User Guide

WE866C6 Hardware Design Guide
1VV0301658 Rev. 1 Page 22 of 58 2020-06-16
Power Supply Sequencing
The recommended power sequence between VDD_3.3V and VDDIO inputs is as shown
below:
VBATT
VDDIO
VDD_3.3V
WL_EN
BT_EN
LF_CLK_IN
Power up Normal Operation Power downNormal OperationReset
90% of VDDIO to 10% of 3.3V
Minimum 0 Sec
90% of 3.3V to WL_EN and BT_EN high
Minimum 10 uSec
WLAN_EN valid to LF_CLK_IN
Minimum 0 Sec
WL_EN and BT_EN low to 90% of 3.3V
Minimum 10 uSec
Notes:
1. VDDIO voltage should match VIO voltage of the host. In some applications, it may
connect to 3.3 V matching the Host VIO voltage.
2. All host interface signals must stay floating or low before valid power on sequence
WL_EN/BT_EN = ”High”, and after WL_EN/BT_EN = “Low”.
Warning:
Please carefully follow the recommended power Up/Down sequencing.
Not following the recommended procedure might damage the device and
consequently void the warranty.