Keszoox
AC-DC Precision Buck Converter — 220V to 5V/9V/12V, 3.5W, Isolated, PCB Mount
AC-DC Precision Buck Converter 220V to 5V/9V/12V, 3.5W, Isolated, PCB Mount
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AC-DC Precision Buck Converter — 85–265V AC to 5V / 9V / 12V DC, 3.5W, Isolated, PCB Mount
This isolated AC-DC precision buck converter module accepts 85–265V AC mains input and delivers a regulated 5V, 9V, or 12V DC output at up to 700mA (3.5W), directly on a compact PCB-mount module. With galvanic isolation between mains and output, full protection (OCP, OVP, SCP, thermal shutdown), 80% efficiency, and an MTBF of 16,000 hours, it is the standard solution for embedding a mains power supply directly into IoT devices, smart home modules, and industrial control boards without a separate external power adapter.
Key Specifications
| Parameter | Value |
|---|---|
| Input Voltage | 85V – 265V AC (universal mains) |
| Output Voltage | 5V / 9V / 12V DC (select variant) |
| Max Output Current | 700mA (5V) / 390mA (9V) / 290mA (12V) |
| Max Output Power | 3.5W |
| Isolation | Galvanic isolation (mains to output) |
| Efficiency | ~80% |
| Protection | OCP, OVP, SCP, thermal shutdown |
| MTBF | 16,000 hours |
| Operating Temperature | -40°C to +85°C |
| Mounting | PCB mount (through-hole pins) |
Output Variant Comparison
| Variant | Output Voltage | Max Current | Best For |
|---|---|---|---|
| 5V | 5.0V DC | 700mA | ESP8266, Arduino, USB 5V devices |
| 9V | 9.0V DC | 390mA | Arduino Uno (Vin), 9V sensors |
| 12V | 12.0V DC | 290mA | Relay coils, LED strips, 12V sensors |
Why Choose This AC-DC Module?
- Galvanic isolation — mains voltage fully isolated from output, safe for direct MCU connection
- Universal 85–265V input — works worldwide (100V Japan, 120V USA, 230V Europe, 240V UK/AU)
- PCB mount — solder directly onto your product PCB, no external power adapter needed
- Full protection suite — OCP/OVP/SCP/thermal shutdown for robust field deployment
- -40°C to +85°C — industrial temperature range for outdoor and harsh environment use
Compatible With / Common Use Cases
- Smart home switch: 5V output powers ESP8266/ESP32 inside a mains wall switch or socket module
- IoT sensor node: 3.5W sufficient for ESP32 + sensors + relay coil from mains supply
- Industrial controller: 12V output for relay coils and 12V sensors in PLC-style control panels
- LED driver supply: 12V/290mA for small LED strip segments or indicator lighting
- Arduino mains project: 9V output to Arduino Vin for mains-powered Arduino without external adapter
Frequently Asked Questions
Q: Is this module safe to use inside a product connected to mains voltage?
A: Yes — the galvanic isolation separates the mains input from the DC output. However, mains wiring must comply with local electrical codes. Use appropriate insulation, creepage distances, and enclosures. This module is intended for integration by qualified engineers into products with proper mains safety design. Do not expose mains connections in open-air prototypes.
Q: Can this module power an ESP32 with WiFi active?
A: The 5V/700mA variant provides 3.5W. ESP32 draws ~80mA average and up to ~300mA peak during WiFi TX. With a 3.3V LDO (AMS1117-3.3), the module can power ESP32 reliably for most IoT applications. Avoid running high-power peripherals (large servos, high-current LEDs) simultaneously to stay within the 700mA limit.
Q: What is the output ripple voltage of this module?
A: Typical output ripple is <50mV peak-to-peak. For noise-sensitive applications (ADC, audio), add a 100μF electrolytic + 100nF ceramic capacitor at the output to further reduce ripple. The isolated topology inherently provides better noise isolation than non-isolated buck converters.
Package Contents
- 1× AC-DC Precision Buck Converter Module (output voltage as selected)
