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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Supervisors

onsemi NCP803SN308T1G

Name: NCP803SN308T1G
Brand: onsemi
SKU: NCP803SN308T1G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: NCP803SN308T1G

Manufacturer:: onsemi

Category:: Supervisors

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: NCP803SN308T1G.pdf

Description:: IC SUPERVISOR 1 CHANNEL SOT23-3

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Product details

Overview

NCP803SN308T1G from onsemi is a 3-pin SOT-23 microprocessor reset supervisor IC designed to monitor V_CC in digital systems and assert an open-drain active-low RESET signal when supply voltage falls below 3.08 V. It features factory-trimmed 140–460 ms power-on reset timeout, operates from 1.2 V to 5.5 V, draws only 0.5 µA at 3.3 V, and supports industrial temperature range (−40°C to +105°C). It is used in embedded systems requiring reliable brownout detection and glitch-immune reset generation.

For engineers reviewing the NCP803SN308T1G datasheet, pinout, applications, or equivalent options, key selection criteria include precise 3.08 V threshold accuracy (±2% over temperature), guaranteed RESET validity down to V_CC = 1.0 V, transient immunity up to 100 mV/5 µs, no external components required, and Pb-free SOT-23 package compatibility with automated assembly.

Technical Context

The NCP803SN308T1G integrates a precision voltage detector, oscillator, and digital timeout counter to generate a deterministic reset pulse after V_CC rises above 3.08 V. Its internal comparator uses trimmed reference circuitry to maintain ±2% threshold accuracy across −40°C to +105°C, with <30 ppm/°C temperature coefficient.

It employs an open-drain output stage capable of sinking 1.2 mA at V_TH = 2.1–4.0 V, enabling flexible pull-up configuration to separate logic rails. The device rejects fast transients via internal filtering - negative excursions ≤100 mV lasting ≤5 µs do not trigger reset assertion.

Key Specifications

Parameter	Value and Actual Design Meaning
Reset Threshold	3.08 V ±2% (min 3.04 V, max 3.11 V at +25°C); ensures reliable detection of 3.3 V supply sags before system instability.
Reset Timeout	140–460 ms (guaranteed minimum); provides sufficient hold time for microprocessor initialization and clock stabilization.
Supply Current	0.5 µA typical at V_CC = 3.3 V, +25°C; enables multi-year battery life in low-power IoT sensors and portable devices.
Operating Voltage Range	1.2 V to 5.5 V; supports direct monitoring of 1.8 V, 2.5 V, 3.3 V, and 5.0 V rails without level-shifting.
Temperature Range	−40°C to +105°C; qualified for industrial and extended-temperature embedded control applications.
V_CC Transient Immunity	Rejects ≤100 mV negative glitches lasting ≤5 µs; prevents spurious resets during switching noise or ESD events.
RESET Output Type	Open-drain active-low; allows wired-OR configuration and interface to multiple voltage domains via external pull-up.

Pinout & Package

SOT-23-3 (TO-236) package, 1.3 mm × 2.9 mm × 1.0 mm body, Pb-free, RoHS compliant.

Pin/Terminal	Circuit Role	Design Meaning
1	GND	Ground reference for internal voltage reference and comparator; must be connected to system ground plane for accurate threshold sensing.
2	RESET	Open-drain active-low reset output; requires external pull-up resistor (typically 10–100 kΩ) to host logic rail; sinks up to 1.2 mA.
3	V_CC	Power supply input; bypass capacitor (100 nF ceramic) recommended between V_CC and GND for noise immunity and transient rejection.

Key Features

Feature	Design Value
Precision 3.08 V threshold	Factory-trimmed to ±2% tolerance over full temperature range; eliminates need for external resistor divider calibration.
No external components	Self-contained reset generation - no capacitors, resistors, or additional ICs required for basic operation.
Ultra-low quiescent current	0.5 µA at 3.3 V enables use in energy-harvesting and coin-cell-powered systems without compromising battery life.
V_CC transient immunity	Internal filtering rejects ≤100 mV/5 µs supply noise; avoids false resets in electrically noisy environments like motor drives or SMPS proximity.
Valid RESET down to 1.0 V	Output remains actively driven until V_CC drops to 1.0 V; ensures clean deassertion sequence during controlled power-down.

Applications

Industrial PLC Controller	Smart Meter Power Monitoring
Use Scenario: Monitors 3.3 V microcontroller supply in programmable logic controller exposed to wide ambient temperatures and EMI from relay switching. IC Role / Device Role / Timing Role: Voltage supervisor providing power-on reset and brownout protection; asserts RESET until V_CC stabilizes above 3.08 V and holds for ≥140 ms. Use Value: Prevents firmware corruption during line sags and ensures deterministic boot sequence despite 100 mV transients induced by contactor coil discharge.	Use Scenario: Embedded metering SoC powered from switched-mode AC/DC converter with variable load-induced ripple. IC Role / Device Role / Timing Role: Dedicated reset generator detecting 3.3 V rail collapse; open-drain output pulled to 1.8 V logic domain for low-voltage MCU interface. Use Value: Guarantees reset assertion during >100 ms undervoltage events while rejecting high-frequency switching noise (<5 µs) from DC-DC regulator.
Wireless Sensor Node	Medical Diagnostic Handheld
Use Scenario: Battery-powered environmental sensor using coin cell and ultra-low-power MCU, requiring multi-year operation. IC Role / Device Role / Timing Role: Low-current reset supervisor monitoring 3.3 V LDO output; triggers hard reset if battery voltage decays below 3.08 V. Use Value: 0.5 µA supply current extends shelf life; 140–460 ms timeout accommodates slow LDO startup and crystal oscillator stabilization.	Use Scenario: Portable ultrasound device with dual-voltage rails (3.3 V core, 1.8 V I/O) and strict safety-critical boot integrity requirements. IC Role / Device Role / Timing Role: Primary reset source asserting active-low signal to ARM Cortex-M7; RESET valid down to V_CC = 1.0 V ensures safe shutdown sequencing. Use Value: Factory-trimmed 3.08 V threshold matches nominal 3.3 V rail tolerance; −40°C to +105°C rating covers clinical operating environment extremes.

Industrial PLC Controller

Smart Meter Power Monitoring

Use Scenario: Monitors 3.3 V microcontroller supply in programmable logic controller exposed to wide ambient temperatures and EMI from relay switching.

IC Role / Device Role / Timing Role: Voltage supervisor providing power-on reset and brownout protection; asserts RESET until V_CC stabilizes above 3.08 V and holds for ≥140 ms.

Use Value: Prevents firmware corruption during line sags and ensures deterministic boot sequence despite 100 mV transients induced by contactor coil discharge.

Use Scenario: Embedded metering SoC powered from switched-mode AC/DC converter with variable load-induced ripple.

IC Role / Device Role / Timing Role: Dedicated reset generator detecting 3.3 V rail collapse; open-drain output pulled to 1.8 V logic domain for low-voltage MCU interface.

Use Value: Guarantees reset assertion during >100 ms undervoltage events while rejecting high-frequency switching noise (<5 µs) from DC-DC regulator.

Wireless Sensor Node

Medical Diagnostic Handheld

Use Scenario: Battery-powered environmental sensor using coin cell and ultra-low-power MCU, requiring multi-year operation.

IC Role / Device Role / Timing Role: Low-current reset supervisor monitoring 3.3 V LDO output; triggers hard reset if battery voltage decays below 3.08 V.

Use Value: 0.5 µA supply current extends shelf life; 140–460 ms timeout accommodates slow LDO startup and crystal oscillator stabilization.

Use Scenario: Portable ultrasound device with dual-voltage rails (3.3 V core, 1.8 V I/O) and strict safety-critical boot integrity requirements.

IC Role / Device Role / Timing Role: Primary reset source asserting active-low signal to ARM Cortex-M7; RESET valid down to V_CC = 1.0 V ensures safe shutdown sequencing.

Use Value: Factory-trimmed 3.08 V threshold matches nominal 3.3 V rail tolerance; −40°C to +105°C rating covers clinical operating environment extremes.

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor reset monitoring applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX803SQ308T1G	Same 3.08 V threshold and 140–460 ms timeout, but SC-70-3 package (smaller footprint, different thermal resistance).	Preferred where board space is constrained and thermal dissipation is less critical than in SOT-23 layouts.	Select MAX803SQ308T1G only if SC-70 package compatibility and existing layout constraints justify requalification.
NCP803SN308D2T1G	Identical SOT-23-3 package and 3.08 V threshold, but shorter 20–66 ms timeout variant.	Suitable for fast-booting MCUs with minimal initialization delay requirements, not for systems needing longer stabilization windows.	Choose NCP803SN308D2T1G only when application timing budget permits sub-100 ms reset hold time.

Compared with NCP803SN308T1G, MAX803SQ308T1G offers identical electrical behavior in a smaller SC-70 package with higher thermal resistance (314°C/W vs. 301°C/W), while NCP803SN308D2T1G trades guaranteed 140 ms minimum timeout for faster reset release - both require validation against specific PCB layout, thermal profile, and MCU boot timing.

Availability

NCP803SN308T1G is available at Aetrix Electronics and suitable for industrial automation, smart metering, and wireless sensor node designs requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for NCP803SN308T1G 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 manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.

The NCP803SN308T1G belongs to the NCP803 Series of precision reset supervisors, engineered for cost-sensitive, low-power embedded systems requiring robust power-on and brownout reset functionality without external components.

FAQ

What is the exact reset voltage threshold of the NCP803SN308T1G?

The NCP803SN308T1G has a nominal reset threshold of 3.08 V, with guaranteed min/max values of 3.04 V and 3.11 V at +25°C. Over the full operating temperature range (−40°C to +105°C), the threshold remains within ±2% of 3.08 V, supported by a temperature coefficient of ≤30 ppm/°C per the datasheet.

Does the NCP803SN308T1G require external components to function?

No, the NCP803SN308T1G requires no external components for basic reset supervision. A 100 nF bypass capacitor between V_CC and GND is recommended for optimal transient immunity, and an external pull-up resistor on the RESET pin is mandatory due to its open-drain output architecture - but no timing resistors or dividers are needed.

What is the guaranteed minimum reset timeout duration for the NCP803SN308T1G?

The NCP803SN308T1G guarantees a minimum reset timeout of 140 ms after V_CC rises above the 3.08 V threshold. The maximum timeout is 460 ms, and this range is factory-trimmed - no user adjustment is possible. This ensures sufficient hold time for most 32-bit microcontrollers to initialize clocks and peripherals.

Can the NCP803SN308T1G operate with a 1.8 V supply rail?

Yes, the NCP803SN308T1G operates from 1.2 V to 5.5 V, so it can monitor a 1.8 V rail - but its fixed 3.08 V threshold means it will not assert reset unless that rail exceeds 3.08 V. For 1.8 V systems, a lower-threshold variant like NCP803SN160T1G (1.60 V) is appropriate; NCP803SN308T1G is intended for 3.3 V applications.

Is the NCP803SN308T1G pin-compatible with other parts in the NCP803 series?

Yes, all NCP803 variants in SOT-23-3 package - including NCP803SN308T1G, NCP803SN293T1G, and NCP803SN463T1G - share identical pinout (Pin 1: GND, Pin 2: RESET, Pin 3: V_CC) and footprint. Threshold voltage and timeout duration differ by part number, but PCB layout and soldering process remain unchanged across the family.

NCP803SN308T1G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Programmable:: Not Verified

Type:: Simple Reset/Power-On Reset

Number of Voltages Monitored:: 1

Voltage - Threshold:: 3.08V

Output:: Open Drain or Open Collector

Reset:: Active Low

Reset Timeout:: 140ms Minimum

Operating Temperature:: -40°C ~ 105°C (TJ)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3 (TO-236)

NCP803SN308T1G FAQ

1.How can I place an order for NCP803SN308T1G through Aetrix?

Please submit a Request for Quotation (RFQ) for NCP803SN308T1G 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 NCP803SN308T1G reliable?

The price and inventory of NCP803SN308T1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for NCP803SN308T1G is usually 5 days.

3.What payment methods are accepted for NCP803SN308T1G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for NCP803SN308T1G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for NCP803SN308T1G?

NCP803SN308T1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your NCP803SN308T1G 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 NCP803SN308T1G?

For technical support, including NCP803SN308T1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your NCP803SN308T1G requirements.

6.How does Aetrix verify that NCP803SN308T1G is sourced from the original manufacturer or authorized distributors?

All NCP803SN308T1G 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 NCP803SN308T1G meets industry standards.

7.What is the process for return or replacement of NCP803SN308T1G?

All NCP803SN308T1G units undergo pre-shipment inspection (PSI). If there is an issue with NCP803SN308T1G, 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 NCP803SN308T1G part is unused and in its original packaging.

Return procedure for NCP803SN308T1G:

1.Submit a request within 90 days.

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

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