 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SP6655ER Datasheet(PDF) 11 Page - Sipex Corporation |
|
||||||||||||||||||||||||||||||
SP6655ER Datasheet(HTML) 11 Page - Sipex Corporation |
|
|
11 / 16 page  11 Date: 7/12/04 SP6655 High Efficiency 400mA Synchronous Buck Regulator © Copyright 2004 Sipex Corporation For the typical SP6655 application circuit with inductor size of 10 µH, and KON of 2V*µsec, the SP6655 current ripple would be about 200mA, and driver latch and open the switch to prevent inductor current reversal. This circuit along with the on-timer puts the converter into PFM mode and improves light load efficiency when the load current is less than half the inductor ripple current defined by KON/L. Thermal Shutdown The converter will open both power switches if the die junction temperature rises above 140 °C. The die must cool down below 126 °C before the regulator is re-enabled. This feature protects the SP6655 and surrounding circuitry from exces- sive power dissipation due to fault conditions. Shutdown/Enable Control The D0, D1 pins 4,5 of the device are logic level control pins that according to Table 1 shut down the converter when both are a logic low, or enables the converter when either are a logic high. When the converter is shut down, the power switches are opened and all circuit bias- ing is extinguished leaving only junction leak- age currents on supply pins 1 and 2. After pins 4 or 5 are brought high to enable the converter, there is a turn on delay to allow the regulator circuitry to re-establish itself. Power conversion begins with the assertion of the internal refer- ence ready signal which occurs approximately 150 µs after the enable signal is received. Battery Low Indicator The BLON function is a differential measure- ment of (VIN -VOUT) which causes the open drain NMOS on pin 3 to sink current to ground when (VIN -VOUT) < 300mV. Tying a resistor from pin 3 to VIN or VOUT creates a logic level battery low indicator. A low bandwidth com- parator and 3% hysteresis filter the input voltage ripple to prevent noisy transitions at the thresh old. BLON is forced Low when in UVLO. External Feedback Pin The FB pin 6 is compared to an internal refer- ence voltage of 0.8V to regulate the SP6655 output. The output voltage can be externally programmed within the range +1.0V to +5.0V by tying a resistor from FB to ground and FB to VOUT (pin7). See the applications section for resistor selection information. Inductor Selection The SP6655 uses a specially adapted minimum on-time control of regulation utilizing a preci- sion comparator and bandgap reference. This adaptive minimum on-time control has the ad- vantage of setting a constant current ripple for a given inductor size. From the operations section it has been shown: Inductor Current Ripple, ILR ≈ KON L THEORY OF OPERATION APPLICATION INFORMATION would be fairly constant for different input and output voltages, simplifying the selection of com- ponents for the SP6655 power circuit. Other inductor values could be selected, as shown in Table 2 Components Selection. Using a larger value than 10 µH in an attempt to reduce output voltage ripple would reduce inductor current ripple and may not produce as stable an output ripple. For larger inductors with the SP6655, which has a peak inductor current of 0.625A, most 15 µH or 22 µH inductors would have to be larger physical sizes, limiting their use in small por- table applications. Smaller values like 10 µH would more easily meet the 0.625A limit and come in small case sizes, and the increased |
Similar Part No. - SP6655ER |
|
Similar Description - SP6655ER |
|
|
|
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 |
English ▼
English
Chinese
German
Japanese
Russian
Korean
Spanish
French
Italian
Portuguese
Polish
Vietnamese
Indian
Mexican
British
New Zealand
