📋 Overview
The WGI10-48S12L is an industrial-grade isolated DC-DC step-down converter that accepts a wide DC input range of 36V–75V (nominal 48V) and delivers a stable 12V output at up to 10A (120W). Built with synchronous rectification technology, it achieves 92% efficiency at full load while maintaining complete galvanic isolation between input and output — a critical safety barrier that protects sensitive downstream electronics from high-voltage transients, ground loops, and electrical noise. The sealed aluminum enclosure carries an IP65 waterproof rating, making it suitable for outdoor, marine, and industrial environments.
⭐ Key Features
- Wide Input Range: 36V–75V DC (nominal 48V), compatible with battery banks, telecom power plants, and solar arrays
- Galvanic Isolation: ≥1500V input-to-output isolation eliminates ground loops and protects downstream electronics
- High Efficiency: 92% typical at 48V input and full load — minimizes heat generation and extends component life
- IP65 Waterproof Rating: Sealed aluminum enclosure protects against dust and water jets
- Comprehensive Protection Suite: Short circuit, overcurrent, overvoltage, over-temperature, undervoltage lockout, and reverse polarity protection — all with automatic recovery
- Wide Operating Temperature: −40°C to +50°C ambient — rated for extreme environments
- Synchronous Rectification: Advanced switching topology for superior efficiency and reduced thermal dissipation
- Premium Internal Capacitors: NCC & NICHICON capacitors for high reliability and long service life
- 100% Factory Burn-In Tested: Every unit is tested at full load before shipment
- RoHS and CE Compliant
📊 Specifications
Input
| Parameter | Value |
|---|---|
| Input Voltage Range | 36V – 75V DC |
| Nominal Input Voltage | 48V DC |
| Maximum Input Voltage (Continuous) | 78V DC |
| Undervoltage Shutdown | 30V – 36V (typical 31.5V), auto-recovery |
| Undervoltage Recovery | 31V – 36V (typical 34V) |
| Maximum Input Current | 5A (at 36V input, 10A output) |
| No-Load Input Current | 80mA – 300mA (at 48V input) |
| Recommended Input Fuse | 7.5A |
| Recommended Wire Gauge | 16 AWG (input and output) |
Output
| Parameter | Value |
|---|---|
| Output Voltage | 12V DC (11.65V – 12.35V) |
| Output Current | 0 – 10A |
| Output Power | 120W maximum |
| Efficiency | 92% typical (48V input, 10A output, 25°C) |
| Voltage Regulation Accuracy | ±2% |
| Load Regulation | ±2% |
| Output Ripple & Noise | 50mV typical, 200mV max (20MHz bandwidth) |
| Output Voltage Rise Time | 8ms – 50ms |
| Boot Delay Time | 30ms – 100ms |
| Output Voltage Overshoot | ≤5% |
| Maximum External Capacitance | 2000µF |
Isolation & Safety
| Parameter | Value |
|---|---|
| Input-to-Output Isolation | ≥1500V DC |
| Input-to-Shell Isolation | ≥1500V DC |
| Output-to-Shell Isolation | ≥500V DC |
| Insulation Resistance | ≥50MΩ (test voltage 500V) |
Protection
| Protection Type | Threshold / Behavior |
|---|---|
| Overvoltage Protection (OVP) | 13.8V – 15V output; hiccup mode, auto-recovery |
| Overcurrent Protection (OCP) | 10.5A – 14A; hiccup mode, auto-recovery |
| Short Circuit Protection (SCP) | Continuous; hiccup mode; survives 4-hour short |
| Over-Temperature Protection (OTP) | Shuts down at 85°C shell temp; restores at 80°C |
| Undervoltage Lockout (UVLO) | 30V – 36V shutdown; auto-recovery |
| Reverse Polarity Protection | Yes — prevents damage from reversed input connections |
Environmental & General
| Parameter | Value |
|---|---|
| Operating Ambient Temperature | −40°C to +50°C |
| Shell Ambient Temperature | −40°C to +80°C |
| Storage Temperature | −55°C to +100°C |
| Operating Humidity | 5% – 95% (non-condensing) |
| Waterproof Rating | IP65 |
| Cooling Method | Natural convection (no fan required) |
| Maximum Altitude | 4,000m |
| Switching Frequency | 250 ±30 KHz |
| MTBF | ≥200,000 hours |
| Dimensions (L × W × H) | Approx. 110 × 70 × 23 mm (4.33 × 2.76 × 0.91 inches) L × W × H |
| Weight | ≤250g (8.8 oz) |
| Certifications | RoHS, CE |
WGI10-48S12L Mechanical Drawing
🔌 Wiring & Connections
The WGI10-48S12L uses screw terminal blocks for both input and output connections. Terminal labels are printed directly on the module housing. The module also includes an optional CNT (Remote On/Off) pin for system-level power control.
Terminal Connections
| Terminal | Label | Function |
|---|---|---|
| Input Positive | V_IN(+) | Connect to the positive (+) side of your DC input source |
| Input Negative | V_IN(−) | Connect to the negative (−) side of your DC input source |
| Output Positive | V_OUT(+) | +12V isolated output — connect to your load's positive terminal |
| Output Negative | V_OUT(−) | Isolated output ground — connect to your load's negative terminal |
| N/C | NC | Not connected in this version. Used for optional Remote On/Off |
⚠️ Important: Always verify polarity before applying power. Although the module includes reverse polarity protection, connecting input leads backwards adds unnecessary stress to the protection circuitry. Use a multimeter to confirm correct polarity before energizing the circuit.
Basic Wiring Steps
- Disconnect your DC power source before making any connections.
- Run the input positive lead (16 AWG or heavier) from your power source to V_IN(+). Include a 7.5A fuse in this lead, close to the power source.
- Run the input negative lead from your power source to V_IN(−).
- Connect your load's positive wire to V_OUT(+) and the load's negative wire to V_OUT(−). Use 16 AWG or heavier wire here as well.
- Verify all connections are tight and correctly polarized.
- Apply power and measure the output — you should read approximately 12V DC between V_OUT(+) and V_OUT(−).
💡 Tip: The output ground V_OUT(−) is galvanically isolated from the input ground V_IN(−). In most installations, you do not need to connect them together. However, in some rack-mounted or safety-critical installations, the output ground is intentionally bonded to chassis or earth ground. If you are unsure, leave the output ground floating — that is the safe default for most applications.
📡 Using the WGI10-48S12L in a −48V Telecom System
Understanding the −48V Negative Ground Convention
Telecom power systems use a negative ground convention that catches many people off guard the first time they encounter it. In a familiar 12V automotive system, the negative terminal is grounded and the positive terminal is the working supply. Telecom systems do the opposite: the positive terminal is grounded (tied to earth), and the negative terminal is the supply rail. This convention dates back to the earliest telephone networks and persists for good reasons — it dramatically reduces electrolytic corrosion on buried copper cable infrastructure and is mandated by Telcordia (formerly Bellcore) standard GR-1089-CORE for central office equipment.
The two bus conductors in a standard telecom power plant are:
| Terminal Name | Voltage | Also Called |
|---|---|---|
| Battery Return (RTN) | 0V — Earth Referenced | BATT RTN, BR, Return |
| Battery (BATT) | −48V — Supply Rail | BAT, Battery |
The RTN (return) bus sits at 0V and is bonded to earth ground at the power distribution unit (PDU) in most central office installations. The BATT bus is the −48V supply rail. Current flows from RTN (0V) through the equipment and back out at BATT (−48V).
📝 Note: A "−48V" telecom system does not stay at exactly −48V. During float charge under normal operation, the bus typically sits between −54V and −56V. Under battery discharge it may drop to −42V or lower. This is why telecom equipment must tolerate a defined voltage window. With an input range of 36V–75V, the WGI10-48S12L covers the entire operating window of a standard −48V telecom power plant.
Connecting the WGI10-48S12L to a −48V Bus
Because the telecom system uses a negative ground convention, the input connections to the converter are the reverse of what you might expect from a standard positive-ground system:
- V_IN(+) → RTN Bus (0V / Battery Return): This is the positive input of the converter. In the telecom system, RTN is the positive side of the battery — it sits at 0V and is referenced to earth ground.
- V_IN(−) → BATT Bus (−48V): This is the negative input of the converter. BATT is the supply rail sitting at −48V.
The voltage differential across the converter's input terminals is: 0V − (−48V) = 48V. The math works out exactly as expected — you are applying 48V across V_IN(+) and V_IN(−), with the polarity determined by which bus each terminal connects to.
Wiring Diagram
The diagram below shows the WGI10-48S12L connected to a −48V telecom power system, with the fuse correctly placed in the BATT (live) line and the isolated 12V output feeding a telecom load such as a router, switch, or line card.
Key Points from the Diagram
- V_IN(+) connects to the RTN Bus (0V): This is counterintuitive but correct. In the negative ground system, RTN is the positive side of the supply.
- V_IN(−) connects to the BATT Bus (−48V): This is the live supply rail and the negative side of the converter input.
- Fuse placement: The fuse (F1) is placed in the BATT (−48V) line — the live rail. The RTN line is the grounded conductor and is typically left unfused in standard telecom central office installations.
- Isolated output: V_OUT(+) delivers +12V and V_OUT(−) is an isolated ground reference. It does not automatically connect to RTN or earth ground. In many rack-mounted installations, operators intentionally bond V_OUT(−) to chassis ground — this is acceptable and sometimes required. However, the safe default is to leave it floating unless your installation specifically requires bonding.
⚠️ Important: In central office and carrier-grade telecom installations, the RTN bus is bonded to earth ground at the PDU. This means the equipment chassis and the RTN bus are both at earth potential. Never touch the BATT (−48V) terminal while you are grounded — doing so creates a circuit through your body. Although −48V is below the threshold typically classified as "immediately dangerous to life," it can still deliver a painful and potentially harmful shock. Always de-energize the circuit before making or breaking connections, and treat −48V with the same caution you would give any live electrical conductor.
⚠️ Important: Reverse polarity in a −48V system — connecting BATT to V_IN(+) and RTN to V_IN(−) — applies the voltage backwards. The WGI10-48S12L includes reverse polarity protection, but do not rely on it as a wiring safety net. Always verify bus polarity with a multimeter before connecting the module, and clearly label your input leads before installation.
⚠️ Protection Features
The WGI10-48S12L includes a full suite of automatic protection features that keep the converter and your load safe under fault conditions. Unless noted otherwise, all protections use hiccup mode — the converter shuts down briefly, then attempts to restart. Once the fault is cleared, the converter resumes normal operation on its own without requiring a manual reset.
- Short Circuit Protection (SCP): The converter enters hiccup mode and can sustain a continuous output short for up to 4 hours without damage. It restarts automatically when the short is removed.
- Overcurrent Protection (OCP): Activates when output current exceeds 10.5A–14A. The converter enters hiccup mode and recovers when the overload is removed.
- Output Overvoltage Protection (OVP): Triggers at 13.8V–15V to protect downstream equipment from voltage spikes. Hiccup mode with auto-recovery.
- Over-Temperature Protection (OTP): Shuts the converter down if the shell temperature reaches 85°C. Restarts automatically when the shell cools below 80°C. Ensure adequate airflow to prevent nuisance tripping under heavy load.
- Input Undervoltage Lockout (UVLO): Prevents operation when input voltage drops below approximately 31.5V (typical). Restarts automatically when voltage recovers above the recovery threshold.
- Reverse Polarity Protection: Prevents damage from accidental reversal of input connections. This is a safety backstop — do not substitute it for correct wiring practice.
💡 Tip: If the converter appears to be cycling on and off rapidly, it is in hiccup mode. The most likely causes are an output short circuit, an overloaded output (load drawing more than 10A), or an input voltage that is too low. Check your load current, inspect for wiring faults, and verify input voltage before assuming the converter is faulty.
💡 Installation Tips
- Use 16 AWG or heavier wire for all input and output connections. Undersized wire introduces resistive losses and can overheat at high current loads.
- Install a 7.5A fuse in the input positive lead (or the BATT lead in a −48V telecom system) as close to the power source as practical.
- The module uses natural convection cooling — no external fan is required under normal conditions. Ensure there is adequate clearance around the module, particularly above the finned heatsink, for air to circulate freely.
- For installations at or near full load (10A) in a warm environment, mount the module vertically to maximize chimney-effect airflow through the heatsink fins. Light forced-air cooling can also extend the thermal margin significantly.
- The IP65 waterproof rating protects against dust ingress and direct water jets. The module is not rated for submersion in water.
- Four corner mounting holes (Ø3.8mm) allow secure panel mounting. In high-ambient-temperature environments, mounting to a metal panel or enclosure wall also helps transfer heat away from the module.
- Do not exceed 2000µF of external capacitance on the output. Excessive output capacitance can cause slow startup or trigger overvoltage protection during power-on transients.
🎯 Applications
- Telecommunications: Powering 12V equipment from standard −48V central office and telecom power plants
- Solar & Alternative Energy: Off-grid and grid-tied solar installations with 48V battery banks
- Electric Vehicles & Golf Carts: Auxiliary 12V accessory power derived from a 48V drive bus
- Marine & Boating: Waterproof design is ideal for boats, yachts, and marine electronics enclosures
- Industrial Automation: PLCs, sensors, and control systems powered from a 48V plant bus
- Military & Defense: Ruggedized isolated power conversion for field-deployed electronics
🏪 Where to Buy the WGI10-48S12L Isolated DC-DC Converter
The WGI10-48S12L is available from Envistia Mall:
Buy the WGI10-48S12L 48V to 12V Isolated DC-DC Converter →
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📚 Resources & Downloads
- Manufacturer's Datasheet: WGI10-48S12L Datasheet (PDF)
This guide is provided by Envistia Mall for educational and technical reference purposes. The manufacturer and Envistia LLC (dba Envistia Mall) are not responsible for any damages or losses resulting from the use of this product. Always follow proper electrical safety practices when working with electronic components. Specifications are based on manufacturer data and are subject to change without notice.