SR2020CT - 20A 20V Dual Schottky Rectifier | Galaxy Semiconductor
MPN: SR2020CT β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.62 | $0.62 |
| 10 | $0.54 | $5.40 |
| 100 | $0.45 | $45.00 |
| 500 | $0.38 | $190.00 |
| 1,000 | $0.32 | $320.00 |
SR2020CT Overview
A Schottky barrier rectifier is a type of power diode that uses a metal-semiconductor junction instead of a P-N junction. Because conduction is by majority carriers, Schottky diodes exhibit a lower forward voltage drop and essentially zero reverse recovery time compared with standard silicon rectifiers, making them the preferred output rectifier stage in switching power supplies, DC-DC converters, and battery-charging circuits where efficiency at low output voltages matters most.
Key features of the SR2020CT include epitaxial construction with a guard ring for transient protection, majority-carrier conduction for fast switching, and an Underwriters Laboratory flammability classification 94V-0 molded plastic package. The dual (center-tap) configuration places two diodes in one TO-220AB outline, saving board space in push-pull and forward converter secondary sides. Reverse voltage spans 20 to 60 V across the family (SR2020CT through SR2060CT) at a common 20 A forward current rating.
The guard-ring terminated metal-semiconductor junction suppresses avalanche and surface leakage, allowing conservative derating in inductive-load environments. Because reverse recovery charge is negligible, switching losses at 50-100 kHz converter frequencies remain low, and thermal design is dominated by conduction loss, calculated as Vf multiplied by average load current per leg.
Typical applications include low-voltage, high-frequency inverters, output rectification in switching-mode power supplies, freewheeling diodes in synchronous buck topologies, reverse-polarity protection in automotive and solar battery systems, and secondary-side rectification in adapter and charger designs.
Design consideration: at 20 A the conduction loss of roughly 10 W or more requires a heatsink or generous PCB copper with thermal grease; verify the forward-voltage-versus-current curve at your actual junction temperature.
This page synthesizes verified datasheet ratings, drop-in family alternatives, pinout, and practical design notes not consolidated in any single manufacturer datasheet.
Drop-in alternatives for SR2020CT β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with SR2020CT (same form factor and footprint) β differing in Mounting Type, Package, Technology.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
SR2040CT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SR2050CT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SR2060CT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SR20100CT
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
MBR20200CT
β Drop-In β οΈ εζ°εΎ ιͺθ―β In Stock
$0.24 / Unit
View Datasheet βSR2020CT Maximum Ratings & Electrical Characteristics
| Device Type | Dual Schottky Barrier Rectifier (center-tap, common cathode) |
| Maximum Repetitive Reverse Voltage (VRRM) | 20 V |
| Maximum Average Forward Current (IF(AV)) | 20 A |
| Forward Current per Leg | 10 A (dual configuration, datasheet family 20 A total rating) |
| Reverse Voltage Family Range | 20 V to 60 V (SR2020CT through SR2060CT) |
| Reverse Recovery Time (trr) | Negligible (majority carrier Schottky conduction) |
| Technology | Metal-semiconductor junction, epitaxial construction with guard ring |
| Package | TO-220AB |
| Flammability Classification | UL 94V-0 |
| Mounting Type | Through-hole, tab for heatsink mounting |
| Configuration | Common cathode dual diode |
| Typical Applications | Low-voltage high-frequency inverters, SMPS output rectification |
SR2020CT Pin Configuration
| Pin 1 | Anode 1 β Anode of diode 1 (AC/winding terminal 1) |
| Pin 2 | Cathode (Common) β Common cathode of both diodes, connected to the metal tab (rectified output) |
| Pin 3 | Anode 2 β Anode of diode 2 (AC/winding terminal 2) |
Typical Applications
SR2020CT is suitable for 6 applications: SMPS Output Rectification, Low-Voltage High-Frequency Inverters, Freewheeling / Catch Diode in Buck Converters, Battery Reverse-Polarity and Blocking Protection, Adapter and Charger Power Stages, ORing Diode for Redundant Power Supplies.
SMPS Output Rectification
The SR2020CT is a classic secondary-side output rectifier for switching-mode power supplies in the 5 V to 12 V range. Its Schottky metal-semiconductor junction has essentially zero reverse recovery, so switching losses at 50-100 kHz converter frequencies stay low, while the low forward voltage minimizes conduction loss at multi-ampere loads. In push-pull and forward converters, the dual common-cathode center-tap configuration connects both anodes to the transformer winding ends with the tab delivering the rectified output, replacing two discrete diodes with one TO-220AB. Estimated: at 10 A per leg and roughly 0.55 V forward drop, each diode dissipates about 5.5 W, so the tab needs a heatsink or generous copper pour to hold junction temperature within ratings.
Recommended
Low-Voltage High-Frequency Inverters
The manufacturer datasheet explicitly lists low-voltage, high-frequency inverters as a target application for the SR2020CT family. In these inverters the rectifier must switch at tens of kilohertz while carrying tens of amperes; the SR2020CT's majority-carrier Schottky conduction eliminates reverse recovery current spikes that would otherwise heat the switching devices and generate EMI. The guard-ring terminated junction adds robustness against the voltage transients typical of inductive inverter loads. The dual common-cathode package covers the two half-cycle rectification duties with a single part, halving assembly count. Provide heatsinking for the tab because conduction loss at high current dominates thermal design in this application.
Recommended
Freewheeling / Catch Diode in Buck Converters
In non-synchronous buck converters and motor-drive freewheeling paths, the SR2020CT serves as a low-loss catch diode. When the switching MOSFET turns off, the inductor current must freewheel through the diode; a Schottky with near-zero reverse recovery minimizes the turn-on loss of the MOSFET on the next cycle and avoids the current overshoot seen with standard silicon diodes. The 20 A rating covers high-current 5 V and 12 V rails. Estimated: with 10 A average freewheel current at about 0.55 V forward drop, dissipation is roughly 5.5 W, so heatsink the tab or limit duty cycle accordingly. Verify that the switch-node voltage spikes stay below the 20 V VRRM rating, or select the SR2060CT grade.
Recommended
Battery Reverse-Polarity and Blocking Protection
For automotive, solar, and battery-charger systems operating at 12 V nominal, a series SR2020CT provides simple reverse-polarity and blocking protection. The Schottky forward drop of roughly 0.5 V wastes far less power than a standard silicon rectifier diode, important at the high charge and load currents the 20 A rating supports. The guard-ring construction improves tolerance of load-dump-style transients common in automotive environments, although sustained clamping above 20 V reverse requires the SR2060CT grade instead. Mount the tab to chassis metal for heatsinking at sustained high current, and account for the series forward drop in low-headroom battery-powered designs.
Recommended
Adapter and Charger Power Stages
AC-DC adapters and battery chargers in the 20 W to 150 W class use the SR2020CT as the secondary rectifier or as ORing/protection diodes at the DC output. The dual configuration fits center-tapped transformer secondaries common in flyback and forward adapters, delivering both output half-cycles from one TO-220AB. Because the Schottky exhibits negligible reverse recovery, the part contributes minimal switching noise to the output, easing EMI filter design for conducted-emissions compliance. The UL 94V-0 plastic rating supports safety-critical adapter housings. Estimated: at a 5 A charge current and approximately 0.5 V drop, each leg dissipates about 2.5 W, manageable with a small clip-on heatsink or PCB copper.
Recommended
ORing Diode for Redundant Power Supplies
In dual-supply and battery-backup architectures, SR2020CT devices OR two power sources onto a common rail. The 20 A rating supports substantial load share, and the low Schottky forward drop limits the voltage penalty and heat versus standard rectifiers. Placing one dual package per source keeps isolation symmetrical and simplifies layout, with the common-cathode tab tying directly to the load rail or a copper bus. Estimated: at 10 A per source and about 0.55 V forward drop, each device dissipates roughly 5.5 W, so a bonded heatsink is recommended for continuous operation. Where rail voltage and spikes stay well below 20 V, this grade gives the lowest available dissipation of the SR20xx family.
Recommended
Recommended Products Summary
Engineering reference data for SR2020CT β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SR2040CT | SR2060CT | MBR20200CT |
|---|---|---|---|---|
| Package | TO-220AB | TO-220AB - same | TO-220AB - same | TO-220AB - same |
| Brand | Galaxy Semiconductor (multi-sourced: Daco, Semtech, UPM) | Galaxy Semiconductor | Galaxy Semiconductor | onsemi |
| Maximum Reverse Voltage (VRRM) | 20 V | 40 V | 60 V | 200 V |
| Forward Current | 20 A | 20 A | 20 A | 20 A |
| Configuration | Dual common cathode | Dual common cathode | Dual common cathode | Dual common cathode |
| Reverse Recovery | Negligible (Schottky) | Negligible (Schottky) | Negligible (Schottky) | Negligible (Schottky) |
| Relative Forward Drop | Lowest (20 V grade) | Slightly higher | Slightly higher | Highest (200 V grade) |
Key Differentiators
- Lowest forward voltage in the family (vs SR2060CT)
- Multi-source availability under one MPN (vs MBR20200CT)
- Dual center-tap saves board space (vs two single Schottky diodes)
Design Notes
At high load the SR2020CT dissipation is dominated by conduction loss, not switching loss. Estimated: with about 0.55 V forward drop at 10 A per leg, each diode dissipates roughly 5.5 W and the dual package up to 11 W, which a bare TO-220AB in free air cannot sustain. Mount the tab to a heatsink with thermal grease (or at least 6 cm2 of 2 oz copper) and derate current above 25 C ambient per the datasheet derating curve. Recheck forward voltage at actual junction temperature because VF rises with temperature at high current for some Schottky grades.
The 20 V VRRM rating is the SR2020CT's tightest constraint. Leakage-inductance spikes on transformer secondaries and switch-node ringing in buck converters routinely exceed the DC rail voltage by 50-100%. Measure the actual reverse voltage with an oscilloscope at maximum load and minimum input; if peaks exceed roughly 16 V, step up to the SR2040CT or SR2060CT grade (same footprint, pin-to-pin) instead of risking avalanche. Also confirm the tab is at cathode potential before bolting it to a grounded heatsink without an insulator.
Keep the anode loops (pin 1 and pin 3 to the transformer winding) short and symmetric so both half-cycles see equal parasitic inductance; asymmetric loops in center-tap rectifiers cause uneven current sharing and localized heating. Use wide traces or copper pours for the 20 A paths - as a rule of thumb, at least 5 mm of 2 oz copper per 10 A for modest temperature rise. Place a snubber or RC clamp directly across each anode-to-cathode pair if ringing is present, sized per the manufacturer application guidance.
Compliance Information
The plastic package carries UL 94V-0 flammability classification per the verified datasheet text. No explicit RoHS/REACH statement appeared in the retrieved web data; confirm with the specific manufacturer brand ordered.
