SI8220 Datasheet, PDF (14/31 Pages) Silicon Laboratories – 0.5 AND 2.5 AMP ISODRIVERS WITH OPTO INPUT (2.5, 3.75, AND 5.0 KVRMS)

Si8220/21
5. Technical Description
5.1. Device Behavior
Truth tables for the Si8220/21 are summarized in Table 9.
Table 9. Si8220/21 Truth Table Summary
Cathode Anode Diode Current (I_F)
V_DD
VO
Comments
X
X
X
< UVLO
L
Device turned off
Hi-Z
X
0
> UVLO
L
Logic low state
X
Hi-Z
0
> UVLO
L
Logic low state
GND
GND
0
> UVLO
L
Logic low state
VF
VF
0
> UVLO
L
Logic low state
GND1
VF
< I_F(OFF
> UVLO
L
Logic low state
GND1
VF
> I_F(OFF)
> UVLO
H
Logic high state
Note: “X” = don’t care. This truth table assumes VDD is powered. If VDD is below UVLO, see "5.3.Under
Voltage Lockout (UVLO)" on page 15 for more information.
5.2. Device Startup
Output V_O is held low during power-up until V_DD rises above the UVLO+ threshold for a minimum time period of
t_START. Following this, the output is high when the current flowing from anode to cathode is > I_F(ON). Device startup,
normal operation, and shutdown behavior is shown in Figure 8.
UVLO+
UVLO-
V_DDHYS
V_DD
I_F(ON)
I_F
I_HYS
t_START
t_PHL t_PLH
t_START
V_O
Figure 8. Si8220/21 Operating Behavior (I_F > I_F(MIN) when V_F > V_F(MIN))
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Rev. 1.5