SI8640BA-B-IU Datasheet, PDF (6/42 Pages) Silicon Laboratories – Low-Power Quad-Channel Digital Isolators

Si864x Data Sheet
Device Operation
3. Device Operation
Device behavior during start-up, normal operation, and shutdown is shown in Figure 3.1 Device Behavior during Normal Operation on
page 7, where UVLO+ and UVLO– are the respective positive-going and negative-going thresholds. Refer to the following tables to
determine outputs when power supply (VDD) is not present and for logic conditions when enable pins are used.
Table 3.1. Si86xx Logic Operation
V_I Input^{1, 2} EN Input^{1, 2, 3, 4} VDDI State^{1, 5, 6} VDDO State^{1, 5, 6} V_O Output^{1, 2}
Comments
H
H or NC
P
P
H
Enabled, normal operation.
L
H or NC
P
P
L
X⁷
L
P
P
Hi-Z⁸
Disabled.
X⁷
H or NC
UP
P
L⁹
Upon transition of VDDI from unpowered to
powered, V_O returns to the same state as V_I
H⁹
in less than 1 µs.
X⁷
L
UP
P
Hi-Z⁸
Disabled.
X⁷
X⁷
P
UP
Undetermined Upon transition of VDDO from unpowered to
powered, VO returns to the same state as V_I
within 1 µs, if EN is in either the H or NC
state. Upon transition of VDDO from unpow-
ered to powered, V_O returns to Hi-Z within 1
µs if EN is L.
Note:
1. VDDI and VDDO are the input and output power supplies. V_I and V_O are the respective input and output terminals. EN is the
enable control input located on the same output side.
2. X = not applicable; H = Logic High; L = Logic Low; Hi-Z = High Impedance.
3. It is recommended that the enable inputs be connected to an external logic high or low level when the Si86xx is operating in noisy
environments.
4. No Connect (NC) replaces EN1 on Si8640/45. No Connect replaces EN2 on the Si8645. No Connects are not internally connec-
ted and can be left floating, tied to VDD, or tied to GND.
5. “Powered” state (P) is defined as 2.5 V < VDD < 5.5 V.
6. “Unpowered” state (UP) is defined as VDD = 0 V.
7. Note that an I/O can power the die for a given side through an internal diode if its source has adequate current.
8. When using the enable pin (EN) function, the output pin state is driven into a high-impedance state when the EN pin is disabled
(EN = 0).
9. See 1. Ordering Guide 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). For default high devi-
ces, the data channels have pull-ups on inputs/outputs. For default low devices, the data channels have pull-downs on inputs/
outputs.
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