STMicroelectronics TS556CDT

Overview

TS556CDT 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 battery-operated pulse generation circuits.

For engineers reviewing the TS556CDT datasheet, TS556CDT pinout, TS556CDT application, or TS556CDT equivalent, key selection criteria include its ultra-low ICC vs. bipolar NE556, reduced supply current spikes during output transitions, high-impedance trigger/threshold inputs, and SO14 package compatibility with legacy 556 layouts.

Technical Context

The TS556 integrates two independent CMOS-based 555-style timers sharing a common supply and ground. Each timer uses resistor-divider threshold/trigger comparators, SR flip-flop control logic, and push-pull output stage with dedicated discharge transistor - enabling precise RC-based timing without external components for basic operation.

Its architecture eliminates bipolar supply current spikes during output transitions, reduces decoupling capacitor requirements, and maintains timing accuracy (±2% astable, ±4% monostable) across -40°C to +125°C and 2–16 V supply - due to supply-independent comparator reference ratios and matched internal resistor ladders.

Key Specifications

Pinout & Package

TS556CDT is housed in a 14-pin SOIC (SO14) plastic micropackage, 8.75 mm × 4.0 mm body, 1.27 mm pitch, with gull-wing leads and ECOPACK® environmental compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NE556DR and LM556CN/NOPB, TS556CDT provides 27× lower quiescent current, 27× higher max frequency, and SO14 packaging - making it optimal for space-constrained, battery-aware, and high-accuracy timing systems where bipolar drive strength is unnecessary.

Availability

TS556CDT is available at Aetrix Electronics and suitable for industrial relay debounce circuits, low-power sensor wake-up timers, ultrasonic transducer drivers, and PWM generator modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TS556CDT 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 TS556 belongs to ST's precision analog timer product line, engineered specifically to replace legacy bipolar 556 timers while delivering ultra-low power, high-frequency operation, and robust performance across harsh industrial and automotive environments.

FAQ

Can TS556CDT operate from a single 3.3 V supply?

Yes. TS556CDT is fully specified down to 2 V supply voltage. At 3.3 V, it draws 180 µA typical supply current, delivers 2.5 V VOH and 0.3 V VOL output swing, and maintains ±3% astable accuracy - making it ideal for mixed-voltage systems interfacing with 3.3 V microcontrollers.

What is the maximum load the DISCH pin can drive?

The DISCH pin is an NMOS open-drain transistor rated for 100 mA sink current absolute maximum. In practice, it reliably discharges 100 pF–10 nF timing capacitors at frequencies up to 2.7 MHz with <100 ns turn-off delay, provided the external pull-up resistor is sized to limit peak current below 50 mA.

How does TS556CDT achieve supply-independent timing?

Both the trigger (1/3 VCC) and threshold (2/3 VCC) comparator reference voltages are derived from internal resistor dividers tied to VCC. Since timing capacitor charge/discharge rates scale linearly with VCC, the RC time constant remains invariant - yielding <0.5 %/V supply sensitivity in both monostable and astable modes.

Is TS556CDT pin-compatible with NE556 in SO14 packages?

Yes. TS556CDT uses identical SO14 pinout and electrical signaling as the obsolete NE556(a), including matching trigger, threshold, discharge, reset, control voltage, and output pin assignments - enabling direct replacement without layout changes or firmware updates.