Microchip Technology MIC1555YMU-T5

Overview

MIC1555YMU-T5 from Microchip Technology is a rail-to-rail CMOS RC timer/oscillator IC designed for precision monostable and astable operation with separate trigger (TRG) and threshold (THR) inputs. It operates from +2.7V to +18V, delivers <15Ω output on-resistance, achieves ±2% timing accuracy over temperature, and supports timing ranges from microseconds to hours in a 10-pin UTDFN (2 mm × 2 mm × 0.4 mm) package - used in micropower LED blinkers, missing-pulse detectors, and voltage converter timing control.

For engineers reviewing the MIC1555YMU-T5 datasheet, MIC1555YMU-T5 pinout, MIC1555YMU-T5 application, or MIC1555YMU-T5 equivalent, this page provides verified functional identity, validated pin roles, confirmed timing stability specs (<0.005%/°C), real-world application constraints (e.g., leakage-limited >10 s delays), and direct alternative part comparisons with documented differences in chip select behavior and oscillator-only capability.

Technical Context

The MIC1555YMU-T5 implements a BiCMOS RS flip-flop architecture with two independent comparators: a dominant threshold comparator (THR) that forces output low when ≥2/3VS, and a trigger comparator (TRG) that sets output high when ≤1/3VS. Its internal resistive divider establishes precise 1/3VS and 2/3VS reference points, enabling stable RC-based timing independent of supply variation.

Unlike legacy 555 timers, it omits FC and open-collector discharge pins, uses CMOS totem-pole output (no cross-conduction spikes), and integrates chip select (CS) for <1 μA shutdown - a feature absent in SOT-23 variants but essential for battery-powered applications requiring intermittent operation.

Key Specifications

Pinout & Package

Package: 10-pin Ultra-Thin DFN (UTDFN), 2 mm × 2 mm × 0.4 mm body, exposed thermal pad (not electrically connected), rated θJA = 90°C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RC timer/oscillator applications.

Compared with MIC1555YM5-TR, MIC1555YMU-T5 adds chip select for ultra-low-power sleep modes without changing timing performance; compared with MIC1557YMU-T5, it retains full monostable/astable configurability at the cost of slightly higher complexity in oscillator wiring.

Availability

MIC1555YMU-T5 is available at Aetrix Electronics and suitable for precision timer, micropower oscillator, and voltage converter timing applications requiring stable component supply, long-lifecycle availability, and traceable sourcing for industrial and medical electronics.

Supply support for MIC1555YMU-T5 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

Microchip Technology Inc. is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and timing solutions, with ISO/TS-16949:2009 certification across wafer fabrication and design centers.

The MIC1555/57 IttyBitty RC Timer/Oscillator product line was designed for space- and power-constrained applications requiring rail-to-rail precision timing - replacing legacy bipolar 555 timers with CMOS efficiency and enhanced stability.

FAQ

What is the primary function of the MIC1555YMU-T5?

The MIC1555YMU-T5 is a CMOS RC timer/oscillator IC supporting both monostable (one-shot) and astable (oscillator) configurations. Its core function is precision timing generation using external R and C components, with rail-to-rail CMOS output, separate TRG/THR inputs, and chip select for <1 μA shutdown. The MIC1555YMU-T5 replaces legacy 555 timers in applications demanding low power, high accuracy, and small footprint.

Does the MIC1555YMU-T5 support monostable operation?

Yes, the MIC1555YMU-T5 fully supports monostable operation using separate TRG and THR inputs. A low pulse on TRG initiates the output high state; the external RC network then charges until THR reaches 2/3VS, forcing output low. This enables accurate, adjustable one-shot pulses from microseconds to hours. The MIC1555YMU-T5's threshold-dominant architecture prevents retriggering during the pulse, ensuring clean, repeatable timing.

What is the role of the CS pin on the MIC1555YMU-T5?

The CS (chip select) pin on the MIC1555YMU-T5 is an active-high digital control input that enables hardware-level power gating. When pulled high (>2/3VS), the device operates normally; when pulled low (<1/3VS), it enters shutdown mode with supply current <1 μA. If unused, CS must be tied to VS - floating CS causes unpredictable behavior. This feature is unique to UTDFN variants like MIC1555YMU-T5 and absent in SOT-23 versions.

Can the MIC1555YMU-T5 generate a 50% duty cycle square wave?

Yes, the MIC1555YMU-T5 can generate a precise 50% duty cycle square wave using only one resistor and one capacitor in astable configuration (TRG tied to THR). This is enabled by its internal comparator thresholds at 1/3VS and 2/3VS, which produce symmetrical charge/discharge timing. Unlike the MIC1557YMU-T5, the MIC1555YMU-T5 requires external connection of TRG to THR for oscillator use, retaining full monostable capability.

What package type does the MIC1555YMU-T5 use?

The MIC1555YMU-T5 uses a 10-pin Ultra-Thin DFN (UTDFN) package measuring 2 mm × 2 mm × 0.4 mm, with an exposed thermal pad (non-functional). This package offers θJA = 90°C/W - significantly better thermal performance than SOT-23 variants (θJA = 250°C/W) - and enables high-density placement in compact PCBs such as wearable sensors and portable instrumentation where the MIC1555YMU-T5 is commonly deployed.