SMARTMESH-SHIELD02#PBF - ANALOG DEVICES

Dust Networks

Eterna Integration Guide

2 ETERNA INTEGRATION GUIDE

Table of Contents

Design Process ......................................................................................................... 4

About This Guide ...................................................................................................... 5

Audience ................................................................................................................. 5

Related Documents .................................................................................................. 5

Conventions and Terminology.................................................................................... 5

Revision History ....................................................................................................... 5

General Design Guidelines........................................................................................ 7

Schematic Design ..................................................................................................... 7

Crystal Selection ...................................................................................................... 9

System Configuration ..............................................................................................10

PCB Layout .............................................................................................................10

Eterna QFN 72 Lead Recommended Land Pattern (QFN package QH072AF2A) ...........12

Stencil Design for Ground Paddle (QFN package QH072AF2A) ..................................14

EMI Considerations ..................................................................................................14

Antenna ESD Considerations ....................................................................................16

Supply Design .........................................................................................................16

Voltage Supervision and Reset .................................................................................16

Design for Manufacture ............................................................................................17

External Memory Support ....................................................................................... 18

Schematic Design ....................................................................................................18

Device Configuration ...............................................................................................21

List of Figures

Figure 1 Eterna Example Schematic .......................................................................... 7

Figure 2 Sample 20 MHz Crystal Routing ................................................................. 11

Figure 3 Triple 20 MHz crystal footprint with solder mask over pad ............................ 12

Figure 4 72 Lead QFN Land Pattern (QFN package QH072AF2A) ................................ 13

Figure 5 Ground Paddle Stencil ............................................................................... 14

Figure 6 Eterna Extended Memory Example Schematic (page 1 of 2) ......................... 19

Figure 7 Eterna Extended Memory Example Schematic (page 2 of 2) ......................... 20

ETERNA INTEGRATION GUIDE 3

List of Tables

Table 1 Sample BOM .................................................................................................. 8

Table 2 20 MHz Crystals ............................................................................................. 9

Table 3 32 kHz Crystals............................................................................................ 10

Table 4 Recommended Land Pattern Dimensions ........................................................ 13

Table 5 External Memory Reference Bill of Materials ................................................... 20

4 ETERNA INTEGRATION GUIDE

Design Process

The design process when working with the LTC5800 based products is very similar

to the design process when working with an embedded microprocessor with some

significant and important differences covered in this section. The integration guide

focuses on the steps to design and manufacture LTC5800 based PCAs. Design of a

system solution should be completed with an understanding of the integration guide

and the network as described in either the SmartMesh IP User Guide or the

SmartMesh WirelessHART User Guide. In addition, if developing software on the

LTC5800-IPM, the software development process and API definitions are provided

on www.dustcloud.org.

After defining how the product(s) should operate in network and how the design will

be partitioned between hardware and software the design will typically take the

following steps:

1) Review the example schematic provided in this document to gain familiarity

with the required additional PCA components.

2) For customers developing software on the LTC5800-IPM, use the Fuse Table

application as described in the Eterna Board Specific Configuration Guide to

assign functions, such as SPI, I2C and GPIO to IOs.

3) Follow this document to complete the schematic design and layout.

4) Use the Fuse Table application as described in the Eterna Board Specific

Configuration Guide to create a fuse table for the design.

5) Use the Eterna Serial Programmer to load all of the required images onto the

LTC5800, the Fuse Table, Loader, Partition table and Image.

6) As described in the Eterna Serial Programmer Guide, characterize the 20MHz

crystal in the design. Update the Fuse Table with the new 20 “MHz load trim

(ox13)” value.

7) Develop and debug the design. Use the commands described in the ETERNA RF

Certification Users Guide, to perform out of network RF tests as needed.

8) Have the design pre-screened for RF certification on each revision of the PCB.

9) Develop production tests. The Eterna Serial Programmer is intended for loading

flash images in production. The LTC5800 BDSL file provides an efficient

method to test PCB interconnect.

10) The ETERNA RF Certification Users Guide provides a complete set of the

LTC5800 specific information and commands required to certify an LTC5800

based PCB worldwide. Certification can be a lengthy process requiring

significant supporting documentation from the manufacturer. Customers are

recommended to work with a certification agency familiar with the regulations

in the geography/geographies the design will be certified. The ETERNA2 RF

Certification Users Guide and the ETERNA2 Certification Package can be used

as an example for the radio specific documentation required for several

geographies, including: Canada, United States of America, the European

Economic Union, Japan, Taiwan, Korea, Australia, New Zealand and India.

ETERNA INTEGRATION GUIDE 5

About This Guide

This document provides the design guidelines essential for incorporating a

LTC5800-based design. The document covers design, layout, EMI, some device

configuration and manufacturing considerations.

Audience

This document is intended for system developers, hardware designers, and layout

engineers.

Related Documents

The following related documents are available:

Eterna Integration Guide (this guide)

600- 0180 MASTER_SCHEMATIC_ETERNA_MOTE_EUPHRATES.pdf

600- 0180 MASTER_SCHEMATIC_ETERNA_MOTE_EUPHRATES.dsn

600- 0180 ETERNA_MOTE_EUPHRATES.pcb

Eterna Board Specific Configuration Guide

Eterna Serial Programmer Guide

605-0211 MASTER_SCHEMATIC_ETERNA_MEMORY_REFERENCE_ELWHA.pdf

605-0211 MASTER_SCHEMATIC_ETERNA_MEMORY_REFERENCE_ELWHA.dsn

Conventions and Terminology

This guide uses the following text conventions:

 Computer type indicates information that you enter, such as a URL.

 Bold type indicates buttons, fields, and menu commands.

 Italic type is used to introduce a new term.

 Note: Notes provide more detailed information about concepts.

 Caution: Cautions advise about actions that might result in loss of data.

 Warning: Warnings advise about actions that might cause physical harm to the

hardware or your person.

Revision History

Revision

Date

Description

040-0102 rev 1

5/6/2011

Initial Release

040-0102 rev 2

11/8/2011

Added QH072F1A Land Pattern

Recommendations. Added Solder mask

over pad recommendations for the 20 MHz

xtal. Added recommendations for

QH072F1A paddle solder stencil design.

6 ETERNA INTEGRATION GUIDE

Corrected pin out for J3 Target SPI

programming header.

040-0102 rev 3

2/9/2012

040-0102 rev 4

7/18/2012

Added description for RF filtering options.

040-0102 rev 5

10/15/2012

Corrected BOM part number and value fields

for C6 and C16.

040-0102 rev 6

12/14/2012

Added support of external memory and

updated status of the crystal verification.

Added warning for the use of the Fractus

FR05-S1-N-0-102 chip antenna.

040-0102 rev 7

4/2/2013

Defined the differences between the -IPRA

and –IPRB performance and configuration

requirements.

040-0102 rev 8

5/8/2013

Added hyperlinks to published references.

040-0102 rev 9

1/7/2015

Added design process section.

040-0102 rev 10

6/3/2015

Added additional qualified crystals.

ETERNA INTEGRATION GUIDE 7

General Design Guidelines

Schematic Design

The schematic shown in Figure 1 includes all the external connections and

components necessary for the operation of a full-featured Eterna-based design.

Please use the corresponding Bill of Materials (BOM), see Table 1, as the definitive

reference for the part numbers and values.

Figure 1 Eterna Example Schematic

8 ETERNA INTEGRATION GUIDE

The design includes power supply filtering via C23, C16, R14, and L1. The capacitor,

C16, must always be included and must be a ceramic type (X7R is recommended for

solutions requiring a wide temperature range and X5R otherwise) in order to

support the high frequency transient currents on the Eterna power supply. Note that

R14 is present to de-Q L1. The Eterna is most sensitive to supply noise in the 100 to

2000 kHz band. The included filter will reduce noise in the most sensitive band by

roughly an order of magnitude and is not required for all supply designs. However, it

is essential to meet the Eterna’s power supply requirements for maximum noise

considering both steady state operation and transient response.

An RF shield is typically required to obtain modular certification. However, it

provides minimal benefit in typical environments in providing isolation from RF and

magnetic fields. The RF shield matching the reference designs is available from

DigiKey and LTC eCOM (part number DUST-SHLD01).

Capacitors C6 through C13 and C16 through C21 are used for on chip regulation of

power supplies and should be placed as close as possible to their corresponding

package leads. These capacitors must be X7R. L2, C22 and C28 are placeholders for

a Pi matching network, where these components may be either capacitors or

inductors as dictated by the match required. The values in the BOM represent the

current matching required for a 50-Ohm load. Warning: C29, acting as DC

blocking capacitor is required to connect Eterna’s ANTENNA pin to a DC grounded

antenna or a DC grounded ¼ wave stub.

STUB1, connected to the RF path near the antenna connector is a ¼ wave, at 2.44

GHz, microstrip terminated to ground. The ¼ wave stub provides a notch filter at

the 2nd harmonic, enabling Eterna to easily meet world wide certification

requirements while only having slight impact on radio performance. The use of the

¼ wave stub significantly improves ESD performance while having near zero cost

and is the preferred approach to lowering the 2nd Harmonic emissions. It should be

expected to trim the layout of a ¼ wave stub in layout to center the notch of the ¼

wave stub. Using the Pi matching network will have a higher production cost and

lower ESD performance; however, the Pi matching network provides customers with

the ability to tune the filter without requiring a spin of the PCB. Warning: The

Fractus FR05-S1-N-0-102 chip antenna has demonstrated high gain lobes when

used in combination with a ¼ wave stub which may prevent a design from passing

radio certification. When using the Fractus FR05-S1-N-0-102, ESD the Pi-filter

comprising L2, C22 andC28 should be used. When using a ¼ wave stub designs

need not incorporate L2, C22 and C28; however, conservative practice would be to

include the layout supporting those components and loading L2 with a 100 pF

capacitor (this allows for matching and additional filtering should it be necessary).

Should layout considerations prevent the use of a ¼ wave stub, a low pass Pi-filter

comprised of L2, C22 and C28 may be used. Board stack up should be chosen such

that the trace width of the RF path, a 50 ohm impedance, is equal to or near the pad

side for the 0201 components.

Table 1 Sample BOM

Reference

Value

Vendor

Vendor P/N

R14

Yageo

RC0603JR-070RL

237

Vishay

CRCW0402237RFKED

C7, C8, C9, C10,

C11, C12, C17,

C18, C19, C20

56 nF

Kemet

C0402C563K9RACTU

C21

220 nF

Taiyo

Yuden

JMK105B7224KV-F

C22*, C28*

1 pF

Murata

GRM610C0G010B25K500

ETERNA INTEGRATION GUIDE 9

Reference

Value

Vendor

Vendor P/N

C29

100 pF

Murata

GRM0335C1E101JD01D

C6,C16

100 nF

Murata

GRM155R71C104KA88D

C23

2.2 µF

Murata

GRM188R71A225KE15D

C13

470 nF

TDK

C1005X5R0J474K

2.2 µH

Murata

LQM18FN2R2M00D

L2*

3.3 nH 0201 or

2.7 nH 0402

Coilcraft

0201DS-3N3XJL

0402CS-2N7XJL

JST

AYU1-1P-02676-120

32.768 kHz

ECS Inc.

ECS-.327-12.5-17X-TR

20.000 MHz

ECS Inc.

ECS-200-CDX-0914

J2, J3

5x2 header

Molex

87831-1020

SH1

Fotofab

DUST-SHLD01

Note: * - these components are not needed if a ¼ stub is implemented.

Crystal Selection

The 20 MHz source (either X2, X4 or X5 on the schematic) is required for radio

operation. The 32 kHz source, either X1 or X3 on the schematic, is required for long

term precise timing. For mesh network applications, selection of crystal sources is

significant as Eterna mesh networks depend on maintaining timing more precise

than provided by the crystal accuracy itself. While alternate sources for the 20 MHz

and 32 kHz crystals may operate without issue, it is strongly recommended that

designs incorporate crystals from Table 2 and Table 3 below, such that the designs

will benefit from the verification performed against those crystals. Commonly

available crystals have failed Dust Networks qualification suite. Network

performance for unverified crystals can not be guaranteed.

Selection of a particular 20MHz crystal for use in a design should be matched by

selecting the same crystal in the Board Support Parameter “20 MHz xtal Part

Number” in the Fuse Table application. The ECS-200-CDX-0998 and the Kyocera

CX3225SB20000F0FZZC1 may be used interchangeably with a single Fuse Table

image.

Table 2 20 MHz Crystals

Vendor

Part Number

Form Factor

ECS

ECS-200-CDX-0998*

3.2x2.5x0.8mm, SMD

KYOCERA

CX3225SB20000F0FZZC1*

3.2x2.5x0.9mm, SMD

ECS

ECS-200-CDX-0778

2.5x2.0x0.55mm, SMD

ECS

ECS-200-CDX-0914

7.6x4.1x2.3mm, SMD

* These crystals are both footprint compatible and will work with a single Fuse Table

configuration. As a result one can be second sourced for the other.

10 ETERNA INTEGRATION GUIDE

Table 3 32 kHz Crystals

Vendor

Part Number

Form Factor

ECS

ECS-.327-12.5-17X

8.7x3.7x2.5mm, SMD

Abracon

ABS07-32.768KHZ-4-T

3.2x1.5x0.9mm, SMD

ECS

ECS-.327-12.5-34B-TR

3.2x1.5x0.9mm, SMD

NDK

NX3215SA-32.768K-STD-MUA-8

3.2x1.5x0.9mm, SMD

System Configuration

Eterna supports hardware and software configuration of devices via two tables

stored in the first page of Eterna’s flash. These configurations are set by creating a

2kB image via the Eterna Board Specific Configuration application described in the

Eterna Board Specific Configuration Guide and written to Eterna’s flash via the

Eterna Serial Programmer described in the Eterna Serial Programmer Guide.

Eterna includes a hardware engine for configuring the device immediately on exit

from power-on reset and is the preferred method for configuring the

multifunction IO. Configuration controls include the mapping of pins to functions,

setting drive strength, IO direction, GPIO output value, pull enable, pull direction,

and input enable. In addition the Eterna’s Hardware lock key, a user defined key

that locks all external access (including debug access) to flash and RAM memory,

can be set via the Eterna Board Specific Configuration application. The Eterna

Board Specific Configuration application inherently provides an expedient method

to map out the functions assigned to Eterna’s multifunction IO, greatly reducing the

need to manually cross reference multiple tables in the product’s data sheet.

PCB Layout

Eterna-based designs should adhere to the following layout-sensitive guidelines:

1. The trace from the ANTENNA pin to the antenna connector should be 50-Ohm

characteristic impedance. Note that the drawn trace width will be a function of

the dielectric constant, height of the dielectric and the thickness of the plating.

For example, for an 8-mil FR4 substrate with 0.5 oz copper plating, the width

for a 50-Ohm trace is 14.5 mils. Keep all other active signals as far as possible

from this trace and at least five times the dielectric height to the RF ground

plane. No signals should be routed between this trace and its respective ground

plane.

2. The ground return for the ANTENNA pin is through the QFN paddle. The layout

should ensure that at least a 25 mils wide ground (and preferably as wide as

practically manageable) continues in a straight line through to the points where

the paddle is via stitched to ground.

3. Capacitors C6 through C13 and C16 through C21 should be placed no further

than 250 mils from their respective leads. All power supply traces for VSUPPLY,

VPRIME, VDDPA, VOSC, VCORE and VDDA should be a minimum of 25 mils

wide.

4. Noise from other digital signals can couple onto the 20 MHz crystal reference

and impair the radio performance. Traces from the 20 MHz crystal should be

routed on the same outside layer as the Eterna QFN, with no overlap from any

ETERNA INTEGRATION GUIDE 11

other signal, as shown in Figure 2. The adjacent layer on the PCB shall provide a

ground plane, isolating the crystal traces from other traces on the PCB. The

crystal leads and the corresponding traces should be surrounded by a co-planer

ground trace to reduce coupling onto the crystal pads and traces. If a shield is

present in the design the signals should rout through an opening in the exposed

metal trace described in the RF shield section below.

Figure 2 Sample 20 MHz Crystal Routing

5. Noise from other digital signals can couple onto the 32-kHz crystal reference

creating timing jitter for the low frequency clock. Traces from the 32 kHz crystal

should be routed on the same outside layer as the Eterna QFN, with no overlap

from any other signal. The adjacent layer on the PCB shall provide a ground

plane, isolating the crystal traces from other traces on the PCB. If a shield is

present in the design the signals should rout through an opening in the exposed

metal trace described in the RF shield section below.

6. In applications where EMI necessitates the inclusion of an RF shield, a thick

outside layer exposed metal trace, tapped to ground approximately every 100 to

250 mils, should encircle (save the path for the antenna and crystal signals) the

device. Determination for the size of the shield should account for the routing

challenges placed due to the limited area to create vias from the outside layer

with the QFN to other layers for routing. The shield will create a bounding box

on the outside with the QFN paddle will create an internal bounding box. Also,

consider the number of connections that should be as short as possible for the

required power supply components that should be placed near the QFN leads.

12 ETERNA INTEGRATION GUIDE

7. The recommended land pattern for the smaller footprint crystals, 3.2mm x

1.5mm, includes pads that are much wider than the crystal leads. Creating a

dual footprint for both the large and smaller form factor 20 MHz crystals further

enlarges the pad size. The large pad size can result in crystals drifting from their

placement during the reflow process. Reducing the pad size reduces a design’s

robustness to vibration, which could be an important factor given the mass of

either the larger 20 MHz crystals. With the purpose of reducing the drift of the

crystal during the reflow process, it is recommended to include additional solder

mask over the pad as show in red in Figure 3.

Figure 3 Triple 20 MHz crystal footprint with solder mask over pad

An example layout corresponding to the provided example schematic, can be found

in 600- 0180 ETERNA_MOTE_EUPHRATES.pcb, a PADs formatted PCB file and

it’s corresponding gerber files.

Eterna QFN 72 Lead Recommended Land Pattern (QFN package QH072AF2A)

Two common practices for defining land patterns are Non Solder Mask Defined,

NSMD, and Solder Mask Defined, SMD. Given the lead pitch of the QH072AF2A

package and that tolerances for metal etch are commonly more precise than solder

mask deposition, the use of NSMD land patterns is recommended and documented

here. The solder mask opening should provide sufficient margin for registration

tolerance to avoid solder mask infringing on the pad, typically 60 to 75 um from the

edge of the pad and the solder mask. Note that the lead length for the corner

leads are shorter than the non-corner leads.

While Eterna does not require the ground paddle to dissipate significant thermal

energy, the paddle provides the RF return path and should both be low inductance

and provide a path near the ANTENNA pin for a return path. A pattern of 3 x 3 vias

separated over a 4.5 mm x 4.5 mm square is recommended. Vias should be plugged

with epoxy or tented to avoid solder wicking into the plated through holes,

potentially resulting in low package standoff height or secondary reflow on the

reverse side of the PCB.

ETERNA INTEGRATION GUIDE 13

Land Pattern and Via placement dimensions are provided in Table 4 and illustrated

in Figure 4.

Table 4 Recommended Land Pattern Dimensions

Symbol

Description

Dimension (mm)

Min

Typ

Max

Lead land width

0.25

0.29

Lead land length

0.85

Corner Lead land length

0.75

Lead land pad inside dimension

8.70

8.80

Corner lead land pad inside

dimension

8.90

9.00

Lead land pad outside dimension

10.50

Ground paddle land width

6.15

Center first lead to package edge

0.75

Ground via spacing center to

center

4.5

Figure 4 72 Lead QFN Land Pattern (QFN package QH072AF2A)

14 ETERNA INTEGRATION GUIDE

Stencil Design for Ground Paddle (QFN package QH072AF2A)

As the Eterna (QH072AF2A QFN) includes a 6 x 6 mm ground paddle, appropriate

care should be taken in designing the solder stencil. Large apertures in the solder

stencil can lead to:

1) inadequate solder paste due to “scooping”

2) splatter and solder balling as a result of outgassing

3) increased standoff mismatch between leads on a QFN package

4) solder bridging

It is recommended to use smaller openings separated by at least 0.2 mm, with a

coverage of between 50 and 80%. An example of such a stencil with 1.6 mm

squares separated by 0.3 mm, providing 64% coverage is shown in Figure 5.

Figure 5 Ground Paddle Stencil

EMI Considerations

Like all radio devices, Eterna can be sensitive to EMI. In cases where the

deployment environment is known to have very low EMI, both in and out of band,

the RF shield may not be necessary. It should be noted; however, that for modular

radio certifications, regulatory bodies regularly require an RF shield. The following

considerations should be taken into account when selecting an RF shield for an

Eterna based design:

1. The RF shield should provide at least 0.5 mm (20 mils) clearance around the

Eterna package in the X and Y dimensions.

2. The RF shield should provide 1 mm (40 mils) of clearance above the top of the

PCB to the inside of the shield.

3. The RF shield should have a minimum of three asymmetric through hole pins.

In vibration intensive use cases, a minimum of four through hole pins should be

used and the RF shield should mate those pins to plated mounting holes and the

majority of the shield perimeter should be soldered to the PCB.

4. Ideally, the RF shield should allow for the smallest opening, but still greater

than 5 times the dielectric thickness between the antenna trace and the ground

plane from edge/top of the antenna trace to the nearest edge of the shield, for

ETERNA INTEGRATION GUIDE 15

the antenna signal to exit on the top layer of the PCB. This needs to be traded-off

against the cost of manufacture, including the ability to clean the PCB

underneath the shield.

5. In environments with high AC and DC magnetic fields, the use of a mu-metal

shield is recommended. Further, RF shield thickness is application dependent.

Consult your Linear FAE for support.

16 ETERNA INTEGRATION GUIDE

Antenna ESD Considerations

The antenna pin is a particularly sensitive node for electro-static discharge (ESD)

since it must detect small, high-frequency signals. ESD damage to the Eterna may

result in decreased receive or transmit performance, or other system failure. Many

applications for the Eterna have an exposed antenna that provides an entry point for

ESD events. Proper consideration of antenna design as well as antenna protection

can substantially improve ESD robustness in harsh environments.

A radome (protective covering) made of highly resistive material may be used to

prevent direct contact with the antenna and/or dissipate charge. To avoid ESD

events caused by triboelectric charging generated by wind passing over the antenna

in dry climates, the radome design should consider bulk and surface resistivity as

well as the size of the gap between the antenna metal and the interior of the radome.

In general, DC-grounded antennas (the antenna and ground have a DC short)

provide superior protection to ESD events. DC-grounded antennas are highly

recommended in harsh environments. Additionally, a DC path-to-earth ground

should be provided whenever possible to help bleed off accumulated charge from the

antenna as well as leak charge from the radome.

While these general guidelines should improve robustness to ESD events, individual

implementations may have unique factors that complicate ESD protection. Upon

request, your Linear FAE can provide contact information for an external consultant

able to perform a review for ESD and other system considerations.

Supply Design

Due to the heavy duty cycling, the Eterna’s current consumption can change

substantially over a short period. This does not represent an issue for systems with

supplies having low source impedance (less than 5 Ohms). Regulated supplies,

however, may have difficulty in the sudden changes in current consumption (more

than an order of magnitude in less than 1 µs), resulting in transient voltages on the

supply co-incident with the higher current consumption of the radio operation. To

ensure proper operation of the radio, a supply should be able to ramp from 250 µA

to 10 mA in less than 1 µs without generating a transient greater than 200 mV. For

systems with regulated supplies, consultation with your Linear Technology FAE is

strongly recommended.

The Eterna can be configured to support current limited supplies. Contact your

Linear FAE for details.

Voltage Supervision and Reset

The Eterna includes a power-on reset to safely set its own state during power up,

and includes a brown-out circuit that immediately halts flash erase cycles and

interrupts flash write cycles at the next 32-bit boundary, generating an interrupt to

the CPU and maintaining state for the CPU to correct should the power supply

return to normal operating levels. In the interest in avoiding flash corruption, it is

not considered best practice to connect the Eterna RESETn lead to a voltage

supervisor or to asynchronously assert RESETn without previously suspending

network and flash activity.

ETERNA INTEGRATION GUIDE 17

Design for Manufacture

The schematic shown in Figure 1 includes a header, J3, intended to provide an

interface to allow programming the Eterna. A mechanism to program the Eterna for

manufacturing is needed and prudent for design development. The header provides

connectivity through a cable to the DC9010 USB serial programmer described in the

Eterna Serial Programmer Guide. Software provided for controlling the

programmer allows users to program and verify pages in flash, and optionally the

entire flash contents. Note that the DC9010 programmer has a limited capability for

supplying current to the DUT – see the Specifications section of the Eterna Serial

Programmer Guide for details. A BDSL file for the LTC5800 can be found here.

18 ETERNA INTEGRATION GUIDE

External Memory Support

Without the addition of external SRAM, Eterna IP managers are limited to

supporting networks of 32 or fewer motes. External memory may be added to

Eterna IP Manager products to:

1) manage networks of up to 100 motes – and / or –

2) increase throughput of the manager from 24 to 36 packets per second

The LTC5800-IPRA is limited to supporting 32 motes with or without external

RAM; however, a license key can be purchased to raise the limit to 100 motes,

provided the external RAM is populated. To obtain a license key, a certificate must

first be purchased. Contact your Linear Sales representative for details on how to

order license key certificates. The certificate contains a product key and instructions

for requesting the generation of a license key, which typically takes one to two

business days to receive a license key. License keys are entered via either the set

config command documented in SmartMesh IP Manager CLI Guide or the

setLicense command documented in the SmartMesh IP Manager API Guide. The

LTC5800-IPRA by itself has a maximum sustained throughput of 24 packets per

second. The LTC5800-IPRB with external SRAM support has a maximum sustained

throughput of 36 packets per second.

The LTC5800-IPRB supports networks of up to 100 motes and has a maximum

throughput of 36 packets per second; however, external RAM must be provided.

Schematic Design

The schematic shown in Figure 6 and Figure 7 includes all the external connections

and components necessary to add the external RAM. The schematic differs from the

base schematic shown in Figure 1 in that:

1) CLI access is on UARTC1, not UARTC0

2) Mapping of external bus signals to Eterna’s general purpose function pins

3) The Memory, latches and pulse generators shown in Figure 7

The reference Bill of Materials (BOM) for the addition components needed for the

external memory interface is shown in Table 1. Common footprints exist for

128Kbyte, 256Kbyte and 512Kbyte RAMs. While the LTC5800-IPRB only requires

128Kbyte of RAM, it is recommended to include support for 256Kbyte and 512Kbyte

RAM variants in the layout, providing flexibility in using alternate equivalent

components during manufacture.

ETERNA INTEGRATION GUIDE 19

Figure 6 Eterna Extended Memory Example Schematic (page 1 of 2)

20 ETERNA INTEGRATION GUIDE

Figure 7 Eterna Extended Memory Example Schematic (page 2 of 2)

Eterna’s External memory function has been tested with the BOM options shown in

Table 5. The RAM components shown have been selected for low power operation

and their use will result in an increase of a few uA of current consumption. For

designs that are not energy constrained, substitution of general purpose RAMs with

equal or faster speed grades should be possible. Substitution of the multi-function

logic and octal latch components should be done carefully to maintain the timing

generated by the pulse generation circuits.

Table 5 External Memory Reference Bill of Materials

Reference

Value

Vendor

Vendor P/N

R6,R7,R9

Panasonic

ERJ-1GE0R00C

100 kOhm

Panasonic

ERJ-1GEJ104C

R8,R10

499 Ohm

Vishay

CRCW0201499RFKED

C25,C27

30 pF

Murata

GRM0335C1E300JD01D

C21,C22,C23,

C24,C26

100 nF

Murata

GRM155R71C104KA88D

ETERNA INTEGRATION GUIDE 21

Reference

Value

Vendor

Vendor P/N

128K x 8-bit RAM

Cypress

CY62128EV30LL-45ZAXI

U3 Alternate

128K x 8-bit RAM

Renasas

R1LV0108ESA-5SI#B0

U5, U6

Multifunction

Logic

NXP

74AUP1G58GM, 132

U2, U4

Octal Latch

NXP

74AHC573BQ,115

logic and octal latch components should be done carefully to maintain the timing

generated by the pulse generation circuits.

logic and octal latch components should be done carefully to maintain the timing

generated by the pulse generation circuits.

Device Configuration

Per the Eterna Board Specific Configuration Guide, the LTC5800-IPRA or

LTC5800-IPRB must have both the IO configured and the board support parameters

set to function correctly. The IO is configured by enabling the “External Bus” check

box on the IO Configuration page. On the “Board Support Parameters” page the

“CLI Port Selection (0x03)” check box must be checked and the “UARTC1” option

must be set in the selection box. In addition, the “IP Manager Ext. Memory Size

(0x17)” check box must be checked and the appropriate LTC –dash option / memory

foot print option must be set in the selection box. Please see the Eterna Board

Specific Configuration Guide, for complete details on all of the IO Configuration

settings and Board Support Parameters.

22 ETERNA INTEGRATION GUIDE

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Dust Networks, Inc is a wholly owned subsidiary of Linear Technology Corporation.

Document Number:

040-0102 Eterna Integration Guide

Last Revised:

June 11, 2015

Document Status

Product Status

Definition

Advanced Information

Planned or under

development

This document contains the design specifications for product development. Dust

Networks reserves the right to change specifications in any manner without notice.

Preliminary

Engineering samples

and pre-production

prototypes

This document contains preliminary data; supplementary data will be published at a

later date. Dust Networks reserves the right to make changes at any time without

notice in order to improve design and supply the best possible product. The

product is not fully qualified at this point.

No identification noted

Full Production

This document contains the final specifications. Dust Networks reserves the right to

make changes at any time without notice in order to improve design and supply the

best possible product.

Obsolete

Not in production

This document contains specifications for a product that has been discontinued by

Dust Networks. The document is printed for reference information only.

ETERNA INTEGRATION GUIDE 23