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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

onsemi NCP691MN33T2G

Name: NCP691MN33T2G
Brand: onsemi
SKU: NCP691MN33T2G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: NCP691MN33T2G

Manufacturer:: onsemi

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 6-VDFN Exposed Pad

Datasheet:: NCP691MN33T2G.pdf

Description:: IC REG LINEAR 3.3V 1A 6DFN

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Product details

Overview

NCP691MN33T2G from onsemi is a fixed-output 3.3 V, 1 A CMOS low-dropout (LDO) voltage regulator in a 6-lead DFN3x3 package. It features ±2% output voltage tolerance over −40°C to 125°C, 190 mV dropout at 1 A (V_OUT = 2.5 V), active low enable (EN), and active output discharge - designed for space-constrained portable battery-powered systems such as FPGA and microprocessor core rails.

For engineers reviewing the NCP691MN33T2G datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed 1 A output current with low ground current (145 µA typical at 1 A), high PSRR (62 dB at 120 Hz), low noise (50 µV_rms), thermal shutdown (175°C), and compatibility with low-ESR ceramic capacitors without minimum ESR requirements.

Technical Context

The NCP691MN33T2G implements a PMOS pass transistor architecture with bandgap reference, internal current limiting, and thermal shutdown. Its active-low EN pin enables precise power sequencing control in multi-rail systems, while the SNS (sense) pin provides remote output voltage sensing for improved load regulation under PCB trace resistance.

It operates across 1.5 V to 6.0 V input range and delivers stable 3.3 V output with ±2% tolerance across full temperature and load conditions. The device supports operation down to −40°C and up to 125°C junction temperature, with integrated active discharge ensuring rapid output voltage decay upon disable - critical for safe power-down in DSP and PCI card applications.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.3 V with ±2% tolerance over −40°C to 125°C - ensures reliable core logic supply under thermal stress and aging.
Max Output Current	Guaranteed 1 A continuous - supports demanding digital loads like FPGA I/O banks and microprocessor cores.
Dropout Voltage	190 mV at 1 A (V_OUT = 2.5 V, T_J = 25°C); ≤250 mV across full temp/load - enables operation from 3.55 V input while maintaining regulation.
Ground Current	145 µA typical at 1 A load - minimizes quiescent power loss in battery-backed systems.
PSRR	62 dB at 120 Hz, 55 dB at 1 kHz - suppresses switching noise from upstream DC/DC converters feeding the LDO input.
Noise Voltage	50 µV_rms (200 Hz–100 kHz, no bypass capacitor) - eliminates need for external noise-reduction caps in sensitive analog/digital mixed-signal rails.
Enable Logic	Active-low EN with 0.4 V max low-level threshold - compatible with standard 1.8 V/3.3 V GPIOs for controlled power-up sequencing.

Pinout & Package

Package: DFN6 3×3 mm, 0.95 mm pitch, exposed thermal pad (Case 506AH, MN suffix). Pin 1 marked by notch or dot; pins 1 and 6 are parallel IN inputs requiring connection together for full 1 A capability.

Pin/Terminal	Circuit Role	Design Meaning
1, 6	IN	Dual input voltage pins - must be shorted externally to deliver full 1 A output current and reduce trace IR drop.
2	GND	Power ground tied to exposed EPAD - requires soldering to ≥64 mm² copper pour for thermal management (R_JA = 70°C/W).
3	EN	Active-low enable - pulled high internally; drives regulator ON when ≥0.9 V, OFF when ≤0.4 V; supports power sequencing.
4	OUT	Regulated 3.3 V output - connects directly to load; SNS pin must be shorted to this pin for fixed-voltage operation.
5	SNS	Sense input - tied directly to OUT in fixed versions; enables remote sensing for improved load regulation in high-current layouts.

Key Features

Feature	Design Value
Active Output Discharge	Internal NMOS discharges OUT to GND within microseconds after EN deactivation - prevents floating rail during power-down.
Enhanced ESD Protection	4 kV HBM / 200 V MM - exceeds JEDEC JESD22-A114/A115, enabling robust handling in automated assembly lines.
Ceramic Capacitor Stability	Stable with ≥1 µF ceramic output cap (no minimum ESR required) - reduces BOM cost and board area vs. tantalum alternatives.
Thermal Shutdown	175°C trip with 10°C hysteresis - protects against sustained overload or poor heatsinking without latch-up.
Low Noise Operation	50 µV_rms broadband noise without bypass cap - eliminates need for external RC filters in RF or ADC reference supplies.

Applications

Laptop Core Power Rail	FPGA I/O Bank Supply
Use Scenario: Powers 3.3 V I/O banks of Xilinx Artix-7 FPGA in ultra-thin notebook designs with tight thermal constraints. IC Role / Device Role / Timing Role: Primary post-regulation LDO delivering clean, sequenced 3.3 V to FPGA I/O pins with fast transient response. Use Value: Active discharge ensures safe I/O state retention during suspend-to-RAM; 190 mV dropout enables use of shared 3.55 V intermediate bus.	Use Scenario: Supplies configurable 3.3 V I/O banks in industrial PLC modules requiring long-term reliability and wide temperature operation. IC Role / Device Role / Timing Role: Fixed-output LDO providing stable voltage to FPGA I/O under varying load transients and ambient temperatures. Use Value: ±2% tolerance and 62 dB PSRR maintain signal integrity across 0–100 MHz I/O speeds; DFN3x3 footprint saves PCB area in dense control modules.
PCI Express Add-in Card	Hard Disk Drive Controller
Use Scenario: Delivers regulated 3.3 V to PCIe Gen3 retimer ICs and SerDes PHYs on telecom line cards with strict noise budgets. IC Role / Device Role / Timing Role: Low-noise, high-PSRR LDO decoupling upstream switching converter ripple before high-speed serial interfaces. Use Value: 50 µV_rms noise and 55 dB PSRR at 1 kHz prevent jitter accumulation in 8 GT/s data lanes; EN pin enables hot-plug compliance.	Use Scenario: Powers ARM-based disk controller SoC in 2.5-inch HDDs where battery backup and thermal margin are critical. IC Role / Device Role / Timing Role: Main 3.3 V supply for controller logic and interface buffers, operating continuously across −10°C to 70°C ambient. Use Value: 145 µA ground current extends backup runtime; thermal shutdown (175°C) prevents failure during sustained write operations.

Laptop Core Power Rail

FPGA I/O Bank Supply

Use Scenario: Powers 3.3 V I/O banks of Xilinx Artix-7 FPGA in ultra-thin notebook designs with tight thermal constraints.

IC Role / Device Role / Timing Role: Primary post-regulation LDO delivering clean, sequenced 3.3 V to FPGA I/O pins with fast transient response.

Use Value: Active discharge ensures safe I/O state retention during suspend-to-RAM; 190 mV dropout enables use of shared 3.55 V intermediate bus.

Use Scenario: Supplies configurable 3.3 V I/O banks in industrial PLC modules requiring long-term reliability and wide temperature operation.

IC Role / Device Role / Timing Role: Fixed-output LDO providing stable voltage to FPGA I/O under varying load transients and ambient temperatures.

Use Value: ±2% tolerance and 62 dB PSRR maintain signal integrity across 0–100 MHz I/O speeds; DFN3x3 footprint saves PCB area in dense control modules.

PCI Express Add-in Card

Hard Disk Drive Controller

Use Scenario: Delivers regulated 3.3 V to PCIe Gen3 retimer ICs and SerDes PHYs on telecom line cards with strict noise budgets.

IC Role / Device Role / Timing Role: Low-noise, high-PSRR LDO decoupling upstream switching converter ripple before high-speed serial interfaces.

Use Value: 50 µV_rms noise and 55 dB PSRR at 1 kHz prevent jitter accumulation in 8 GT/s data lanes; EN pin enables hot-plug compliance.

Use Scenario: Powers ARM-based disk controller SoC in 2.5-inch HDDs where battery backup and thermal margin are critical.

IC Role / Device Role / Timing Role: Main 3.3 V supply for controller logic and interface buffers, operating continuously across −10°C to 70°C ambient.

Use Value: 145 µA ground current extends backup runtime; thermal shutdown (175°C) prevents failure during sustained write operations.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
NCP690MN33T2G	Same 3.3 V fixed output, but lacks EN pin (pin 3 = N/C); no enable control or active discharge.	Suitable only for always-on rails; cannot support power sequencing or fast discharge requirements.	Select when enable functionality is unnecessary and lowest BOM cost is prioritized.
NCP692MN33T2G	Identical specs except EN pin is active-high (0.9 V threshold), not active-low.	Requires inverted enable signal or level-shifting in existing active-low control architectures.	Choose only if system GPIOs are active-high or if redesign accommodates polarity change.

Compared with NCP690MN33T2G and NCP692MN33T2G, the NCP691MN33T2G uniquely combines active-low enable with active output discharge - enabling precise power-down control and safe I/O state management in multi-rail embedded systems without external circuitry.

Availability

NCP691MN33T2G is available at Aetrix Electronics and suitable for laptop power subsystems, FPGA carrier boards, PCIe add-in cards, and hard disk drive controllers requiring stable component supply, automotive-grade reliability, and long-lifecycle support.

Supply support for NCP691MN33T2G 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, sensor, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.

The NCP691MN33T2G belongs to onsemi's NCP69x CMOS LDO family, engineered for portable and space-constrained battery-powered applications demanding high PSRR, low noise, and robust thermal protection.

FAQ

What is the maximum input voltage rating for the NCP691MN33T2G?

The NCP691MN33T2G has an absolute maximum input voltage (V_IN) of 6.5 V. However, its recommended operating input range is 1.5 V to 6.0 V. Exceeding 6.5 V risks permanent damage per Absolute Maximum Ratings (Table 3). For reliable 3.3 V output, minimum input is V_OUT + V_DO ≈ 3.55 V at 1 A load.

Does the NCP691MN33T2G require an external bypass capacitor for noise reduction?

No, the NCP691MN33T2G does not require an external bypass capacitor for noise reduction. Its typical output noise is 50 µV_rms (200 Hz–100 kHz) without any bypass cap, as confirmed in Table 6 and Applications Information section. This eliminates added cost, board area, and startup delay associated with traditional low-noise LDOs.

How is the enable function implemented on the NCP691MN33T2G?

The NCP691MN33T2G features an active-low enable (EN) pin (Pin 3). The regulator turns ON when EN ≥ 0.9 V and OFF when EN ≤ 0.4 V. When unused, EN must be tied to VIN to ensure continuous operation. Its enable input current is ≤250 nA, minimizing control circuit loading - a key detail specified in Table 6 under "Enable Input Current (Enable Active Low)".

What thermal performance can be expected from the NCP691MN33T2G in a standard PCB layout?

With the NCP691MN33T2G mounted on FR4 with 64 mm² copper area, its junction-to-ambient thermal resistance (R_JA) is 70°C/W (Table 4). At 1 A load with 3.55 V input, power dissipation is ~225 mW, resulting in ~16°C junction rise above ambient - well within the −40°C to 125°C operating range. Larger copper pours further reduce thermal resistance.

Is the NCP691MN33T2G suitable for automotive applications?

The NCP691MN33T2G is not AEC-Q100 qualified. For automotive use, onsemi offers the pin-compatible NCV8690MN33T2G (NCV prefix), which is AEC-Q100 qualified and PPAP capable. The NCP691MN33T2G is intended for industrial, computing, and consumer applications where extended temperature range (−40°C to 125°C) is required but formal automotive qualification is not mandated.

NCP691MN33T2G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: 6-VDFN Exposed Pad

Packaging:: Tape & Reel (TR)

Product Status:: Active

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 6V

Voltage - Output (Min/Fixed):: 3.3V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.25V @ 1A

Current - Output:: 1A

Current - Quiescent (Iq):: 200 µA

Current - Supply (Max):: 240 µA

PSRR:: -

Control Features:: Enable

Protection Features:: Over Temperature, Short Circuit

Operating Temperature:: -40°C ~ 85°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 6-DFN (3x3)

NCP691MN33T2G FAQ

1.How can I place an order for NCP691MN33T2G through Aetrix?

Please submit a Request for Quotation (RFQ) for NCP691MN33T2G on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for NCP691MN33T2G reliable?

The price and inventory of NCP691MN33T2G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP691MN33T2G is usually 5 days.

3.What payment methods are accepted for NCP691MN33T2G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP691MN33T2G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for NCP691MN33T2G?

NCP691MN33T2G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your NCP691MN33T2G order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for NCP691MN33T2G?

For technical support, including NCP691MN33T2G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP691MN33T2G requirements.

6.How does Aetrix verify that NCP691MN33T2G is sourced from the original manufacturer or authorized distributors?

All NCP691MN33T2G products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that NCP691MN33T2G meets industry standards.

7.What is the process for return or replacement of NCP691MN33T2G?

All NCP691MN33T2G units undergo pre-shipment inspection (PSI). If there is an issue with NCP691MN33T2G, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The NCP691MN33T2G part is unused and in its original packaging.

Return procedure for NCP691MN33T2G:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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