STMicroelectronics TS555CD

Overview

TS555CD from STMicroelectronics is a low-power single CMOS timer IC designed for precision timing in battery-powered and space-constrained systems. It delivers 110 µA typical supply current at 5 V, supports 2.7 MHz maximum astable frequency, operates across 2–16 V supply range, and maintains accurate monostable/astable timing-used in portable instrumentation, sensor wake-up circuits, and LED flash controllers.

For engineers reviewing the TS555CD datasheet, TS555CD pinout, TS555CD application, or TS555CD equivalent, key selection criteria include ultra-low ICC (90 µA @ 3 V), high input impedance (10¹² Ω), reduced supply current spikes during transitions, and functional compatibility with legacy NE555 designs while enabling smaller decoupling and timing capacitors.

Technical Context

The TS555CD implements a CMOS-based bistable multivibrator architecture with dual comparators, SR flip-flop, and open-drain discharge transistor. Its high-impedance inputs (10¹² Ω) minimize loading on RC timing networks, and internal voltage dividers set precise 1/3 VCC and 2/3 VCC thresholds for trigger and threshold pins.

Unlike bipolar 555 timers, it eliminates large supply current transients during output switching via optimized driver stages-reducing required decoupling capacitance-and supports rail-to-rail operation down to 2 V while maintaining stable timing accuracy over -40°C to +125°C.

Key Specifications

Pinout & Package

TS555CD is housed in an SO8 (plastic micropackage) with 1.27 mm pitch, compliant with ECOPACK environmental standards and rated for surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NE555P and LMC555IMX, TS555CD offers the highest frequency (2.7 MHz), widest operating temperature (−40°C to +125°C), and lowest ICC (90 µA @ 3 V), making it optimal for extended-life, high-reliability embedded timing where thermal robustness and power efficiency are critical.

Availability

TS555CD is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor interfaces, and automotive interior lighting requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TS555CD 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for automotive, industrial, and consumer markets.

The TS555 belongs to ST's precision analog timer product line, engineered specifically to replace legacy bipolar 555 timers with CMOS efficiency while preserving functional compatibility and enhancing timing stability in harsh environments.

FAQ

What is the minimum supply voltage for reliable TS555CD operation?

The TS555CD is specified to operate reliably from 2 V to 16 V. At 2 V, it maintains functional timing accuracy in both monostable and astable modes, with supply current dropping to ~65 µA. Output drive strength decreases at lower voltages, so load current must be limited to ≤1 mA when VCC < 3 V to ensure VOL remains below 0.35 V.

Can TS555CD replace NE555 in existing PCB layouts?

Yes-TS555CD uses the same SO8 package and pinout as industry-standard NE555 variants, including identical GND (1), Trigger (2), Output (3), Reset (4), Control Voltage (5), Threshold (6), Discharge (7), and VCC (8) assignments. No layout modification is needed, though decoupling capacitor values may be reduced due to lower supply current spikes.

How does TS555CD achieve timing independence from supply voltage?

TS555CD achieves supply-independent timing by deriving its internal comparator reference voltages (1/3 VCC and 2/3 VCC) directly from the supply rail via matched resistor dividers. Since both the RC time constant and threshold levels scale proportionally with VCC, the resulting timing interval remains stable across the full 2–16 V operating range.

What is the maximum output sink current for TS555CD at 12 V supply?

At VCC = 12 V, TS555CD guarantees a maximum output sink current of 50 mA while maintaining VOL ≤ 2.8 V (typical 1.2 V). This is validated per Table 9 in the datasheet. Sustained operation above 20 mA requires attention to thermal dissipation, as Rthja is 125 °C/W on a 4-layer PCB-derating is recommended above 30 mA continuous load.