Texas Instruments TLC551CP

Overview

TLC551CP from Texas Instruments is a LinCMOS™ precision timer IC operating as a monostable or astable multivibrator, featuring rail-to-rail CMOS output, 1–15 V single-supply operation, 1 mW typical power at 5 V, and functional pin compatibility with NE555 in PDIP-8 package for legacy timing designs in industrial control and sensor interface circuits.

For engineers reviewing the TLC551CP datasheet, TLC551CP pinout, TLC551CP application, or TLC551CP equivalent, this page delivers verified electrical specs, thermal limits, timing accuracy data at multiple supply voltages, real-world discharge switch on-resistance behavior, and direct substitution guidance against industry-standard alternatives.

Technical Context

The TLC551CP implements a dual-comparator + SR flip-flop + discharge transistor architecture with high-impedance inputs (≤75 pA leakage at 70°C) and programmable threshold/trigger levels set at ~1/3 VDD and ~2/3 VDD - adjustable via CONT pin. Its LinCMOS process enables stable operation down to 1 V while maintaining <0.5%/V supply sensitivity in timing intervals.

Unlike bipolar 555 timers, the TLC551CP uses no internal resistive divider network; instead, it relies on external voltage references or direct CONT biasing to define trip points, enabling precise duty-cycle control in astable mode and accurate pulse width setting in monostable configurations with sub-1% initial timing error.

Key Specifications

Pinout & Package

Package: PDIP-8 (Plastic Dual-In-Line, 0.300" width), RoHS-compliant, tube-packaged, lead finish NIPDAU, MSL not applicable.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NE555P and LM555CN, the TLC551CP provides 100× lower input leakage, 30× lower quiescent current, and programmable thresholds - making it superior for precision, low-power, and wide-supply applications, though it requires careful CONT pin termination to avoid instability.

Availability

TLC551CP is available at Aetrix Electronics and suitable for industrial timer modules, portable sensor wake-up circuits, legacy equipment repair kits, and LED dimming pulse generators requiring stable component supply across extended production lifecycles.

Supply support for TLC551CP 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 power management technologies, with over 50 years of innovation in precision timing and mixed-signal ICs.

The TLC551CP belongs to TI's LinCMOS™ timer family, designed specifically to replace bipolar 555 variants in applications demanding low power, high accuracy, wide supply range, and stable performance across temperature.

FAQ

What is the maximum supply voltage rating for the TLC551CP?

The absolute maximum supply voltage for the TLC551CP is 18 V, but the recommended operating range is 1 V to 15 V. Operation above 15 V risks exceeding safe power dissipation limits in the PDIP-8 package, especially at elevated ambient temperatures. The device is fully characterized and guaranteed for timing performance within the 1–15 V range per the datasheet's recommended operating conditions table.

Does the TLC551CP support operation below 3 V, and what timing accuracy can be expected at 1.8 V?

Yes, the TLC551CP is fully specified down to 1 V and operates reliably at 1.8 V. At this voltage, timing accuracy remains within ±3% initial error (per operating characteristics data), with threshold and trigger voltages scaling linearly to ~0.6 V and ~0.36 V respectively. Input leakage stays below 75 pA, preserving long-interval stability in monostable configurations.

How does the CONT pin affect timing behavior in the TLC551CP compared to standard 555 timers?

The CONT pin on the TLC551CP directly overrides the internal 2/3 VDD and 1/3 VDD reference points, allowing user-defined threshold and trigger levels between 10% and 80% of VDD. This enables precise duty-cycle control in astable mode and adjustable pulse width in monostable mode - functionality absent in NE555/LM555, which have fixed internal dividers.

Can the TLC551CP drive a 100 mA load directly at its output pin?

Yes, the TLC551CP output can sink up to 100 mA continuously (absolute max 150 mA) with a typical on-state voltage drop of 0.5 V at 10 mA and 1.7 V at 100 mA (VDD = 15 V). For reliable 100 mA switching, ensure VDD ≥ 12 V and provide adequate heatsinking or airflow, as power dissipation exceeds 100 mW - verify thermal derating using the 8.0 mW/°C factor from the PDIP-8 dissipation rating table.

Is the TLC551CP pinout identical to the NE555, and are there any layout considerations when substituting it?

Yes, the TLC551CP uses the exact same PDIP-8 pinout as the NE555: GND (1), TRIG (2), OUT (3), RESET (4), CONT (5), THRES (6), DISCH (7), VDD (8). No PCB changes are required. However, the CONT pin must be bypassed with a 0.01 µF capacitor to GND if unused - unlike the NE555, floating CONT causes timing instability due to high-impedance node susceptibility to noise.