STMicroelectronics TS556IDT

Overview

TS556IDT from STMicroelectronics is a dual CMOS timer IC providing two independent 555-style timing circuits in a single SO14 package. It delivers ultra-low quiescent current (220 µA typ at 5 V), high astable frequency up to 2.7 MHz, and operates across 2–16 V supply range-enabling precision timing in battery-powered sensor nodes, portable instrumentation, and low-power industrial control interfaces.

For engineers reviewing the TS556IDT datasheet, TS556IDT pinout, TS556IDT application, or TS556IDT equivalent, key selection criteria include supply current vs. voltage scaling, monostable/astable timing accuracy (±2% at 5 V), discharge pin leakage (<100 nA), output drive capability (±100 mA), and compatibility with TTL/CMOS logic families.

Technical Context

The TS556 integrates two identical CMOS-based timer cores, each featuring high-impedance (10¹² Ω) trigger and threshold inputs, rail-to-rail output swing, and internal voltage divider for 1/3–2/3 VCC reference generation. Its architecture eliminates bipolar transistor switching spikes, reducing supply current transients during output transitions.

Each timer supports both monostable (one-shot) and astable (oscillator) modes with timing intervals independent of supply voltage due to proportional charge/discharge thresholds and current sources. The discharge pin provides open-collector-like control of external timing capacitors, enabling precise duty-cycle tuning in astable configurations via RA/RB resistor ratios.

Key Specifications

Pinout & Package

TS556IDT is housed in a 14-pin SOIC (SO14) plastic micropackage, 8.55–8.75 mm wide, 3.80–4.00 mm body width, 1.27 mm lead pitch, with gull-wing leads suitable for automated SMT assembly and IPC Class 2/3 reliability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NE556DR and LM556CN, TS556IDT offers 27× higher maximum frequency, >25× lower supply current, and SO14 packaging for modern SMT lines - making it optimal for new designs demanding low power, high speed, and automated assembly.

Availability

TS556IDT is available at Aetrix Electronics and suitable for portable medical devices, industrial PLC modules, smart home sensor hubs, and automotive cabin lighting systems requiring stable component supply across extended product lifecycles.

Supply support for TS556IDT 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The TS556 belongs to ST's precision analog timer product line, engineered specifically for applications needing low-power, high-accuracy timing with robust industrial temperature range (-40 °C to +125 °C) and AEC-Q200 readiness.

FAQ

What is the maximum recommended load capacitance for stable TS556IDT output switching?

The TS556IDT output stage is characterized with 10 pF load in datasheet timing specs (tR = 25 ns, tF = 20 ns). Driving >50 pF loads may increase rise/fall times and cause ringing; for >100 pF, add a series 10–33 Ω resistor near the output pin to dampen reflections and maintain clean edges.

Can TS556IDT operate reliably at 2 V supply with full timing accuracy?

Yes - the TS556IDT guarantees operation down to 2 V with verified timing accuracy: monostable timing error remains within ±1% at 2 V (R = 10 kΩ, C = 0.1 µF), and supply voltage coefficient is 0.5 %/V in monostable mode, ensuring predictable behavior across the full 2–16 V range.

How does the discharge pin function differ between monostable and astable modes?

In monostable mode, the discharge pin actively pulls LOW during the timing interval to short the external capacitor; in astable mode, it alternately pulls LOW (during capacitor discharge phase) and floats (during charge phase), enabling RC network control of duty cycle via RA/RB ratio - unlike bipolar 556 variants that exhibit higher discharge pin leakage.

Is TS556IDT pin-compatible with NE556 despite CMOS architecture?

Yes - TS556IDT maintains identical SO14 pinout and functional mapping to NE556, including Reset, Trigger, Output, Threshold, Control Voltage, Discharge, and Ground assignments. Logic thresholds scale with VCC (1/3 and 2/3 points), preserving drop-in replacement capability in existing layouts.