TO-220-2L 650V SiC Schottky Diode EL-SAF01 665JA Datasheet - Package 15.6x9.99x4.5mm - Voltage 650V - Current 16A - English Technical Document

1. Product Overview

The EL-SAF01 665JA is a Silicon Carbide (SiC) Schottky barrier diode designed for high-efficiency, high-frequency power conversion applications. Encapsulated in a standard TO-220-2L package, this device leverages the superior material properties of Silicon Carbide to deliver performance characteristics that significantly surpass traditional silicon-based diodes. Its core function is to provide unidirectional current flow with minimal switching losses and reverse recovery charge, making it an ideal choice for modern power supplies and inverters where efficiency and power density are critical.

The primary market for this component includes designers and engineers working on switch-mode power supplies (SMPS), solar energy conversion systems, uninterruptible power supplies (UPS), motor drive controllers, and data center power infrastructure. Its key advantage lies in enabling system designs that operate at higher frequencies, which in turn allows for the reduction of passive component sizes (like inductors and capacitors), leading to overall system cost and size savings. Furthermore, its low thermal resistance reduces cooling requirements, contributing to simpler and more reliable thermal management solutions.

2. In-Depth Technical Parameter Analysis

2.1 Electrical Characteristics

The electrical parameters define the operational boundaries and performance of the diode under specific conditions.

• Maximum Repetitive Peak Reverse Voltage (VRRM): 650V. This is the maximum instantaneous voltage the diode can withstand in the reverse-biased direction without breakdown. It defines the voltage rating for applications like 400VAC rectification or boost PFC stages.
• Continuous Forward Current (IF): 16A. This is the maximum average forward current the device can conduct continuously, typically specified at a case temperature (Tc) of 25°C. Derating is necessary at higher ambient temperatures.
• Forward Voltage (VF): Typically 1.5V at IF=16A and Tj=25°C, with a maximum of 1.85V. This parameter is crucial for calculating conduction losses (P_loss = VF * IF). The datasheet also specifies VF at the maximum junction temperature (Tj=175°C), which is typically higher (1.9V typ.), important for worst-case loss calculations.
• Reverse Current (IR): Very low leakage current, typically 2µA at VR=520V and Tj=25°C. Even at high temperature (175°C), it remains manageable at 30µA typ. Low leakage minimizes standby power losses.
• Total Capacitive Charge (QC): A critical parameter for SiC Schottky diodes, specified as 22nC typ. at VR=400V. Unlike conventional diodes, SiC Schottkys have no minority carrier storage, so their switching loss is primarily capacitive. QC represents the charge that must be supplied/discharged during each switching cycle, directly influencing switching loss (E_sw ~ 0.5 * QC * V). This low value enables high-frequency operation.

2.2 Thermal Characteristics

Thermal management is paramount for reliability and performance.

• Junction-to-Case Thermal Resistance (RθJC): 1.3°C/W typical. This low value indicates efficient heat transfer from the semiconductor junction to the package case. It allows the heat generated by power dissipation (conduction and switching losses) to be effectively removed via a heatsink attached to the case.
• Maximum Junction Temperature (TJ): 175°C. The absolute maximum temperature the silicon carbide junction can reach. Operating close to this limit reduces long-term reliability, so design margins are recommended.
• Total Power Dissipation (PD): 115W at Tc=25°C. This is the maximum power the device can dissipate under ideal cooling conditions (case held at 25°C). In real applications, the allowable dissipation is lower and depends on the heatsink's ability to keep the case temperature low.

2.3 Maximum Ratings and Robustness

These ratings define the absolute limits beyond which permanent damage may occur.

• Surge Non-Repetitive Forward Current (IFSM): 56A for a 10ms half-sine wave. This rating indicates the diode's ability to withstand short-circuit or inrush current events, a key factor for reliability in fault conditions.
• Storage Temperature Range (TSTG): -55°C to +175°C. Defines the safe temperature range for the device when not powered.
• Mounting Torque (Md): 0.8 to 8.8 N·m (or 7 to 78 lbf·in) for an M3 or 6-32 screw. Proper torque is essential for good thermal contact between the package tab and the heatsink.

3. Performance Curve Analysis

The datasheet provides several graphical representations of device behavior, which are essential for detailed design.

• VF-IF Characteristics: This graph shows the relationship between forward voltage and forward current at different junction temperatures. It is used to precisely calculate conduction losses at various operating points, not just the single datapoint given in the table. The curve typically shows that VF decreases slightly with increasing temperature for a given current (negative temperature coefficient for VF at low currents, becoming positive at high currents), which is a characteristic of Schottky diodes.
• VR-IR Characteristics: Plots reverse leakage current against reverse voltage, typically at multiple temperatures. It helps designers understand the off-state losses and ensure the leakage at the application's maximum voltage and temperature is acceptable.
• VR-Ct Characteristics: Shows how the diode's junction capacitance (Ct) varies with reverse voltage (VR). Capacitance decreases as reverse voltage increases. This graph is vital for modeling the capacitive switching behavior and calculating QC for specific operating voltages.
• Maximum Ip – TC Characteristics: Illustrates how the maximum allowable continuous forward current (Ip) must be derated as the case temperature (TC) increases. This is the primary graph for thermal design, dictating the required heatsink performance.
• Power Dissipation vs. TC: Similar to the current derating, this shows how the maximum allowable power dissipation decreases as case temperature rises.
• IFSM – PW Characteristics: Details the surge current capability for pulse widths (PW) other than the standard 10ms. It allows assessment of survivability under various transient conditions.
• EC-VR Characteristics: Plots the stored capacitive energy (EC) against reverse voltage. Switching loss energy can be derived from this (E_sw ≈ EC).
• Transient Thermal Impedance vs. Pulse Width: Crucial for evaluating temperature rise during short power pulses. The thermal impedance for a single short pulse is lower than the steady-state RθJC, allowing higher instantaneous power without overheating the junction.

4. Mechanical and Package Information

4.1 Package Outline and Dimensions

The device uses the industry-standard TO-220-2L (two-lead) package. Key dimensions from the datasheet include:

• Overall length (D): 15.6 mm (typ.)
• Overall width (E): 9.99 mm (typ.)Overall height (A): 4.5 mm (typ.)
• Lead spacing (e1): 5.08 mm (basic, fixed)
• Mounting hole distance (E3): 8.70 mm (reference)
• Tab dimensions and lead form details are provided for mechanical integration and PCB footprint design.

4.2 Pin Configuration and Polarity

The pinout is clearly defined:

• Pin 1: Cathode (K).
• Pin 2: Anode (A).
• Case (Metal Tab): This is electrically connected to the Cathode (Pin 1). This connection is critical for safety and design: the heatsink will be at cathode potential, so it must be isolated from other system parts (like chassis ground) if they are at a different potential. Proper insulation kits (mica/washers, silicone pads) are required.

4.3 Recommended PCB Pad Layout

A surface-mount leadform pad layout is suggested for PCB design. This ensures proper solder joint formation and mechanical stability when the device is mounted on a PCB, typically in conjunction with a heatsink.

5. Soldering and Assembly Guidelines

While specific reflow profiles are not detailed in the provided excerpt, general guidelines for power devices in TO-220 packages apply:

• Handling: Observe ESD (Electrostatic Discharge) precautions as SiC devices can be sensitive.
• Soldering: For through-hole mounting of the leads, standard wave or hand soldering techniques can be used. The package body temperature should not exceed the maximum storage temperature (175°C) for an extended period. For the surface-mount leadform, follow standard reflow soldering profiles for lead-free assemblies (peak temperature typically 245-260°C).
• Heatsink Mounting:
  1. Ensure the mounting surface of the heatsink and diode tab are clean, flat, and free of burrs.
  2. Apply a thin, even layer of thermal interface material (thermal grease or pad) to improve heat transfer.
  3. If electrical isolation is needed, use an insulating washer (e.g., mica, polyimide) and a shoulder washer for the screw. Apply thermal compound on both sides of the insulator.
  4. Secure the diode using the specified mounting torque (0.8 to 8.8 N·m) with an M3 or 6-32 screw and nut. Avoid overtightening, which can crack the package or strip threads.
• Storage: Store in a dry, anti-static environment within the specified temperature range (-55°C to +175°C).

6. Application Suggestions

6.1 Typical Application Circuits

• Power Factor Correction (PFC) Boost Diode: In continuous conduction mode (CCM) boost PFC circuits, the diode's low Qc and fast switching are essential for high efficiency at high switching frequencies (e.g., 65-100 kHz). It handles the high voltage stress when the main switch turns on.
• Solar Microinverter Output Stage: Used in the high-frequency inverter bridge or as a freewheeling diode. Its high-temperature capability suits the demanding environmental conditions of solar applications.
• Uninterruptible Power Supply (UPS) Inverter/Converter: Functions as a freewheeling or clamping diode in the DC-AC inverter or DC-DC converter stages, improving overall system efficiency.
• Motor Drive DC Bus Clamping/Flyback Diode: Protects IGBTs or MOSFETs from voltage spikes by clamping the inductive energy from the motor windings.

6.2 Critical Design Considerations

• Snubber Circuits: Due to the very fast switching and low Qc, parasitic inductance in the circuit can cause significant voltage overshoot (L*di/dt). Careful PCB layout to minimize loop area is paramount. An RC snubber across the diode may be necessary to dampen ringing.
• Thermal Design: Calculate total power losses (P_conduction = VF_avg * IF_avg, P_switching ≈ 0.5 * QC * V * f_sw). Use the maximum junction temperature (Tj_max=175°C), the thermal resistance RθJC, and the estimated heatsink thermal resistance (RθSA) to ensure Tj remains within a safe margin (e.g., 150°C or lower).
• Parallel Operation: The datasheet states the device can be paralleled without thermal runaway. This is due to the positive temperature coefficient of forward voltage at high currents, which promotes current sharing. However, for optimal sharing, ensure symmetrical layout and use individual gate resistors if driving associated switches.
• Voltage Derating: For improved long-term reliability, especially in high-temperature or high-reliability applications, consider derating the operating reverse voltage (e.g., use a 650V diode for a 400V bus, not a 480V bus).

7. Technical Comparison and Advantages

Compared to standard silicon fast recovery diodes (FRDs) or even ultrafast recovery diodes (UFRDs), the EL-SAF01 665JA offers distinct advantages:

• Essentially Zero Reverse Recovery Charge (Qrr): Silicon diodes have a significant Qrr due to minority carrier storage, causing large current spikes and losses during turn-off. SiC Schottky diodes are majority carrier devices, so Qrr is negligible. The switching loss is purely capacitive (QC), which is much lower than Qrr-based loss.
• Higher Operating Temperature: Silicon Carbide's wide bandgap allows a maximum junction temperature of 175°C, compared to 150°C or 125°C for many silicon diodes, enabling operation in hotter environments or with smaller heatsinks.
• Higher Switching Frequency Capability: The combination of low QC and no Qrr enables efficient operation at frequencies well above 100 kHz, allowing magnetic components (inductors, transformers) to be significantly smaller.
• Lower Forward Voltage at High Temperature: While VF at room temperature might be comparable to a silicon Schottky, a SiC Schottky's VF increases less with temperature, leading to better high-temperature conduction performance.

8. Frequently Asked Questions (FAQs)

8.1 Based on Technical Parameters

Q: The QC is 22nC. How do I calculate the switching loss?
A: The energy lost per switching cycle is approximately E_sw ≈ 0.5 * QC * V, where V is the reverse voltage it switches off against. For example, at 400V, E_sw ≈ 0.5 * 22nC * 400V = 4.4µJ. Multiply by switching frequency (f_sw) to get power loss: P_sw = E_sw * f_sw. At 100 kHz, P_sw ≈ 0.44W.

Q: Why is the case connected to the cathode? Is isolation always needed?
A: The internal die is mounted on a substrate electrically connected to the cathode tab for thermal and mechanical reasons. Isolation is required if the heatsink (or chassis it's attached to) is at a different potential than the cathode in your circuit. If the cathode is at ground potential and the heatsink is also grounded, isolation may not be necessary, but it is often used as a safety best practice.

Q: Can I use this diode directly as a replacement for a silicon diode in my existing circuit?
A: Not directly without review. While the voltage and current ratings may match, the extremely fast switching can cause severe voltage overshoot and EMI due to circuit parasitics that were not problematic with the slower silicon diode. PCB layout and snubber design must be re-evaluated.

9. Practical Design and Usage Cases

Case Study: High-Density 2kW Server PSU PFC Stage. A designer replaces a 600V/15A silicon ultrafast diode in a 80kHz CCM boost PFC with the EL-SAF01. The silicon diode had Qrr=45nC and Vf=1.7V. Calculations show the SiC diode reduces switching loss by ~60% (from 1.44W to 0.58W per diode) and slightly improves conduction loss. This 0.86W saving per diode allows the switching frequency to be increased to 140kHz to shrink the boost inductor size by ~40%, meeting the target power density increase. The existing heatsink remains adequate due to lower total loss.

Case Study: Solar Microinverter H-Bridge. In a 300W microinverter, four EL-SAF01 diodes are used as the freewheeling diodes for the H-bridge MOSFETs. Their high-temperature rating (175°C) ensures reliability in rooftop environments where enclosure temperatures can exceed 70°C. The low QC minimizes losses at the high switching frequency (e.g., 16kHz fundamental with high-frequency PWM), contributing to a higher overall conversion efficiency (>96%) which is critical for solar energy harvest.

10. Operating Principle

A Schottky diode is formed by a metal-semiconductor junction, unlike a standard PN junction diode. The EL-SAF01 uses Silicon Carbide (SiC) as the semiconductor. The Schottky barrier formed at the metal-SiC interface allows for majority carrier (electrons) conduction only. When forward biased, electrons are injected from the semiconductor into the metal, allowing current flow with a relatively low forward voltage drop (typically 0.7-1.8V). When reverse biased, the Schottky barrier prevents current flow. The key distinction from PN diodes is the absence of minority carrier injection and storage. This means there is no diffusion capacitance associated with stored charge in the drift region, leading to the "zero reverse recovery" characteristic. The only capacitance is the junction depletion layer capacitance, which is voltage-dependent and gives rise to the measurable QC. Silicon Carbide's wide bandgap (≈3.26 eV for 4H-SiC) provides the high breakdown field strength that enables the 650V rating in a relatively small die size, and its high thermal conductivity aids in heat dissipation.

11. Technology Trends

Silicon Carbide power devices, including Schottky diodes and MOSFETs, represent a significant trend in power electronics towards higher efficiency, frequency, and power density. The market is moving from 600-650V devices (competing with superjunction silicon MOSFETs and IGBTs) to higher voltage classes like 1200V and 1700V for industrial motor drives and electric vehicle traction inverters. Concurrently, there is a trend towards lower cost per amp as wafer sizes increase (from 4-inch to 6-inch and now 8-inch) and manufacturing yields improve. Integration is another trend, with the emergence of modules combining SiC MOSFETs and Schottky diodes. Furthermore, research continues into improving the Schottky barrier interface to reduce forward voltage drop further and enhance reliability. The adoption of SiC is driven globally by energy efficiency standards and the electrification of transportation and renewable energy systems.