Datasheet NCP500, NCV500 (ON Semiconductor) - 12

link to page 13 link to page 14
NCP500, NCV500 DEFINITIONS Load Regulation Line Regulation
The change in output voltage for a change in output load The change in output voltage for a change in input voltage. current at a constant temperature. The measurement is made under conditions of low dissipation or by using pulse technique such that the average
Dropout Voltage
chip temperature is not significantly affected. The input/output differential at which the regulator output no longer maintains regulation against further reductions in
Line Transient Response
input voltage. Measured when the output drops 2% below its Typical over and undershoot response when input voltage nominal. The junction temperature, load current, and is excited with a given slope. minimum input supply requirements affect the dropout level.
Thermal Protection Output Noise Voltage
Internal thermal shutdown circuitry is provided to protect This is the integrated value of the output noise over a the integrated circuit in the event that the maximum junction specified frequency range. Input voltage and output load temperature is exceeded. When activated at typically 160°C, current are kept constant during the measurement. Results the regulator turns off. This feature is provided to prevent are expressed in mVRMS or nV Hz Ǹ . failures from accidental overheating.
Quiescent Current Maximum Package Power Dissipation
The current which flows through the ground pin when the The power dissipation level at which the junction regulator operates without a load on its output: internal IC temperature reaches its maximum operating value, i.e. operation, bias, etc. When the LDO becomes loaded, this 125°C. term is called the Ground current. It is actually the difference between the input current (measured through the LDO input pin) and the output current.
APPLICATIONS INFORMATION
The NCP500 series regulators are protected with internal classical bypass capacitor impacts the start up phase of thermal shutdown and internal current limit. A typical standard LDOs. However, thanks to its low noise application circuit is shown in Figure 27. architecture, the NCP500 operates without a bypass element and thus offers a typical 20 ms start up phase.
Input Decoupling (C1)
A 1.0 mF capacitor either ceramic or tantalum is
Enable Operation
recommended and should be connected close to the NCP500 The enable pin will turn on or off the regulator. These package. Higher values and lower ESR will improve the limits of threshold are covered in the electrical specification overall line transient response. section of this data sheet. The turn−on/turn−off transient voltage being supplied to the enable pin should exceed a
Output Decoupling (C2)
slew rate of 10 mV/ms to ensure correct operation. If the The NCP500 is a stable component and does not require enable is not to be used then the pin should be connected a minimum Equivalent Series Resistance (ESR) or a to V minimum output current. The minimum decoupling value is in. 1.0 mF and can be augmented to fulfill stringent load
Thermal
transient requirements. The regulator accepts ceramic chip As power across the NCP500 increases, it might become capacitors as well as tantalum devices. Larger values necessary to provide some thermal relief. The maximum improve noise rejection and load regulation transient power dissipation supported by the device is dependent response. Figure 29 shows the stability region for a range of upon board design and layout. Mounting pad configuration operating conditions and ESR values. on the PCB, the board material, and the ambient temperature effect the rate of junction temperature rise for the part. This
Noise Decoupling
is stating that when the NCP500 has good thermal The NCP500 is a low noise regulator without the need of conductivity through the PCB, the junction temperature will an external bypass capacitor. It typically reaches a noise level be relatively low with high power dissipation applications. of 50 mVRMS overall noise between 10 Hz and 100 kHz. The
www.onsemi.com 12