onsemi NCP303LSN36T1G

NCP303LSN36T1G Voltage Supervisor Summary of Features and Applications by onsemi

The NCP303LSN36T1G from onsemi is a precision IC supervisor designed to ensure reliable voltage monitoring and reset control for microprocessor-based systems. Housed in a compact TSOP-5 package, the NCP303LSN36T1G is part of the NCP303 series and features an open drain N-channel output with an active low reset, making it well-suited for portable electronics and other sensitive embedded platforms. Its extremely low quiescent current and accurate threshold detection address both energy efficiency and precision requirements, which are essential for safeguarding system operations in demanding applications.

Main Attributes of NCP303LSN36T1G

Ultra-low typical quiescent current of 0.5 μA, optimizing power consumption for battery-powered devices.

High-precision undervoltage detection, maintaining a threshold accuracy within 2% for reliable system triggering.

Externally programmable time delay generator on the reset signal, enabling customized system recovery constraints.

Broad operating voltage range from 0.8 V to 10 V, supporting a variety of logic and supply rails.

Open drain output with active low reset (NCP303 series), compatible with multiple microprocessor reset architectures.

Operation assured across a wide temperature span from −40°C to +125°C, apart from some low voltage options.

Pb-Free and RoHS compliance for environmental responsibility.

Automotive-grade variants (NCV prefix) are available, meeting AEC-Q100 and PPAP requirements.

Comprehensive Electrical Specifications of NCP303LSN36T1G

The NCP303LSN36T1G delivers consistent performance under extended environmental and supply conditions. The device’s detector thresholds are accurate and stable, with guaranteed limits for voltage options above 1.1 V across the −40°C to +125°C range (threshold accuracy within ±3%). For variants with voltage options below 1.2 V, threshold accuracy is validated at +25°C.

Current consumption is exceptionally low, ensuring minimal impact on overall system battery life—a critical attribute for portable and battery-powered solutions. Input voltage hysteresis is integrated to counteract noise and supply fluctuations, further enhancing reset reliability.

The reset output timing is determined by an external capacitive delay, allowing engineers to tailor the time delay for release after power restoration according to system needs. Various tables and figures describe the relationship between input voltage, output voltage, current characteristics, and timing delays versus temperature or capacitance.

Operating Principles and Timing Details of NCP303LSN36T1G

At its core, the NCP303LSN36T1G integrates a highly accurate voltage detector with an intelligent delay mechanism. Upon initialization, if the monitored supply voltage remains above the upper threshold (VDET+), the reset output stays inactive (high for active low variants). Any drop below the lower threshold (VDET-) triggers immediate discharge of the external delay capacitor via a built-in N-channel MOSFET, promptly setting the reset output low to signal a fault or undervoltage event.

When voltage returns to nominal, the detector releases the MOSFET, and the delay capacitor begins recharging through a pull-up resistor, orchestrating a programmable reset release delay. Once the capacitor voltage exceeds a defined threshold (≈0.675 × Vin), the reset output returns to its normal state. This design ensures robust protection against power glitches and supply brownouts, reducing the risk of erratic microprocessor states.

Application Examples Featuring NCP303LSN36T1G

The versatility of NCP303LSN36T1G is evident in its wide array of application circuits supporting various system reliability requirements:

Microprocessor Reset Controller: Precise undervoltage detection and programmable recovery delay provide reliable system initialization after voltage disturbances.

Low Battery Detection: Ensures timely notification and system shutdown or switchover in case battery levels drop below safe operating thresholds.

Power Fail Indicator and Battery Backup Detection: Safeguards mission-critical systems by signaling power interruptions and orchestrating backup transitions.

Frequency or Missing Pulse Detection: Utilizes the delay generator for event timing in clock monitoring applications.

Multi-Rail Supply Monitoring: Facilitates simultaneous voltage supervision across multiple rails, generating a unified Power Good signal only when all supplies are within spec.

Configurable hysteresis (via external resistance) and flexible output arrangements allow further optimization for specific design goals, such as minimizing false resets in noisy environments or customizing reset logic for complex supply sequencing.

Physical Design and Installation Guidelines for NCP303LSN36T1G

The NCP303LSN36T1G is supplied in the space-saving TSOP-5 (CASE 483) package, offering good thermal performance for its compact footprint (3.00 × 1.50 × 0.95 mm). Recommended PCB mounting layouts are provided to ensure optimal electrical and thermal connection, with guidelines adhering to ASME Y14.5-2018 for dimensioning and tolerancing. The lead finish is Pb-free, and soldering recommendations align with modern manufacturing standards for surface mount devices.

Compatible or Substitute Devices for NCP303LSN36T1G

Given the discontinuation status of some members of the NCP303 series, engineers should be aware of alternative models when specifying parts for new designs:

NCP302 series (by onsemi): Provides complementary output with options for active high or active low reset signals and is available in threshold voltages matching the NCP303 series.

Custom configurations in the NCP302 and NCP303 range: onsemi supports undervoltage thresholds from 0.9 V to 4.9 V in 100 mV increments, both for active low (NCP302/3L) and active high (NCP302H) outputs.

Automotive-grade variants (NCV prefix): For applications demanding AEC-Q100 qualification, consider NCV-prefixed models with the same core functionality and extended reliability testing.

When transitioning from NCP303LSN36T1G, review system requirements for output type (open drain vs. complementary), threshold accuracy, delay programmability, and package compatibility to ensure seamless replacement.

Conclusion

: Selection Guidance for Engineers

The NCP303LSN36T1G supervisor from onsemi delivers robust performance in voltage monitoring and reset control for microprocessor-driven systems, uniquely combining low-power operation, precision detection, and programmable timing. Its flexible output and scalable threshold options adapt to varied engineering needs, spanning portable devices to automotive systems. However, with some models being discontinued, careful consideration of replacement strategies using related series or custom variants is crucial to maintaining reliability and long-term availability.

For engineers and procurement professionals, the NCP303LSN36T1G and its sibling products remain a benchmark for supervisor ICs in advanced embedded designs. Evaluating threshold options, timing flexibility, package compatibility, and environmental ratings will help ensure optimal device choice and secure system operation.