LM555CMM - 555 Timer Oscillator 100kHz | Texas Instruments
料号： LM555CMM ✓ 量产中LM555CMM 概述
A 555 timer is a programmable analog timing building block. By combining an internal voltage reference, comparators, flip-flop, discharge transistor, and output stages with external resistors and capacitors, it can operate as a one-shot monostable circuit or as a continuously running astable oscillator. The LM555 family is widely used in industrial control, instrumentation, pulse generation, debounce circuits, converters, and low-cost embedded timing systems. It remains popular because it combines a simple external network with predictable logic-level outputs and flexible trigger and reset control.
The LM555CMM’s key operating characteristics include its 100 kHz maximum oscillator frequency, 555 monostable or astable operating modes, trigger and reset functions, and 8-VSSOP surface-mount construction. The external timing network determines the delay or repetition rate, while the trigger and reset terminals allow synchronization, cascading, and fault-controlled shutdown. Because the timing accuracy depends on resistor tolerances, capacitor stability, and the internal threshold reference, component selection and PCB layout remain important in precision applications.
In astable mode, two resistors and one capacitor establish the charge and discharge timing. The output waveform frequency and duty cycle are set by those external values, while the LM555 provides threshold comparison, discharge control, and a buffered output. In monostable mode, one resistor and one capacitor establish the output pulse duration, and a negative-going trigger creates the timed pulse. The reset terminal can inhibit operation during initialization or fault conditions.
The LM555 is suitable for LED flash timing, pulse-width generation, debounce networks, simple clock circuits, tone generation, and general-purpose industrial control. Designers should check output-current limits, supply voltage, trigger and reset timing, and absolute maximum ratings against the manufacturer datasheet. For a new design, the trigger and reset paths should be kept short, timing capacitors should be positioned near the relevant pins, and unwanted pickup on high-impedance timing nodes should be minimized.
This page provides a structured technical overview, verified manufacturer and distributor references, replacement guidance, application context, and design notes for engineers evaluating LM555CMM. It is intended to support component selection and circuit planning rather than replace the complete Texas Instruments datasheet.
直接替换替代料： LM555CMM ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： LM555CMM （相同外形与封装尺寸） ——差异在于 Package.
LM555CMM/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
TLC555
✅ 直接替换📋 参考替代料（不在目录中）
LMC555CM
✅ 直接替换📋 参考替代料（不在目录中）
NE555DR
✅ 直接替换联系询价
查看数据手册 →ICM7555
✅ 直接替换📋 参考替代料（不在目录中）
LM555CMM 规格参数
| Device Type | 555 Type, Timer/Oscillator (Single) IC |
| Maximum Oscillator Frequency | 100 kHz |
| Operating Mode | Monostable or astable |
| 封装 | 8-VSSOP |
| 安装类型 | Surface mount |
| Timing Control | One external resistor and one external capacitor in monostable mode |
| Astable Control | External resistor-capacitor network |
| Trigger Function | Available |
| Reset Function | Available |
LM555CMM 8-vssop 引脚配置指南
LM555CMM（8-vssop 封装）的引脚配置。 引脚编号、功能和连接图在制造商数据手册中定义。请参阅该手册以了解确切的封装尺寸和焊接指南。
暂无详细引脚数据： LM555CMM.
请参阅 数据手册 以查看完整引脚配置。
典型应用
LM555CMM 适用于 6 应用s: LED Flash Timing, Pulse-Width Generation, Industrial Debounce Circuits, Simple Tone Generation, Delay and Sequencing Control, Switching Power-Control Support.
LED Flash Timing
The LM555CMM fits LED flash timing because its monostable mode uses one external resistor and one external capacitor to establish the flash interval, while the trigger input starts the timing cycle. The output can control a transistor when the LED current exceeds the timer’s permitted output load. Use a current-limiting resistor sized for the LED and verify the output-drive limits in the Texas Instruments LM555 datasheet. For repeatable production timing, specify tight-tolerance timing resistors and a suitable capacitor, and account for threshold and temperature effects when calculating the visible flash duration.
推荐
Pulse-Width Generation
For pulse-width generation, the LM555CMM provides a straightforward monostable timer with trigger and reset control. A trigger pulse starts the timing interval, and the output changes state for the interval determined by the external timing network. This arrangement is useful for retriggerable pulse shaping, delayed actuator commands, and controlled test pulses. The designer should verify trigger pulse width, reset behavior, output rise and fall characteristics, and the maximum operating frequency of 100 kHz before using the circuit in high-speed systems.
推荐
Industrial Debounce Circuits
The LM555CMM is suitable for mechanical-switch debounce because monostable timing can reject short contact transients and produce a clean, fixed-duration logic event. The trigger input receives the switch network, while the output provides a stable pulse to the next control stage. Keep the timing network close to the timer pins, provide a defined reset state, and select capacitor and resistor tolerances according to the required debounce interval. The 8-VSSOP package supports compact PCB layouts, although the exact footprint and pin orientation must be checked against the package drawing.
推荐
Simple Tone Generation
In astable mode, the LM555CMM can generate a continuous square-wave tone using two resistors and a timing capacitor. The internal threshold comparator and discharge transistor establish the charge and discharge cycles, while the output provides the square-wave signal. This application works well for audible alarms, test tones, and simple clock sources. Component tolerances and the timer’s 100 kHz maximum oscillator frequency determine the usable frequency range, and the output should be buffered when driving a speaker, transducer, or larger capacitive load.
推荐
Delay and Sequencing Control
The LM555CMM can act as a delayed sequencing element when one timing channel must change state after another has completed. The trigger and reset inputs allow the timer to be synchronized with a system enable or fault signal, and the output can gate a control input or drive a relay-driver stage. For multi-rail sequencing, define the reset behavior during power-up and verify that the timing pulse remains within the downstream device’s setup and hold requirements. The simple external network makes the circuit useful for inexpensive industrial and instrumentation control boards.
推荐
Switching Power-Control Support
The LM555CMM can support oscillator, delay, and supervisory functions around a switching power-converter control circuit. Its 555 architecture is useful for periodic reset, soft-start timing, or a simple clock signal, provided the external timing network and the timer’s current limits are compatible with the controller. Isolation between the timer and the power stage is essential in high-voltage designs. Keep the timing loop compact, isolate high-energy switching nodes, and use the manufacturer’s application guidance to define reset and fault behavior.
推荐
推荐产品汇总
工程参考数据： LM555CMM ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | LM555CMM/NOPB | TLC555 | LMC555CM | NE555 | ICM7555 |
|---|---|---|---|---|---|---|
| Device Type | Single 555 Type Timer/Oscillator IC | Single 555 Type Timer/Oscillator IC | 555-family timer, implementation not specified | 555-family timer | 555-family timer | 555-family timer |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | 8-VSSOP | 8-VSSOP | 8-VSSOP | 8-VSSOP | 8-VSSOP | 8-VSSOP |
关键差异点
- Direct 555 timer family continuity （对比 TLC555)
- Exact ordering-family identification （对比 LMC555CM)
- Single-timer architecture （对比 NE556)
设计说明
Place the timing resistor and timing capacitor close to the LM555 timing, threshold, and discharge pins. Keep trigger and reset traces short, provide a defined ground reference, and avoid routing high-current switching paths beneath the timing network. The verified package designation is 8-VSSOP, so use the manufacturer’s land pattern and verify pin numbering against the package drawing before releasing the PCB footprint.
Do not assume that every 555-family timer is a drop-in replacement. CMOS alternatives can differ in supply range, output-drive capability, trigger thresholds, discharge-transistor behavior, and timing accuracy. Validate the exact candidate MPN, package dimensions, pin assignment, electrical limits, and timing waveform before substituting a TLC555, NE555, LMC555CM, or ICM7555 into an LM555CMM design.
Check the output state and load current whenever the LM555 drives an LED, relay, transistor gate, or logic family. The timer’s output stage and discharge transistor have finite current and voltage limits. Use a suitable transistor or driver when the load is inductive, capacitive, or above the permitted output current, and account for the additional supply current and dissipation in the overall power budget.
For timing accuracy, select resistor and capacitor tolerances appropriate to the required interval and consider temperature drift. High-impedance nodes can pick up noise, so keep the timing network compact and provide a clean ground path. In astable operation, measure the output waveform with an appropriate probe and verify that the repetition rate and duty cycle remain within system requirements across supply and temperature conditions.
合规信息
The verified product references identify the LM555 timer family and LM555CMM ordering designation but do not state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status. Compliance fields remain unknown.
