NCV8506 ON Semiconductor, NCV8506 Datasheet - Page 9

• Manufacturer Part Number: NCV8506
• Description: Micropower 400 mA LDO Linear Regulators
• Manufacturer: ON Semiconductor

control function RESET (Figure 13).
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.
DELAY Function
external capacitor) delay on the RESET output lead.
Voltage, Delay Switching Threshold, and the Delay Charge
Current. The delay follows the equation:
Example:
DELAY
V
RESET
t DELAY +
V
OUT
The NCV8506 contains the microprocessor compatible
A RESET signal (low voltage) is generated as the IC
The RESET output is an open collector NPN transistor,
The reset delay circuit provides a programmable (by
The delay time is controlled by the Reset Delay Low
Using C
Assume reset Delay Low Voltage = 0.
Use the typical value for V
Use the typical value for Delay Charge Current = 4.2 mA.
IN
Figure 13. Reset and Delay Circuit Wave Forms
REGULATOR CONTROL FUNCTIONS
5.0 V options).
t DELAY +
DELAY
[ C DELAY (V dt * Reset Delay Low Voltage) ]
SETTING THE DELAY TIME
T
d
OUT
= 33 nF.
OUT
[ 33 nF(1.8 * 0) ]
is within 1.5% of the regulated output
drops out of regulation,and is lower
Delay Charge Current
4.2 mA
dt
T
d
= 1.8 V (2.5 V, 3.3 V, and
+ 14 ms
CIRCUIT DESCRIPTION
OUT
APPLICATION NOTES
Threshold
Threshold
http://onsemi.com
as low
RESET
DELAY
(V
DT
)
9
to the external DELAY capacitor during the following
proceedings:
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 (1.30 V
typical).
three main characteristics of a linear regulator: start−up
delay, load transient response and loop stability.
availability, size and temperature constraints. A tantalum or
aluminum electrolytic capacitor is best, since a film or
ceramic capacitor with almost zero ESR can cause
instability. The aluminum electrolytic capacitor is the least
expensive solution, but, if the circuit operates at low
temperatures (−25°C to −40°C), both the value and ESR of
the capacitor will vary considerably. The capacitor
manufacturers data sheet usually provides this information.
The DELAY lead provides source current (typically 4.0 mA)
Figure 14 shows the device setup for a user configurable
The output or compensation capacitor helps determine
The capacitor value and type should be based on cost,
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.
STABILITY CONSIDERATIONS
NCV8506
Figure 14. Adjustable Output
V
V
OUT
ADJ
Voltage
1.28 V
15 k
5.1 k
ADJ
≈5.0 V
pin is taken from
C
OUT