Texas Instruments LMC555CMX

Overview

LMC555CMX from Texas Instruments is a CMOS timer IC providing precision monostable and astable timing functions with 1.5V–15V supply operation, <1mW typical power dissipation at 5V, 3MHz maximum astable frequency, and pin-for-pin compatibility with legacy 555 timers - used in battery-powered pulse-width modulators and low-voltage sensor interface timing circuits.

For engineers reviewing the LMC555CMX datasheet, LMC555CMX pinout, LMC555CMX application, or LMC555CMX equivalent, key selection criteria include its 1.5V minimum operating voltage, sub-100pA trigger/threshold currents, 75ppm/°C timing stability, and DSBGA-8 package footprint for space-constrained designs.

Technical Context

The LMC555CMX implements a dual-comparator + SR latch architecture with internal resistor divider (2/3 V+, 1/3 V+) to generate precise time delays and oscillations. Its CMOS input stage enables ultra-low leakage (<10pA) at trigger, threshold, and control voltage pins, enabling high-impedance RC timing networks.

Timing accuracy is maintained across supply (±0.3%/V) and temperature (75ppm/°C) due to proportional reference design. Output drive supports TTL/CMOS logic levels at 5V, with tested sink/source capability of −10mA/50mA and 15ns rise/fall times into 10pF.

Key Specifications

Pinout & Package

LMC555CMX is packaged in an 8-bump DSBGA (YBF) measuring 1.75mm × 1.75mm, optimized for ultra-compact PCB layouts in wearables and medical sensors.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar timer IC applications.

Compared with TLC555CP and NE555P, the LMC555CMX delivers 1.5V operation, 3MHz frequency, and 75ppm/°C stability in a chip-scale package - making it the sole choice for miniaturized, long-life, and wide-supply applications requiring true 555 compatibility.

Availability

LMC555CMX is available at Aetrix Electronics and suitable for precision timing, pulse generation, and time-delay applications requiring stable component supply, long-lifecycle support, and consistent DSBGA-8 packaging across production batches.

Supply support for LMC555CMX includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in precision analog ICs.

The LMC555CMX belongs to TI's precision timer product line, engineered specifically for ultra-low-power, wide-supply, and miniaturized timing applications where legacy 555 functionality must be retained without design rework.

FAQ

What is the minimum supply voltage for reliable operation of the LMC555CMX?

The LMC555CMX is specified to operate down to 1.5V across the full industrial temperature range (−40°C to +85°C), with functional timing performance verified at this voltage in TI's SNAS558N datasheet. At 1.5V, supply current is 130µA typical, and output remains compatible with CMOS logic. This enables direct use with single-cell alkaline, NiMH, or low-voltage energy harvesting sources without regulation - a key differentiator from bipolar 555 variants and many CMOS alternatives like TLC555.

Is the LMC555CMX pin-compatible with standard 555 timers such as the NE555?

Yes, the LMC555CMX is explicitly designed as a pin-for-pin replacement for the NE555, LM555, and SE555 in SOIC, VSSOP, PDIP, and DSBGA packages. Pin functions (TRIGGER, THRESHOLD, OUTPUT, DISCHARGE, etc.) match identically, and electrical behavior - including output drive strength, timing equations, and control voltage scaling - is fully compatible. This allows drop-in substitution in existing 555-based designs without schematic or layout modification, while delivering lower power and extended voltage range.

What is the maximum astable frequency achievable with the LMC555CMX?

The LMC555CMX achieves a maximum astable frequency of 3MHz at 5V supply, as confirmed in Section 5.6 of the SNAS558N datasheet under "Maximum frequency test circuit." This exceeds the 500kHz limit of standard bipolar 555 timers and the 2MHz limit of the TLC555. The 3MHz capability is enabled by TI's LMCMOS process and low-output impedance, supporting high-speed PWM carriers and clock generation in compact timing applications.

How does the LMC555CMX achieve improved timing stability compared to traditional 555 timers?

The LMC555CMX achieves 75ppm/°C timing stability (vs. ~100ppm/°C for NE555) through proportional reference design: both the 1/3 V+ and 2/3 V+ comparator thresholds scale linearly with supply voltage, and the internal CMOS comparators exhibit lower thermal drift. This is validated in the "Timing shift with temperature" parameter (Section 5.6), ensuring <0.1% total timing error over −40°C to +85°C - critical for industrial one-shot delays and medical device timing cores.

What package type is used for the LMC555CMX, and what are its dimensions?

The LMC555CMX uses Texas Instruments' 8-bump DSBGA (package code YBF), with nominal dimensions of 1.75mm × 1.75mm and a 0.5mm ball pitch. This chip-scale package is documented in Section 11 of SNAS558N and offers >70% board area reduction versus SOIC-8. It is optimized for automated assembly in high-density portable electronics and requires adherence to TI's DSBGA layout guidelines, including ground plane use and tight bypass capacitor placement.