Datasheet LM3722, LM3723, LM3724 (Texas Instruments) - 7
| 制造商 | Texas Instruments |
| 描述 | 5-Pin Microprocessor Reset Circuits |
| 页数 / 页 | 20 / 7 — LM3722. , LM3723,. LM3724. www.ti.com. Timing Diagram. Figure 12. Timing … |
| 文件格式/大小 | PDF / 1.1 Mb |
| 文件语言 | 英语 |
LM3722. , LM3723,. LM3724. www.ti.com. Timing Diagram. Figure 12. Timing Diagram. Circuit Information. RESET OUTPUT. RESET THRESHOLD
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LM3722 , LM3723, LM3724 www.ti.com
SNVS154E – MAY 2001 – REVISED MARCH 2013
Timing Diagram Figure 12. Timing Diagram 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 VCC ≥ 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 VCC drops below the reset threshold (such as during a brownout), the reset activates (see the NEGATIVE- GOING VCC TRANSIENTS section). When VCC again rises above the reset threshold, the internal timer starts. Reset holds until VCC 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 (MR) section. The LM3722/LM3723/LM3724 reset outputs ignore short duration glitches on VCC and MR. See the Applications Information section for details.
RESET THRESHOLD
The LM3722/LM3723/LM3724 are available with reset voltages 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 Texas Instruments for details. Copyright © 2001–2013, Texas Instruments Incorporated Submit Documentation Feedback 7 Product Folder Links: LM3722 LM3723 LM3724 Document Outline FEATURES APPLICATIONS DESCRIPTION Typical Application Circuits Connection Diagram Absolute Maximum Ratings Electrical Characteristics Typical Performance Characteristics Timing Diagram Circuit Information RESET OUTPUT RESET THRESHOLD MANUAL RESET INPUT (MR) Applications Information BENEFITS OF PRECISION RESET THRESHOLDS ENSURING A VALID RESET OUTPUT DOWN TO VCC = 0V OPEN DRAIN OUTPUT (LM3724) NEGATIVE-GOING VCC TRANSIENTS INTERFACING TO µPS WITH BIDIRECTIONAL RESET PINS Typical Application Circuits Revision History
LM3722 , LM3723, LM3724 www.ti.com
SNVS154E – MAY 2001 – REVISED MARCH 2013
Timing Diagram Figure 12. Timing Diagram 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 VCC ≥ 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 VCC drops below the reset threshold (such as during a brownout), the reset activates (see the NEGATIVE- GOING VCC TRANSIENTS section). When VCC again rises above the reset threshold, the internal timer starts. Reset holds until VCC 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 (MR) section. The LM3722/LM3723/LM3724 reset outputs ignore short duration glitches on VCC and MR. See the Applications Information section for details.
RESET THRESHOLD
The LM3722/LM3723/LM3724 are available with reset voltages 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 Texas Instruments for details. Copyright © 2001–2013, Texas Instruments Incorporated Submit Documentation Feedback 7 Product Folder Links: LM3722 LM3723 LM3724 Document Outline FEATURES APPLICATIONS DESCRIPTION Typical Application Circuits Connection Diagram Absolute Maximum Ratings Electrical Characteristics Typical Performance Characteristics Timing Diagram Circuit Information RESET OUTPUT RESET THRESHOLD MANUAL RESET INPUT (MR) Applications Information BENEFITS OF PRECISION RESET THRESHOLDS ENSURING A VALID RESET OUTPUT DOWN TO VCC = 0V OPEN DRAIN OUTPUT (LM3724) NEGATIVE-GOING VCC TRANSIENTS INTERFACING TO µPS WITH BIDIRECTIONAL RESET PINS Typical Application Circuits Revision History