| Datenblatt-Suchmaschine für elektronische Bauteile |
|
SP705 Datenblatt(PDF) 12 Page - Sipex Corporation |
|
|
|||||||||||||||||||||||||||||
SP705 Datenblatt(HTML) 12 Page - Sipex Corporation |
|
12 / 18 page ![]() SP705DS/09 SP705 Low Power Microprocessor Supervisory Circuits © Copyright 2000 Sipex Corporation 12 sensitivity to high-frequency noise on the line being monitored. RESET can be used to monitor voltages other than the +5V V CC line. Connect PFO to MR to initiate a RESET pulse when PFI drops below 1.25V. Figure 17 shows the SP705/706/707/708 configured to assert RESET when the +5V supply falls below the RESET threshold, or when the +12V supply falls below approximately 11V. Monitoring a Negative Voltage Supply The power-fail comparator can also monitor a negative supply rail, shown in Figure 18. When the negative rail is good (a negative voltage of large magnitude), PFO is LOW. By adding the resistors and transistor as shown, a HIGH PFO triggers RESET. As long as PFO remains HIGH, the SP705-708/813L/813M will keep RESET asserted (where RESET = LOW and RESET = HIGH). Note that this circuit's accuracy de- pends on the PFI threshold tolerance, the V CC line, and the resistors. Figure 18. Monitoring a Negative Voltage Supply Figure 19. Interfacing to Microprocessors with Bidirectional RESET I/O for the SP705/706/707/708 Interfacing to mPs with Bidirectional RESET Pins µPs with bidirectional RESET pins, such as the Motorola 68HC11 series, can contend with the SP705/706/707/708 RESET output. If, for example, the RESET output is driven HIGH and the µP wants to pull it LOW, indeterminate logic levels may result. To correct this, connect a 4.7K Ω resistor between the RESET output and the µP reset I/O, as shown if Figure 19. Buffer the RESET output to other system components. VCC +5V GND VCC +5V GND RESET RESET 4.7K Ω µP Buffered RESET connects to System Components PFI PFO R2 R1 VCC +5V GND PFO V- +5V VTRIP 0V 0V 5.0 - 1.25 R1 1.25 - VTRIP R2 V- = 10K Ω 10K Ω RESET to µP 2N3904 , VTRIP < 0 V- MR 0V +5V MR 100K Ω 100K Ω |
|
|
Link URL |
| War ALLDATASHEET hilfreich? [ DONATE ] |
Über Alldatasheet | Werbung | Kontakt | Privatsphäre und Datenschutz | Link zum Datenblatt | Linktausch | Hersteller 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 |