Texas Instruments TLC555CDR

Overview

TLC555CDR from Texas Instruments is a CMOS monolithic timer IC functionally interchangeable with the NE555 and featuring identical 8-pin SOIC pinout. It delivers rail-to-rail CMOS output swing, 100mA sink / 10mA source capability, and ultra-low 1mW typical power consumption at 5V - enabling precision timing in battery-powered sensor nodes and industrial control sequencers.

For engineers reviewing the TLC555CDR datasheet, TLC555CDR pinout, TLC555CDR application, or TLC555CDR equivalent, key selection considerations include its 2V–15V single-supply operation, 2MHz maximum astable frequency, ±1000V HBM ESD rating, and compatibility with CMOS/TTL/MOS logic families across temperature ranges up to 70°C.

Technical Context

The TLC555CDR implements a dual-comparator architecture with internal resistor divider (1/3 VDD and 2/3 VDD thresholds), SR latch, and high-current output stage. Its CMOS input structure provides picoampere-level trigger/threshold input currents (≤75pA typ), enabling use with high-impedance timing networks and smaller capacitors than bipolar 555 variants.

Timing accuracy is enhanced by supply-voltage-independent threshold ratios and low supply current sensitivity (0.1–0.5%/V). The discharge transistor operates as an open-collector switch with <0.5V on-state voltage at 10mA (VDD = 5V), while the CONT pin allows external adjustment of comparator reference levels for linear ramp or PWM generation.

Key Specifications

Pinout & Package

Package: SOIC (8), 4.9mm × 6.0mm body size, surface-mount, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NE555P and LMC555IMX/NOPB, the TLC555CDR offers optimal balance of ultra-low power (350µA), commercial-temp reliability, and proven NE555 pin compatibility - making it ideal for cost-sensitive, space-constrained, and battery-aware timing functions where full industrial temp range is unnecessary.

Availability

TLC555CDR is available at Aetrix Electronics and suitable for industrial sequencing, precision sensor timing, LED dimming control, and battery-powered pulse generator applications requiring stable component supply and long-term sourcing continuity.

Supply support for TLC555CDR 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 50 years of innovation in precision timing solutions.

The TLC555 product line was designed to deliver CMOS-level efficiency and noise immunity in legacy 555-compatible form factors - targeting cost-sensitive industrial controls, instrumentation, and consumer electronics where low power and logic compatibility are critical.

FAQ

What is the maximum operating frequency of the TLC555CDR in astable mode?

The TLC555CDR achieves a maximum astable frequency of 2.1MHz under specified conditions (RA = 470Ω, CT = 200pF, RB = 200Ω, VDD = 5V, TA = 25°C). This performance stems from its CMOS architecture and optimized internal propagation delays. Real-world designs should derate by 10–20% for temperature and supply variation. The TLC555CDR datasheet Section 5.8 confirms this value as a tested characteristic.

Is the TLC555CDR pin-compatible with the NE555?

Yes, the TLC555CDR is functionally interchangeable with the NE555 and features identical pin configuration and numbering for SOIC-8, PDIP-8, and SOP-8 packages. Texas Instruments explicitly states this compatibility in the device description and pin-function tables. However, designers must verify timing network values due to differences in input bias current and output drive strength between the CMOS and bipolar implementations.

What is the recommended bypass capacitor for the CONT pin on the TLC555CDR?

A 10nF ceramic capacitor is recommended between the CONT pin (Pin 5) and GND to suppress noise and stabilize the internal voltage divider reference. This value is specified in TI's application guidance (Section 7.2) and validated in typical circuit examples (Figures 6-5, 6-2). Larger values (e.g., 100nF) may be used if board layout introduces significant high-frequency coupling, but values below 5nF risk timing instability.

Can the TLC555CDR operate from a 3.3V supply?

Yes, the TLC555CDR supports operation down to 2V, making it fully compatible with 3.3V systems. At 3.3V, the trigger threshold is ~1.1V and threshold level ~2.2V (per Section 5.5), and output swing remains rail-to-rail. Supply current drops to ~250µA typical, enhancing efficiency. Ensure external timing resistors are sized to maintain adequate current into TRIG/THRES inputs given reduced voltage headroom.

How does the discharge transistor behave in monostable mode on the TLC555CDR?

In monostable mode, the TLC555CDR's DISCH pin (Pin 7) acts as an open-collector switch that goes low only when the output (OUT) is low. During the timing interval (when OUT is high), DISCH is high-impedance, allowing the external timing capacitor to charge through RA. When timing completes and OUT goes low, DISCH pulls to GND, rapidly discharging the capacitor. This behavior is defined in Section 4 and Figure 6-2 of the TLC555CDR datasheet.