Electronic Components Datasheet Search |
|
NCV4266-2CST50T3G Datasheet(PDF) 8 Page - ON Semiconductor |
|
NCV4266-2CST50T3G Datasheet(HTML) 8 Page - ON Semiconductor |
8 / 11 page NCV4266−2C www.onsemi.com 8 Circuit Description The NCV4266−2C is an integrated low dropout regulator that provides a regulated voltage at 150 mA to the output. It is enabled with an input to the enable pin. The regulator voltage is provided by a PNP pass transistor controlled by an error amplifier with a bandgap reference, which gives it the lowest possible dropout voltage. The output current capability is 150 mA, and the base drive quiescent current is controlled to prevent oversaturation when the input voltage is low or when the output is overloaded. The regulator is protected by both current limit and thermal shutdown. Thermal shutdown occurs above 150 °C to protect the IC during overloads and extreme ambient temperatures. Regulator The error amplifier compares the reference voltage to a sample of the output voltage (VQ) and drives the base of a PNP series pass transistor via a buffer. The reference is a bandgap design to give it a temperature−stable output. Saturation control of the PNP is a function of the load current and input voltage. Oversaturation of the output power device is prevented, and quiescent current in the ground pin is minimized. See Figure 2, Test Circuit, for circuit element nomenclature illustration. Regulator Stability Considerations The input capacitors (CI1 and CI2) are necessary to stabilize the input impedance to avoid voltage line influences. Using a resistor of approximately 1.0 W in series with CI2 can stop potential oscillations caused by stray inductance and capacitance. The output capacitor helps determine three main characteristics of a linear regulator: startup delay, load transient response and loop stability. The capacitor value and type should be based on cost, availability, size and temperature 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 the output capacitor CQ, shown in Figure 2, should work for most applications; see also Figures 3 and 12 for output stability at various load and Output Capacitor ESR conditions. Stable region of ESR in Figures 3 and 12 shows ESR values at which the LDO output voltage does not have any permanent oscillations at any dynamic changes of output load current. Marginal ESR is the value at which the output voltage waving is fully damped during five periods after the load change and no oscillation is further observable. ESR characteristics were measured with ceramic capacitors and additional series resistors to emulate ESR. Low duty cycle pulse load current technique has been used to maintain junction temperature close to ambient temperature. Enable Input The enable pin is used to turn the regulator on or off. By holding the pin down to a voltage less than 0.8 V, the output of the regulator will be turned off. When the voltage on the enable pin is greater than 3.5 V, the output of the regulator will be enabled to power its output to the regulated output voltage. The enable pin may be connected directly to the input pin to give constant enable to the output regulator. |
Similar Part No. - NCV4266-2CST50T3G |
|
Similar Description - NCV4266-2CST50T3G |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |