Electronic Components Datasheet Search |
|
AAT3218IGV-1.9-T1 Datasheet(PDF) 10 Page - List of Unclassifed Manufacturers |
|
AAT3218IGV-1.9-T1 Datasheet(HTML) 10 Page - List of Unclassifed Manufacturers |
10 / 18 page AAT3218 150mA MicroPower™ High Performance LDO 10 3218.2004.02.1.0 Applications Information Equivalent Series Resistance (ESR): ESR is a very important characteristic to consider when selecting a capacitor. ESR is the internal series resistance asso- ciated with a capacitor, which includes lead resist- ance, internal connections, size and area, material composition and ambient temperature. Typically capacitor ESR is measured in milliohms for ceramic capacitors and can range to more than several ohms for tantalum or aluminum electrolytic capacitors. Ceramic Capacitor Materials: Ceramic capacitors less than 0.1µF are typically made from NPO or COG materials. NPO and COG materials are typi- cally tight tolerance very stable over temperature. Larger capacitor values are typically composed of X7R, X5R, Z5U and Y5V dielectric materials. Large ceramic capacitors, typically greater then 2.2µF are often available in the low cost Y5V and Z5U dielectrics. These two material types are not rec- ommended for use with LDO regulators since the capacitor tolerance can vary more than ±50% over the operating temperature range of the device. A 2.2µF Y5V capacitor could be reduced to 1µF over temperature, this could cause problems for circuit operation. X7R and X5R dielectrics are much more desirable. The temperature tolerance of X7R dielectric is better than ±15%. Capacitor area is another contributor to ESR. Capacitors which are physically large in size will have a lower ESR when compared to a smaller sized capacitor of an equivalent material and capacitance value. These larger devices can improve circuit tran- sient response when compared to an equal value capacitor in a smaller package size. Consult capacitor vendor data sheets carefully when selecting capacitors for LDO regulators. Enable Function The AAT3218 features an LDO regulator enable/ disable function. This pin (EN) is active high and is compatible with CMOS logic. To assure the LDO regulator will switch on, the EN turn on control level must be greater than 1.5 volts. The LDO regulator will go into the disable shutdown mode when the voltage on the EN pin falls below 0.6 volts. If the enable function is not needed in a specific applica- tion, it may be tied to VIN to keep the LDO regula- tor in a continuously on state. When the LDO regulator is in the shutdown mode, an internal 1.5k Ω resistor is connected between VOUT and GND. This is intended to discharge COUT when the LDO regulator is disabled. The internal 1.5k Ω has no adverse effect on device turn on time. Short Circuit Protection The AAT3218 contains an internal short circuit pro- tection circuit that will trigger when the output load current exceeds the internal threshold limit. Under short circuit conditions the output of the LDO regu- lator will be current limited until the short circuit condition is removed from the output or LDO regu- lator package power dissipation exceeds the device thermal limit. Thermal Protection The AAT3218 has an internal thermal protection cir- cuit which will turn on when the device die temper- ature exceeds 150°C. The internal thermal protec- tion circuit will actively turn off the LDO regulator output pass device to prevent the possibility of over temperature damage. The LDO regulator output will remain in a shutdown state until the internal die temperature falls back below the 150°C trip point. The combination and interaction between the short circuit and thermal protection systems allow the LDO regulator to withstand indefinite short circuit conditions without sustaining permanent damage. No-Load Stability The AAT3218 is designed to maintain output volt- age regulation and stability under operational no- load conditions. This is an important characteristic for applications where the output current may drop to zero. Reverse Output to Input Voltage Conditions and Protection Under normal operating conditions a parasitic diode exists between the output and input of the LDO regulator. The input voltage should always remain greater then the output load voltage main- taining a reverse bias on the internal parasitic diode. Conditions where VOUT might exceed VIN should be avoided since this would forward bias the internal parasitic diode and allow excessive current flow into the VOUT pin possibly damaging the LDO regulator. |
Similar Part No. - AAT3218IGV-1.9-T1 |
|
Similar Description - AAT3218IGV-1.9-T1 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | 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 |