STMicroelectronics TS556IN

Overview

TS556IN from STMicroelectronics is a dual CMOS timer IC designed for precision timing in monostable and astable configurations. It delivers 220 µA typical supply current at 5 V, supports up to 2.7 MHz astable frequency, operates across 2–16 V supply range, and features 10¹² Ω input impedance-enabling low-power sensor interface and portable instrumentation applications.

For engineers reviewing the TS556IN datasheet, TS556IN pinout, TS556IN application, or TS556IN equivalent, key selection criteria include low quiescent current, high-frequency astable capability, wide voltage tolerance, and compatibility with legacy NE556-based designs requiring reduced power and improved timing stability.

Technical Context

The TS556 integrates two independent CMOS-based 555-style timers sharing a common supply and ground. Each timer uses high-impedance comparators (10¹² Ω input) and rail-to-rail output stages compatible with TTL, CMOS, and logic MOS loads. Timing accuracy remains stable over temperature (±75 ppm/°C) and supply voltage variations (as low as ±0.1 %/V in astable mode).

Its internal architecture eliminates supply current spikes during output transitions-reducing decoupling capacitor requirements-and enables precise RC timing with minimal capacitor values due to negligible input bias current (<10 pA on trigger/threshold pins).

Key Specifications

Pinout & Package

TS556IN is housed in a 14-pin SOIC (SO14) plastic micropackage with 1.27 mm pitch, compliant with ECOPACK environmental standards. The package measures 8.75 mm × 4.0 mm × 1.75 mm (L × W × H), suitable for automated SMT assembly and space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NE556N and LM556CN, the TS556IN offers 27× lower quiescent current, 27× higher maximum frequency, and true CMOS logic compatibility-making it the sole viable option for compact, battery-operated, or wide-supply-range timing applications.

Availability

TS556IN is available at Aetrix Electronics and suitable for portable medical devices, industrial motor controllers, smart fire safety equipment, and energy-harvesting sensor nodes requiring stable component supply across extended product lifecycles.

Supply support for TS556IN 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, specializing in power management, analog, MEMS, and microcontroller technologies for automotive, industrial, and consumer markets.

The TS556 belongs to ST's precision analog timer product line, engineered specifically to replace legacy bipolar 555/556 timers in low-power, high-accuracy timing applications while maintaining full pin and functional compatibility.

FAQ

What is the maximum recommended load capacitance for stable TS556IN output switching?

The TS556IN output stage is characterized with 10 pF load in datasheet timing specs (tR = 25 ns, tF = 20 ns). While it can drive up to 50 mA, capacitive loads exceeding 50 pF may cause ringing or delayed transitions. For loads >20 pF, add a series 22–100 Ω resistor near the output pin to dampen overshoot and ensure clean edges in high-speed applications.

Can TS556IN operate reliably at 2 V supply with full functionality?

Yes-TS556IN is fully specified down to 2 V: supply current is 130 µA (typ), output high voltage reaches 1.5 V (min), and timing accuracy remains within ±4 % in monostable mode. However, maximum astable frequency drops to ~200 kHz at 2 V, and output drive strength is reduced; verify load requirements against VOL/VOH specs at 2 V before final design sign-off.

How does the TS556IN handle simultaneous trigger and reset events?

When a negative-going pulse is applied to both trigger (pin 2/6) and reset (pin 4/10) simultaneously, the reset function takes priority: output forces LOW, timing capacitor discharges immediately, and the cycle restarts on the rising edge of the reset pulse. This behavior is explicitly confirmed in Figure 4 and Section 4.1 of the datasheet.

Is the control voltage pin (pin 5/11) internally buffered?

No-the control voltage pin connects directly to the comparator reference input without internal buffering. Its 10¹² Ω input impedance means it must be driven by a low-impedance source (e.g., op-amp buffer or DAC with ≤1 kΩ output Z) or bypassed with ≥1 nF capacitor to ground to prevent noise coupling into timing thresholds.