Product Info

Design Guidelines
Power Supply :
The ACM is designed to be operated at a nominal input voltage of 3.6VDC. The actual
operating input voltage of the ACM can vary from a minimum of 2.8VDC to a maximum of
3.8VDC. This wide range of input voltage supports designs powered from a primary battery
source. There are two voltage inputs, one for high current and one for low current. They can be
powered from different battery sources if needed. The low current input voltage, VBAT_LO,
provides power for the MCU and its peripherals. The high current input voltage, VBAT_HI,
provides power for the RF circuitry and the regulated supply. The regulated supply can draw up
to 1.0 Amp of current while providing a regulated 3.6VDC supply to the RF circuitry. This
regulated supply assures consistent RF power levels over the entire range of input voltage.
Antenna :
The ACM antenna output shall connect to a host board strip-line that provides a 50 ohm
controlled impedance path to an antenna. The strip-line can connect to a RF connector in order
to support an external (off-board) antenna or it can connect to an etched (on-board) antenna
with a matching network to provide the proper 50 ohm termination for the strip-line. The ACM’s
maximum RF output level is 30dBm (1 Watt) of RF power. There is a maximum gain limit of
+5dBi for the ACM antenna. Antenna placement shall be at least 100cm from any operator.
Antenna type shall be EM Wave 073-0010 or equivalent.
Host Board Stackup :
The Host PCB stackup shall be at least a 2-layer stackup with an overall thickness of
0.062” +/- 0.005” and use a minimum copper weight of 1/4oz. Ground flooding is allowed
underneath the ACM module to provide further isolation from any digital interference. The ACM
is a surface mount device (SMD) that uses castellated vias for pins and can be reflowed along
with other SMD devices. High temperature board materials, such as Isola 410 or FR-408, with
Tg ratings of 170C minimum shall be used to maintain coplanarity.
This information should be enough to assure a proper installation of the ACM into any
new Aclara end point device that requires 450MHz to 470MHz licensed narrow band RF
transmission. PCB Footprints and mechanical drawings can be provided by Aclara Engineering.