Features• Based on S2-LP radio• S2-LP narrow band ultra-low power sub-1 GHz transceiver tuned for 860 - 940

MHz frequency band• Programmable RF output power up to +16 dBm• Modulation schemes: 2-FSK, 2-GFSK, 4-FSK, 4-GFSK, OOK and ASK• Air data rate from 0.1 to 500 kbps• Ultra-low power consumption: 7 mA RX and 10 mA TX at +10 dBm• IEEE 802.15.4g hardware packet support with whitening, FEC, CRC and dual

SYNC word detection• RX and TX 128 byte FIFO buffers• Support to wireless M-Bus• Excellent performance of receiver sensitivity (up to -130 dBm)• Automatic acknowledgement, retransmission and timeout protocol engine• Compatible with STM32 Nucleo boards• Compatible with Arduino UNO R3 connectors• BALF-SPI2-01D3 IPD balun for matching network and harmonics filter• Sigfox compatible• Sample firmware for P2P communication• 6LoWPAN compatible thanks to STM32Cube• RoHS and WEEE compliant

DescriptionThe X-NUCLEO-S2868A2 expansion board is based on the S2-LP ultra-low powerRF transceiver and operates in the 868 MHz ISM frequency band.

The X-NUCLEO-S2868A2 interfaces with the STM32 Nucleo microcontroller via SPIconnections and GPIO pins. You can change some of the GPIOs by mounting orremoving the resistors.

The expansion board is compatible with ST morpho and Arduino UNO R3connectors.

Product summary

Sub-1 GHz RFexpansion board basedon S2-LP radio forSTM32 Nucleo

X-NUCLEO-S2868A2

Ultra-low power, highperformance, sub-1 GHztransceiver

S2-LP

50 Ω nominal input/conjugate match balun toS2-LP, 868-930 MHzwith integrated harmonicfilter

BALF-SPI2-01D3

ApplicationsISM RadioSubGHz

Sigfox

Sub-1 GHz 868 MHz RF expansion board based on S2-LP radio for STM32 Nucleo

X-NUCLEO-S2868A2

Data brief

DB4048 - Rev 1 - December 2019For further information contact your local STMicroelectronics sales office.

www.st.com

1 Schematic diagrams

Figure 1. X-NUCLEO-S2868A2 circuit schematic

LL__1100UU__00880055

RR__110000kk__004400

CS

N

1100uuFF

TX

VDDANASYNTH

SDA

SSTTSSAAFFEE--AA110000

CC__115500nn__00440022

1100RR

CC11

GPI

O1

LL1122NNMM

C2

ANT B2

22

1100ppFF

7SCL

NNMM

LL1111

1. 4 V t o 1. 8 V max

VRSYNTH

VDDSMPS

2 SDI

18

SDI 17

CC3322

nS1

RR__110000kk__00440022

1 RESET

LL33

GN

D25

OUT

RR3366

CC__115500nn__00440022

CC3344

CCRRYYSSTTAALL__NNXX11661122SSAA

CC__44..77UU__00660033

VDDVCOTX

+3V3

SDO

C1

RX_NG

PIO

0

CC__110000pp__00440022

CC22

10V

DD

VC

OTX

TX

VDD

SS22--LLPP

SDO

1

VDD

GP

IO1

21

NC 8

RX_PA1

CC__11uu__00660033

AAMM1111DDGG--SSTT0011

7

CC__110000pp__00440022

VDDSMPS

RR337700RR

110000ppFF

VSMPS2

11

VR

RF

12

CC55

CC4422

CC2222

GPI

O3

B1

RR3355

IN

LL__1122nnHH__00660033

4 GND

NC3

CC1100

CC1122

VRSYNTH

RR3388

VCC2

19G

PIO

020

D 5

NM

OUT

IN

JJ11

NNMMCC1177

SDN

GPI

O2

CC99

A2

4

CC__115500nn__00440022

22..22KK

3

CC1188

RR__110000kk__00440022

UU44

CC3366

VDDRXDIGG

PIO

2

22..22KK

CC__115500nn__00440022

RR33

CC__110000pp__00440022

RR22

CC__110000pp__00440022

CC1166

NM

nW3

110000ppFFRXN 13

RR11

UU22

22..77ppFF,,00440022

CC__1122ppFF__00660033

UU33

SMPS1

3V

DD

AN

AS

YN

TH

8

2

VCC 8

YY11

CC3300

110000nnFF

CC1133

NC 6

4 VSS

CSN

14

15

SSMMAA AANNTTEENNNNAA

MM9955664400

7

CC2255

+3V3

+3V3

CC44 CC88

44..77nnHH

RXP

SDN6

CC__115500nn__00440022

SCLK

VSMPS2

nS

VR

SY

NTH

9

VDD

1

LL88

CC__110000nn__00440022

CC__447700pp__00440022

SCL

SCLK

+3V3

VDDRXDIG

SDO

Q2

+3V3

22..22KK

nHOLD

C 6

CC4411

VDDRXDIG

SDA

VDD

VCO

TX

CC__115500nn__00440022

GND1

XOUT

5 XIN

NNMMLL1133

CC3355

VR

EFV

CO

EE11LL77

CC__115500nn__00440022

RR2244

LL__3399nnHH__00440022

SDI

CC66

5

16

SCLK

UU11

VDDANASYNTH

VDD

VDDSMPS

SMPS2

4

LL22

GND2

GP

IO3

23

VR

DIG

24

CC1144

BBAALLFF--SSPPII22--0011DD33

Figure 2. X-NUCLEO-S2868A2 circuit schematic - Arduino connectors

RR1100

RR1111

SDA

43V3

GPIO3

SDN

+5V

D8

and Female on

CCNN55

RR1166

A0 1

D45

10

D67

1

GPIO0

SCL

5V 5

00

RR1155

nS

00

1

SCL

TXD/D1

PWM/D93

1

JJPP11

PA3RR2233

NNMM

6GND

A3 4

CSN

Top

8 Pass-Through:Male on Bottom

00

AREF9 SDA

RR1133

PWM/D104

RXD/D02

00

PA2

RR55

D78

PC7

nS

RR66

RR1122

A4 5

RR44SDI

8+3V3

LLEEDD

SCLK

RR1188 NNMM

SDO

GPIO0

PC7

RESET

NNMM

CCNN88

6 Pass-Through:Male on Bottom

Topand Female on

Pass-Through:Male on Bottom

Topand Female on

Pass-Through:Male on Bottom

Topand Female on

NC 1

A5 6

CCNN66

7GND

D34

VIN 8 NNMMRR1177

D56

MISO/D126

CSN00

IOREF

RR99

RR2222

VDD

MOSI/PWM/D115

NNMM2

00

RESET2

GPIO1RR114400

SCK/D137 GND

NNMMRR1199

00

SDN

A2 3

RR77

CCNN99

SCLK

VIN

JJUUMMPPEERR

D23

32

333300DD11

GPIO2

AVDDIOREF

00A1 2

00

Arduino UNO R3 SX connector Arduino UNO R3 DX connector

X-NUCLEO-S2868A2Schematic diagrams

DB4048 - Rev 1 page 2/5

Figure 3. X-NUCLEO-S2868A2 circuit schematic - ST morpho connectors

1315

RESET+3V3

2527

ST morpho DX connector

Pass-Through: Female onBottom and Male on Top

Pass-Through: Female onBottom and Male on Top

PC9

BOOT0

22

PD81113

3638

IOREF

1719

PA13 PA6PA7

AGND

PC10

PA15

31

2426

PC2PC3 37

11

246810

21

E5V

PA14

PB0PC1

2628

PB15

PC12

PB10

2 302729 PB13

1214

CN7

PC0

PC5

PC15

PA3

PB14

PA8

33 PA10PH1/PF1/PD1

PA12

35

13579

34

NC/PF7

32

PC11PD2

13579

PH0/PF0/PD0

PA2

PA4

PA9

246810

PC14

16PA11

3032

3534

PB4

PB1

9

18PC7

1214

PC6

PB12

23

PA5

333638

28

19

PB5

17

1

20

PB8

PC13

U5V

VIN

PB616

PC4

NC/PF6

PB2

NC/PF4

25

18

PB9AVDD

3

37

CN10

2123

2224

PB3

PB7

15

PA0PA1

+5V

NC/PF5

PC8

VLCD/VBAT

PB11/NC

VDD

20

ST morpho SX connector

X-NUCLEO-S2868A2Schematic diagrams

DB4048 - Rev 1 page 3/5

Revision history

Table 1. Document revision history

Date Version Changes

12-Dec-2019 1 Initial release.

X-NUCLEO-S2868A2

DB4048 - Rev 1 page 4/5

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X-NUCLEO-S2868A2

DB4048 - Rev 1 page 5/5