ncv8508b ON Semiconductor, ncv8508b Datasheet - Page 8

• Manufacturer Part Number: ncv8508b
• Description: Ncv8508b 5.0 V, 250 Ma Ldo With Watchdog And Reset
• Manufacturer: ON Semiconductor

regulator with very low quiescent current (100 mA typical at
250 mA load). A typical dropout voltage is 450 mV at
150 mA for 5 V option. Microprocessor control logic
includes Watchdog, Wakeup and RESET. This unique
combination of extremely low quiescent current and full
microprocessor control makes the NCV8508B ideal for use
in battery operated, microprocessor controlled equipment in
addition to being a good fit in the automotive environment.
microprocessor out of Sleep mode. The microprocessor in
turn signals its Wakeup status back to the NCV8508B by
issuing a Watchdog signal.
(WDI) from the microprocessor. The NCV8508B responds
to the falling edge of the Watchdog signal which it expects
at least once during each Wakeup period. When the correct
Watchdog signal is received, a falling edge is issued on the
Wakeup signal line.
V
The NCV8508B is a precision micropower voltage
The
The Watchdog logic function monitors an input signal
BAT
NCV8508B
MRA4004T3
Wakeup
0.1 mF
V
function
IN
NCV8508B
DETAILED OPERATING DESCRIPTION
GND
Figure 16. Application Circuit
brings
Delay
http://onsemi.com
the
60 k
8
output voltage as low as 1.0 V. A signal is issued in any of
three situations. During power up, the RESET is held low
until the output voltage is in regulation. During operation, if
the output voltage shifts below the regulation limits, the
RESET toggles low and remains low until proper output
voltage regulation is restored. Finally, a RESET signal is
issued if the regulator does not receive a Watchdog signal
within the Wakeup period.
Wakeup delay time are all set by one external resistor,
R
can be used as a reference for an external tracking regulator
as shown in Figure 16.
runaway conditions. The device runs through 45 volt
transients, making it suitable for use in automotive
environments.
Delay
RESET is independent of V
The RESET pulse width, Wakeup signal frequency, and
The Delay pin is a buffered bandgap voltage (1.25 V). It
The regulator is protected against short circuit and thermal
1.0 mF
0.1 mF
.
V
V
IN
REF
/ENABLE
CS8182
GND
V
Adj
OUT
IN
and operates correctly to an
200 mA
3.9 k
12 k
10 mF
5 V