onsemi NCP561SN28T1G

Overview

NCP561SN28T1G from onsemi is a fixed 2.8 V, 150 mA CMOS low-dropout linear regulator in TSOP-5 package, featuring 3.0 µA typical quiescent current, 170 mV dropout at full load, and ±2.0% output voltage accuracy - designed for battery-powered handheld instruments requiring ultra-low standby power.

For engineers reviewing the NCP561SN28T1G datasheet, pinout, applications, or equivalent options, key selection criteria include dropout performance at 150 mA, thermal shutdown behavior, enable logic thresholds, ceramic capacitor compatibility, and industrial temperature range support (-40°C to +85°C).

Technical Context

The NCP561SN28T1G integrates a PMOS pass transistor with internal voltage reference, error amplifier, current limit, and thermal shutdown circuitry. It operates without requiring minimum load or specific ESR output capacitors, supporting stable regulation with ≥1.0 µF ceramic or tantalum capacitors.

Its enable input accepts logic-level control (V_TH(HI) = 1.3 V, V_TH(LO) = 0.2 V), and it delivers regulated 2.8 V output across input voltages from 3.1 V to 6.0 V. Dropout is specified at 140 mV (typ) / 230 mV (max) at 150 mA and -40°C to +85°C.

Key Specifications

Pinout & Package

Package: TSOP-5 (3.00 × 1.50 × 0.95 mm, 0.95 mm pitch), Pb-free, surface-mount - optimized for space-constrained portable PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2802E/TT and TCS2102-2800V, the NCP561SN28T1G offers the optimal balance of ultra-low IQ, industrial temperature range, and proven ceramic-capacitor stability - making it preferred for long-life, wide-temperature embedded systems where footprint and reliability are prioritized over marginal current headroom.

Availability

NCP561SN28T1G is available at Aetrix Electronics and suitable for portable medical sensors, wireless sensor nodes, handheld test equipment, and industrial data loggers requiring stable component supply with guaranteed Pb-free compliance and traceable sourcing.

Supply support for NCP561SN28T1G 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 delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The NCP561 series belongs to onsemi's precision analog LDO portfolio, engineered specifically for ultra-low-power battery-operated systems where quiescent current, dropout voltage, and small-footprint packaging are critical design constraints.

FAQ

What is the maximum input voltage for NCP561SN28T1G?

The absolute maximum input voltage for NCP561SN28T1G is 6.0 V, as specified in the Maximum Ratings table. Operation above this voltage risks permanent damage. For reliable long-term use, the recommended operating input range is 3.1 V to 6.0 V - ensuring sufficient headroom above the 2.8 V output while maintaining low dropout and thermal safety. The NCP561SN28T1G must not be used with inputs exceeding 6.0 V even briefly unless protected by external clamping or pre-regulation.

Does NCP561SN28T1G require an external resistor divider for output voltage setting?

No, the NCP561SN28T1G does not require an external resistor divider. It is a fixed-output LDO with internally trimmed 2.8 V regulation, confirmed by the ordering code "SN28" and electrical characteristics tables showing V_OUT = 2.8 V ±2.0%. All feedback resistors are integrated within the die - simplifying layout, reducing component count, and eliminating drift or tolerance errors associated with external networks.

Can NCP561SN28T1G operate with a 1.0 µF ceramic output capacitor?

Yes, the NCP561SN28T1G is explicitly characterized and guaranteed stable with a minimum 1.0 µF ceramic output capacitor, as stated in both the Features list and Applications Information section. Unlike many older LDOs, it imposes no ESR requirements - enabling use of low-cost, small-size X5R/X7R MLCCs without risk of oscillation. This is validated across temperature and load conditions per Figure 2–12 in the datasheet.

What happens to NCP561SN28T1G when the Enable pin is left floating?

If the Enable pin of the NCP561SN28T1G is left floating, device behavior is undefined and may result in erratic turn-on/turn-off or increased quiescent current due to noise coupling. The datasheet explicitly states: "If this function is not used, Enable should be connected to VIN." Tying Enable to VIN ensures guaranteed activation and avoids metastability - a mandatory design practice verified in all onsemi application circuits (e.g., Figure 13).

Is thermal shutdown in NCP561SN28T1G automatically reset after cooling?

Yes, the thermal shutdown circuit in the NCP561SN28T1G is fully automatic and self-resetting. When junction temperature exceeds ~160°C, the regulator disables output; once the die cools below the hysteresis threshold (~140°C), normal regulation resumes without external intervention. This behavior is intrinsic to the internal protection architecture and requires no external reset signal or power cycle - ensuring robust fault recovery in thermally constrained enclosures.