequency between the
different active channels.

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Figure 3 Example of AFH hop sequence (active set in color, trial set in black/gray)
The frequency hopping algorithm, when no swaps between the active and trial channel sets
occur, goes through a sequence of 70 hops over the course of which every RF channel has
been used.
This 70-hop macrosequence consists of 14 repetitions of a
o5-hop microsequence during which
Each of the four active RF channels are used once
One of the trial RF channels is used once (cycling through all trial
channels over the course of a macrosequence)
Figure 3 illustrates this concept. This gives an average steady-state RF channel usage in an
audio network of:
Each of the four active channels are used 20% of the time
Each trial channel is used 1.43% of the time
The channels correspond to center frequencies as follows:
Channel Center Frequency
[MHz] Channel Center Frequency [MHz]
1 2406 10 2442
2 2410 11 2446
3 2414 12 2450
4 2418 13 2454
5 2422 14 2458

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6 2426 15 2462
7 2430 16 2466
8 2434 17 2470
9 2438 18 2474
2.3. Applications
Wireless headphones
Wireless headsets
Wireless speakers
Wireless studio equipment
Wireless microphones
3. Product Approvals
The A8520E24A91 have been designed to meet FCC and Industrie Canada (IC) regulations. In
particular the radio modules have been certified to the following.
3.1. USA (Federal Communications Commission, FCC, )
The A8520E24A91, with integrated antenna has been tested to comply with FCC CFR47 Part
15 sub-part C “Intentional Radiators. The devices meet the requirements for modular transmitter
approval as detailed in FCC public notice DA 00-1407 Released: June 26, 2000. The
A8520E24A91 module can be integrated into a finished product with obtaining subsequent FCC
approvals.
(15.19a3) The modules complies with part 15 of the FCC rules. Operation is subject to the
following two conditions: (1) this device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may cause undesired
operation.
Any changes or modifications not expressly approved by the party responsible for compliance
could void the users authority to operate the equipment.
Anaren
FCC ID: X7J-A10051701

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3.1.1. FCC Labeling Requirements
The A8520E24A91 modules have been labeled with their own FCC ID number and if the FCC
ID is not visible when the module is installed inside another device, then the outside of the
finished product into which the module is installed must also display a label referring to the
enclosed module. This exterior label can use wording such as the following:
Contains Transmitter Module FCC ID: X7J-A10051701
-or-
Contains FCC ID: X7J-A10051701
This device complies with Part 15 of the FCC Rules.
Operation is subject to the following two conditions:
(1) this device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
3.1.2. End User Manual
The end user manual should include the following statement:
This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable
protection against harmful interference in a residential installation. This equipment generates,
uses and can radiate radio frequency energy and, if not installed and used in accordance with
the instructions, may cause harmful interference to radio communications. However, there is no
guarantee that interference will not occur in a particular installation. If this equipment does
cause harmful interference to radio or television reception, which can be determined by turning
the equipment off and on, the user is encouraged to try to correct the interference by one or
more of the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver
is connected.
Consult the dealer or an experienced radio/TV technician for help.

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3.1.3. RF Exposure
All transmitters regulated by FCC must comply with RF exposure requirements. OET Bulletin 65
“Evaluating Compliance with FCC Guidelines for Human Exposure to Radio Frequency
Electromagnetic Fields” provides assistance in determining whether proposed or existing
transmitting facilities, operations or devices comply with limits for human exposure to Radio
Frequency (RF) fields adopted by the Federal Communications Commission (FCC). The bulletin
offers guidelines and suggestions for evaluating compliance.
If appropriate, compliance with exposure guidelines for mobile and unlicensed devices can be
accomplished by the use of warning labels and by providing users with information concerning
minimum separation distances from transmitting structures and proper installation of antennas.
The following statement must be included as a CAUTION statement in manuals and OEM
products to alert users of FCC RF Exposure compliance:
To satisfy FCC RF Exposure requirements for mobile and base station transmission devices, a
separation distance of 20 cm or more should be maintained between the antenna of this device
and persons during operation. To ensure compliance, operation at closer than this distance is
not recommended. The antenna(s) used for this transmitter must not be co-located or operating
in conjunction with any other antenna or transmitter.
If the A8520E24A91 module is used in a portable application (antenna is less than 20 cm from
persons during operation), the integrator/OEM is responsible for performing Specific Absorption
Rate (SAR) testing in accordance with FCC rules 2.1093.
3.2. Canada (Industry Canada, IC)
The A8520E24A91 modules has been certified for use in Canada under Industry Canada (IC)
Radio Standards Specification (RSS) RSS-210 and RSS-Gen.
Host devices which contain separately certified modules do not need to be recertified, provided
that they meet the following conditions:
a) The host device, as a stand-alone unit without any separately certified modules, complies
with all applicable Radio Standards Specifications.
b) The host device and all the separately certified modules it contains jointly meet the RF
exposure compliance requirements of RSS-102, if applicable.
c) The host device complies with the certification labeling requirements of each of the modules it
contains.
Note: Compliance of a module in its final configuration is the responsibility of the applicant. A
host device will not be considered certified if the instructions regarding antenna configuration

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provided in the original description, of one or more separately certified modules it contains, were
not followed.
3.2.1. IC Labeling Requirements
From section 3.2.1 RSS-Gen, Issue 3, December 2010, Labeling Requirements for the Host
Device:
The host device shall be properly labeled to identify the modules within the host device. The
Industry Canada certification label of a module shall be clearly visible at all times when installed
in the host device, otherwise the host device must be labeled to display the Industry Canada
certification number of the module, preceded by the words “Contains transmitter module”, or the
word “Contains”, or similar wording expressing the same meaning
From section 5.2, RSS-Gen, Issue 3, December 2010, Equipment Certification Numbers and
Labels: Every unit of Category I radio apparatus certified for marketing and use in Canada shall
bear a permanent label on which is indelibly displayed the model number and Industry Canada
certification number of the equipment model (transmitter, receiver, or inseparable combination
thereof). Each model shall be identified by a unique combination of a model number and a
certification number, which are assigned as described below in this section.
The label shall be securely affixed to a permanently attached part of the device, in a location
where it is visible or easily accessible to the user, and shall not be readily detachable. The label
shall be sufficiently durable to remain fully legible and intact on the device in all normal
conditions of use throughout the device’s expected lifetime. These requirements may be met
either by a separate label or nameplate permanently attached to the device or by permanently
imprinting or impressing the label directly onto the device.
The label text shall be legible without the aid of magnification, but is not required to be larger
than 8-point font size. If the device is too small to meet this condition, the label information may
be included in the user manual upon agreement with Industry Canada.
Label:
Contains/Contient IC: 8975A- A10051701
Notice: This device complies with Industry Canada licence-exempt RSS standard(s). Operation
is subject to the following two conditions: (1) this device may not cause interference, and (2) this
device must accept any interference, including interference that may cause undesired operation
of the device.
Avis: Cet appareil est conforme avec Industrie Canada RSS standard exempts de licence (s).
Son fonctionnement est soumis aux deux conditions suivantes: (1) cet appareil ne peut pas
provoquer d'interférences et (2) cet appareil doit accepter toute interférence, y compris les
interférences qui peuvent causer un mauvais fonctionnement du dispositif.

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For more information see: Industry Canada http://www.ic.gc.ca/
3.2.2. RF Exposure
All transmitters regulated by IC must comply with RF exposure limits as set forth in RSS-102,
Issue 4, section 4, “Exposure Limits”. Furthermore RSS-102, Issue 4, Section 2 “Certification
Requirements”, provides assistance in determining the specific requirements for compliance. If
appropriate, compliance with exposure guidelines for mobile and unlicensed devices can be
accomplished by the use of warning labels and by providing users with information concerning
minimum separation distances from transmitting structures and proper installation of antennas.
The following statement must be included as a CAUTION statement in manuals and OEM
products to alert users of IC RF Exposure compliance:
Notice: To satisfy IC RF Exposure requirements for mobile and base station transmission
devices, a separation distance of 20 cm or more should be maintained between the antenna of
this device and persons during operation. To ensure compliance, operation at closer than this
distance is not recommended. The antenna(s) used for this transmitter must not be co-located
or operating in conjunction with any other antenna or transmitter.
Avis: Pour répondre à la IC d'exposition pour les besoins de base et mobiles dispositifs de
transmission de la station, sur une distance de séparation de 20 cm ou plus doit être maintenue
entre l'antenne de cet appareil et les personnes en cours de fonctionnement. Pour assurer le
respect, l'exploitation de plus près à cette distance n'est pas recommandée. L'antenne (s) utilisé
pour cet émetteur ne doit pas être co-localisés ou fonctionner conjointement avec une autre
antenne ou transmetteur.
If the A8520E24A91 module is used in a portable application (antenna is less than 20 cm from
persons during operation), the integrator/OEM is responsible for performing Specific Absorption
Rate (SAR) testing in accordance with IC rules and methods of RSS-102.
3.3. Potential Interference Sources
The two main mechanisms that allow a PurePath wireless system to co-exist amicably in close
proximity to other 2.4 GHz radio systems are:
The adaptive frequency hopping scheme described in section 2.4.3 that ensures that RF
channels used by other radio systems are avoided
Adaptive listen-before-talk mechanism that measures energy in RF channel before
transmitting and avoids transmitting if the channel is already in use
These mechanisms together ensure that other radio systems are minimally impacted by a
PurePath Wireless audio network in normal circumstances. However, since a low-latency audio
network by its very nature transports a very time-critical data stream, both mechanisms have

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adaptive thresholds to ensure that the audio network is given its fair share of RF spectrum in
very crowded RF environments.
4. Electrical Characteristics
4.1. Absolute Maximum Ratings
Under no circumstances must the absolute maximum ratings given in Table 1 be violated.
Stress exceeding one or more of the limiting values may cause permanent damage to the
device.
Caution!
ESD sensitive device. Precaution should be
used when handling the device in order to
prevent permanent damage.

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Parameter Min Max Unit Condition/Note
Supply Voltage (Vdd) -0.3 3.6 V
Voltage on any digital pin -0.3 Vdd+0.3,
max 3.6 V
RF input power 0 dBm
Storage Temperature -50 150 ˚C
Solder reflow temperature 260 ˚C According to IPC/JEDEC J-
STD-020D
ESD <500 V
A
ccording to JEDEC STD 22,
method A114, Human body
model
ESD 400 V
A
ccording to JEDEC STD 22,
C101C, Charged Device
Model (CDM)
Table 1 Absolute Maximum Ratings
4.2. Operating Conditions
Parameter Min Max Unit Condition/Note
Supply Voltage (Vdd) 2.2 3.6 V
Supply Voltage IOVdd 1.8 3.6 V
Temperature Range -40 +85 ˚C
4.3. Pin Out
The A85xxE24Axx radio’s share a common pin-out and foot print, thus enabling the use of the
same application PCB layout for US/Europe and low power (short range) versus higher power
(long range). Below the footprint is shown.

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Figure 4 Module pin-out view