 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
MIC5357-GFYMME Datasheet(PDF) 7 Page - Micrel Semiconductor |
|
||||||||||||||||||||||||||||||
MIC5357-GFYMME Datasheet(HTML) 7 Page - Micrel Semiconductor |
|
|
7 / 11 page  Micrel, Inc. MIC5357 January 2011 7 M9999-011311 Applications Information Enable/Shutdown The MIC5357 is provided with dual active high enable pins that allow each regulator to be enabled independently. Forcing both enable pins low disables the regulators and sends it into a “zero” off-mode-current state. In this state, current consumed by the regulator goes nearly to zero. Forcing the enable pin high enables the output voltage. The active high enable pin uses CMOS technology and the enable pin cannot be left floating; a floating enable pin may cause an indeterminate state on the output. Input Capacitor The MIC5357 is a high performance, high bandwidth device. Therefore, it requires a well bypassed input supply for optimal performance. A 2.2µF capacitor is required from the input to ground to provide stability. Low ESR ceramic capacitors provide optimal performance at a minimum of space. Additional high frequency capacitors, such as small valued NPO dielectric type capacitors, help filter out high frequency noise and are good practice in any RF based circuit. Output Capacitor The MIC5357 requires an output capacitor of 2.2µF or greater to maintain stability. The design is optimized for use with low ESR ceramic chip capacitors. High ESR capacitors may cause high frequency oscillation. The output capacitor can be increased, but performance has been optimized for a 2.2µF ceramic output capacitor and does not improve significantly with larger capacitance. X7R/X5R dielectric type ceramic capacitors are recommended because of their superior temperature performance. X7R type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Z5U and Y5V dielectric capacitors change value by as much as 50% and 60%, respectively, over their operating temperature ranges. To use a ceramic chip capacitor with Y5V dielectric, the value must be much higher than an X7R ceramic capacitor to ensure the same minimum capacitance over the equivalent operating temperature range. Bypass Capacitor A capacitor can be placed from the noise bypass pin to ground to reduce output voltage noise. The capacitor bypasses the internal reference. A 0.1µF capacitor is recommended for applications that require low noise outputs. The bypass capacitor can be increased, further reducing noise and improving PSRR. Turn on time increases slightly with respect to bypass capacitance. A unique, quick start circuit allows the MIC5357 to drive a large capacitor on the bypass pin without significantly slowing the turn on time. No-Load Stability Unlike many other voltage regulators, the MIC5357 will remain stable with no load. This is especially important in CMOS RAM keep alive applications. Thermal Considerations The MIC5357 is designed to provide 500mA of continuous current for VOUT1 and 500mA for VOUT2 in a small package. The maximum ambient operating temperature can be calculated based on the output current and the voltage drop across the part. Given that the input voltage is 3.6V, the output voltage is 3.3V for VOUT1, 2.8V for VOUT2 and the output current of 500mA and 500mA respectively. The actual power dissipation of the regulator circuit can be determined using the equation: PD = (VIN – VOUT1) IOUT1 + (VIN – VOUT2) IOUT2+ VIN IGND Because this device is CMOS and the ground current is typically <100µA over the load range, the power dissipation contributed by the ground current is < 1% and can be ignored for this calculation. PD = (3.6V – 3.3V) × 500mA + (3.6V -2.8) × 500mA PD = 0.55W To determine the maximum ambient operating temperature of the package, use the junction-to-ambient thermal resistance of the device and the following basic equation: PD(MAX) = TJ(MAX) - TA JA ⎝ ⎛ TJ(max) = 125°C, the maximum junction temperature of the die θJA thermal resistance = 64.4°C/W. |
Similar Part No. - MIC5357-GFYMME |
|
Similar Description - MIC5357-GFYMME |
|
|
|
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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
