NCV8501 ON Semiconductor, NCV8501 Datasheet - Page 10

• Manufacturer Part Number: NCV8501
• Description: 2.5v, 3.3v, 5.0v, 8v, 10v, Adj./150ma Low Quiescent Current Ldo W/ Reset, Enable And Early Warning
• Manufacturer: ON Semiconductor

control function RESET (Figure 14).
DELAY
RESET Function
powers up until V
voltage, or when V
than 8.0% below the regulated output voltage. Hysteresis is
included in the function to minimize oscillations.
controlled by a low voltage detection circuit. The circuit is
functionally independent of the rest of the IC thereby
guaranteeing that the RESET signal is valid for V
as 1.0 V.
ENABLE Function
pin is held low. The part has an internal pull down if the pin
is left floating. This is intended for failure modes only. An
external connection (active pulldown, resistor, or switch) for
normal operation is recommended.
directly to the battery line through an external resistor. It will
withstand load dump potentials in this configuration.
DELAY Function
external capacitor) delay on the RESET output lead.
RESET
V
V
V
OUT
BAT
The NCV8501 contains the microprocessor compatible
IN
A RESET signal (low voltage) is generated as the IC
The RESET output is an open collector NPN transistor,
The part stays in a low I
The integrity of the ENABLE pin allows it to be tied
The reset delay circuit provides a programmable (by
Figure 14. Reset and Delay Circuit Wave Forms
10 k
REGULATOR CONTROL FUNCTIONS
T
Figure 15. ENABLE Function
d
OUT
OUT
is within 6.0% of the regulated output
drops out of regulation,and is lower
V
ENABLE
IN
Q
sleep mode when the ENABLE
NCV8501
T
GND
d
V
OUT
CIRCUIT DESCRIPTION
OUT
Threshold
Threshold
NCV8501 Series
http://onsemi.com
as low
RESET
DELAY
(V
DT
)
10
to the external DELAY capacitor during the following
proceedings:
FLAG/Monitor Function
warning to the microprocessor of a possible reset signal. The
reset signal typically turns the microprocessor off
instantaneously. This can cause unpredictable results with
the microprocessor. The signal received from the FLAG pin
will allow the microprocessor time to complete its present
task before shutting down. This function is performed by a
comparator referenced to the bandgap reference. The actual
trip point can be programmed externally using a resistor
divider to the input monitor (MON) (Figure 16). The typical
threshold is 1.20 V on the MON pin.
Voltage Adjust
output voltage. The feedback to the V
a voltage divider referenced to the output voltage. The loop
is balanced around the Unity Gain threshold (1.28 V
typical).
V
BAT
The DELAY lead provides source current (typically 2.5 mA)
An on-chip comparator is provided to perform an early
Figure 17 shows the device setup for a user configurable
1. During Power Up (once the regulation threshold
2. After a reset event has occurred and the device is
has been verified).
back in regulation. The DELAY capacitor is
discharged when the regulation (RESET threshold)
has been violated. This is a latched incident. The
capacitor will fully discharge and wait for the
device to regulate before going through the delay
time event again.
Figure 17. Adjustable Output Voltage
Figure 16. FLAG/Monitor Function
NCV8501
V
MON
R
DELAY
IN
ADJ
NCV8501
V
V
OUT
ADJ
RESET
GND
FLAG
V
OUT
15 k
1.28 V
5.1 k
ADJ
≈5.0 V
C
pin is taken from
OUT
C
OUT
V
I/O
RESET
CC
mP