数据搜索系统,热门电子元器件搜索 |
|
LM3723 数据表(PDF) 8 Page - National Semiconductor (TI) |
|
|
LM3723 数据表(HTML) 8 Page - National Semiconductor (TI) |
8 / 12 page Timing Diagram 20014412 Circuit Information Reset Output The reset input of a µP initializes the device into a known state. The LM3722/LM3723/LM3724 microprocessor voltage monitoring circuits assert a forced reset output to prevent code execution errors during power-up, power-down, and brownout conditions. RESET is guaranteed valid for V CC ≥ 1V. Once VCC exceeds the reset threshold, an internal timer maintains the output for the reset timeout period. After this interval, reset goes high and the microprocessor initializes itself into a known state. The LM3722 and LM3724 offer an active-low RESET; the LM3723 offers an active-high RESET. As V CC drops below the reset threshold (such as during a brownout), the reset activates (see the Negative-Going VCC Transients section). When V CC again rises above the reset threshold, the internal timer starts. Reset holds until V CC exceeds the reset threshold for longer than the reset timeout period. After this time, reset releases. Additionally, the Manual Reset input (MR) will initiate a forced reset. See the Manual Reset Input section. The LM3722/LM3723/LM3724 reset outputs ignore short du- ration glitches on V CC and MR. See the Applications Infor- mation section for details. Reset Threshold The LM3722/LM3723/LM3724 are available with reset volt- ages of 4.63V, 3.08V, and 2.32V which are suitable for monitoring 5.0V, 3.3V, and 2.5V supplies respectively. Other reset thresholds in the 2.20V to 5.0V range, in 10 mV steps, are available; contact National Semiconductor for details. Manual Reset Input (MR) Many µP-based products require a manual reset capability, allowing the operator to initiate a reset. The MR input is fully debounced and provides an internal 22 k Ω pull-up. When the MR input is pulled below V IL (0.25VCC) for more than 100 ns, reset is asserted after a typical delay of 2 µs. Reset remains active as long as MR is held low, and releases after MR rises above V IH and the reset timeout period expires. Use MR with digital logic to assert reset or to daisy chain supervisory circuits. Applications Information Benefits of Precision Reset Thresholds A microprocessor supply supervisor must provide a reset output within a predictable range of the supply voltage. A common threshold range is between 5% and 10% below the nominal supply voltage. The 4.63V, 3.08V and 2.32V options of the LM3722/LM3723/LM3724 use highly accurate circuitry to ensure that the reset threshold occurs only within this range (for 5.0V, 3.3V and 2.5V supplies). Table 1 shows how the standard reset thresholds apply to 5.0V, 3.3V, and 2.5V nominal supply voltages. www.national.com 8 |
类似零件编号 - LM3723 |
|
类似说明 - LM3723 |
|
|
链接网址 |
隐私政策 |
ALLDATASHEETCN.COM |
ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 链接交换 | 制造商名单 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 |