NCV8503 ON Semiconductor, NCV8503 Datasheet - Page 9

• Manufacturer Part Number: NCV8503
• Description: 2.5v, 3.3v, 5.0v, Adjustable/400ma Ldo W/ Reset, Delay, Adjustable Reset, Enable And Early Warning
• Manufacturer: ON Semiconductor

control function RESET (Figure 15).
RESET Function
powers up until V
voltage, or when V
than 4.0% 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.
Adjustable Reset Function
external resistor divider to the R
lead, as displayed in Figure 16. This lead is grounded to
select the default value of 4.6 V (on the 5.0 V option).
DELAY
V
V
R(ADJ)
RESET
V
The NCV8503 contains the microprocessor compatible
OUT
A RESET signal (low voltage) is generated as the IC
The RESET output is an open collector NPN transistor,
The reset threshold can be made lower by connecting an
IN
Figure 15. Reset and Delay Circuit Wave Forms
REGULATOR CONTROL FUNCTIONS
R
ADJ
T
DELAY
Figure 16. Adjustable RESET
d
NCV8503
OUT
C
OUT
DELAY
RESET
is within 1.5% of the regulated output
drops out of regulation,and is lower
V
OUT
T
d
ADJ
R
RST
lead from the V
CIRCUIT DESCRIPTION
OUT
C
OUT
to mP and
System
Power
to mP and
RESET
Port
NCV8503 Series
Threshold
Threshold
http://onsemi.com
as low
RESET
DELAY
OUT
(V
DT
)
9
ENABLE Function
pin is held low. The part has an internal pull down if the pin
is left floating.
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.
to the external DELAY capacitor during the following
proceedings:
FLAG/Monitor Comparator
terminal is tied to the on-chip band gap voltage reference.
This provides a very temperature stable referenced
comparator with versatile uses in any system. The trip point
can be programmed externally using a resistor divider to the
input monitor (MON) (Figure 18). The typical threshold is
1.28 V on the MON pin.
V
V
Up to 45 V
V
MON
BAT
BAT
The part stays in a low I
The integrity of the ENABLE pin allows it to be tied to the
The reset delay circuit provides a programmable (by
The DELAY lead provides source current (typically 4.0 mA)
A general use comparator is included whose positive input
1. During Power Up (once the regulation threshold
2. After a reset event has occurred and the device is
10 k
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 18. Flag/Monitor Function
Figure 17. ENABLE Function
V
MON
DELAY
R
IN
ADJ
NCV8503
RESET
GND
FLAG
V
V
ENABLE
OUT
IN
Q
sleep mode when the ENABLE
NCV8503
GND
V
OUT
C
OUT
V
I/O
RESET
CC
mP