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RN-171-DS
RN-171 802.11 b/g Wireless LAN Module
Features
• FCC/CE/IC certified 2.4-GHz IEEE 802.11b/g
transceiver
• Small form factor: 1050 x 700 x 130 mil
• Configurable transmit power: 0 to 10 dBm
• RF pad connector for antennas
• Certified antennas: chip antenna, 4” dipole, PCB
trace, and wire antenna
• Ultra-low power: 4-uA sleep, 38-mA Rx, 120-mA Tx
at 0 dBm
• High throughput: 921 Kbps TX, 500 Kbps RX data
rate with TCP/IP and WPA2 over UART, up to
2 Mbps over SPI slave
• 8-Mbit flash memory and 128-KB RAM
• 10 general-purpose digital I/O pins
• 8 analog sensor interfaces
• Real-time clock for wakeup and time stamping
• Accepts 3.3-V regulated power supply or 3-V
battery
• Supports ad hoc and infrastructure networks
• Complete on-board TCP/IP networking stack
• Environmentally friendly: RoHS compliant
Applications
• Remote equipment monitoring
• Telemetry
• Industrial sensors and home automation controls
• Home automation
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Description
The RN-171 module is a complete, standalone TCP/IP
wireless networking module. With its small form factor
and extremely low power consumption, the RN-171 is
perfect for mobile wireless applications such as asset
monitoring, sensors, and portable battery operated
devices. It incorporates a 2.4-GHz radio, 32-bit SPARC
processor, TCP/IP stack, real-time clock, crypto
accelerator, power management, and analog sensor
interfaces.
The module is preloaded with firmware to simplify
integration and minimize application development. In
the simplest configuration, the hardware only requires
four connections (PWR, TX, RX, and GND) to create a
wireless data connection. Additionally, the analog sensor
inputs can connect to a variety of sensors such as
temperature, audio, motion, and acceleration. The ability
to go into deep sleep mode and automatically scan and
associate to an access point when awake makes the
RN-171 suitable for roaming applications. The RN-171
also includes a built-in HTML client to post serial UART
data or sensor data to a web server automatically.
Figure 1. RN-171 Block Diagram
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128-KB
RAM
2.4-GHz
Radio
2.4-GHz
PA
Crypto
accelerator
32-Bit
CPU
802.11 b/g
MAC/PHY
ADC
2-MB ROM
Timers
SPI
GPIO
SDIO
Sensor Interface
2-KB NVM
Pwr
Mgmt
Flash
Memory
SPI
GPIO
UART
VDD IN
VDD BATT
2.4 GHz
TX/RX
Trace for
PCB Antenna
RN-171
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OVERVIEW
• Host data rates up to 921 Kbps TX, 500 Kbps RX for the UART, up to 2 Mbps over the SPI slave
• Intelligent, built-in power management with programmable wakeup
• Real-time clock for time stamping, auto-sleep, and auto-wakeup
• Configuration using simple ASCII commands
• Software controlled transmit power (0 to 10 dBm) for ultra-low-power applications
• Memory: 128-KB RAM, 2-MB ROM, 2-KB battery-backed memory, 8-Mbit flash
• Secure Wi-Fi authentication using WEP-128, WPA-PSK (TKIP), and WPA2-PSK (AES)
• Built-in networking applications: DHCP, UDP, DNS, ARP, ICMP, TCP, and HTML client
• 802.11 power save and roaming functions
• Castellated pads for reliable soldering
The module’s moisture sensitivity level (MSL) is 1. The modules size and weight are:
• Size—1.06 x 0.70 x 0.12 inches (27 x 18 x 3.1 mm)
• Weight—0.09 oz
Tables 1 through 5 provide detailed specifications for the module.
Table 1. Environmental Conditions
Parameter
RN-171
Temperature Range (Operating)
-40 oC ~ +85 oC
Temperature Range (Storage)
-40oC ~ +85 oC
Relative Humidity (Operating)
≤90%
Relative Humidity (Storage)
≤90%
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Table 2. Electrical Characteristics (Provisional)
Supply Voltage
Min.
Typ.
Units
Supply voltage (VBATT option)
3.0
3.3
VDC
Digital input
Input logic high VIH
2.3
VDC
Input logic low VIL
VDC
Digital Output Drive
GPIO 4, 5, 6, 7, 8
24
mA
GPIO 9, 10, 11, 12, 13
8
mA
Power Consumption
Sleep
4
uA
Standby (doze)
-
15
mA
Connected (idle, RX)
40
mA
Connected (TX)*
0 dBm
120
mA
12 dBm
190
mA
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Table 3. Analog Sensor Inputs
Parameter
Value
Sensor 0, 1, 2, 3 wakeup detection threshold
500 mV
AD sensor 0 - 7 measurement range
0 - 400 mV (Do not exceed 1.2-V DC)
Resolution
14 bits = 12uV
Accuracy
5% un-calibrated, .01% calibrated
Minimum conversion time
35 us (5 kHz over Wi-Fi)
Sensor power (pin 33) output resistance 3.3V
10 ohms, maximum current = 50 mA
Table 4. Radio Characteristics
Parameter
Specifications
Frequency
2,402 ~ 2,480 MHz
Modulation
802.11b compatibility: DSSS (CCK-11, CCK-5.5, DQPSK-2, DBPSK-1)
802.11g: OFDM (default)
Channel intervals
5 MHz
Channels
1 – 14
Transmission rate (over the air)
1 – 11 Mbps for 802.11b / 6 – 54 Mbps for 802.11g
Receive sensitivity
-83 dBm typical
Output level (class1)
-2 dBm to +12 dBm (configurable via software)
Table 5. Transmit Power
Output Power
802.11 b (2 Mbps)
Current in mA Note (1)
802.11 g (24 Mbps)
Current in mA Note (1)
0
120
135
2
130
150
4
170
190
6
175
200
8
180
210
10
185
225
12
190
240
Note:
1. Measured at 3.3-V DC VCC. The power consumption is the average power, active during actual power consumption.
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TYPICAL APPLICATION SCHEMATIC
Figure 2 shows a typical application schematic with a battery boost circuit; Figure 3 shows a typical schematic with a linear
regulator.
Figure 2. Application Schematic with Battery Boost Circuit
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Figure 3. Typical Application Circuit with Linear Regulator
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Figure 4 shows the pin pads and Table 6 describes the pins.
Figure 4. Pin Pads
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48
49
28
29
30
31 33
3432
21
22
23
24
25
26
27
Top View
35 37 39 41 43 45
36 38 4240 44 46
47
20
19
18
17 15
1416
13 11 9 7 5 3
12 10 6842
1
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Table 6. Pin Description
Pad
Number
Signal Name
Description
Optional
Function
Direction
Note (1)
1
GND
Ground.
-
2
Unused
Do not connect.
No Connect
3
Unused
Do not connect.
No Connect
4
GPIO9
Enable ad hoc mode, restore factory defaults, 8 mA drive,
3.3-V tolerant.
I/O
5
GPIO8
GPIO, 24-mA drive, 3.3-V tolerant.
The RN-171 drives GPIO8 HIGH on powerup, which
overrides software configured powerup values, such as
set sys value 0x0000 on GPIO8.
I/O
6
GPIO7
GPIO, 24-mA drive, 3.3-V tolerant.
I/O
7
GPIO6
GPIO, 24-mA drive, 3.3-V tolerant, connection status on
Roving Networks’ firmware.
Status of access
point association
I/O
8
GPIO5
GPIO, 24-mA drive, 3.3-V tolerant.
Data Tx/Rx status
I/O
9
GPIO4
GPIO, 24-mA drive, 3.3-V tolerant.
Connected over
TCP status
I/O
10
VDD_3.3V
3.3-V power supply.
11
GPIO3
GPIO, 8-mA drive, 3.3-V tolerant.
I/O
12
GPIO2
GPIO, 8-mA drive, 3.3-V tolerant.
I/O
13
GPIO1
GPIO, 8-mA drive, 3.3-V tolerant.
I/O
14
GND
Ground.
-
15
Unused
Do not connect.
No Connect
16
Unused
Do not connect.
No Connect
17
Unused
Do not connect.
No Connect
18
Unused
Do not connect.
No Connect
19
Unused
Do not connect.
No Connect
20
GND
Ground.
-
21, 22,
23
GND
Ground.
-
24
ANTENNA
802.11b/g 2.4-Ghz antenna.
-
25, 26,
27
GND
Ground.
-
28
GND
Ground.
-
29
SENSOR 0 (2), (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
30
SENSOR 1 (2), (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
31
SENSOR 2 (2), (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
32
SENSOR 3 (2), (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
33
SENSOR POWER
Output voltage from module, 3.3 V max.
-
34
VDD_3.3V_RF
3.3-V RF power supply (connect to 3.3-V rail).
-
35
SENSOR 4 (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
36
SENSOR 5 (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
37
SENSOR 6 (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
38
SENSOR 7 (3)
Sensor interface, analog input to module, 1.2-V tolerant.
Input
39
GND
Ground.
-
40
RESET
Optional module reset signal (active low), 100-k pull up,
apply pulse of at least 160 us, 3.3-V tolerant.
Input
41
FORCE_AWAKE
Optional module awake signal (active high), 100-k pull
down, apply pulse of at least 260 us, 3.3-V tolerant.
Input
42
GPIO 14
GPIO, 8 mA drive, 3.3-V tolerant.
I/O
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Pad
Number
Signal Name
Description
Optional
Function
Direction
Note (1)
43
UART_RTS
UART RTS flow control, 8-mA drive, 3.3-V tolerant.
Output
44
UART_CTS
UART CTS flow control, 3.3-V tolerant.
Input
45
UART_RX
UART RX, 3.3-V tolerant.
Input
46
UART_TX
UART TX, 8-mA drive, 3.3-V tolerant.
Output
47
GND
Ground.
-
48
SREG_3V3_CTRL
Boost regulator control.
Output
49
VDD-BATT
Battery input, 2.0 - 3.3 V with boost regulator in use,
connect to VDD if not using boost regulator.
-
Notes:
1. Signals marked as input are inputs to the RN-171 module. Signals marked as output are outputs from the module.
2. Any of the sensors 0 - 3 can be used to wake the module. The sensor pins are 1.2-V tolerant. DO NOT apply 3.3-V on these pins. DO
NOT apply 3.3-V on any of sensor pins.
3. When sensor pins are used as sensor inputs, they saturate at 400 mV. Sensor pins will accept input voltages up to 1.2 V but will
saturate at 400 mV. DO NOT apply 3.3 V on any of sensor pins.
Figure 5 shows the module’s physical dimensions.
Figure 5. Module Physical Dimensions
1 mil = 0.0254 millimeters
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700 mil
1,050 mil
35 mil
150 mil
135 mil
35 mil 50 mil
185 mil
185 mil
Pad Dimensions: 40 x 90 mil (rounded ends)
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DESIGN CONCERNS!
The following sections provide information on designing with the RN-171 module, including antenna design, solder reflow,
boost regulator, etc.
Antenna Design
The RN-171 supports several antenna designs, including a PCB trace antenna, chip antenna, wire antenna, and U.FL
connector.
PCB Trace Antenna
Figure 6 shows Roving Networks’ recommended PCB trace antenna pattern. The antenna ground should be connected to
the ground plane and/or ground polygon on both the top and bottom layers with at least 2 vias. The ground plane should
come close to the antenna, exactly as shown in Figure 6; the distance is critical. There should be no ground place/trace
under the antenna under any circumstances.
The antenna feed goes through the polygon on a 50-ohm impedance trace to the source of the signal. Unless the antenna
trace is exactly 50 ohms and the source has a 50-ohm output impedance, you should use a matching PI filter (2
capacitors and an inductor).
The left side of the antenna should be placed on the PCB edge. If that is not possible, leave at least 1 inch of clearance
from any trace or ground plane. The top and bottom of the antenna (the shorter side) should be placed on the PCB edge
or should have at least 1-inch clearance from any trace or ground plane.
To control the impedance of the antenna feed the board should be 4 layers with a dedicated ground plane and a thickness
of around 8 - 14 mils between the ground plane and the top layer (where the antenna feed is routed).
A 2-layer board would not be thin enough to obtain the desired impedance using an acceptable trace width.
Figure 6. PCB Trace Antenna Pattern
Antenna Feed
Antenna Ground
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The trace from the RF pad to the antenna feed should be 12 mils thick on a 4-layer PCB to achieve 50 ohms of impedance
matching as shown in Figure 7.
Figure 7. Trace from RF Pad to Antenna Feed
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Chip Antenna
If your design uses a chip antenna, Roving Networks recommends the 2450AT42A100 manufactured by Johanson. Refer
to the antenna’s data sheet for additional information such as dimensions, mounting considerations, and radiation
patterns. Figure 8 shows the antenna dimensions.
12-mil Thick Trace from
RF Pad to Antenna Feed
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Figure 8. 450AT42A100 Chip Antenna Dimensions
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Figure 9 shows the chip antenna’s mounting considerations.
Figure 9. Chip Antenna Mounting Considerations
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Figure 10 shows the recommended chip antenna layout.
Figure 10. Recommended Chip Antenna Layout
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L
W
a
T
0.197 ± 0.0008
0.079 ± 0.0008
0.043 ± 0.0008
0.020 ± 0.0012
5.00 ± 0.20
2.00 ± 0.20
1.10 ± 0.20
0.50 ± 0.30
L
W
T
a
Inches mm
Feeding Point
No Connect
Function
1
2
No.
12
Terminal Conguration
1.0
1.0
1.8
3.9
8.9
4.0
Units: mm
Line width should be designed
to provide 50-ohm impedence
matching characteristics.
Mount these devices with
the brown mark facing up.
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The feed connecting the antenna to the RF pad must be 50 ohm in impedance. If this feed is shorter than 0.2" the board
can be 2 layers and the thickness of the feed is the same as described in the manufacturer’s data sheet. If the trace is
longer, you need a 4-layer board with controlled impedance, i.e., a ground plane directly under the top layer. The
thickness should be calculated accordingly.
Wire Antenna
To implement a wire antenna, drill a hole through the board on the RF pad (pin 24) to place the wire antenna. To provide
50 ohms of impedance matching, the RF path from the RF pad (Pin 24) to the location of the wire antenna should be
12 mils thick on a 4-layer PCB. See Figure 11. Roving Networks recommends that you use an 18-gauge wire with a length
of 1 inch ± 0.25. For best performance, the wire antenna should be perpendicular to the ground plane.
NOTE: There should be no thermal relief connectors on GND for RF path and on the ground plane.
Figure 11. Wire Antenna Location
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U.FL Connector
Figure 12 shows one option for implementing a U.FL connector. The trace from the RF pad to the U.FL connector should
be 12 mils thick to achieve 50 ohms of impedance matching on a 4-layer board. The part number of the U.FL connector
used for certification of the module is U.FL-R-SM from Hirose.
28
29
30
31
32
21
22
23
24
25
26
27
20
19
18
17
16
A1
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Figure 12. U.FL Connector
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Using Batteries
The RN-171 module does not have a boost regulator circuit. The battery choice is absolutely critical because if the battery
voltage drops below 3 V, the module performance starts to degrade. One possible battery of choice is the 3.6-V ER14505
battery, which has a long battery life. If this battery is used to power the module, Roving Networks recommends that you
use a 1,000 – 3,000 uF bypass capacitor because the ER14505 battery has high output impedance.
Boost Regulator
The RN-171 does not have an on-board boost regulator. Figure 13 shows a recommended circuit for the boost regulator.
Designs that include the boost regulator will provide good power supply to the flash memory even when the battery voltage
drops close to 1.8 V. If a board containing the RN-171 does not include a boost regulator, it SHOULD include a 2.7-V
under-voltage reset circuit to prevent the module from accessing the flash memory when the supply voltage falls below
2.7 V. All supported flash chips are rated for a minimum VDD of 2.7 V.
28
29
30
31
32
21
22
23
24
25
26
27
20
19
18
17
16
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Figure 13. Boost Regulator Circuit
Table 7 shows the recommended components for the boost regulator circuit.
Table 7. Boost Regulator Circuit Components
Designator
Description
Value
Manufacturer
Manufacturer
Part Number
Vendor
Vendor Part
Number
D
Diode Schottky
1A 20V SMA
SS12
Micro Commercial Co
SS12-TP
DigiKey
SS12-TPCT-ND
L
Inductor 1.0uH
30% SMD
1uH
Taiyo Yuden
NR3015T1R0N
DigiKey
587-1647-1-ND
Q
MOSFET N-CH
20V 5.9 A
DMN2050L
Diodes Inc.
DMN2050L-7
DigiKey
DMN2050LDICT-ND
Roving Networks recommends that you use a low voltage detector circuit, such as the XC61 from Torex, tied to the RN-171
module’s RESET pin to protect from low voltage.
Powering from a 3.3-V Regulated Source
Apply 3.3 V regulated power to pins 10, 34, and 49. Leave pin 48 (SREG_3V3_CTRL) unconnected.
NOTE: Do not connect pin 48 to ground. Leave it unconnected.
Solder Reflow
The reflow temperature must not exceed 220° C. To reflow solder the RN-171 module onto a PCB, Roving Networks
recommends a RoHS compliant solder paste equivalent to the NIHON ALMIT paste or OMNIX OM-310 solder paste from
Alpha metals. The module pads must have a solder past thickness of 5 mil.
NOTE: Use no clean flux. Do NOT water wash!
The temperature profile is based on the IC level and other components level only (without the shield can). From the
perspective of the module only, a profile above 245° C should be acceptable. See Figures 14 and 15.
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Figure 14. Solder Reflow Temperature Profile
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Figure 15. Solder Reflow Curve
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COMPLIANCE INFORMATION
Table 8 describes the module’s compliance information.
Table 8. Compliance Information
Specification
Compliance
FCC
Part 15.247 FCC T9J-RN171
IC
RSS-210 low-power communication device
CE
ID # 0681
REG
U9M21103-4249-C
RADIO
EN 300328 V1.7.1 (10/2006)
EMC
EN 301489-1 V1.8.1 (04/2008)!
EN 301489-17 V2.1.1 (05/2009)
SAFETY
EN 60950-1:2006+A11:2010!
EN 50371 2002-03
RoHs
Compliant
ORDERING INFORMATION
Table 9 provides ordering information.
Table 9. Ordering Information
Part Number
Description
RN-171
Industrial Temperature (- 40 to + 85 C) with RF pad for external antenna.
RN-174
Development board for RN-171 module containing an RS-232 and TTL UART hardware interface,
status LEDs, power regulator, and sensor connections.
RN-SMA4-RP
4” external antenna with reverse polarity SMA connector. Used with RN-UFL-SMA6.
RN-UFL-SMA6
6” cable with U.FL connector on one end and SMA on the other.
For other configurations, contact Roving Networks directly.
Go to http://www.rovingnetworks.com for current pricing and a list of distributors carrying Roving Networks products.
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Roving Networks, Inc.
102 Cooper Court
Los Gatos, CA 95032
+1 (408) 395-5300
www.rovingnetworks.com
Copyright © 2012 Roving Networks. All rights reserved. Roving Networks is a
registered trademark of Roving Networks. Apple Inc., iPhone, iPad, iTunes, Made
for iPhone are registered trademarks of Apple Computer.
Roving Networks reserves the right to make corrections, modifications, and other
changes to its products, documentation and services at any time. Customers
should obtain the latest relevant information before placing orders and should verify
that such information is current and complete.
Roving Networks assumes no liability for applications assistance or customer’s
product design. Customers are responsible for their products and applications
which use Roving Networks components. To minimize customer product risks,
customers should provide adequate design and operating safeguards.
Roving Networks products are not authorized for use in safety-critical applications
(such as life support) where a failure of the Roving Networks product would
reasonably be expected to cause severe personal injury or death, unless officers of
the parties have executed an agreement specifically governing such use.