onsemi NCP502SQ31T1G

Overview

NCP502SQ31T1G from onsemi is a fixed-output, low-quiescent-current CMOS linear voltage regulator delivering 3.1 V at up to 80 mA with 40 µA typical quiescent current and 850 mV typical dropout voltage at 80 mA. It features PMOS pass transistor architecture, ±2.0% output voltage accuracy over temperature, and operates across −40 °C to +85 °C - ideal for battery-powered handheld instruments requiring stable low-power bias.

For engineers reviewing the NCP502SQ31T1G datasheet, pinout, applications, or equivalent options, key selection criteria include ultra-low IQ for extended battery life, SC70-5 package footprint constraints, enable threshold compatibility (1.3 V high / 0.3 V low), and ceramic-capacitor stability without ESR requirements.

Technical Context

The NCP502SQ31T1G implements a PMOS-based LDO architecture with internal voltage reference, error amplifier, and thermal/current limiting protection. Its enable input controls output state with defined logic-high (≥1.3 V) and logic-low (≤0.3 V) thresholds, and it requires no minimum load for stability.

Designed for low-noise, low-power operation, it achieves 55 dB ripple rejection at 1 kHz and 180 µV_RMS output noise (100 Hz–100 kHz), while supporting input voltages up to 12 V and maintaining regulation down to 850 mV dropout at full 80 mA load across industrial temperature range.

Key Specifications

Pinout & Package

Package: SC70-5 (Case 419A), 1.25 mm × 1.65 mm × 0.95 mm, Pb-free, surface-mount.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with MCP1700T-3102E/TT, NCP502SQ31T1G offers enable control and thermal protection at cost of higher IQ; versus TNIV502SQ31T1G, it trades automotive qualification for lower unit cost in non-automotive designs.

Availability

NCP502SQ31T1G is available at Aetrix Electronics and suitable for portable medical sensors, wearable fitness trackers, handheld test meters, and smart home sensor nodes requiring stable component supply with long-term manufacturability assurance.

Supply support for NCP502SQ31T1G 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

onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, and sensor solutions for automotive, industrial, and portable electronics.

The NCP502 series belongs to onsemi's low-power linear regulator product line, engineered specifically for battery-constrained applications where ultra-low quiescent current, small footprint, and ceramic-capacitor compatibility are critical design requirements.

FAQ

What is the maximum input voltage rating for the NCP502SQ31T1G?

The NCP502SQ31T1G has an absolute maximum input voltage rating of 12 V, as specified in the Maximum Ratings table. Operation above this voltage risks permanent damage. For reliable long-term performance, design with headroom - e.g., limit Vin to ≤10 V when ambient temperature exceeds 70 °C to maintain safe junction temperature.

Does the NCP502SQ31T1G require an external output capacitor, and what value is recommended?

Yes, the NCP502SQ31T1G requires an external output capacitor for stability and transient response. The datasheet specifies a minimum of 1.0 µF ceramic capacitor (X5R/X7R dielectric), placed as close as possible to the Vout and GND pins. Larger values (up to 10 µF) improve load transient suppression and noise filtering without compromising stability.

Can the NCP502SQ31T1G be used with a 2.5 V input supply?

No - the NCP502SQ31T1G cannot regulate with a 2.5 V input because its typical dropout voltage is 850 mV at 80 mA. To maintain 3.1 V output, Vin must be ≥3.1 V + 0.85 V = 3.95 V minimum under full load. At light loads (<1 mA), dropout drops to ~600 mV, still requiring Vin ≥3.7 V for guaranteed regulation.

What is the function of Pin 4 (N/C) on the NCP502SQ31T1G SC70-5 package?

Pin 4 on the NCP502SQ31T1G is designated N/C (No Connection) - it has no internal bond wire or circuit connection. It may be left unconnected, tied to GND, or routed as a keep-out zone. The datasheet explicitly states it is a true no-connect; using it for grounding or signal routing provides no functional benefit and may risk mechanical stress on the die bond.

How does the enable functionality behave during power-up and power-down sequences?

The NCP502SQ31T1G enable pin asserts output only when voltage rises above 1.3 V (typical) and deasserts when falling below 0.3 V (typical). During power-up, Vout follows Vin only after enable crosses threshold - preventing brown-out glitches. During power-down, output disables cleanly before Vin collapses, avoiding backfeed into upstream supplies. No external pull-up is required if tied directly to Vin.