Electronic Components Datasheet Search |
|
MAX793EPE Datasheet(PDF) 10 Page - Maxim Integrated Products |
|
MAX793EPE Datasheet(HTML) 10 Page - Maxim Integrated Products |
10 / 20 page Reset Threshold The MAX793T/MAX795T are intended for 3.3V systems with a ±5% power-supply tolerance and a 10% systems tolerance. Except when MR is asserted, reset will not assert as long as the power supply remains above 3.15V (3.3V - 5%). Reset is guaranteed to assert before the power supply falls below 3.0V (3.3V - 10%). The MAX793S/MAX795S are designed for 3.3V ±10% power supplies. Except when MR is asserted, they are guaranteed not to assert reset as long as the supply remains above 3.0V (3.0V is just above 3.3V - 10%). Reset is guaranteed to assert before the power supply falls below 2.85V (3.3V - 14%). The MAX793R/MAX795R are optimized to monitor 3.0V ±10% power supplies. Reset will not occur until VCC falls below 2.7V (3.0V - 10%), but is guaranteed to occur before the supply falls below 2.55V (3.0V - 15%). Program the MAX794’s reset threshold with an external voltage divider to RESET IN. The reset-threshold toler- ance will be a combination of the RESET IN tolerance and the tolerance of the resistors used to make the external voltage divider. Calculate the reset threshold as follows: VRST = VRST IN (R1 / R2 + 1) Using the standard application circuit (Figure 3), the reset threshold may be programmed anywhere in the range of VSW (the battery switch threshold) to 5.5V. Reset is asserted when VCC falls below VSW. Battery Freshness Seal The MAX793/MAX794’s battery freshness seal discon- nects the backup battery from internal circuitry until it is needed. This allows an OEM to ensure that the backup battery connected to BATT will be fresh when the final product is put to use. To enable the freshness seal, connect a battery to BATT, ground PFO, bring VCC above the reset threshold and hold it there until reset is deasserted following the reset timeout period, then bring VCC back down again (Figure 4). Once the bat- tery freshness seal is enabled (disconnecting the back- up battery from the internal circuitry and anything connected to OUT), it remains enabled until VCC is brought above VRST. Note that connecting PFO to MR will not interfere with battery freshness seal operation. BATT OK Output (MAX793) BATT OK indicates the status of the backup battery. When reset is not asserted, the MAX793 checks the battery voltage continuously. If VBATT is below VBOK (2.0V min), BATT OK goes low; otherwise, it remains pulled up to VCC. BATT OK also goes low when VCC goes below VSW. Watchdog Input (MAX793/MAX794) In the MAX793/MAX794, the watchdog circuit monitors the µP’s activity. If the µP does not toggle the watch- dog input (WDI) within 1.6sec, WDO goes low. The internal 1.6sec timer is cleared and WDO returns high 3.0V/3.3V Adjustable Microprocessor Supervisory Circuits 10 ______________________________________________________________________________________ MAX794 RESET LOWLINE WDI CE IN CE OUT 3.3V +5V BATT RESET IN A0-A15 MR +5V SUPPLY FAILURE BATT ON PFI 4.7k WDO OUT CMOS RAM ADDRESS DECODER 0.1 µF PMOS 0.1 µF VCC PFO VRST = VRST IN (R1 + 1) GND I/O NMI RESET VCC VCC 0.1 µF 3.6V R1 D S R2 (OPTIONAL) Si9433DY SILICONIX R2 Figure 3. MAX794 Standard Application Circuit VCC VRST VRST RESET PFO (EXTERNALLY HELD AT 0V) RESET PULLED UP TO VCC PFO STATE LATCHED, FRESHNESS SEAL ENABLED. tRP Figure 4. Battery Freshness Seal Enable Timing |
Similar Part No. - MAX793EPE |
|
Similar Description - MAX793EPE |
|
|
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 |