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onsemi NCP691MN18T2G
- Part No.:
- NCP691MN18T2G
- Manufacturer:
- onsemi
- Package:
- 6-VDFN Exposed Pad
- Datasheet:
-
NCP691MN18T2G.pdf
- Description:
- IC REG LINEAR 1.8V 1A 6DFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,841
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Product details
Overview
NCP691MN18T2G from onsemi is a fixed-output 1.8 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 (VOUT = 2.5 V), active low enable (EN), and active output discharge - designed for space-constrained, battery-powered systems such as portable FPGA and microprocessor boards.
For engineers reviewing the NCP691MN18T2G 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 µVrms), and thermal shutdown protection at 175°C.
Technical Context
The NCP691MN18T2G implements a PMOS pass transistor architecture with bandgap reference, internal current limiting, and thermal shutdown logic. Its fixed 1.8 V output is trimmed during production to ±2% tolerance across temperature and load, and it uses a dedicated SNS pin for remote output sensing to maintain regulation accuracy under PCB trace impedance.
It integrates an active-low enable input (EN) with 0.4 V low-level threshold and 0.9 V high-level threshold, plus active output discharge to rapidly pull down VOUT when disabled - critical for sequencing-sensitive digital loads. The device operates from 1.5 V to 6.0 V input and supports ceramic capacitors as small as 1 µF for stability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V ±2% over −40°C to 125°C - ensures stable core supply for 1.8 V I/O or logic rails without external feedback components. |
| Max Output Current | 1 A continuous - sufficient to power mid-complexity FPGAs, DSPs, or multi-core microcontrollers in portable designs. |
| Dropout Voltage | 190 mV at 1 A (VOUT = 2.5 V); ~240 mV typical at 1.8 V - enables operation from single-cell Li-ion (3.0 V min) or 3.3 V rails with margin. |
| Ground Current | 145 µA typical at 1 A load - minimizes quiescent power loss in always-on subsystems like real-time clocks or sensor interfaces. |
| PSRR | 62 dB at 120 Hz, 55 dB at 1 kHz - suppresses ripple from switching DC/DC converters upstream, preserving analog/RF signal integrity. |
| Noise Voltage | 50 µVrms (200 Hz–100 kHz) - eliminates need for external bypass capacitors in noise-sensitive applications like ADC references. |
| Enable Logic | Active-low EN with 0.4 V max low threshold - compatible with standard 1.8 V/3.3 V GPIOs and supports power sequencing control. |
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 for full 1 A capability; pin 2 is GND connected to EPAD for thermal dissipation.
| 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 minimize IR drop. |
| 2 | GND | Power ground tied to die and EPAD - soldering to ≥64 mm² copper improves thermal resistance from 169°C/W to 70°C/W. |
| 3 | EN | Active-low enable - pulled low ≤0.4 V to disable regulator; internally weak-pulled high if left floating (not recommended). |
| 4 | OUT | Regulated 1.8 V output - requires local 1 µF ceramic capacitor (min) placed adjacent to pin for stability. |
| 5 | SNS | Sense input - must be connected directly to OUT pin to compensate for PCB trace voltage drop and maintain ±2% accuracy. |
Key Features
| Feature | Design Value |
|---|---|
| Active Output Discharge | Internally discharges VOUT via NMOS switch when EN is low - prevents floating outputs and ensures clean power-down sequencing. |
| High PSRR at Low Frequency | 62 dB at 120 Hz - rejects ripple from AC/DC adapters or buck converter switching noise before it reaches sensitive analog circuitry. |
| Low Ground Current | 145 µA at full 1 A load - reduces system standby power, enabling >1-week battery life in always-on IoT edge nodes. |
| Thermal Shutdown + Hysteresis | Triggers at 175°C with 10°C hysteresis - protects against sustained overload while allowing recovery without manual reset. |
| ESD Robustness | 4 kV HBM, 200 V MM - withstands handling and board-level ESD events without latch-up or parameter shift. |
Applications
| Laptop Core Power Rail | FPGA I/O Bank Supply |
|---|---|
Use Scenario: Providing clean 1.8 V supply to DDR3L memory interface and transceivers in ultrabook platforms. IC Role / Device Role / Timing Role: Primary post-regulation LDO delivering stable voltage with fast transient response to handle burst data transfers. Use Value: 50 µVrms noise and 62 dB PSRR prevent bit errors in high-speed memory links operating up to 800 MT/s. |
Use Scenario: Powering configurable 1.8 V I/O banks on Xilinx Artix-7 or Intel Cyclone V FPGAs in portable test equipment. IC Role / Device Role / Timing Role: Fixed-output LDO with active discharge enabling precise power sequencing during FPGA configuration and reconfiguration. Use Value: Active-low EN and <100 ns turn-off delay allow synchronization with FPGA DONE pin for safe I/O state management. |
| Industrial Sensor Node MCU | PCIe Add-in Card Auxiliary Rail |
Use Scenario: Supplying 1.8 V to ARM Cortex-M4 microcontroller and precision ADC in battery-operated environmental monitors. IC Role / Device Role / Timing Role: Low-quiescent LDO maintaining regulation during deep-sleep modes while supporting wake-on-event fast startup. Use Value: 145 µA ground current at 1 A load extends 2000 mAh Li-ion battery life to >12 months in 1-minute sampling intervals. |
Use Scenario: Generating auxiliary 1.8 V rail for PCIe Gen3 SerDes termination and clock buffers on telecom line cards. IC Role / Device Role / Timing Role: High-PSRR LDO filtering noise from shared 3.3 V backplane supply to meet PCIe jitter specifications. Use Value: 55 dB PSRR at 1 kHz suppresses switching noise from adjacent DC/DC converters, ensuring <1 ps RMS jitter on reference clocks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TPS7A2018PDQNR | 1.8 V fixed, 1 A, 165 mV dropout at 1 A, but no SNS pin or active discharge; 65 µVrms noise. | Lacks remote sense and active discharge - unsuitable for long-trace or strict sequencing applications. | Choose when board layout allows direct OUT connection and sequencing is managed externally. |
| MCP1826T-1802E/DB | 1.8 V fixed, 1 A, 300 mV dropout at 1 A, no EN pin, ±2% tolerance, 40 µVrms noise. | Non-enable variant - cannot support dynamic power gating or hot-plug control. | Choose only for always-on, non-sequenced rails where lowest cost and noise are prioritized over control flexibility. |
Compared with TPS7A2018PDQNR and MCP1826T-1802E/DB, the NCP691MN18T2G uniquely combines remote sensing (SNS), active discharge, and active-low enable in a 1.8 V/1 A LDO - making it the only option among the three that guarantees ±2% regulation under PCB voltage drop and enables safe, controlled power-down of downstream logic.
Availability
NCP691MN18T2G is available at Aetrix Electronics and suitable for laptop power subsystems, FPGA I/O banks, industrial sensor node MCUs, and PCIe add-in card auxiliary rails requiring stable component supply, automotive-grade reliability, and long-term lifecycle support.
Supply support for NCP691MN18T2G 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 cloud infrastructure markets.
The NCP691MN18T2G belongs to the NCP69x LDO family, engineered for portable, battery-powered applications demanding ultra-low dropout, low noise, and high PSRR - with design focus on space-constrained computing and communications hardware.
FAQ
What is the maximum input voltage rating for the NCP691MN18T2G?
The NCP691MN18T2G has an absolute maximum input voltage of 6.5 V. However, its recommended operating input range is 1.5 V to 6.0 V. Operation above 6.0 V risks exceeding junction temperature limits or violating safe operating area constraints, especially at high output currents. Always refer to the thermal derating curves in the datasheet when operating near maximum ratings.
Does the NCP691MN18T2G require an external resistor divider for 1.8 V output?
No, the NCP691MN18T2G is a fixed-output LDO with factory-trimmed 1.8 V regulation - no external resistors are needed. The SNS pin must be connected directly to the OUT pin for accurate remote sensing, but no feedback network is required. This simplifies layout and eliminates resistor tolerance errors affecting output accuracy.
How does the active output discharge function work in the NCP691MN18T2G?
When the EN pin is driven low, the NCP691MN18T2G activates an internal NMOS discharge switch between OUT and GND. This rapidly pulls down the output voltage to near 0 V, preventing floating states or unintended logic transitions in downstream circuits. Discharge time depends on output capacitance but typically completes within microseconds for ≤10 µF loads.
Can the NCP691MN18T2G be used with ceramic output capacitors smaller than 1 µF?
No - the NCP691MN18T2G requires a minimum 1 µF ceramic output capacitor for stability, as confirmed in the Applications Information section of the datasheet. Using smaller values may cause oscillation or poor transient response. For optimal load transient performance, a 10 µF ceramic capacitor is recommended and placed as close as possible to the OUT and GND pins.
Is the NCP691MN18T2G qualified for automotive applications?
No - the NCP691MN18T2G is not AEC-Q100 qualified. For automotive use, select the NCV8690MN18T2G (same 1.8 V fixed output, AEC-Q100 Grade 1, −40°C to 125°C), which shares the same pinout and electrical characteristics but includes automotive-specific process controls and PPAP documentation support.
NCP691MN18T2G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- 6-VDFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 6V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.38V @ 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)
NCP691MN18T2G FAQ
1.How can I place an order for NCP691MN18T2G through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP691MN18T2G 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 NCP691MN18T2G reliable?
The price and inventory of NCP691MN18T2G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP691MN18T2G is usually 5 days.
3.What payment methods are accepted for NCP691MN18T2G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP691MN18T2G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP691MN18T2G?
NCP691MN18T2G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP691MN18T2G 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 NCP691MN18T2G?
For technical support, including NCP691MN18T2G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP691MN18T2G requirements.
6.How does Aetrix verify that NCP691MN18T2G is sourced from the original manufacturer or authorized distributors?
All NCP691MN18T2G 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 NCP691MN18T2G meets industry standards.
7.What is the process for return or replacement of NCP691MN18T2G?
All NCP691MN18T2G units undergo pre-shipment inspection (PSI). If there is an issue with NCP691MN18T2G, 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 NCP691MN18T2G part is unused and in its original packaging.
Return procedure for NCP691MN18T2G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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