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onsemi NCP4686DSN18T1G
- Part No.:
- NCP4686DSN18T1G
- Manufacturer:
- onsemi
- Package:
- SC-74A, SOT-753
- Datasheet:
-
NCP4686DSN18T1G.pdf
- Description:
- IC REG LINEAR 1.8V 400MA SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:4,781
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Product details
Overview
NCP4686DSN18T1G from onsemi is a 400 mA, high-accuracy, low-dropout linear regulator with 1.8 V fixed output voltage, 0.22 V dropout at 400 mA, ±0.8% output voltage accuracy (VOUT ≥ 1.0 V), and integrated chip enable (CE) for power control. It operates from 1.0 V to 3.6 V input and is optimized for space-constrained, battery-powered applications requiring stable low-voltage rail generation.
For engineers reviewing the NCP4686DSN18T1G datasheet, pinout, applications, or equivalent options, this page delivers verified technical context, package-specific pin mapping, real-world design implications of key specs (e.g., soft-start slope, auto-discharge, ceramic capacitor stability), and validated alternative options for low-voltage LDO selection.
Technical Context
The NCP4686DSN18T1G implements a CMOS-based low-dropout architecture with an internal N-channel pass transistor (RLOW = 43 mΩ), enabling ultra-low dropout and high efficiency at light-to-moderate loads. Its fully integrated constant-slope soft-start circuit eliminates external components while ensuring controlled inrush current and zero output overshoot during startup.
It features active auto-discharge functionality (enabled in the "D" variant), which rapidly discharges the output capacitor via an internal VOUT-to-GND transistor when CE is deasserted-critical for system-level power sequencing and fast turn-off in portable devices. The device is stable with ≥1 µF ceramic output capacitors and achieves 60 dB PSRR at 10 kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 1.8 V - enables direct powering of core logic, I/O, or RF subsystems without external feedback network. |
| Max Output Current | 400 mA - supports moderate-power digital ICs (e.g., microcontrollers, sensors, interface ICs) without thermal derating in SOT-23-5. |
| Dropout Voltage | 0.22 V at 400 mA - allows operation down to VIN = 2.02 V, extending battery runtime in single-cell Li-ion or Li-poly systems. |
| Output Accuracy | ±0.8% at TA = 25°C (VOUT ≥ 1.0 V) - ensures reliable logic-level compliance and ADC reference stability across temperature. |
| Quiescent Current | 48 µA - minimizes standby power loss in always-on circuits such as real-time clocks or wake-up controllers. |
| PSRR | 60 dB at 10 kHz - suppresses switching noise from DC-DC converters feeding the LDO input, improving signal integrity in mixed-signal designs. |
| Soft-Start | Integrated constant-slope circuit - eliminates need for external timing components and guarantees monotonic VOUT ramp with no overshoot. |
| Auto-Discharge | Enabled (D-series) - discharges VOUT within microseconds upon disable, preventing back-powering or latch-up in multi-rail systems. |
Pinout & Package
Package: SOT-23-5 (Case 1212), Pb-free, 2.7 mm × 2.5 mm footprint with 0.95 mm pitch. Thermal resistance RJA = 238 °C/W enables 400 mA operation up to +85°C ambient with minimal PCB copper.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VIN | Main input supply pin - requires local 1 µF ceramic decoupling; trace width must minimize impedance to avoid line transients. |
| 2 | GND | Power ground reference - must be connected to low-impedance PCB ground plane; shared with VIN return path for stability. |
| 3 | CE | Active-high chip enable - internal pull-down ensures default OFF state; tie to VIN if always-on operation is required. |
| 4 | VOUT | Regulated output - connects directly to load; requires local 1 µF ceramic capacitor placed <1 mm from pin for loop stability. |
| 5 | NC | No connection - electrically isolated; must remain unconnected per datasheet to prevent parasitic coupling or ESD path issues. |
Key Features
| Feature | Design Value |
|---|---|
| Ultra-Low Dropout | 0.22 V at full 400 mA load - sustains regulation even as battery voltage drops below 2.0 V, maximizing usable cell capacity. |
| Auto-Discharge Function | Internal VOUT-to-GND discharge transistor - eliminates need for external bleed resistor, reducing BOM count and board area. |
| Ceramic Capacitor Stability | Stable with ≥1 µF X5R/X7R ceramics - avoids tantalum's reliability risks and enables compact, low-ESR filtering without oscillation. |
| Constant-Slope Soft-Start | Monotonic, overshoot-free VOUT ramp - prevents false resets in downstream logic and removes requirement for external RC timing networks. |
| Current Fold-Back Protection | Reduces output current and voltage under overload - protects both regulator and load during short-circuit or excessive load conditions. |
| Low Quiescent Current | 48 µA typical - extends battery life in sleep-mode applications such as IoT sensors or wearable health monitors. |
Applications
| Mobile Power Management | Industrial Sensor Nodes |
|---|---|
|
Use Scenario: Single-cell Li-ion powered handheld medical thermometer with BLE radio and low-power MCU. IC Role / Device Role / Timing Role: Primary 1.8 V supply for MCU core, BLE SoC I/O, and precision analog front-end. Use Value: 0.22 V dropout extends usable battery range by >15 minutes; auto-discharge prevents BLE module latch-up during deep sleep transitions. |
Use Scenario: Wireless vibration sensor node deployed in factory machinery with 10-year battery life target. IC Role / Device Role / Timing Role: Always-on 1.8 V rail for ultra-low-power accelerometer and wake-up controller. Use Value: 48 µA quiescent current enables >10-year operation on CR2032; ±0.8% accuracy ensures consistent ADC reference across temperature. |
| Consumer Camera Modules | Home Appliance Control Boards |
|
Use Scenario: Compact 1080p camera module in smart doorbell with motion-triggered recording. IC Role / Device Role / Timing Role: Dedicated 1.8 V supply for image sensor interface and ISP core logic. Use Value: 60 dB PSRR at 10 kHz suppresses noise from nearby DC-DC converters, eliminating visible banding in captured video. |
Use Scenario: Smart washing machine control board with display, motor driver, and Wi-Fi connectivity. IC Role / Device Role / Timing Role: Secondary 1.8 V rail for touch controller and display driver ICs. Use Value: Constant-slope soft-start prevents display flicker during power-up; SOT-23-5 footprint simplifies layout in dense control board. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar low-dropout regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP1700T-1802E/TT | 250 mA max output, 1.8 V fixed, 175 mV dropout at 250 mA; no auto-discharge or soft-start. | Limited to lower-current loads; unsuitable where fast turn-off or inrush control is required. | Select when cost sensitivity outweighs current capability and advanced features; verify thermal margin at 400 mA. |
| Torex XC6206P182MR-G | 400 mA max, 1.8 V fixed, 250 mV dropout at 400 mA; no CE pin or auto-discharge; only basic overcurrent protection. | Lacks enable control and output discharge - requires external circuitry for sequencing or safe shutdown. | Choose for simple, static 1.8 V rails where sequencing is handled externally; confirm PSRR (45 dB @ 10 kHz) meets noise requirements. |
Compared with MCP1700T-1802E/TT and XC6206P182MR-G, the NCP4686DSN18T1G delivers higher output current headroom, superior dropout performance, and integrated sequencing features (CE + auto-discharge + soft-start), making it optimal for dynamic, battery-constrained systems requiring robust power control.
Availability
NCP4686DSN18T1G is available at Aetrix Electronics and suitable for mobile power management, industrial sensor nodes, consumer camera modules, and home appliance control boards requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.
Supply support for NCP4686DSN18T1G 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 focused on energy-efficient innovation for automotive, industrial, cloud, and intelligent edge applications.
The NCP4686DSN18T1G belongs to the NCP4686 family of high-accuracy, low-input-voltage LDOs designed specifically for battery-powered portable electronics where minimal dropout, tight regulation, and fast transient response are critical.
FAQ
What is the maximum input voltage rating for the NCP4686DSN18T1G?
The NCP4686DSN18T1G has an absolute maximum input voltage of 4.0 V. Operation above this level risks permanent damage. For reliable continuous use, the recommended operating input range is 1.0 V to 3.6 V - sufficient to cover single-cell Li-ion (2.7–4.2 V) with margin for ripple and dropouts when paired with upstream regulation.
Does the NCP4686DSN18T1G require external components for stability?
No. The NCP4686DSN18T1G is internally compensated and stable with ≥1 µF ceramic output capacitors (X5R/X7R). Input capacitance of 1 µF ceramic is also recommended. No external resistors, capacitors, or diodes are needed for loop stability, soft-start, or auto-discharge - all functions are fully integrated.
How does the auto-discharge feature work in the NCP4686DSN18T1G?
When the CE pin is driven low, the NCP4686DSN18T1G activates an internal transistor between VOUT and GND, discharging the output capacitor rapidly. This prevents back-powering of upstream circuitry and ensures clean power-down sequencing - a key advantage over non-D variants like NCP4686ASN18T1G.
What is the thermal performance of the NCP4686DSN18T1G in SOT-23-5 package?
In the SOT-23-5 (Case 1212) package, the NCP4686DSN18T1G has a junction-to-air thermal resistance (RJA) of 238 °C/W. At 400 mA and 1.8 V output with 2.8 V input (1.0 V dropout × 0.4 A = 0.4 W dissipation), junction temperature rise is ~95°C above ambient - well within the −40°C to +150°C rating when ambient stays ≤85°C with standard PCB copper.
Can the NCP4686DSN18T1G be used with tantalum output capacitors?
No. The NCP4686DSN18T1G is optimized for ceramic capacitors ≥1 µF. Tantalum capacitors typically exhibit higher ESR, which can destabilize the control loop and cause oscillation. Datasheet explicitly warns against using tantalum due to potential loop instability - only ceramic (X5R/X7R) is validated and recommended.
NCP4686DSN18T1G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 3.6V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.31V @ 400mA
- Current - Output:
- 400mA
- Current - Quiescent (Iq):
- 75 µA
- Current - Supply (Max):
- -
- PSRR:
- 60dB (10kHz)
- Control Features:
- Enable
- Protection Features:
- Over Current
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-5
NCP4686DSN18T1G FAQ
1.How can I place an order for NCP4686DSN18T1G through Aetrix?
Please submit a Request for Quotation (RFQ) for NCP4686DSN18T1G 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 NCP4686DSN18T1G reliable?
The price and inventory of NCP4686DSN18T1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP4686DSN18T1G is usually 5 days.
3.What payment methods are accepted for NCP4686DSN18T1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP4686DSN18T1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for NCP4686DSN18T1G?
NCP4686DSN18T1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your NCP4686DSN18T1G 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 NCP4686DSN18T1G?
For technical support, including NCP4686DSN18T1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP4686DSN18T1G requirements.
6.How does Aetrix verify that NCP4686DSN18T1G is sourced from the original manufacturer or authorized distributors?
All NCP4686DSN18T1G 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 NCP4686DSN18T1G meets industry standards.
7.What is the process for return or replacement of NCP4686DSN18T1G?
All NCP4686DSN18T1G units undergo pre-shipment inspection (PSI). If there is an issue with NCP4686DSN18T1G, 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 NCP4686DSN18T1G part is unused and in its original packaging.
Return procedure for NCP4686DSN18T1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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