NCP786L

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5

APPLICATION INFORMATION

The typical application circuit for the NCP786L device is shown below.

Figure 7. Typical Application Schematic

NCP786L

2.2 uF

Vout = 1.27 V – 15 V / 5 mA

IN

GND

OUT

ADJ

Vin = (55 – 450) Vdc

NCP786L

2.2 uF

Vout = 1.27 V – 15 V / 5 mA

IN

GND

OUT

ADJ

Vin = (40 – 320) Vac

NCP786L

2.2 uF

Vout = 1.27 V – 15 V / 5 mA

IN

GND

OUT

ADJ

Vin = (40 – 320) Vac

Input Decoupling (C1)

A 1.0

mF capacitor either ceramic or electrolytic is

recommended and should be connected close to the input pin

of NCP786L. Higher value 2.2

mF is necessary to keep the

input voltage above the required minimum input voltage at

full load for AC voltage as low as 85 V with half wave

rectifier. The capacitor 1

mF could be acceptable for DC

input voltage from 55 V up to 450 V or AC input voltage

235 V

±20%. There must be assured minimum Input

Voltage more than 55 V at input pin of NCP786L regulator

in order to keep stable desired output voltage with

guaranteed parameters at AC supply.

Output Decoupling (C2)

The NCP786L Regulator does not require any specific

Equivalent Series Resistance (ESR). Thus capacitors

exhibiting ESRs ranging from a few m

W up to 0.5 W can be

used safely. The minimum decoupling value is 2.2

mF. The

regulator accepts ceramic chip capacitors as well as

tantalum devices or low ESR electrolytic capacitors. Larger

values improve noise rejection and especially load transient

response.

Layout Recommendations

wide. When the impedance of these lines is high, there is a

chance to pick up a noise or to cause the malfunction of

regulator by induced parasitic signal.

Set external components, especially the output capacitor,

as close as possible to the circuit, and make leads as short as

possible.

Thermal

As power across the NCP786L increases, it might become

necessary to provide some thermal relief. The maximum

power dissipation supported by the device is dependent

upon board design layout and used package. Mounting pad

configuration on the PCB, the board material, and also the

ambient temperature affect the rate of temperature rise for

the part. This is stating that when the NCP786L has good

thermal conductivity through the PCB, the junction

temperature will be relatively low with high power

dissipation applications.