SI8421AD Datasheet, PDF (22/37 Pages) List of Unclassifed Manufacturers – LOW-POWER, SINGLE AND DUAL-CHANNEL DIGITAL ISOLATORS

Si8410/20/21 (5 kV)
Si8422/23 (2.5 & 5 kV)
3. Device Operation
Device behavior during start-up, normal operation, and shutdown is shown in Figure 7, where UVLO+ and UVLO-
are the positive-going and negative-going thresholds respectively. Refer to Table 12 to determine outputs when
power supply (V_DD) is not present.
Table 12. Si84xx Logic Operation Table
V_I Input^1,4 VDDI State^1,2,3 VDDO State^1,2,3 V_O Output^1,4
Comments
H
P
P
L
P
P
H
Normal operation.
L
X⁵
UP
X⁵
P
P
H⁶ (Si8422/23) Upon transition of VDDI from unpowered to
L⁶ (Si8410/20/21) powered, V_O returns to the same state as V_I in
less than 1 µs.
UP
Undetermined Upon transition of VDDO from unpowered to
powered, V_O returns to the same state as V_I
within 1 µs.
Notes:
1. VDDI and VDDO are the input and output power supplies. V_I and V_O are the respective input and output terminals.
2. Powered (P) state is defined as 2.72.60 V < VDD < 5.5 V.
3. Unpowered (UP) state is defined as VDD = 0 V.
4. X = not applicable; H = Logic High; L = Logic Low.
5. Note that an I/O can power the die for a given side through an internal diode if its source has adequate current.
6. See "6. Ordering Guide" on page 29 for details. This is the selectable fail-safe operating mode (ordering option). Some
devices have default output state = H, and some have default output state = L, depending on the ordering part number
(OPN).
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Rev. 1.3