Anaren A8520E24A91 User manual

Anaren Integrated Radio
A8520E24A91 User’s
Manual
Release Date: 02/27/12

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USER'S MANUAL
Model A8520E24A91
Contents
1. Overview ..........................................................................................................................................................5
1.1. Features.......................................................................................................................................................6
1.2. Theory of Operation..................................................................................................................................6
1.2.1. Network Topology and Nomenclature ................................................................................................8
1.2.2. Adaptive Frequency Hopping .............................................................................................................9
1.3. Applications.............................................................................................................................................10
2. Approvals and Usage ...................................................................................................................................11
2.1. Product Approvals..................................................................................................................................11
2.1.1. USA (Federal Communications Commission, FCC).........................................................................11
2.1.1.1. FCC Labeling Requirements ................................................................................................11
2.1.1.2. End User Manual ...................................................................................................................12
2.1.1.3. RF Exposure............................................................................................................................12
2.1.2. Canada (Industry Canada, IC)..........................................................................................................13
2.1.2.1. IC Labeling Requirements ....................................................................................................13
2.1.2.2. RF Exposure............................................................................................................................14
2.1.3. Europe (Conformité Européenne, )...............................................................................................15
2.2. Potential Interference Sources ...............................................................................................................16
2.3. Approved Usage .....................................................................................................................................16
2.3.1. USA and Canada...............................................................................................................................16
2.3.2. Europe ...............................................................................................................................................17
3. Electrical Characteristics ..............................................................................................................................18
3.1. Absolute Maximum Ratings ..................................................................................................................18
3.2. Operating Conditions .............................................................................................................................19
3.3. Pin Out......................................................................................................................................................19
3.4. Recommended Layout (dimensions in mm) ......................................................................................21
3.5. Power Supply Considerations...............................................................................................................22
4. Mechanical and Process................................................................................................................................24
4.1. Radio Module Details (dimensions in mm)........................................................................................24
4.2. Packaging Details (dimensions in mm)...............................................................................................24
4.2.1. Matrix Tray Packaging .....................................................................................................................25
4.2.2. Tape-Reel Packaging .........................................................................................................................25
4.3. Soldering...................................................................................................................................................26
4.3.1. Manual Mounting Procedure ...........................................................................................................26
4.3.2. Automated Mounting Procedure ......................................................................................................27
5. Configuration and Programming ...............................................................................................................29
5.1. Calibrating Transmit Power ..................................................................................................................29
5.2. Programming...........................................................................................................................................30

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A8520E24A91 –User’s Manual Page 5 of 34
Release Date 02/27/12
1. Overview
The A8520E24A91 module is a surface mount module integrating a CC8520PurePath™
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
regulatory compliance as well as filtering on all digital lines for noise reduction and sensitivity.
The module operates in the global non-licensed 2.4GHz ISM/SRD frequency band. This radio
module is 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 module has received regulatory approvals for modular devices in the United
States (FCC), Canada (IC) and Europe (ETSI). 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 2.3 has information on the requirements
for the end user/integrator to fulfill in order to use the modules without intentional radiator
regulatory testing.
The A8520E24A91 is based on the CC8520 transceiver and the CC2591 range extender chips,
both from Texas Instruments (TI). All control lines are provided at module level for full control of
its operation. Please see the datasheets for CC8520 and CC2591 (www.ti.com) for how to
operate, program and control the module. The PurePath™ protocol is developed, by TI,
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 using
algorithms like interpolation, to make intermittent connectivity inaudible. Thus the A8520E24A91
module is not suitable for strict data transport.
The module/protocol must be 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 CC8520 datasheet, users’
guide and PurePath™ documentation on TI website (www.ti.com). Specifics pertaining to
calibrating the transmit power from the module is covered in section 5.1.
The A8520E24A91 module measures 11 mm x 19 mm x 2.5 mm.

Page 6 of 34 A8520E24A91 –User’s Manual
Release Date 02/27/12
1.1. Features
Features:
Un-Compressed Wireless Audio
Connectivity
Pre-defined protocol
Configurable human interface
Autonomous or Hosted mode
2.2 to 3.6 V operation
Programmable output power up to +19
dBm
RoHS Compliant
Very small package size:
11mm x 19mm x 2.5mm
Benefits Summary:
Operating temperature-40to +85C
100% RF Tested in production for
repeatable performance
No RF engineering experience
necessary
No protocol experience necessary
Only requires a 2 layer Host PCB
implementation
FCC & IC certified, ETSI compliant
No regulatory “Intentional radiator”
testing required for integrating module
into end product. Simple certification
labeling replaces testing.
1.2. Theory of Operation
The A8520E24A91 interfaces directly to an audio Codec chip through the I2S for audio data and
I2C for volume control and other Codec chip settings.
A block diagram is given for the A8520E24A91 module in Figure 1.
Antenna
oThe antenna couples energy between the air and the module. The integral
antenna (fc= 2441.75 MHz) 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 depends 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, provides reduced susceptibility to power supply and digital noise,
and filters 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
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.

A8520E24A91 –User’s Manual Page 7 of 34
Release Date 02/27/12
Figure 1 The functionality of the A8520E24A91, using an integral antenna
Table 1 Approved Antenna
Item
Part Number
Manufacturer
Type
Gain dBi)
1
Integral part of A8520E24A91
Anaren
Integral Antenna
2

Page 8 of 34 A8520E24A91 –User’s Manual
Release Date 02/27/12
1.2.1. Network Topology and Nomenclature
An 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 regenerates the audio reference clock based on the packets received. Audio can be
transmitted from the PM to the PS. The device receiving the audio is called an Audio Sink, and
the device sending the audio is called an Audio Source. A device can be both an Audio Sink
and an Audio Source at the same time (bidirectional audio will be supported in future revisions
of the TI PurePath firmware). The A8520E24A91 network also includes a Data Side-Channel
which is a bi-directional data link between the PM and all PSs in the network.
Figure 2 A8520E24A91 topologies supported for different A8520E24A91 firmware revisions.
See TI website for latest releases

A8520E24A91 –User’s Manual Page 9 of 34
Release Date 02/27/12
1.2.2. 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 the 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
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 that 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.
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

Page 10 of 34 A8520E24A91 –User’s Manual
Release Date 02/27/12
Figure 3 Example of AFH hop sequence (active set in color, trial set in black/gray)
The channels correspond to center frequencies as given in Table 2.
Table 2 Channel to center frequency
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
6
2426
15
2462
7
2430
16
2466
8
2434
17
2470
9
2438
18
2474
1.3. Applications
Wireless headphones
Wireless headsets
Wireless speakers
Wireless studio equipment
Wireless microphones