
Rev. 1.1
23
S i 8 4 1 0 / 2 0 / 2 1 ( 5 k V )
S i 8 4 2 2 / 2 3 ( 2 . 5 & 5 k V )
3.1. Device Startup
Outputs are held low during powerup until
V
DD
is above the UVLO threshold for time period tSTART. Following this,
the outputs follow the states of inputs.
3.2. Under Voltage Lockout
Under Voltage Lockout (UVLO) is provided to prevent erroneous operation during device startup and shutdown or
when
V
DD
is below its specified operating circuits range. Both Side A and Side B each have their own undervoltage
lockout monitors. Each side can enter or exit UVLO independently. For example, Side A unconditionally enters
UVLO when V
DD1
falls below V
DD1(UVLO–)
and exits UVLO when V
DD1
rises above V
DD1(UVLO+)
. Side B operates
the same as Side A with respect to its V
DD2
supply.
Figure 7. Device Behavior during Normal Operation
INPUT
V
DD1
UVLO-
V
DD2
UVLO+
UVLO-
UVLO+
OUTPUT
tSTART
tSTART
tSTART
tPHL
tPLH
tSD