si8405 Silicon Laboratories, si8405 Datasheet - Page 16

• Manufacturer Part Number: si8405
• Description: Bidirectional I 2c Isolators With Unidirectional Digital Channels
• Manufacturer: Silicon Laboratories

Si840x
3.3. Input and Output Characteristics for Non-I
The Si84xx inputs and outputs are standard CMOS drivers/receivers. The nominal output impedance of an isolator
driver channel is approximately 50 , ±40%, which is a combination of the value of the on-chip series termination
resistor and channel resistance of the output driver FET. When driving loads where transmission line effects will be
a factor, output pins should be terminated with 50  controlled impedance PCB traces. Table 11 details powered
and unpowered operation of the Si84xx’s non-I
16
Notes:
V
I
1. VDDI and VDDO are the input and output power supplies. V
2. Powered (P) state is defined as 3.0 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.
Input
H
X
X
L
1, 4
VDDI State
UP
P
P
P
1,2,3
VDDO State
UP
P
P
P
Table 11. Si84xx Operation Table
1,2,3
2
Preliminary Rev. 0.1
C digital channels.
Undetermined
V
O
Output
H
L
L
1, 4
2
I
C Digital Channels
and V
Normal operation.
Upon transition of VDDI from unpowered to pow-
ered, V
than 1 µs.
Upon transition of VDDO from unpowered to pow-
ered, V
1 µs.
O
are the respective input and output terminals.
O
O
returns to the same state as V
returns to the same state as V
Comments
I
I
in less
within