User's Guide
LM940 HW Design Guide
1VV0301352 Rev. 2 Page 34 of 68 2017-07-19
Parameter Min Max Unit Comment
IIL Low-level input leakage
current
-- 1000 [uA] No pull-up
IIH High-level input leakage
current
-20 20 [uA] No pull-down
Power On
The LM940 is automatically turning on when the VBATT is supplied.
Information – To turn on the LM940 module, the W_DISABLE_N pin
must not be asserted low.
6.2.1. Initialization and Activation State
After turning on the LM940 module, the LM940 is not yet activated because the SW
initialization process of the LM940 module is still in process internally. It takes some time
to fully complete the HW and SW initialization of the module.
For this reason, it is impossible to access LM940 during the Initialization state.
As shown in below figure, the LM940 becomes operational (in the Activation state) at least
15 seconds after the VBATT is supplied.
LM940 Initialization and Activation
InitializationState ActivationState
InternalState
VREG_L6_1P8
W_DISABLE_N
OFFState
TBDsec
USBDriverLoaded
AllInterfacesAndPinsConfigured
VBATT
TBDsec