STMicroelectronics TS556CD

Overview

TS556CD from STMicroelectronics is a dual low-power CMOS timer IC providing two independent 555-style timing circuits in a single SO-14 package. It delivers 220 µA typical supply current at 5 V, supports 2.7 MHz maximum astable frequency, operates across 2–16 V supply range, and maintains ±3% astable frequency accuracy with <75 ppm/°C temperature drift - used in precision timing control for battery-powered sensor nodes and industrial logic sequencers.

For engineers reviewing the TS556CD datasheet, TS556CD pinout, TS556CD application, or TS556CD equivalent, key selection criteria include ultra-low quiescent current, high-frequency astable capability, wide supply voltage tolerance, reduced output transition current spikes, and functional compatibility with legacy NE556 designs while enabling smaller decoupling and timing capacitors.

Technical Context

The TS556CD integrates two identical CMOS-based timer cells, each implementing a precision comparator pair (trigger and threshold), SR flip-flop, discharge transistor, and push-pull output stage. Its high input impedance (10¹² Ω) eliminates loading on RC timing networks, and internal voltage dividers set fixed 1/3 and 2/3 V_CC thresholds for monostable and astable operation.

Each timer cell supports both monostable (one-shot) and astable (free-running) modes without external component changes. Timing accuracy remains stable over supply voltage (±0.1 %/V in astable mode) and temperature (75 ppm/°C), enabled by supply-proportional reference generation and matched internal resistor ladders.

Key Specifications

Pinout & Package

TS556CD is housed in a 14-pin SOIC (SO14) plastic micropackage with 1.27 mm pitch, JEDEC MS-012AC compliant, and RoHS-compliant ECOPACK2 grade.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NE556N and LM556CN, TS556CD delivers 27× lower power, 27× higher frequency, and 50× lower input leakage - making it the sole viable option for modern low-power, high-precision dual-timing applications.

Availability

TS556CD is available at Aetrix Electronics and suitable for industrial sequencing controllers, battery-powered sensor wake-up timers, LED dimming pulse generators, and ultrasonic transducer drivers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TS556CD 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 microcontrollers, power management ICs, analog chips, and MEMS sensors for industrial, automotive, and consumer markets.

The TS556CD belongs to ST's precision analog timer product line, engineered specifically for low-power, high-accuracy timing functions in harsh environments - targeting applications where reliability, supply voltage flexibility, and long-term parametric stability are critical.

FAQ

Can TS556CD operate from a 3.3 V supply?

Yes, TS556CD is fully specified for operation from 2 V to 16 V, including 3.3 V logic rails. At 3 V, typical supply current is 180 µA, output high voltage is 2.5 V (min), and trigger threshold is 0.9 V - all compatible with standard 3.3 V CMOS interfaces without level shifters.

What is the maximum load capacitance the TS556CD output can drive directly?

The TS556CD output is characterized for C_LOAD ≤ 10 pF in timing-critical applications, with 25 ns rise and 20 ns fall times. For heavier capacitive loads (e.g., >50 pF), an external buffer is recommended to maintain timing accuracy and avoid output stage stress.

How does the Control Voltage (CV) pin affect timing accuracy?

Applying an external voltage to the CV pin overrides the internal 2/3 V_CC threshold, enabling adjustable duty cycle or frequency modulation. However, CV pin impedance is high (10¹² Ω), so source impedance must be <1 kΩ to prevent timing drift; bypassing CV to ground restores nominal 555 behavior.

Is TS556CD pin-compatible with DIP-14 packaged versions of the same device?

No - TS556CD refers specifically to the SO-14 surface-mount variant. While electrically identical to through-hole TS556 variants, the SO-14 package has different mechanical dimensions, thermal resistance (105 °C/W vs. ~65 °C/W for DIP), and soldering requirements; layout and reflow profiles must match SOIC specifications.