onsemi NCP703SN18T1G

Overview

NCP703SN18T1G from onsemi is a 300 mA, fixed 1.8 V output ultra-low-noise LDO voltage regulator in TSOP-5 package, featuring 12 µA typical quiescent current, 13 µV_RMS output noise (100 Hz–100 kHz), 180 mV typical dropout at 300 mA, and ±2% output accuracy over load/line/temperature - designed for powering RF power amplifiers in satellite radios and infotainment systems.

For engineers reviewing the NCP703SN18T1G datasheet, pinout, applications, or equivalent options, key selection criteria include ultra-low noise performance without bypass capacitors, dynamic I_Q management for battery longevity, EN-controlled active discharge, stability with 1 µF ceramic output capacitor, and thermal shutdown/current limit protection.

Technical Context

The NCP703SN18T1G employs a PMOS pass transistor architecture enabling low dropout and reverse-current immunity, with integrated soft-start to limit inrush current and internal bandgap reference for high DC accuracy. Its adaptive ground current circuitry reduces I_Q to 12 µA at no load while maintaining fast transient response.

It delivers 68 dB PSRR at 1 kHz and achieves ultra-low noise via optimized internal compensation - eliminating need for external noise-reduction capacitors. The EN pin provides logic-level control with 0.4 V low-threshold shutdown and 0.9 V high-threshold enable, plus built-in 2 mV hysteresis to prevent oscillation.

Key Specifications

Pinout & Package

Package: TSOP-5 (Case 483), 3.00 × 1.50 × 0.95 mm, Pb-free, moisture-sensitive level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B182MR-G and BD70522GUL, the NCP703SN18T1G uniquely balances 300 mA drive, 12 µA I_Q, 13 µV_RMS noise, and EN-controlled active discharge in a compact TSOP-5 - making it optimal for space-constrained RF and portable medical designs requiring both precision and efficiency.

Availability

NCP703SN18T1G is available at Aetrix Electronics and suitable for satellite radio modules, automotive infotainment head units, and portable medical diagnostic equipment requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for NCP703SN18T1G 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 silicon solutions for automotive, industrial, cloud, medical, and IoT applications.

The NCP703SN18T1G belongs to onsemi's high-performance LDO family engineered specifically for noise-sensitive RF and precision analog subsystems in battery-powered portable electronics.

FAQ

What is the maximum input voltage rating for the NCP703SN18T1G?

The NCP703SN18T1G has an absolute maximum input voltage rating of 6 V, with recommended operating range from 2.0 V to 5.5 V. Exceeding 6 V may cause permanent damage. For reliable operation, VIN should remain ≥ (VOUT + 0.5 V) = 2.3 V to ensure specified dropout and regulation performance across temperature and load conditions. The device incorporates undervoltage lockout (UVLO) that disables regulation below ~1.6 V.

Does the NCP703SN18T1G require an external noise bypass capacitor?

No, the NCP703SN18T1G does not require an external noise bypass capacitor. Its internal design achieves 13 µV_RMS output noise (100 Hz–100 kHz) without C_NR, as confirmed in the datasheet Figure 3–6 and Applications Information section. This eliminates board space, cost, and reliability risk associated with adding discrete noise-filtering components - a key differentiator versus legacy LDOs.

What is the purpose of the N/C pin (Pin 3) on the NCP703SN18T1G TSOP-5 package?

Pin 3 of the NCP703SN18T1G in TSOP-5 is a no-connect (N/C) terminal - it is not bonded internally and serves no electrical function. Per datasheet Table 1 and Pin Connections diagram, it may be left floating or connected to GND solely to improve thermal conduction from the die to the PCB copper plane. It must never be used as a signal or power path, as it has no internal connection to the silicon.

How does the enable (EN) pin control active discharge in the NCP703SN18T1G?

When the EN pin voltage falls below 0.4 V, the NCP703SN18T1G enters shutdown mode and activates an internal 320 Ω pull-down transistor between OUT and GND. This active discharge rapidly discharges the output capacitor, bringing V_OUT to near-zero volts within milliseconds - critical for power sequencing in multi-rail systems. During normal operation (EN > 0.9 V), the discharge path is disabled to avoid loading the regulated output.

Can the NCP703SN18T1G operate stably with a 0.47 µF output capacitor?

No - the NCP703SN18T1G is specified to be stable with a minimum effective output capacitance of 0.1 µF, but the datasheet explicitly recommends 1 µF (X5R/X7R ceramic) for guaranteed stability across temperature, voltage, and aging. A 0.47 µF capacitor may fall below the effective capacitance threshold under DC bias or low temperature, risking oscillation or degraded transient response. Always use ≥1 µF per Applications Information Section and Figure 49.