We tried to interface an external speaker with the UMTs & LTE EVB_V2.2 board using the NCP2823A amplifier mounted on the EVB.
We routed the speaker output pin (73,74) by wire from the EC200U module to the NCP2823A circuitry and shorted the J604 connector as required. We then connected an external speaker (8 ohm, 3W) to the output pins of the NCP2823A circuit. However, the setup is not working as expected.
In the software, we have configured the following parameters:
Selected the internal embedded codec.
Enabled the Class-D amplifier mode for the NCP2823A.
Please advise on any additional steps or checks needed to make the speaker function correctly.
On EC200U, pins 73/74 are LOUDSPK_P / LOUDSPK_N, which are differential analog loudspeaker outputs. This output already includes a built-in power amplifier (default Class AB, and can be configured to Class D), and it is designed to directly drive an 8 Ω load without referencing either pin to GND.
So the first definitive recommendation is: do not feed LOUDSPK_P/N into another power amplifier stage unless you specifically need an external PA for higher power. For bring-up, connect the 8 Ω speaker directly across LOUDSPK_P and LOUDSPK_N (differential), and verify the audio path is working first.
For software bring-up and a quick “speaker path” verification:
Set audio mode to loudspeaker and set a reasonable volume level (EC200U supports loudspeaker).
Play a local tone to confirm the speaker path without needing a voice call.
If you still want to use the EVB’s onboard NCP2823A stage, then the most common reason for “no sound” is that the amplifier enable/shutdown control is not asserted, so the PA stays in shutdown. In the EC200U reference design guidance, the PA enable is expected to be controlled by a module GPIO (AUDIO_PA_SHUTDOWN concept) and must be driven to the correct level to turn the amplifier on.
In other words: your “embedded codec + Class-D” configuration does not automatically guarantee the external PA is enabled; you must also confirm the PA EN/SHDN pin is active on the EVB circuitry.
Recommended checks on the EVB path (when using the onboard PA):
Confirm the PA has its supply (VBAT/PA power rail) present.
Confirm the PA EN/SHDN pin is at the active level (not floating).
Confirm J604 is routing the signal into the PA input as intended, and your speaker is connected only at the PA output (not accidentally at the input).
If the issue still persists kindly share the following information for further debugging:
(1) the exact EC200U firmware revision
(2) a close-up photo of the J604 area wiring (top + bottom),
(I can point out the exact EVB-side node that must be enabled and where LOUDSPK_P/N should be routed.)
