l4946b STMicroelectronics, l4946b Datasheet - Page 6

• Manufacturer Part Number: l4946b
• Description: Quad Voltage Regulator With Inhibit And Reset
• Manufacturer: STMicroelectronics

L4946
FUNCTIONAL DESCRIPTION
The L4946 includes a monitoring circuit to warn
the microprocessor if a low voltage or no voltage
condition is occurring. Between 7V and 8V on the
STCAP pin, the LVW output will go low. This tells
the microprocessor to stop executing code and
save vital information. The reset output will go low
when V
A reset will occur between a minimum of 4.5 and
a maximum of 5V on V
TIMING DIAGRAM
Graphs of the Output Curves for V
6/9
04
drops 0.15V below it’s typical reading.
04
5.0
5.0
. The reset output will go
O1,2,3 and 4
150 s
7.5
150 s
low when V
A reset will occur between a minimum of 4.5V
and a maximum of 5V on V
drops between 4.5 and 5V the RESET output
goes low. It is very important that the RESET out-
put doesn’t go above 0.75V until the V
has gone back above 4.75V (typical). The micro-
processor looks for a rising edge. So, any spike
will tell the microprocessor to start operating.
Once the STCAP line passes 7.5V (typical), the
LVW output will also return to high state.
100 s
7.5
100 s
04
drops 0.15 below it’s typical value.
04
. When the V
04
output
04