NCV8135
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APPLICATIONS INFORMATION
The NCV8135 dual−rail very low dropout voltage
regulator is using NMOS pass transistor for output voltage
regulation from VIN voltage. All the low current internal
control circuitry is powered from the VBIAS voltage.
The use of an NMOS pass transistor offers several
advantages in applications. Unlike PMOS topology devices,
the output capacitor has reduced impact on loop stability. Vin
to Vout operating voltage difference can be very low compared
with standard PMOS regulators in very low Vin applications.
When enabled from Enable (EN) input, the NCV8135
offers smooth monotonic start-up. The controlled voltage
rising limits the inrush current.
The Enable (EN) input is equipped with internal
hysteresis.
Dropout Voltage
Because of two power supply inputs VIN and VBIAS and
one VOUT regulator output, there are two Dropout voltages
specified.
The first, the VIN Dropout voltage is the voltage
difference (VIN – VOUT) when VOUT starts to decrease by
percent specified in the Electrical Characteristics table.
VBIAS is high enough; specific value is published in the
Electrical Characteristics table.
The second, VBIAS dropout voltage is the voltage
difference (VBIAS – VOUT) when VIN and VBIAS pins are
joined together and VOUT starts to decrease.
Input and Output Capacitors
The device is designed to be stable for ceramic output
capacitors with Effective capacitance in the range from
10 mF to 22 mF. The device is also stable with multiple
capacitors in parallel, having the total effective capacitance
in the specified range.
In applications where no low input supplies impedance
available (PCB inductance in VIN and/or VBIAS inputs as
example), the recommended CIN = 1 mF and CBIAS = 0.1 mF
or greater. Ceramic capacitors are recommended. For the
best performance all the capacitors should be connected to
the NCV8135 respective pins directly in the device PCB
copper layer, not through vias having not negligible
impedance.
When using small ceramic capacitor, their capacitance is
not constant but varies with applied DC biasing voltage,
temperature and tolerance. The effective capacitance can be
much lower than their nominal capacitance value, most
importantly in negative temperatures and higher LDO
output voltages. That is why the recommended Output
capacitor capacitance value is specified as Effective value in
the specific application conditions.
Enable Operation
The enable pin will turn the regulator on or off. The
threshold limits are covered in the electrical characteristics
table in this data sheet. To get the full functionality of
soft−start, it is recommended to turn on the VIN and VBIAS
supply voltages first and activate the Enable pin no sooner
than when VIN and VBIAS are on their nominal levels. If the
enable function is not to be used then the pin should be
connected to VIN or VBIAS.
Current Limitation
The internal Current Limitation circuitry allows the
device to supply the full nominal current and surges but
protects the device against Current Overload or Short.
Thermal Protection
Internal thermal shutdown (TSD) circuitry is provided to
protect the integrated circuit in the event that the maximum
junction temperature is exceeded. When TSD activated, the
regulator output turns off. When cooling down under the low
temperature threshold, device output is activated again. This
TSD feature is provided to prevent failures from accidental
overheating.
Activation of the thermal protection circuit indicates
excessive power dissipation or inadequate heatsinking. For
reliable operation, junction temperature should be limited to
+125°C maximum.
ORDERING INFORMATION
Device Marking Voltage Option Package Shipping†
NCV8135AMT040TBG KA 0.4 V Output Active Discharge WDFN6
(Non−Wettable Flank)
(Pb−Free)
3000 / Tape & Reel
NCV8135BMT040TBG KC 0.4 V Non−Active Discharge
NCV8135AMT120TBG KE 1.2 V Output Active Discharge
NCV8135AMTW040TBG K2 0.4 V Output Active Discharge
WDFN6
(Wettable Flank)
(Pb−Free)
NCV8135BMTW040TBG K3 0.4 V Non−Active Discharge
NCV8135AMTW120TBG K4 1.2 V Output Active Discharge
NCV8135AMTW075TBG
(In Development)
KL 0.75 V Output Active Discharge
†For information on tape and reel specifications, including part orientation and tape sizes, please refer to our Tape and Reel Packaging Spe-
cifications Brochure, BRD8011/D.
To order other package and voltage variants, please contact your ON Semiconductor sales representative