UMW AMS1117CD-3.3

UMW AMS1117CD-3.3 Detailed Product Overview -- Linear Voltage Regulator IC

The UMW AMS1117CD-3.3 is a low-dropout (LDO) linear voltage regulator designed to deliver a fixed 3.3V output voltage with a maximum load current of 1A. Engineered for stability and efficiency, this regulator operates with an input voltage range of 4.75V to 15V, making it suitable for applications requiring reliable voltage conversion from higher input sources. Its low dropout voltage (1.2V at 1A load) ensures efficient operation even when the input-to-output differential is minimal, while integrated thermal and over-current protection safeguards against operational hazards.

Key Features

This LDO regulator boasts a ±2% output voltage accuracy across the full temperature range, ensuring precision in sensitive electronic circuits. It incorporates a PNP pass transistor architecture optimized for low quiescent current (typically 5mA) and high ripple rejection (60dB at 120Hz), enhancing energy efficiency and noise suppression. The device requires only a minimal 10μF ceramic output capacitor for stable operation, simplifying board layout and reducing BOM costs. Additionally, its low thermal resistance and compact SOT-223 package enable effective heat dissipation in space-constrained environments.

Technical Specifications

The AMS1117CD-3.3 operates within a junction temperature range of -40°C to +125°C, ensuring reliability in harsh conditions. Its dropout voltage is specified at 1.2V (max) under a 1A load, with a line regulation of 0.2% (typ) and load regulation of 0.4% (typ). The device exhibits a maximum quiescent current of 10mA and a standby current of 1μA in shutdown mode. Input voltage tolerance extends up to 18V during transient conditions, and the output current limit is internally set to 1.5A (typ) for overload protection.

Application Scenarios

This AMS1117CD-3.3 regulator is widely adopted in consumer electronics, IoT devices, and embedded systems, including applications such as 3.3V microcontroller power supplies, sensor modules, wireless communication devices, and battery-powered equipment. Its robust design supports automotive aftermarket systems, industrial control units, and low-power FPGA/ASIC voltage rails. The AMS1117CD-3.3 is particularly favored in scenarios requiring stable voltage conversion for USB peripherals, routers, and portable instrumentation due to its compact footprint and low-noise output.

Package and Reliability

Housed in a surface-mount SOT-223 package (6.5mm x 7.0mm body), the device features three pins (input, output, and ground) with an exposed thermal pad for enhanced PCB heat dissipation. The package is compliant with RoHS directives and supports reflow soldering processes. UMW guarantees industrial-grade reliability with an MTBF (Mean Time Between Failures) exceeding 1,000,000 hours under nominal operating conditions, validated through rigorous thermal cycling and HAST (Highly Accelerated Stress Test) compliance.

Protection Mechanisms

Integrated safeguards include fold-back current limiting to protect against short circuits and sustained over-current conditions, as well as thermal shutdown that activates at 165°C (typ) to prevent thermal runaway. The protection circuitry automatically resets once the fault condition is removed, ensuring uninterrupted operation without external intervention. These features make the regulator resilient to voltage spikes, accidental reverse polarity, and prolonged overload scenarios.

Performance Optimization

For optimal performance, designers are advised to place input and output capacitors as close as possible to the regulator pins. A 22μF tantalum or low-ESR ceramic capacitor on the input side is recommended for high-current applications, while the output capacitor should maintain a minimum 10μF capacitance. Proper PCB copper area allocation under the thermal pad is critical to maximize heat dissipation and avoid thermal throttling under sustained loads.

Competitive Advantages

Compared to similar LDOs, the AMS1117CD-3.3 distinguishes itself through its balance of cost-effectiveness, low dropout voltage, and high current capability. Its ability to operate with ceramic capacitors (unlike older LDOs requiring electrolytic capacitors) reduces long-term maintenance risks. Additionally, UMW’s proprietary process technology ensures lower ground current variation over temperature, a critical factor in precision analog systems.