ZSCT1555D8

Overview

The ZSCT1555D8 is a precision single-cell timer manufactured by Diodes Incorporated, originally designed by Zetex Semiconductors. It operates from a supply voltage range of 0.9V to 6V with a typical quiescent current of 74 µA at 1.5V. The device features pin connections comparable to standard 555 series timers and supports monostable and astable modes. In monostable mode, timing is controlled by a single resistor-capacitor network, while astable mode allows independent frequency and duty cycle control via two resistors and one capacitor. The D8 suffix indicates a DIP-8 package.

Feature Summary

• Operates from a single battery cell with a guaranteed minimum supply voltage of 0.9V
• Very low quiescent current consumption of 74 µA (typical)
• Pin-compatible with standard 555 series timers for easy replacement
• Available in DIL8 (DIP-8) and SO8 packages

Applications

• Portable and battery-powered equipment
• Low voltage and low power systems
• Single cell boost converters generating regulated supplies

Procurement Notes

Verify the manufacturer origin, as the part was originally produced by Zetex Semiconductors before acquisition by Diodes Incorporated. Confirm the specific package type required, as the D8 suffix denotes the DIP-8 variant. Check RoHS compliance status if environmental regulations apply to the target assembly process.

Selection Notes

Select this component when designing circuits requiring precise timing from a single 1.2V or 1.5V battery source. Ensure external timing components are rated for the expected temperature range (-20°C to +100°C). For astable configurations, verify that the chosen resistor values allow for the desired frequency and duty cycle calculations based on the internal threshold levels.

Part Context

This device belongs to the ZSCT1555 family of precision timers. The ZSCT1555D8 specifically refers to the Dual Inline Package (8-pin) version. It shares functional similarities with other low-voltage timer ICs but is distinguished by its optimized performance for single-cell battery operation and compatibility with legacy 555 pinouts.

Replacement Considerations

Standard 555 timers typically require higher voltages (e.g., 4.5V–16V) and cannot operate reliably at 0.9V. When replacing standard 555s with the ZSCT1555D8, ensure the circuit design accommodates the lower supply voltage and verify that the output drive capabilities meet the load requirements.