Electronic Components Datasheet Search |
|
UM810JP Datasheet(PDF) 7 Page - Union Semiconductor, Inc. |
|
UM810JP Datasheet(HTML) 7 Page - Union Semiconductor, Inc. |
7 / 15 page ________________________________________________________________________ http://www.union-ic.com Rev.04 Dec.2013 7/15 UM809/810 Detailed Description A microprocessor’s (µP’s) reset input starts the µP in a known state. The UM809/810 assert reset to prevent code-execution errors during power-up, power-down, or brownout conditions. They assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. The UM809/810 have a push-pull output stage. Applications Information VCC Transient Rejection In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, the UM809/810 are relatively immune to short-duration negative-going VCC transients (glitches). Figure 7 shows typical transient duration vs. reset comparator overdrive, for which the UM809/810 do not generate a reset pulse. The graph was generated using a negative-going pulse applied to VCC, starting 0.5V above the actual reset threshold and ending below it by the magnitude indicated (reset comparator overdrive). The graph indicates the maximum pulse width a negative-going VCC transient can have without causing a reset pulse. As the magnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. Typically, for the UM8_L and UM8_M, a VCC transient that goes 100mV below the reset threshold and lasts 20µs or less will not cause a reset pulse. A 0.1µF bypass capacitor mounted as close as possible to the VCC pin provides additional transient immunity. Figure 7. Maximum Transient Duration vs Overdrive for Glitch Rejection at 25℃ Output signal integrity during power down When VCC falls below 1V, the UM809 RESET _____________ output no longer sinks current—it becomes an open circuit. Therefore, high-impedance CMOS logic inputs connected to RESET _____________ can drift to undetermined voltages. This presents no problem in most applications since most µP and other circuitry is inoperative with VCC below 1V. However, in applications where RESET _____________ must be valid down to 0V, adding a pull-down resistor to RESET _____________ causes any stray leakage currents to |
Similar Part No. - UM810JP |
|
Similar Description - UM810JP |
|
|
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 |