onsemi NCP694D25HT1G

Overview

NCP694D25HT1G from onsemi is a 2.5 V fixed-output, 1 A CMOS low-dropout linear voltage regulator in SOT-89-5 package, featuring −3 mV load regulation at 1 A, 0.10 V typical dropout at 1 A, 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-voltage supply with fast enable control.

For engineers reviewing the NCP694D25HT1G datasheet, pinout, applications, or equivalent options, key selection criteria include its 2.5 V fixed output, ultra-low standby current (≤1.0 µA), built-in thermal shutdown, PMOS pass transistor architecture, and auto-discharge capability unique to the "D" version.

Technical Context

The NCP694D25HT1G employs a PMOS pass transistor enabling ultra-low dropout voltage and eliminating reverse-current flow without external diode. Its internal error amplifier compares feedback against a 1.0 V reference to regulate output, while the CE pin controls enable/disable with logic-high active operation and sub-µA standby current.

Unlike standard LDOs, the "D" variant integrates an auto-discharge transistor tied to the CE pin-activating when CE is pulled low to rapidly discharge the output capacitor. This supports clean power sequencing in handheld instruments and camcorders where controlled ramp-down is critical.

Key Specifications

Pinout & Package

Package: SOT-89-5 (Case 528AB), surface-mount, thermally enhanced 5-pin plastic package with exposed tab for improved heat dissipation (R_JA = 111°C/W on 100 mm² 1 oz Cu).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MCP1700-2502E/TO and XC6206P252MR-G, the NCP694D25HT1G uniquely delivers 1 A output with integrated CE-controlled auto-discharge and 0.10 V dropout-enabling compact, reliable power sequencing in portable instrumentation without external components.

Availability

NCP694D25HT1G is available at Aetrix Electronics and suitable for portable medical sensors, digital camcorders, handheld test meters, and IoT edge node controllers requiring stable component supply, long-lifecycle support, and Pb-free compliance.

Supply support for NCP694D25HT1G 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 sensing solutions for automotive, industrial, and portable electronics.

The NCP694 series was designed specifically for high-current, ultra-low-dropout regulation in space-constrained battery-powered devices-emphasizing thermal robustness, fast enable response, and integrated power sequencing features like auto-discharge.

FAQ

What is the minimum input voltage required for NCP694D25HT1G to maintain regulation at 1 A output?

The NCP694D25HT1G requires Vin ≥ 2.6 V to sustain 2.5 V output at 1 A load, based on its 0.10 V typical dropout voltage. At lower input voltages (e.g., 2.55 V), output may drop below specification due to increased dropout under temperature or process variation. Operation below 1.4 V input is prohibited per absolute maximum ratings.

Does NCP694D25HT1G require an external resistor network to set its output voltage?

No, the NCP694D25HT1G is a fixed-output device with internally trimmed 2.5 V regulation-no external resistors are needed. Pin 1 (ADJ/NC) is not connected internally and must remain unconnected or grounded; using it as an adjust pin would indicate a different part number (e.g., NCP694DADJHT1G).

How does the auto-discharge function operate in NCP694D25HT1G during shutdown?

When the CE pin is driven low, the NCP694D25HT1G disables regulation and activates an internal NMOS transistor between Vout and GND. This discharges the output capacitor rapidly-typically reducing Vout to <100 mV within 100 µs-ensuring clean power-down for downstream logic and preventing latch-up in connected ICs.

Can NCP694D25HT1G be used with ceramic output capacitors, and what is the minimum recommended value?

Yes, NCP694D25HT1G is stable with ceramic output capacitors. The datasheet specifies a minimum of 4.7 µF, and larger values (e.g., 10–22 µF) improve load transient response and PSRR. Avoid high-ESR tantalum capacitors, which may cause oscillation due to degraded phase margin.

What thermal derating applies to NCP694D25HT1G in a standard SOT-89-5 layout on 1 oz copper?

With 100 mm² copper area, the NCP694D25HT1G has R_JA = 111°C/W. At ambient 25°C and 1 A load with 0.10 V dropout (0.1 W dissipation), junction temperature rises ~11°C-well within the 150°C limit. For continuous 1 A at 85°C ambient, power dissipation must stay ≤0.59 W (i.e., dropout ≤0.59 V), requiring Vin ≤3.09 V.