ncv8613b ON Semiconductor, ncv8613b Datasheet - Page 11

• Manufacturer Part Number: ncv8613b
• Description: Ncv8613b Ultra-low Iq Automotive System Power Supply Ic Power Saving Triple-output Linear Regulator
• Manufacturer: ON Semiconductor

therefore is not effected by the soft−start function upon the
device’s return from an over voltage condition. Also, when
VIN_S3 is connected to an independent supply and the
supply is made available after the soft−start function, LDO3
will not have an independent soft−start.
LDO1 Regulator
to a sample of the output voltage (V
of an internal PFET. The reference is a bandgap design to
give it a temperature−stable output.
LDO2 Regulator
to a sample of the output voltage (V
of an internal PFET. The reference is a bandgap design to
give it a temperature−stable output.
LDO3 Regulator
to a sample of the output voltage (V
of an internal PFET. The reference is a bandgap design to
give it a temperature−stable output
Stability Considerations
determine three main characteristics of a linear regulator:
startup delay, load transient response and loop stability. The
capacitor values and type should be based on cost,
availability, size and temperature constraints. Tantalum,
aluminum electrolytic, film, or ceramic capacitors are all
acceptable solutions, however, attention must be paid to
ESR constraints. 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
manufacturer’s data sheet usually provides this information.
The value for each output capacitor C
Figures 20 − 25 should work for most applications;
however, it is not necessarily the optimized solution.
Stability is guaranteed at the following values:
C
C
C
Actual limits are shown in graphs in the Typical
Performance Characteristics section.
Thermal
necessary to provide some thermal relief. The maximum
power dissipation supported by the device is dependent
upon board design and layout. Mounting pad configuration
on the PCB, the board material, and the ambient temperature
affect the rate of junction temperature rise for the part. When
the NCV8613B has good thermal conductivity through the
PCB, the junction temperature will be relatively low with
high power applications.
OUT1
OUT2
OUT3
The LDO1 error amplifier compares the reference voltage
The LDO2 error amplifier compares the reference voltage
The LDO3 error amplifier compares the reference voltage
The output or compensation capacitors, C
As power in the NCV8613B increases, it might become
w 47 mF, ESR v 10 W
w 47 mF, ESR v 10 W
w 47 mF, ESR v 10 W
OUT1
OUT2
OUT3
) and drives the gate
) and drives the gate
) and drives the gate
OUTX
OUTX
shown in
http://onsemi.com
help
11
given by:
and/or if Air Flow is taken into account.
IGNOUT Circuitry
externally pulled up to 3.3 V via a 10 kW resistor. The
IGNOUT pin can be used to monitor the ignition signal of
the vehicle, and send a signal to mute an audio amplifier
during engine crank. The IGNIN pin is ESD protected, and
can handle peak transients up to 45 V. An external diode is
recommended to protect against negative voltage spikes.
for proper operation.
V
stage. The high signal is provided by V
externally fed signal that can be tied to an output, or tied to
another regulated voltage signal, typically 5 V, but as low as
3.0 V. Under this setup, and any setup where LDO’s 1−3 are
tied to V
voltage is reduced due to over current, thermal shutdown, or
overvoltage conditions.
Reset Outputs
Microcontroller. The NCV8613B Reset circuitry monitors
the output on LDO2.
for reliable operation. It pulls low when the output is not
considered to be suitable. The Reset circuitry utilizes a push
pull output stage, with V
of the part shutting down via Battery voltage or Enable, the
Reset output will be pulled to ground.
Output and the relative timing are illustrated in Figure 4,
Reset Timing. Output voltage regulation must be maintained
for the delay time before the reset output signals a valid
condition. The delay for the reset output is defined as the
amount of time it takes the timing capacitor on the delay pin
to charge from a residual voltage of 0 V to the Delay timing
threshold voltage V
I
capacitor on the Delay Pin, the following time delay is
derived:
t
t
capacitor value. The Delay Time can be reduced by
decreasing the capacitance of C
delay can be reduced as desired. Leaving the Delay Pin open
RD
RD
D
PP
The maximum dissipation the NCV8613B can handle is
P
See Figure 18 for R
R
The IGNOUT pin is an open drain output Schmitt Trigger,
The IGNOUT circuitry requires the device to be enabled
The reset and warning circuits utilize a push−pull output
The Reset Output is used as the power on indicator to the
This signal indicates when the output voltage is suitable
The input and output conditions that control the Reset
Other time delays can be obtained by changing the C
of 5 mA. By using typical IC parameters with a 10 nF
D(max)
thJA
= C
= 10 nF * (2 V)/ (5 mA) = 4 ms
Function
could be further decreased by using Multilayer PCB
D
PP
= (T
* V
, loss of the V
DU
J(max)
/ I
D
−T
D
A
of 2 V. The charging current for this is
thJA
)/R
PP
thJA
PP
versus PCB Area.
as the high signal. In the event
signal can occur if the pull up
D
. Using the formula above,
PP
. V
PP
is an
D