onsemi NCP694D33HT1G

Overview

NCP694D33HT1G from onsemi is a 3.3 V fixed-output, 1 A CMOS low-dropout linear voltage regulator in SOT-89-5 package, featuring −3 mV load regulation at 1 A, 0.18 V dropout at 300 mA, and integrated auto-discharge function for rapid output discharge during shutdown. It serves as a primary power rail regulator in portable battery-powered systems requiring stable low-noise 3.3 V supply under high-current transient loads.

For engineers reviewing the NCP694D33HT1G datasheet, pinout, applications, or equivalent options, key selection criteria include ultra-low dropout performance at 1 A, enable-controlled standby mode with 0.1–1.0 µA quiescent current, thermal shutdown (150°C), and Pb-free SOT-89-5 packaging compatible with standard reflow profiles.

Technical Context

The NCP694D33HT1G employs a PMOS pass transistor architecture enabling sub-200 mV dropout at 300 mA and 0.18 V typical dropout at full 1 A load. Its internal error amplifier and precision 1.0 V reference deliver ±2% output voltage accuracy over temperature and line/load variations.

It integrates CE-controlled enable logic with 0–0.4 V logic-low disable threshold and 1–6 V logic-high turn-on threshold, plus an auto-discharge circuit active only in D-version devices that rapidly discharges VOUT when CE is pulled low-critical for system-level power sequencing and fast reset recovery.

Key Specifications

Pinout & Package

SOT-89-5 package (Case 528AB), 5-pin surface-mount with exposed thermal pad (not electrically connected). Pin 1 = ADJ/NC (no connection for fixed-output NCP694D33HT1G); Pin 2 = GND; Pin 3 = CE; Pin 4 = VIN; Pin 5 = VOUT.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1703T-3302E/MB and TLS850F3TAV50, the NCP694D33HT1G uniquely balances 1 A output, ultra-low dropout, and integrated auto-discharge in a compact SOT-89-5 footprint-making it optimal for space-constrained, battery-sensitive portable electronics where precise power sequencing is required.

Availability

NCP694D33HT1G is available at Aetrix Electronics and suitable for portable medical sensors, industrial handheld scanners, wearable fitness trackers, and smart home sensor hubs requiring stable component supply with guaranteed long-term manufacturability.

Supply support for NCP694D33HT1G 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, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The NCP694 series targets portable battery-powered applications demanding high output current, ultra-low dropout, and intelligent enable control - designed specifically for next-generation wearables, medical sensors, and IoT edge devices.

FAQ

What is the maximum input voltage rating for the NCP694D33HT1G?

The NCP694D33HT1G has an absolute maximum input voltage rating of 6.5 V. The recommended operating input voltage range is 1.4 V to 6.0 V. Exceeding 6.5 V may cause permanent damage. For reliable 3.3 V output regulation, VIN must remain ≥ (3.3 V + dropout voltage), i.e., ≥3.48 V at 300 mA and ≥3.62 V at 1 A load.

Does the NCP694D33HT1G require external capacitors, and what values are recommended?

Yes, the NCP694D33HT1G requires both input and output capacitors. A minimum 4.7 µF ceramic capacitor is recommended for CIN, placed as close as possible to VIN and GND pins. For COUT, a minimum 4.7 µF ceramic capacitor with ESR <100 mΩ is required; larger values improve transient response and noise rejection. Tantalum capacitors may be used but require careful ESR selection to avoid oscillation.

How does the auto-discharge feature work on the NCP694D33HT1G?

The auto-discharge feature is exclusive to D-version regulators like the NCP694D33HT1G. When the CE pin is driven low, an internal NMOS transistor connects VOUT to GND, actively discharging the output capacitance. This ensures rapid VOUT collapse - critical for power sequencing, reset timing, and eliminating residual voltage in battery-powered systems during deep sleep.

What is the thermal performance of the NCP694D33HT1G in SOT-89-5 package?

In the SOT-89-5 package, the NCP694D33HT1G has a junction-to-ambient thermal resistance (R_JA) of 111°C/W under standard test conditions (1 oz copper, 100 mm² pad). With 1 A load and 3.6 V input (0.3 V dropout → 0.3 W dissipation), junction temperature rise is ~33°C above ambient - well within the +150°C max rating. Adequate PCB copper area is essential for sustained 1 A operation.

Is the NCP694D33HT1G pin-compatible with other versions in the NCP694 family?

Yes, all SOT-89-5 packaged NCP694 variants (e.g., NCP694D08HT1G, NCP694H33HT1G) share identical pinout and footprint. However, functional differences exist: D-versions include auto-discharge; H-versions do not. Enable logic thresholds and thermal behavior are consistent across versions, but output voltage and internal feedback resistors differ per variant.