AMS1117-3.3 AMS1117-3.3 – 3.3V Fixed Output LDO Voltage Regulator

The UMW AMS1117-3.3 is a low-dropout (LDO) linear regulator designed for applications requiring stable 3.3V DC output at up to 1A current. It features a typical dropout voltage of 1.2V, enabling operation even with input voltages as low as 4.5V.

• Precision Output: ±1.5% voltage accuracy (±50mV at 3.3V) ensures reliable performance.
• Robust Protection: Built-in thermal shutdown (150°C) and overcurrent protection.
• Wide Compatibility: Available in SOT-223-3L, TO-252-2L, and SOT-89-3L packages.

Ideal for embedded systems, wireless modules, and consumer electronics, the AMS1117-3.3 operates across –40°C to +125°C.

Key Features

✅ Fixed 3.3V Output – Tight tolerance (±1.5%) for precision circuits.
✅ Low Dropout Voltage – Only 1.2V typical at 1A load.
✅ High PSRR (75dB) – Excellent ripple rejection for noise-sensitive applications.

Specifications

Applications

The UMW AMS1117-3.3 voltage regulator is designed to meet the rigorous power requirements of modern electronic systems. Below we explore its key applications in greater technical and practical detail:

1. Consumer Electronics

Wi-Fi Routers & IoT Devices

As the backbone of smart homes and offices, Wi-Fi routers demand clean, stable power for reliable operation.

• ESP8266/ESP32 Modules: These popular Wi-Fi/BLE chips require precise 3.3V input (±5% tolerance). The AMS1117-3.3’s ±1.5% accuracy and low noise (<0.003% ripple) prevent signal integrity issues in RF circuits.
• Real-World Benefit: Eliminates Wi-Fi dropouts caused by voltage fluctuations during high traffic loads.

Smart TVs & Displays

Modern TVs integrate dozens of sensitive analog and digital subsystems:

• Display Drivers: TFT/LCD panels need noise-free power to avoid screen artifacts. The regulator’s 75dB PSRR suppresses switching noise from SMPS units.
• Sensor Arrays: Ambient light and motion sensors require microamp-level quiescent current (5mA typ.) for always-on functionality.

Gaming Consoles

High-performance gaming hardware pushes power systems to their limits:

• MCU Power Rails: Provides stable voltage during sudden current spikes when loading games (transient response <50µs).
• Controller Boards: Low dropout (1.2V) maintains regulation even as battery voltage decays during prolonged use.

2. Industrial & IoT Applications

PLC Control Systems

Industrial automation equipment operates in electrically noisy environments:

• Harsh Condition Operation: Withstands -40°C to +125°C temperature ranges in factory settings.
• Isolation Circuits: Paired with optocouplers, creates isolated 3.3V rails for signal conditioning modules.

LoRa/Wi-Fi Gateways

Long-range wireless systems demand exceptional power efficiency:

• RF Power Amplifiers: Maintains stable voltage during transmission bursts (100mA → 1A transitions).
• Solar-Powered Nodes: Ultra-low dropout maximizes energy harvest from 5V solar panels during cloudy conditions.

Industrial Sensors

Critical monitoring applications require years of maintenance-free operation:

• 4-20mA Transmitters: Provides reference voltage for current loop implementations.
• Vibration Sensors: Low-noise output prevents false triggering in ADC measurement circuits.

3. Automotive Electronics

Infotainment Systems

Modern dashboards combine multiple power-hungry subsystems:

• Touchscreen Controllers: Delivers clean power to capacitive touch ICs (noise sensitivity <50mVpp).
• Audio DSPs: High PSRR prevents alternator whine in premium sound systems.

ECU Modules

Engine control units face extreme electrical challenges:

• CAN Bus Transceivers: Maintains regulation during cold-crank events (input dips to 4.5V).
• Sensor Interfaces: Thermal shutdown protection prevents failure in engine bay environments (>105°C ambient).

4. Embedded Systems & DIY

Raspberry Pi Ecosystem

Expansion boards push the limits of the Pi’s 3.3V rail:

• HAT Power Management: Offloads peripherals (GPS, LoRa) from the Pi’s limited 500mA 3.3V supply.
• Prototyping Advantage: SOT-223 package fits breadboards for easy development.

Battery-Powered Devices

Portable applications benefit from intelligent power design:

• Sleep Mode Optimization: 5mA quiescent current extends coin cell lifespan by 30% vs competitors.
• Energy Harvesting: Works down to 4.5V input for solar/LiPo hybrid systems.

Technical Highlights

• Fast Transient Response: Handles sudden load changes (<50µs).
• Minimal External Components: Requires only 10µF input and 22µF output capacitors.
• ESD Protection: Withstands up to 2kV (HBM).

Package Information

Design Considerations

• Heat Dissipation: Use PCB copper pour for TO-252/SOT-223 packages at high loads.
• Input Capacitance: ≥10µF ceramic/tantalum capacitor recommended.
• Output Noise: <0.003% RMS (10Hz–10kHz).

Alternative Solutions & Cross-Reference Guide

For design flexibility or sourcing adaptability, engineers often evaluate alternative LDO regulators to UMW’s AMS1117-3.3. Below we analyze key substitutes with technical differentiators:

1. LM1117MPX-33NOPB (Texas Instruments)

Best For: High-reliability industrial applications
Key Comparisons:

Design Notes:

• TI’s version offers military-grade temperature range (-55°C to +150°C) for extreme environments
• Preferred when Texas Instruments’ supply chain is mandated
• Slightly better thermal performance in compact designs

2. ME1117A33B3G (ON Semiconductor)

Best For: Battery-powered IoT devices
Key Comparisons:

Design Notes:

• Ideal for energy harvesting applications due to ultra-low Iq
• Not recommended for >500mA loads in SOT-89 package (thermal limits)
• Superior choice for always-on sensor nodes where battery life is critical

3. TLV1117-33IDCYR (Texas Instruments)

Best For: Precision analog circuits
Key Features:

• Enhanced Accuracy: ±0.75% vs AMS1117’s ±1.5%
• Advanced PSRR: 85dB @1kHz (vs 75dB @120Hz)
• Wide Vin Range: 2.5V-15V (vs 4.75V-12V)

Tradeoffs:

• Higher Cost: $0.82 @1k qty (3.7x AMS1117 price)
• Larger Package: SOIC-8 (vs SOT-223)

4. AZ1117IH-3.3TRG1 (Diodes Incorporated)

Best For: Automotive ECUs
Unique Attributes:

• AEC-Q100 Qualified for automotive use
• Reverse Polarity Protection (-20V withstand)
• Lower Thermal Resistance: 60°C/W in TO-252

Limitations:

• Higher Min Vin: 5V (vs 4.75V)
• Limited Stock: Frequently on allocation

Selection Methodology

Consider these factors when choosing alternatives:

1. Load Current Requirements
   • For >800mA: Stick with AMS1117 or LM1117 (TO-252 packages)
   • For <300mA: ME1117 saves power
2. Noise Sensitivity
   • Analog circuits: Prioritize TLV1117
   • Digital systems: AMS1117 is sufficient
3. Thermal Constraints
   • Small PCBs: AZ1117’s thermal performance wins
   • Heatsink available: AMS1117 provides best cost/performance

Emergency Substitution Guide

Why AMS1117-3.3 Remains the Default Choice?

Despite alternatives, UMW’s solution dominates due to:
✅ Best Cost-Performance Ratio ($0.22vscompetitors’$0.35+)
✅ Package Flexibility (SOT-223/TO-252/SOT-89)
✅ Proven Reliability >20 years in-market track record

AMS1117-3.3 Datasheet Reference

For load transient graphs and thermal curves, download AMS1117.pdf.