UM1870 Datasheet, PDF (12/58 Pages) STMicroelectronics – BlueNRG-MS development kits

Hardware description
UM1870
2.2
BlueNRG-MS daughterboard
The BlueNRG-MS daughterboard (Figure 3) included in the development kit is a small
circuit board to be connected to the main board. It contains the BlueNRG-MS network
processor (in a QFN32 package), an SMA antenna connector, discrete passive components
for RF matching and balun, and small number of additional components required by the
BlueNRG-MS for proper operation (see the schematic diagram in Figure 18).
Figure 3. BlueNRG-MS daughterboard
The main features of the BlueNRG-MS daughterboard are:
– BlueNRG-MS low power network processor for Bluetooth low energy (BLE), with
embedded host stack
– High frequency 16 MHz crystal
– Low frequency 32 kHz crystal for the lowest power consumption
– Integrated balun and harmonic filter
– SMA connector
The daughterboard is also equipped with a discrete inductor for the integrated high-
efficiency DC-DC converter, for best-in-class power consumption. It is still possible to
disable the DC-DC converter. In this case the following changes must be performed on the
daughterboard (see Figure 18):
– Remove inductor from solder pads 1 and 2 of D1
– Place a 0 ohm resistor between pads 1 and 3
– Move resistor on R2 to R1
For proper operation, jumpers must be set as indicated in Figure 3.
The following tables show the connections between the daughterboard and the main board.
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