 |
Electronic Components Datasheet Search |
|
|
Electronic Components Datasheet Search |
|
SP809NEK-L-3-1TR Datasheet(PDF) 6 Page - Exar Corporation |
|
||||||||||||||||||||||||||||||
SP809NEK-L-3-1TR Datasheet(HTML) 6 Page - Exar Corporation |
|
|
6 / 8 page  S SP P8 80 09 9 / / S SP P8 81 10 0 3 3 P Piin n M Miiccrro op prro occe es ss so orr S Su up pe errv viis so orr C Ciirrccu uiitt © 2011 Exar Corporation 6/8 Rev. 2.0.0 THEORY OF OPERATION μP will be activated at a valid reset state. These μP supervisory circuits assert reset to prevent code execution errors during power- up, power-down, or brownout conditions. Reset is guaranteed to be a logic low for VTH>VCC>0.9V. Once VCC exceeded the reset threshold, an internal timer keeps RESET low for the reset timeout period; after this interval, RESET goes high. If a brownout condition occurs (VCC drops below the reset threshold), RESET goes low. Any time VCC goes below the reset threshold, the internal timer resets to zero, and RESET goes low. The internal timer is activated after VCC returns above the reset threshold, and RESET remains low for the reset timeout period. BENEFIT OF HIGHLY ACCURATE RESET THRESHOLD SP809/810 with specified voltage as 5V±10% or 3V±10% are ideal for systems using a 5V±5% or 3V±5% power supply. The reset is guaranteed to assert after the power supply falls below the minimum specified operating voltage range of the system ICs. The pre- trimmed thresholds are reducing the range over which an undesirable reset may occur. APPLICATION INFORMATION NEGATIVE GOING VCC TRANSIENTS In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, SP809 series are relatively resistant to short-duration negative-going VCC transient. ENSURING A VALID RESET OUTPUT DOWN TO VCC=0 When VCC falls below 0.9V, SP809 RESET output no longer sinks current; it becomes an open circuit. In this case, high-impedance CMOS logic inputs connecting to RESET can drift to undetermined voltages. Therefore, SP809/810 with CMOS is perfect for most applications of VCC down to 0.9V. However in applications where RESET must be valid down to 0V, adding a pull-down resistor to RESET causes any leakage currents to flow to ground, holding RESET low. INTERFACING TO µP WITH BIDIRECTIONAL RESET PINS The RESET output on the SP809N is open drain, this device interfaces easily with μPs that have bidirectional reset pins. Connecting the μP supervisor's RESET output directly to the microcontroller's RESET pin with a single pull-up resistor allows either device to assert reset. TEST CIRCUIT Fig. 10: Test Circuit |
Similar Part No. - SP809NEK-L-3-1TR |
|
Similar Description - SP809NEK-L-3-1TR |
|
|
|
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
