User's Manual

BL652
Datasheet
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Add tuning capacitors of 300 pF on NGC1 pin to GND and 300 pF on NFC2 pins to GND if the PCB track length
is similar as DVK-BL652 devboard.
 nRESET pin (active low)
Hardware reset. Wire out to push button or drive by host.
By default module is out of reset when power applied to VCC pins.
 Optional External 32.768kHz crystal
If the optional external 32.768kHz crystal is needed then use a crystal that meets specification.
 Optional External serial SPI flash IC
If the optional external serial (SPI) flash is required, ensure that manufacturer part number tested by Laird
are used.
PCB Layout on Host PCB - General
Checklist (for PCB):
 MUST locate BL652-Sx module close to the edge of PCB (mandatory for BL652-SA for on-board chip antenna
to radiate properly).
 Use solid GND plane on inner layer (for best EMC and RF performance).
 All module GND pins MUST be connected to host PCB GND.
 Place GND vias close to module GND pads as possible.
 Unused PCB area on surface layer can flooded with copper but place GND vias regularly to connect copper
flood to inner GND plane. If GND flood copper underside the module then connect with GND vias to inner
GND plane.
 Route traces to avoid noise being picked up on VCC supply and AIN (analogue) and SIO (digital) traces.
 Ensure no exposed copper is on the underside of the module (refer to land pattern of BL652 development
board).
PCB Layout on Host PCB for BL652-SA
6.3.1 Antenna Keep-out on Host PCB
The BL652-SA has an integrated chip antenna and its performance is sensitive to host PCB. It is critical to locate
the BL652-SA on the edge of the host PCB (or corner) to allow the antenna to radiate properly. Refer to
guidelines in section PCB land pattern and antenna keep-out area for BL652-SA. Some of those guidelines
repeated below.
 Ensure there is no copper in the antenna keep-out area on any layers of the host PCB. Keep all mounting
hardware and metal clear of the area to allow proper antenna radiation.
 For best antenna performance, place the BL652-SA module on the edge of the host PCB, preferably in the
corner with the antenna facing the corner.
 The BL652 development board has the BL652-SA module on the edge of the board (not in the corner). The
antenna keep-out area is defined by the BL652 development board which was used for module
development and antenna performance evaluation is shown in Figure 9, where the antenna keep-out area is
~4.95mm wide, 25.65 mm long; with PCB dielectric (no copper) height 0.85 mm sitting under the BL652-SA
antenna.