EC25 not entering deep sleep mode – possible issue with USB_VBUS?

IoT Modules LTE Standard Module
1

Hi,

I’m trying to enable sleep mode on the EC25-EU to reduce power consumption. I’ve sent the AT+QSCLK=1 command via UART, and the DTR pin (not connected, floating) reads 1.78 V, which I believe should be considered HIGH.

However, the module does not enter sleep mode — the SLEEP_IND pin stays LOW, and current remains at ~33 mA.

One thing I noticed is that USB_VBUS is still connected to 5 V in my design. Could that be preventing the module from sleeping, even though I’m only using UART for AT commands?

Or could it be something else I’m missing?

Thanks in advance for your help!

2

Hi,@jpujante
The module needs to disconnect the VBUS connection when entering sleep mode, otherwise it will prevent the module from entering sleep mode.