onsemi NCP551SN28T1

Overview

NCP551SN28T1 from onsemi is a fixed-output, low-dropout linear voltage regulator delivering 2.8 V at up to 150 mA with ultra-low 4.0 µA quiescent current, PMOS pass transistor architecture, and ±2.0% output voltage accuracy over −40 °C to +85 °C - designed for battery-powered portable instrumentation requiring stable low-power bias.

For engineers reviewing the NCP551SN28T1 datasheet, pinout, applications, or equivalent options, key selection considerations include dropout voltage (130 mV at 10 mA), TSOP-5 package compatibility, enable-controlled standby mode, and ceramic capacitor stability down to 0.1 µF.

Technical Context

The NCP551SN28T1 implements a PMOS-based LDO topology with internal voltage reference, error amplifier, thermal shutdown, and current-limit protection - enabling regulation with minimal headroom and no external compensation. Its enable input provides logic-level control (V_TH(en) = 1.3 V high, 0.3 V low) for system power sequencing.

Designed for handheld and portable applications, it operates across 2.8 V output with input voltage range up to 12 V, supports load transients up to 150 mA, and maintains regulation under line variations (±30 mV line regulation) and load steps (±65 mV load regulation) without requiring minimum ESR output capacitors.

Key Specifications

Pinout & Package

Package: TSOP-5 (Case 483), 3.00 × 1.50 × 0.95 mm, surface-mount, Pb-free, with exposed pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700T-2802E/TT and TPS70628DRVR, the NCP551SN28T1 uniquely combines TSOP-5 compactness, integrated enable, 130 mV dropout, and guaranteed 2.8 V ±2.0% accuracy - making it optimal for space-constrained, battery-sensitive portable designs requiring precise 2.8 V bias with active power management.

Availability

NCP551SN28T1 is available at Aetrix Electronics and suitable for battery-powered instrumentation, hand-held test equipment, and camcorder subsystems requiring stable component supply with long-lifecycle support.

Supply support for NCP551SN28T1 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 is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The NCP551 series belongs to onsemi's precision analog LDO portfolio, engineered specifically for ultra-low-power portable electronics where extended battery life, small footprint, and robust transient performance are mandatory design requirements.

FAQ

What is the maximum input voltage rating for the NCP551SN28T1?

The NCP551SN28T1 has an absolute maximum input voltage rating of 12 V, as specified in the Maximum Ratings table. Operation above this voltage risks permanent device damage. For reliable long-term use, input voltage should remain within 0 to 12 V, with recommended derating for thermal margin in high-power dissipation scenarios.

Does the NCP551SN28T1 require an external output capacitor, and what value is recommended?

Yes, the NCP551SN28T1 requires an external output capacitor for stability. The datasheet specifies a minimum value of 0.1 µF ceramic capacitor placed close to the Vout and GND pins. Larger values (up to 10 µF) improve load transient response and noise rejection, and the device remains stable across the full ESR range of common ceramic capacitors.

How does the enable pin function on the NCP551SN28T1, and what are its threshold voltages?

The enable pin on the NCP551SN28T1 is active-high. It turns the regulator ON when voltage exceeds 1.3 V (typical) and OFF when voltage drops below 0.3 V (typical). When unused, the pin must be connected directly to Vin to ensure continuous operation. In shutdown mode, quiescent current drops to 4.0 µA, preserving battery charge in idle states.

What is the dropout voltage of the NCP551SN28T1 at full load, and how is it defined?

The dropout voltage of the NCP551SN28T1 is 130 mV at 10 mA output current, measured when Vout drops 3% below nominal (to 2.716 V). At 150 mA, dropout increases due to PMOS R_DS(on); actual value depends on junction temperature and is not explicitly tabulated but remains within practical limits for 2.8 V output with ≥3.0 V input.

Is the NCP551SN28T1 RoHS compliant and lead-free?

Yes, the NCP551SN28T1 is RoHS compliant and Pb-free, as confirmed by the "G" suffix in the ordering code (NCP551SN28T1G) and explicit statement in the Features section. The TSOP-5 package meets JEDEC J-STD-020 moisture sensitivity level 1 and is qualified for standard reflow soldering processes.