RF-Star RF-BM-ND08A User manual
RF-BM-ND08A nRF52811
Multi-Protocols Module Supporting BLE,
Bluetooth Direction Finding, Thread
Version 1.0
Shenzhen RF-star Technology Co., Ltd.
May 25th, 2023
All rights reserved. Those responsible for unauthorized reproduction will be prosecuted.
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1 Device Overview
1.1 Description
RF-BM-ND08A is an RF module based on Nordic SoC nRF52811 with ARM® Cortex®-M4 32-bit processor. It integrates
a 32.768 kHz and a 32 MHz crystal, an LC filter, an antenna matching and antenna options of a meander line inverted-
F PCB antenna and a half-hole interface. It supports Bluetooth® 5.1 Low Energy, Bluetooth Direction Finding and Thread,
and can be preprogrammed with a serial interface communication protocol for simple programming. It includes a range
of analog and digital interfaces such as PDM, PWM, UART, SPI and I2C. It features low power consumption, compact
size, robust connection distance, and rigid reliability. 1.27-mm pitch stamp stick package for easy assembling and cost-
effective PCB design. RF-BM-ND08A is pin-to-pin compatible with RF-BM-ND08/ND08C/ND08I.
1.2 Key Features
•RF Features
- Bluetooth® 5.1 low energy
- Bluetooth Direction Finding
- Thread
•Angle-of arrival (AoA) and angle-of-departure (AoD)
direction finding
•TX power: -20 to +4 dBm
•ARM® Cortex®-M4 32-bit processor, 64 MHz
•Supply voltage range 1.7 V ~ 3.6 V
•Memory
- 192 kB flash
- 24 kB RAM
•Support for concurrent multi-protocol
•Peripherals
- 12-bit, 200 ksps ADC
- 16 GPIOs
- 4-channel PWM
- Digital microphone interface (PDM)
- SPI master/slave
- I2C master/slave
- UART (CTS/RTS)
•Programmable peripheral interconnect (PPI)
•Quadrature decoder (QDEC)
•AES HW encryption
•Real-time counter (RTC)
•Transmission Range: 80 m
•Dimension: 15.2 mm x 11.2 mm x 1.7 mm
1.3 Applications
•Internet of Things (IoT)
•Mouse
•Keyboard
•Mobile HID
•Industrial lighting
•Commercial lighting
•Retail
•Home Automation
•Beacons
•Health and medical
•Virtual reality headsets
•Wearables
•Connectivity device in multi-chip solutions
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1.4 Functional Block Diagram
Figure 1. Functional Block Diagram of RF-BM-ND08A
1.5 Part Number Conventions
The part numbers are of the form of RF-BM-ND08A where the fields are defined as follows:
Figure 2. Part Number Conventions of RF-BM-ND08A
RF
BM
ND
Company Name
RF-STAR
Wireless Type
Bluetooth Module
Chipset Manufacturer
Nordic Semiconductor
-
-
08A
Module Version
nRF52811 Version
nRF52811
GPIO
Debug
Reset
LC Filter
Power Supply
1.7 V ~ 3.6 V
Antenna
Matching
32.0 MHz
32.768 kHz
Half-hole
Interface
PCB
Antenna
Antenna
Switch
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Table of Contents
1 Device Overview............................................................................................................................................................. 1
1.1 Description............................................................................................................................................................ 1
1.2 Key Features ....................................................................................................................................................... 1
1.3 Applications.......................................................................................................................................................... 1
1.4 Functional Block Diagram .............................................................................................................................. 2
1.5 Part Number Conventions.............................................................................................................................. 2
Table of Contents................................................................................................................................................................ 3
2 Module Configuration and Functions ...................................................................................................................... 4
2.1 Module Parameters........................................................................................................................................... 4
2.2 Module Pin Diagram ......................................................................................................................................... 5
2.3 Pin Functions....................................................................................................................................................... 5
3 Specifications ................................................................................................................................................................... 7
3.1 Recommended Operating Conditions ....................................................................................................... 7
3.2 Handling Ratings................................................................................................................................................ 7
4 Application, Implementation, and Layout............................................................................................................... 8
4.1 Module Photos.................................................................................................................................................... 8
4.2 Recommended PCB Footprint...................................................................................................................... 8
4.3 Schematic Diagram........................................................................................................................................... 9
4.4 Antenna.................................................................................................................................................................. 9
4.4.1 Antenna Design Recommendation ................................................................................................ 9
4.4.2 Antenna Output Mode Modification..............................................................................................10
4.5 Basic Operation of Hardware Design ......................................................................................................10
4.6 Trouble Shooting..............................................................................................................................................11
4.6.1 Unsatisfactory Transmission Distance........................................................................................11
4.6.2 Vulnerable Module..............................................................................................................................11
4.6.3 High Bit Error Rate .............................................................................................................................12
4.7 Electrostatics Discharge Warnings ...........................................................................................................12
4.8 Soldering and Reflow Condition.................................................................................................................12
5 Optional Package Specification ..............................................................................................................................14
5 Revision History ............................................................................................................................................................16
6 Contact Us.......................................................................................................................................................................17
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2 Module Configuration and Functions
2.1 Module Parameters
Table 1. Parameters of RF-BM-ND08A
Chipset
nRF52811
Supply Power Voltage
1.7 V ~ 3.6 V, recommended to 3.3 V
Frequency
2402 MHz ~ 2480 MHz
Transmit Power
-20.0 dBm ~ +4.0 dBm (Typical: 0 dBm)
Receiving Sensitivity
-97 dBm sensitivity in 1 Mbps Bluetooth® low energy mode
-104 dBm sensitivity in 125 kbps Bluetooth® low energy mode
(long range)
Power Consumption
4.6 mA peak current in TX (@ 0 dBm)
4.6 mA peak current in RX
Data Rate
Bluetooth® 5.2: 2 Mbps, 1 Mbps, 500 kbps, and 125 kbps
IEEE 802.15.4-2006: 250 kbps
Propriety 2.4 GHz: 2 Mbps, 1 Mbps
GPIO
16
Crystal
32 MHz, 32.768 kHz
RAM
24 KB
Flash
192 KB
Package
SMT packaging (1.27-mm half-hole pitch stamp stick)
Frequency Error
±20 kHz
Dimension
15.2 mm x 11.2 mm x 1.7 mm
Type of Antenna
PCB antenna, half-hole interface
Operating Temperature
-40 ℃ ～ +85 ℃
Storage Temperature
-40 ℃ ～ +125 ℃
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2.2 Module Pin Diagram
Top View Bottom View
Figure 3. Pin Diagram of RF-BM-ND08A
2.3 Pin Functions
Table 2. Pin Functions of RF-BM-ND08A
Pin
Name
Chip Pin
Pin Type
Description
1
ANT
-
-
Antenna interface
2
GND
GND
GND
Ground
3
VCC
VCC
VCC
Power supply 1.7 V ~ 3.6 V, Recommend 3.3 V
4
P25
P0.25
Digital I/O
General purpose I/O
5
P17
P0.17
Digital I/O
General purpose I/O
6
P21/RST
P0.21/RESET
Digital I/O
General purpose I/O. Reset, active low.
7
P13
P0.13
Digital I/O
General purpose I/O
8
P28
P0.28/AIN4
Digital or Analog
General purpose I/O, analog capability
9
P27
P0.27
Digital I/O
General purpose I/O
10
P26
P0.26
Digital I/O
General purpose I/O
11
P09
P0.09
Digital I/O
General purpose I/O
12
P10
P0.10
Digital I/O
General purpose I/O
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13
P19
P0.19
Digital I/O
General purpose I/O
14
P20
P0.20
Digital I/O
General purpose I/O
15
P05
P0.05/AIN3
Digital or Analog
General purpose I/O, analog capability
16
P07
P0.07
Digital I/O
General purpose I/O
17
P06
P0.06
Digital I/O
General purpose I/O
18
P08
P0.08
Digital I/O
General purpose I/O
19
P03
P0.03/AIN1
Digital or Analog
General purpose I/O, analog capability
Note:
SWD debugging ports are on the bottom side of the module, which is not pulled out in the stamp half hole way, please
refer to the module pin diagram for details.
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3 Specifications
3.1 Recommended Operating Conditions
The functional operation does not guarantee performance beyond the limits of the conditional parameter values in the
table below. Long-term work beyond this limit will affect the reliability of the module more or less.
Table 3. Recommended Operating Conditions of RF-BM-ND08A
Items
Condition
Min.
Typ.
Max.
Unit
Operating Supply Voltage
Battery Mode
1.7
3.3
3.6
V
Operating Temperature
/
-40
+25
+85
℃
Environmental Hot Pendulum
/
-20
+20
℃/min
3.2 Handling Ratings
Table 4. Handling Ratings of RF-BM-ND08A
Items
Condition
Min.
Typ.
Max.
Unit
Storage Temperature
Tstg
-40
+25
+125
℃
Human Body Model
HBM
±4000
V
Moisture Sensitivity Level
3
Charged Device Model
±750
V
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4.3 Schematic Diagram
Figure 6. Schematic Diagram of RF-BM-ND08A
4.4 Antenna
4.4.1 Antenna Design Recommendation
1. The antenna installation structure has a great influence on the module performance. It is necessary to ensure the
antenna is exposed and preferably vertically upward. When the module is installed inside of the case, a high-quality
antenna extension wire can be used to extend the antenna to the outside of the case.
2. The antenna must not be installed inside the metal case, which will cause the transmission distance to be greatly
weakened.
3. The recommendation of antenna layout.
The inverted-F antenna position on PCB is free-space electromagnetic radiation. The location and layout of the
antenna is a key factor to increase the data rate and transmission range.
Therefore, the layout of the module antenna location and routing is recommended as follows:
（1）Place the antenna on the edge (corner) of the PCB.
（2）Make sure that there is no signal line or copper foil in each layer below the antenna.
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（3）It is best to hollow out the antenna position in the following figure to ensure that the S11 of the module is
minimally affected.
Figure 7. Recommendation of Antenna Layout
Note: The hollow-out position is based on the antenna used.
4.4.2 Antenna Output Mode Modification
The module has two antenna output modes, which are onboard PCB antenna and stamp half-hole output (ANT pin, see
pin function table for details).
The default delivery is the onboard PCB antenna, L1 position (1NH) is welded. If you want to change to a half-hole
antenna output, disconnect the L1 position capacitor. The location of L1 is shown in the figure below.
Figure 8. Antenna Output Mode Change
4.5 Basic Operation of Hardware Design
1. It is recommended to offer the module with a DC stabilized power supply, a tiny power supply ripple coefficient, and
reliable ground. Please pay attention to the correct connection between the positive and negative poles of the power
supply. Otherwise, the reverse connection may cause permanent damage to the module;
2. Please ensure the supply voltage is between the recommended values. The module will be permanently damaged
if the voltage exceeds the maximum value. Please ensure a stable power supply and no frequently fluctuated voltage.
3. When designing the power supply circuit for the module, it is recommended to reserve more than 30% of the margin,
which is beneficial to the long-term stable operation of the whole machine. The module should be far away from the
power electromagnetic, transformer, high-frequency wiring, and other parts with large electromagnetic interference.
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4. The bottom of the module should avoid high-frequency digital routing, high-frequency analog routing, and power
routing. If it has to route the wire on the bottom of the module, for example, it is assumed that the module is soldered
to the Top Layer, the copper must be spread on the connection part of the top layer and the module, and be close
to the digital part of the module and routed in the Bottom Layer (all copper is well-grounded).
5. Assuming that the module is soldered or placed in the Top Layer, it is also wrong to randomly route the Bottom Layer
or other layers, which will affect the spurs and receiving sensitivity of the module to some degrees;
6. Assuming that there are devices with large electromagnetic interference around the module, which will greatly affect
the module performance. It is recommended to stay away from the module according to the strength of the
interference. If circumstances permit, appropriate isolation and shielding can be done.
7. Assuming that there are routings of large electromagnetic interference around the module (high-frequency digital,
high-frequency analog, power routings), which will also greatly affect the module performance. It is recommended
to stay away from the module according to the strength of the interference. If circumstances permit, appropriate
isolation and shielding can be done.
8. It is recommended to stay away from the devices whose TTL protocol is the same 2.4 GHz physical layer, for
example, USB 3.0.
4.6 Trouble Shooting
4.6.1 Unsatisfactory Transmission Distance
1. When there is a linear communication obstacle, the communication distance will be correspondingly weakened.
Temperature, humidity, and co-channel interference will lead to an increase in communication packet loss rate. The
performances of ground absorption and reflection of radio waves will be poor when the module is tested close to the
ground.
2. Seawater has a strong ability to absorb radio waves, so the test results by the seaside are poor.
3. The signal attenuation will be very obvious if there is a metal near the antenna or the module is placed inside the
metal shell.
4. The incorrect power register set or the high data rate in an open-air may shorten the communication distance. The
higher the data rate, the closer the distance.
5. The low voltage of the power supply is lower than the recommended value at ambient temperature, and the lower
the voltage, the smaller the power is.
6. The unmatchable antennas and modules or the poor quality of the antenna will affect the communication distance.
4.6.2 Vulnerable Module
1. Please ensure the supply voltage is between the recommended values. The module will be permanently damaged
if the voltage exceeds the maximum value. Please ensure a stable power supply and no frequently fluctuated voltage.
2. Please ensure the anti-static installation and the electrostatic sensitivity of high-frequency devices.
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3. Due to some humidity-sensitive components, please ensure suitable humidity during installation and application. If
there is no special demand, it is not recommended to use at too high or too low temperature.
4.6.3 High Bit Error Rate
1. There are co-channel signal interferences nearby. It is recommended to be away from the interference sources or
modify the frequency and channel to avoid interferences.
2. The unsatisfactory power supply may also cause garbled. It is necessary to ensure the power supply's reliability.
3. If the extension wire or feeder wire is of poor quality or too long, the bit error rate will be high.
4.7 Electrostatics Discharge Warnings
The module will be damaged for the discharge of static. RF-star suggests that all modules should follow the 3 precautions
below:
1. According to the anti-static measures, bare hands are not allowed to touch modules.
2. Modules must be placed in anti-static areas.
3. Take the anti-static circuitry (when inputting HV or VHF) into consideration in product design.
Static may result in the degradation in performance of the module, even causing the failure.
4.8 Soldering and Reflow Condition
1. Heating method: Conventional Convection or IR/convection.
2. Solder paste composition: Sn96.5 / Ag3.0 / Cu0.5
3. Allowable reflow soldering times: 2 times based on the following reflow soldering profile.
4. Temperature profile: Reflow soldering shall be done according to the following temperature profile.
5. Peak temperature: 245 ℃.
Table 5. Temperature Table of Soldering and Reflow
Profile Feature
Sn-Pb Assembly
Pb-Free Assembly
Solder Paste
Sn63 / Pb37
Sn96.5 / Ag3.0 / Cu0.5
Min. Preheating Temperature (Tmin)
100 ℃
150 ℃
Max. Preheating Temperature (Tmax)
150 ℃
200 ℃
Preheating Time (Tmin to Tmax) (t1)
60 s ~ 120 s
60 s ~ 120 s
Average Ascend Rate (Tmax to Tp)
Max. 3 ℃/s
Max. 3 ℃/s
Liquid Temperature (TL)
183 ℃
217 ℃
Time above Liquidus (tL)
60 s ~ 90 s
30 s ~ 90 s
Peak Temperature (Tp)
220 ℃ ~ 235 ℃
230 ℃ ~ 250 ℃
Average Descend Rate (Tpto Tmax)
Max. 6 ℃/s
Max. 6 ℃/s
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5 Revision History
Date
Version No.
Description
2020.09.02
V1.0
The initial version is released.
2023.05.25
V1.0
Update MSL level.
Update the Shenzhen office address.
Note:
1. The document will be optimized and updated from time to time. Before using this document, please make sure it is
the latest version.
2. To obtain the latest document, please download it from the official website: www.rfstariot.com and www.szrfstar.com.
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6 Contact Us
SHENZHEN RF-STAR TECHNOLOGY CO., LTD.
Shenzhen HQ:
Add.: Room 502, Podium Building No. 12, Shenzhen Bay Science and Technology Ecological Park, Nanshan District,
Shenzhen, Guangdong, China, 518063
Tel.: 86-755-8632 9829
Chengdu Branch:
Add.: N2-1604, Global Center, North No. 1700, Tianfu Avenue, Hi-Tech District, Chengdu, Sichuan, China, 610095
Tel.: 86-28-8692 5399
Email: sunny@szrfstar.com, sales@szrfstar.com
Web.: www.rfstariot.com, www.szrfstar.com
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