RF-Star RF-CC2540A1 User manual

RF-CC2540A1
Bluetooth Low Energy Module
Version 1.1
Shenzhen RF-star Technology Co., Ltd.
May 15th, 2020

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TI CC254X BLE Module List
Chipset
Core
Flash
(Byte)
RAM
(KB)
TX
Power
(dBm)
Model
Antenna
Dimension
(mm)
Range
(M)
Photo
CC2540
8051
256
8
+4
RF-BM-S01
PCB
13.7  17.4
100
RF-BM-S02
PCB
11.2  15.2
100
RF-BM-S02I
IPEX
11.2  15.2
150
RF-CC2540A1
PCB
15.2  24.1
100
CC2541
8051
256
8
0
RF-BM-S01A
PCB
13.7  17.4
70
RF-BM-S02A
PCB
11.2  15.2
70
RF-BMPA-
2541B1
PCB /
IPEX
13.7  31.4
300
Note:
1. The communication distance is the longest distance obtained by testing the module's maximum transmission power
in an open and interference-free environment in sunny weather.
2. Click the picture to buy modules.

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1 Device Overview
1.1 Description
RF-CC2540A1 is a Bluetooth Low Energy (BLE) module based on TI CC2540F256, an 8051 core BLE System-on-Chip
(SoC). This PCB module integrates a 32 MHz crystal, a 32.768 kHz crystal, an LC balun, an RF matching filter, and a
meander line PCB antenna. It is pre-programmed with the BLE 4.0 stack and an application communication protocol
over its full speed USB interface. It can be used to design a USB dongle to easily establish BLE connection from a
device to smart phones. Very low-power sleep modes are available. Short transition times between operating modes
further enable low power consumption.
1.2 Key Features
•RF
- Bluetooth low energy 4.0 compatible protocol
stack for single-mode
- Excellent link budget (up to 97 dBm), Enabling
long-range applications without external front end
- Accurate Digital Received Signal-Strength
Indicator (RSSI)
- Suitable for systems targeting compliance with
worldwide radio frequency regulations:
ETSI EN 300 328 and EN 300 440 Class 2
(Europe)
FCC CFR47 Part 15 (US)
ARIB STD-T66 (Japan)
•Microcontroller
- High-performance and low-power 8051
microcontroller core
- In-system-programmable flash of 256 KB
- 8-KB SRAM
•Peripherals
- 12 bit ADC with eight channels and configurable
resolution
- Integrated high-power op-amp and ultra-low
power comparator
- General-purpose timers (one 16-bits, two 8-bits)
- 21 General-purpose I/O pins (19 × 4 mA, 2 × 20 mA)
- 32 kHz sleep timer with capture
- Two powerful USARTs with support for several serial
protocols
- Full speed USB interface
- IR generation Circuity
- AES security coprocessor
- Battery monitor and temperature sensor
- Each CC2540 contains a unique 48-bit IEEE address
•Low Power
- Active mode RX down to 19.6 mA
- Active mode TX (-6 dBm): 24 mA
- Power mode 1 (3-μs wake-up): 235 μA
- Power mode 2 (sleep timer on): 0.9 μA
- Power mode 3 (external interrupts): 0.4 μA
- Wide supply voltage range (2.0 V ~ 3.6 V)
- Full RAM and register retention in all power modes
1.3 Applications
•2.4 GHz Bluetooth low energy system
•Mobile phone accessories
•Sports and leisure equipment
•Consumer electronics
•Human interface devices
•Keyboard, mouse

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•Remote control
•USB dongles
•Health care and medical
•Smart lighting
1.4 Functional Block Diagram
Figure 1. Functional Block Diagram of RF-CC2540A1
1.5 Part Number Conventions
The part numbers are of the form of RF-CC2540A1 where the fields are defined as follows:
Figure 2. Part Number Conventions of RF-CC2540A1
RF
CC2540
Company Name
RF-STAR
-
A1
Chipset
TI CC2540
Module Version
The First Verion
CC2540
F256
GPIO
USB
UART
LC Balun
PCB
Antenna
RF-N
RF-P
Filter &
Matching
Reset
Power Supply
2.0 V ~ 3.6 V
32.0 MHz
32.768 kHz

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Table of Contents
TI CC254X BLE Module List .......................................................................................................................................... 1
1 Device Overview............................................................................................................................................................. 2
1.1 Description............................................................................................................................................................ 2
1.2 Key Features ....................................................................................................................................................... 2
1.3 Applications.......................................................................................................................................................... 2
1.4 Functional Block Diagram .............................................................................................................................. 3
1.5 Part Number Conventions.............................................................................................................................. 3
Table of Contents................................................................................................................................................................ 4
Table of Figures................................................................................................................................................................... 5
Table of Tables..................................................................................................................................................................... 5
2 Module Configuration and Functions ...................................................................................................................... 6
2.1 Module Parameters........................................................................................................................................... 6
2.2 Module Pin Diagram ......................................................................................................................................... 7
2.3 Pin Functions....................................................................................................................................................... 7
3 Specifications ................................................................................................................................................................... 9
3.1 Recommended Operating Conditions ....................................................................................................... 9
3.2 Handling Ratings................................................................................................................................................ 9
3.3 Receiver RF Parameters ................................................................................................................................ 9
3.4 Transceiver RF Parameters.........................................................................................................................10
4 Application, Implementation, and Layout.............................................................................................................12
4.1 Module Photos..................................................................................................................................................12
4.2 Recommended PCB Footprint....................................................................................................................12
4.3 Schematic Diagram.........................................................................................................................................13
4.4 Basic Operation of Hardware Design ......................................................................................................13
4.5 Trouble Shooting..............................................................................................................................................15
4.5.1 Unsatisfactory Transmission Distance........................................................................................15
4.5.2 Vulnerable Module..............................................................................................................................15
4.5.3 High Bit Error Rate .............................................................................................................................15
4.6 Electrostatics Discharge Warnings ...........................................................................................................15
4.7 Soldering and Reflow Condition.................................................................................................................16

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4.8 Optional Packaging.........................................................................................................................................17
5 Revision History ............................................................................................................................................................18
6 Contact Us.......................................................................................................................................................................19
Table of Figures
Figure 1. Functional Block Diagram of RF-CC2540A1............................................................................... 3
Figure 2. Part Number Conventions of RF-CC2540A1 .............................................................................. 3
Figure 3. Pin Diagram of RF-CC2540A1 ......................................................................................................... 7
Figure 4. Photos of RF-CC2540A1 ..................................................................................................................12
Figure 5. Recommended PCB Footprint of RF-CC2540A1 (mm)........................................................12
Figure 6. Optional Packaging Mode.................................................................................................................13
Figure 7. Recommendation of Antenna Layout ...........................................................................................14
Figure 8. Recommended Reflow for Lead Free Solder............................................................................16
Figure 9. Optional Packaging Mode.................................................................................................................17
Table of Tables
Table 1. Parameters of RF-CC2540A1............................................................................................................. 6
Table 2. Pin Functions of RF-CC2540A1......................................................................................................... 7
Table 3. Recommended Operating Conditions of RF-CC2540A1.......................................................... 9
Table 4. Handling Ratings of RF-CC2540A1.................................................................................................. 9
Table 5. Table of Receiver RF Parameters...................................................................................................... 9
Table 6. Table of Transceiver RF Parameters..............................................................................................10
Table 7. Temperature Table of Soldering and Reflow................................................................................16

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2 Module Configuration and Functions
2.1 Module Parameters
Table 1. Parameters of RF-CC2540A1
Chipset
CC2540F256
Supply Power Voltage
2.0 V ~ 3.6 V, recommended to 3.3 V
Frequency
2402 MHz ~ 2480 MHz
Transmit Power
Programmable: -23.0 dBm ~ +4.0 dBm
Receiving Sensitivity (low-gain mode)
-87 dBm
Receiving Sensitivity (high-gain mode)
-93 dBm
GPIO
19
Crystal
32 MHz, 32.768 kHz
RAM
8 KB
Flash
256 KB
Package
SMT Packaging
Frequency Error
±20 kHz
Dimension
24.10 mm x 15.2 mm x (1.7 ±0.1) mm
Type of Antenna
PCB Antenna
Operating Temperature (high-temperature mode)
-40 ℃～+85 ℃
Storage Temperature (high-temperature mode)
-40 ℃～+125 ℃
RX Current
19.6 mA
TX Current (-6 dBm)
24.0 mA
Power mode 1 (3-μs wake-up)
235 μA
Power mode 2 (sleep timer on)
0.9 μA
Power mode 3 (external interrupts)
0.4 μA

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2.2 Module Pin Diagram
Figure 3. Pin Diagram of RF-CC2540A1
2.3 Pin Functions
Table 2. Pin Functions of RF-CC2540A1
Pin
Name
Chip Pin
Pin Type
Description
1
VCC
VCC
VCC
Power supply 2.0 V ~ 3.6 V
2
GND
GND
GND
Ground
3
P22
P2.2
Debug
DEBUG_DC
4
P21
P2.1
Debug
DEBUG_DD
5
P20
P2.0
I/O
6
P17
P1.7
I/O
7
P16
P1.6
I/O
8
USB_P
USB+
USB+
USB+
9
USB_N
USB-
USB-
USB-
10
P15
P1.5
I/O
11
P14
P1.4
I/O
12
P13
P1.3
I/O

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13
P12
P1.2
I/O
14
P11
P1.1
I/O
15
P10
P1.0
I/O
16
P07
P0.7
I/O
17
P06
P0.6
I/O
18
P05
P0.5
I/O
19
P04
P0.4
I/O
20
P03
P0.3
I/O
21
P02
P0.2
I/O
22
P01
P0.1
I/O
23
P00
P0.0
I/O
24
RESET
RST
RESET
Reset, active low
25
GND
GND
GND
Ground

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3 Specifications
3.1 Recommended Operating Conditions
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-CC2540A1
Items
Condition
Min.
Typ.
Max.
Unit
Operating Supply Voltage
Battery Mode
2.0
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-CC2540A1
Items
Condition
Min.
Typ.
Max.
Unit
Storage Temperature
Tstg
-40
+25
+125
℃
Human Body Model
HBM
±2000
V
Moisture Sensitivity Level
2
Charged Device Model
±750
V
3.3 Receiver RF Parameters
Table 5. Table of Receiver RF Parameters
When measured on the RF-CC2540A1 reference design with T A = 25 ℃, V BAT = 3.3 V, Fc = 2440 MHz with DC/DC
enabled unless otherwise noted.
1 MBPS, GFSK, 250 kHz deviation, Bluetooth low energy mode, and 0.1% BER1.
Parameters
Test Condition
Min.
Typ.
Max.
Unit
Receiver Sensitivity2
High-gain mode
-93
dBm
Receiver Sensitivity2
Standard mode
-87
dBm
Saturation3
6
dBm
Co-channel Rejection3
-5
dB
Adjacent-channel Rejection3
±1 MHz
-5
dB
Adjacent-channel Rejection3
±2 MHz
30
dB
Blocking3
-30
dBm
Frequency Error Tolerance4
Including both initial tolerance and drift
-250
250
kHz
Symbol Rate Error
-80
80
ppm

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Tolerance5
Spurious Emission. Only
Largest Spurious Emission
Stated within Each Band.
Conducted measurement with a 50-Ω single-
ended load. Complies with EN 300 328, EN 300
440 class 2, FCC CFR47, Part 15 and ARIB
STD-T-66
-75
dBm
Current Consumption
RX mode, standard mode, no peripherals
active, low MCU activity, MCU at 250 kHz
19.6
mA
RX mode, high-gain mode, no peripherals
active, low MCU activity, MCU at 250 kHz
22.1
mA
Note:
1. 0.1% BER maps to 30.8% PER.
2. The receiver sensitivity setting is programmable using a TI BLE stack vendor-specific API command. The default
value is standard mode.
3. Results based on standard gain mode.
4. Difference between center frequency of the received RF signal and local oscillator frequency.
5. Difference between incoming symbol rate and the internally generated symbol rate.
3.4 Transceiver RF Parameters
Table 6. Table of Transceiver RF Parameters
When measured on the RF-CC2540A1 reference design with T A = 25 ℃, V BAT = 3.3 V, Fc = 2440 MHz with DC/DC
enabled unless otherwise noted.
Parameters
Test Condition
Min.
Typ.
Max.
Unit
Output Power
Delivered to a single-ended 50-Ω load through a
balun using maximum recommended output power
setting
4
dBm
Delivered to a single-ended 50-Ω load through a
balun using minimum recommended output power
setting
-23
dBm
Programmable Output
Power Range
Delivered to a single-ended 50 Ω load through a
balun
27
dB
Spurious Emissions
Conducted measurement with a 50-Ω single-ended
load. Complies with EN 300 328, EN 300 440 class
2, FCC CFR47, Part 15 and ARIB STD-T-66
-41
dBm
Current Consumption
TX mode, -23 dBm output power, no peripherals
active, low MCU activity, MCU at 250 kHz
21.1
mA
TX mode, -6 dBm output power, no peripherals
23.8
mA

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active, low MCU activity, MCU at 250 kHz
TX mode, 0 dBm output power, no peripherals
active, low MCU activity, MCU at 250 kHz
27
mA
TX mode, +4. dBm output power, no peripherals
active, low MCU activity, MCU at 250 kHz
31.6
mA
Optimum Load
Impedance
Differential impedance as seen from the RF port
(RF_P and RF_N) toward the antenna
70 + j30
Ω

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4 Application, Implementation, and Layout
4.1 Module Photos
Figure 4. Photos of RF-CC2540A1
4.2 Recommended PCB Footprint
Figure 5. Recommended PCB Footprint of RF-CC2540A1 (mm)

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4.3 Schematic Diagram
Figure 6. Optional Packaging Mode
4.4 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
the 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 the 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.
4. The bottom of 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 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 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.

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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.
9. 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.
10. The antenna must not be installed inside the metal case, which will cause the transmission distance to be greatly
weakened.
11. The recommendation of antenna layout.
The inverted-F antenna position on PCB is free space electromagnetic radiation. The location and layout of 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.
（3）It is the best to hollow out the red part of the antenna position in the following figure so as to ensure that S11
of the module is minimally affected.
Figure 7. Recommendation of Antenna Layout
Note: The hollow-out position is based on the antenna used.

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4.5 Trouble Shooting
4.5.1 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 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 of 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 module or the poor quality of antenna will affect the communication distance.
4.5.2 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 the stable power supply and no frequently fluctuated
voltage.
2. Please ensure the anti-static installation and the electrostatic sensitivity of high-frequency devices.
3. Due to some humidity sensitive components, please ensure the 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.
4.5.3 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 reliability.
3. If the extension wire or feeder wire is of poor quality or too long, the bit error rate will be high.
4.6 Electrostatics Discharge Warnings
The module will be damaged for the discharge of static. RF-star suggest 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 module, even causing the failure.

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4.7 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 7. 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
Time from 25 ℃ to Peak Temperature (t2)
Max. 6 minutes
Max. 8 minutes
Time of Soldering Zone (tP)
20±10 s
20±10 s
Figure 8. Recommended Reflow for Lead Free Solder

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4.8 Optional Packaging
Figure 9. Optional Packaging Mode
Note: Default tray packaging.

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5 Revision History
Date
Version No.
Description
Author
2018.02.07
V1.0
Update module picture.
Aroo Wang
2018.02.26
V1.1
Update operating and storage temperature range.
Aroo Wang
2018.08.02
V1.1
Update company address.
Aroo Wang
2020.05.15
V1.1
Add TI CC254X BLE module list.
Sunny Li
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.szrfstar.com.

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6 Contact Us
SHENZHEN RF-STAR TECHNOLOGY CO., LTD.
Shenzhen HQ:
Add.: Room 601, Block C, Skyworth Building, High-tech Park, Nanshan District, Shenzhen, Guangdong, China
Tel.: [phone]
Chengdu Branch:
Add.: No. B3-03, Building No.1, Incubation Park, High-Tech District, Chengdu, Sichuan, China, 610000
Tel.: [phone]
Email: [e-mail], [e-mail]
Web.: www.szrfstar.com