onsemi NCP4687DH12T1G

Overview

NCP4687DH12T1G from onsemi is a CMOS 500 mA low-dropout linear voltage regulator with 1.2 V fixed output, ±0.8% accuracy at VOUT > 1.8 V (applies to 1.2 V per datasheet footnote), 75 dB PSRR at 1 kHz, and integrated auto-discharge NMOS for fast output capacitor discharge. It operates from 2.5 V to 5.25 V input and targets power-sensitive applications such as DVB-T receivers and car audio systems.

For engineers reviewing the NCP4687DH12T1G datasheet, pinout, applications, or equivalent options, key selection criteria include dropout voltage (0.35 V typical at 500 mA for 1.2 V output), thermal shutdown (165°C), SOT-89-5 package compatibility, and CE-controlled enable functionality with internal pull-down.

Technical Context

The NCP4687DH12T1G implements a CMOS-based error amplifier architecture with precision voltage reference and resistor divider feedback network, enabling tight output regulation across temperature and load. Its high PSRR stems from optimized internal compensation and low-noise biasing, delivering 75 dB rejection at 1 kHz and 70 dB at 10 kHz under 30 mA load.

Thermal protection integrates a junction-sensing circuit with 165°C trip point and 65°C hysteresis, while the CE pin controls both regulator enable and activation of the dedicated 60 Ω RDS(on) NMOS discharge path. The SENSE pin decouples load regulation from PCB trace resistance by sensing voltage directly at the load.

Key Specifications

Pinout & Package

SOT-89-5 package: thermally enhanced 5-pin surface-mount outline with exposed pad (EP) for improved heat dissipation; footprint matches JEDEC MO-220 standard; RJA = 111°C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1826T-1202E/DB and TLC7701QD, the NCP4687DH12T1G delivers superior PSRR, integrated discharge, and thermal robustness in a thermally optimized SOT-89-5 package-making it optimal for noise-sensitive, high-reliability 500 mA loads.

Availability

NCP4687DH12T1G is available at Aetrix Electronics and suitable for DVB-T receivers, car audio systems, and industrial control panels requiring stable component supply, long-term lifecycle support, and Pb-free compliance.

Supply support for NCP4687DH12T1G 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 consumer markets.

The NCP4687DH12T1G belongs to onsemi's NCP4687 family of high-PSRR, auto-discharge LDOs designed specifically for noise-critical portable and automotive electronics demanding precise, low-noise 0.7–3.6 V outputs.

FAQ

What is the maximum input voltage rating for the NCP4687DH12T1G?

The NCP4687DH12T1G has an absolute maximum input voltage of 6 V, as specified in the Absolute Maximum Ratings table. Operation above this level risks permanent damage. For reliable continuous use, the recommended operating input range is 2.5 V to 5.25 V - sufficient to cover Li-ion battery discharge curves and standard 3.3 V/5 V intermediate rails. Exceeding 5.25 V may degrade PSRR and increase dropout voltage unpredictably.

Does the NCP4687DH12T1G require external components for stable operation?

Yes, the NCP4687DH12T1G requires two 1.0 µF ceramic capacitors: one between VIN and GND (input decoupling), and one between VOUT and GND (output stabilization). These must be placed as close as possible to their respective pins. The SENSE pin must be connected directly to the load side of the output capacitor to achieve specified load regulation. Omitting or misplacing these capacitors can cause oscillation or degraded transient response.

How does the SENSE pin improve regulation in the NCP4687DH12T1G?

The SENSE pin in the NCP4687DH12T1G enables remote voltage sensing at the load, bypassing voltage drop across PCB traces between the regulator and load. This reduces load regulation error from up to 55 mV (without SENSE) to ≤20 mV over 1–500 mA, ensuring the actual load receives 1.2 V ±0.8%. It is essential for applications with long or narrow power traces, such as industrial sensor nodes or multi-layer PCBs with distributed power domains.

What is the purpose of the auto-discharge NMOS in the NCP4687DH12T1G?

The auto-discharge NMOS in the NCP4687DH12T1G activates when the CE pin is driven low, connecting VOUT to GND through a 60 Ω RDS(on) path. This rapidly discharges output capacitance - e.g., a 1 µF cap drops from 1.2 V to <100 mV in under 100 µs. This feature prevents unintended device wake-up or latch-up during system power sequencing, meeting functional safety requirements in automotive navigation and medical auxiliary supplies.

Is the NCP4687DH12T1G pin-compatible with other variants in the NCP4687 family?

Yes, all NCP4687 variants - including NCP4687DH12T1G (1.2 V, SOT-89-5), NCP4687DH25T1G (2.5 V), and NCP4687DMX18TCG (1.8 V, uDFN) - share identical pin functions (VIN, GND, CE, SENSE, VOUT) and electrical behavior. However, physical pinout differs across packages: SOT-89-5 uses pin 1=VIN, pin 4=SENSE; uDFN uses pin 6=VIN, pin 4=SENSE. Always verify mechanical layout against the target package's case drawing before PCB release.