onsemi NCV1117ST33T3

Overview

NCV1117ST33T3 from onsemi is an automotive-grade, low-dropout linear voltage regulator delivering a fixed 3.3 V output at up to 1.0 A with ±1.0% output voltage accuracy, 1.2 V max dropout at 800 mA over temperature, and integrated thermal shutdown, current limiting, and safe operating area protection. It operates from 4.75 V to 10 V input and is used in engine control units, ADAS power rails, and infotainment subsystems requiring stable, AEC-Q100-compliant regulation.

For engineers reviewing the NCV1117ST33T3 datasheet, pinout, applications, or equivalent options, key selection criteria include its SOT-223 package thermal performance, 3.3 V fixed output tolerance, automotive temperature range (−40°C to +125°C), and compatibility with standard LDO layout practices for noise-sensitive embedded systems.

Technical Context

The NCV1117ST33T3 implements a bandgap-referenced series pass architecture with internal trimming for ±1.0% initial output accuracy and 0.5% temperature stability. Its dropout behavior is characterized across load (100–800 mA) and temperature (−40°C to +125°C), maintaining regulation down to 1.2 V differential at full rated current.

Protection circuitry includes foldback current limiting, thermal shutdown activation at ~175°C junction temperature, and safe operating area compensation-enabling robust operation in automotive transients without external supervision. Input voltage range (4.75 V to 10 V) is optimized for post-regulation after switching converters or battery-supplied 5 V/12 V rails.

Key Specifications

Pinout & Package

NCV1117ST33T3 is housed in a SOT-223 (Case 318H) surface-mount package with an exposed metal tab thermally connected to Pin 2 (Output). The tab serves as the primary heat path to the PCB copper pour.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV73333PDBVR and TPS7B8733QKVURQ1, the NCV1117ST33T3 delivers optimal balance of automotive qualification, 1.0 A output, proven thermal robustness in SOT-223, and cost-effective integration for mainstream ECU and infotainment applications-without over-specifying for non-safety-critical use cases.

Availability

NCV1117ST33T3 is available at Aetrix Electronics and suitable for engine control units, advanced driver assistance systems, and infotainment head units requiring stable component supply across long production lifecycles and automotive-grade traceability.

Supply support for NCV1117ST33T3 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 (Nasdaq: ON) is a global semiconductor leader delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The NCV1117 series belongs to onsemi's automotive-qualified analog power portfolio, designed specifically to meet stringent AEC-Q100 reliability, thermal, and functional safety requirements for under-hood and cabin electronics.

FAQ

What is the maximum input voltage for NCV1117ST33T3?

The NCV1117ST33T3 supports a maximum input voltage of 10 V, as specified in the Electrical Characteristics table for the 3.3 V fixed-output variant. This limit ensures safe operation within its internal safe operating area and thermal design margins. Exceeding 10 V may trigger overvoltage stress or premature thermal shutdown, especially at high ambient temperatures. Always verify input rail stability and transient overshoot against this rating in final system validation.

Does NCV1117ST33T3 require an output capacitor, and what are the minimum specifications?

Yes, NCV1117ST33T3 requires an output capacitor for stability. The datasheet mandates a minimum 4.7 µF capacitance with ESR between 33 mΩ and 2.2 Ω. Ceramic, tantalum, or aluminum electrolytic types are acceptable if they meet these values across the full operating temperature range (−40°C to +125°C). Omitting or underspecifying Cout risks oscillation, poor transient response, and output voltage instability-particularly under dynamic load changes in automotive applications.

Is NCV1117ST33T3 pin-compatible with the LM317?

No, NCV1117ST33T3 is not pin-compatible with the LM317. While the NCP1117 family (including NCV1117) is functionally compatible with LM317-based circuits in adjustable configurations, the NCV1117ST33T3 is a fixed 3.3 V device in SOT-223 package with Pin 1 = Ground, Pin 2 = Output, Pin 3 = Input. The LM317 uses Pin 1 = Adjust, Pin 2 = Output, Pin 3 = Input-requiring PCB layout revision for direct replacement. Use only as a functional substitute with schematic and layout adaptation.

What is the thermal resistance (R_JA) of NCV1117ST33T3 in SOT-223 package?

The NCV1117ST33T3 in SOT-223 (Case 318H) has a typical junction-to-ambient thermal resistance (R_JA) of 160°C/W with minimum PCB pad size, per the Maximum Ratings table. Actual R_JA depends heavily on PCB copper area: Figure 21 shows it drops to ~60°C/W with 25 mm² of 2 oz. copper connected to the tab. For 1.0 A continuous operation at +85°C ambient, a thermal calculation using R_JA ≤ 40°C/W is recommended to keep junction temperature below 150°C.

How does the dropout voltage of NCV1117ST33T3 vary with load current?

The dropout voltage of NCV1117ST33T3 increases with load current: 0.95 V at 100 mA, 1.01 V at 500 mA, and 1.07 V at 800 mA (measured at V_OUT − 100 mV), per the Electrical Characteristics table. This monotonic rise reflects series pass transistor saturation behavior. At 1.0 A, dropout approaches 1.2 V-defining the minimum input voltage (≥4.5 V) needed to sustain 3.3 V output under full load and high temperature.