Product information

iM871A

M-Bus Wireless Module for different ISM bands

The iM871A Wireless M-Bus module offers a cost-effective RF solution for smart metering applications connecting water, heat, electricity and gas meters with data concentrators in the 868 MHz frequency band. The module supports all major unidirectional and bidirectional wireless M-Bus modes (S1, S1-m, S2, T1, T2,R2, C1 and C2) in addition to all tolerance specifications. The iM871A is pre-qualified according to EN 300 220 and is fully compliant to the EN 13757-4 standard.

With its link budget of up to 120 dB when operating in R2 mode, the iM871A is especially addressing wireless communication requirements in challenging environments inside residential and commercial buildings. The module has an exceptionally small footprint (16.8 mm x 18.6 mm), comes equipped with a serial interface as well as analog and digital inputs and outputs to accommodate interfaces with a customer’s system. With its different ultra low power sleep modes (e.g. deep sleep < 50nA), the iM871A is well-suited for applications requiring long battery life.

Key Features

  • Small footprint 16.8 x 18.6 x 2 mm
  • Compliant to wireless M-Bus specification EN 13757-4
  • Configuration and communication via UART (SPI)
  • Optimized for low power applications
  • Max. output power up to +14 dBm
  • RF range up to 3000 m (line of sight)
  • Digital IOs / I²C-interface
  • Analog inputs
  • 128-bit AES support
  • Solderable like a SMD component
  • 50Ω pad for antenna
  • RoHS conform
  • Flexible wireless M-Bus header configuration
  • Supports S1, S2, T1, T2 and R2 mode

Application Areas

  • Smart Metering (EN 13757)
  • Data concentrators and reader
  • ...

Technical Data

  1. Frequency range:SRD Band 863 to 870 MHz
  2. Modulation:2-FSK
  3. RF output power:up to +14 dBm (50Ω pad)
  4. Receiver sensitivity:up to -109.5 dBm in R2 mode @ BER < 1 %
  5. RF data rate:4.8 / 32.768 / 100 kbps according to EN 13757
  6. Range:up to 3000 m (line of sight)
  7. Operating voltage:2.3 V to 3.6 V
  8. Current Consumption:19 mA (RX)29mA (TX @ 9.2 dBm / 3V* / MCU idle)2 mA (Radio off / MCU idle @ 20 MHz)< 1 µA (Sleep, 32kHz Quarz active)< 50 nA (Deep Sleep)
  9. IO's:Digital IOsAnalog Inputs
  10. Interfaces:Capture und ComparePulse CounterUARTSPII²CRF (EN 13757-4)
  11. Dimension (LxWxH):16.8 x 18.6 x 2 mm
  12. Operating temperature:-20°C to +70°C

Adobe Reader 9 or newer version is required to view following below PDF files. This is a free program available from the Adobe web site. Follow the download directions on the Adobe web site to get your copy of Adobe Reader.

iM871A Datasheet V1.5 (1.1 MB)
iM871A AN007 Sensitivity Measurements V1.1 (1 MB)
iM871A AN009 Firmware Update V1.0 (772.3 KB)
iM871A WMBus UserManual V1.2 (1.1 MB)
WMBus HCI Spec V1.6 (1.2 MB)
WMBus HCIDLL Spec V1.4 (765.8 KB)

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