HBA09-001-70
HB-NEDSP1068
4
3.
Installation
IMPORTANT NOTE: ESD – When handling this module, please take all possible
precautions to ensure that the risk of accidental Electrostatic Discharge is
minimised. Use of a personal grounding strap and static dissipative mat is
recommended.
The NEDSP1068-PCBA module can be used two ways. One is to treat it as a sub-
assembly board and mount it directly to a mother board assembly using 0.1” pitch PCB
Header pins. A drawing showing the PCB dimensions and header locations is provided
in Appendix C of this document. The Header pins and the integrated plastic spacer bar
provide a very good securing medium for the PCB, especially if both the main
connections and the external microphone pins are used. Alternatively, the main
connector may be used and the two M3 securing holes at the other end. The other way
of mounting is to connect the module in-line with the microphone path by wires to follow-
on circuits, then all the mounting holes may be used to mount the pcb in a suitable
location or housing. When using hardware to secure the PCB take care to note the fact
that there are tracks very close to the mounting holes and therefore nylon washers may
be required under the heads of any screws of nuts used. Please note that the securing
holes are not part of the board grounding mechanism.
Note:
Both module versions are supplied with all jumpers and links open. Before
powering up the module, ensure that all the jumper links have been set correctly for
your application and microphone type. In all cases, except when using the line level
input from pin 9 J2, the
PRE
jumper link must be soldered.
4. External Overload Indicator
The module has connections that enable the Overload LED mounted on the PCB to be
duplicated for use on a front panel, or used for monitoring by other circuitry. The
connections for this can be found on J4 (
Ovr
). Pin 5
Ovr
needs to be connected to the
LED cathode, while the LED anode needs to be connected to Pin2 (
V+)
via a 180R
resistor.
5. Use With The On-board Microphone
The on-board Knowles SPM0204HD5 SMD microphone
(NEDSP1068-PCBA-MIC)
makes this PCB extremely useful for many products. However, some consideration
should be given to the way in which the PCB is mounted within the equipment to ensure
that the pcb mounted microphone doesn’t pick up mechanical noise and vibration from
surrounding parts, such as power supplies and fans etc.
6. External Microphones or Signals
The standard
NEDSP1068-PCBA
does not have the on-board a microphone built onto
it, and can be used with a variety of external microphones.
To select the external mic option, ensure that the
PRE
jumper link is soldered, and the
jumper marked
MIC
is open. You may need to remove the solder link carefully using de-
solder braid.
