MBRS1100T3G Equivalent, Alternative & Replacement Guide

MBRS1100T3G vs STPS1H100U vs SS110 vs B2100: Full Comparison

The one-line summary: STPS1H100U is the closest electrical drop-in (770mV, same package, same 175°C); SS110/SK110 wins on price but loses on surge (30-40A) and temperature rating; B2100 gives you 2A headroom in the same footprint for future-proofing.

When to Use STPS1H100U

Second-sourcing the exact spec. If your BOM is already qualified at 100V/1A/SMB, the ST part drops into the same layout with 20mV more VF — negligible. Same 50A surge, same 175°C junction rating.

Per the ST datasheet, it's a genuine same-spec alternative — the right choice when you need a second vendor without re-qualifying thermal behavior.

When to Use SS110 / SK110

Cost-driven designs where 0.8-0.85V is acceptable. The SS110 family is made by a dozen vendors, so spot pricing is aggressively low. But you pay in headroom: surge drops to 30-40A and junction temperature to 125-150°C depending on vendor.

Check the package before ordering — SS110 ships in both SMA (DO-214AC) and SMB (DO-214AA), and the footprints are not interchangeable. Verify the SMB suffix on your BOM.

When to Use B2100-13-F

When you want 2A headroom without a footprint change. The B2100 keeps the SMB package and 50A surge, adds a second amp of continuous current, and costs nearly the same at volume. VF at 1A (0.79V) is within 40mV of the original.

The trade: 150°C junction rating (25°C less than the onsemi part) and no AEC-Q101. Fine for industrial, wrong for automotive qualification.

When NOT to Use This Class of Diode at All

Below ~5V output rails, a 100V Schottky wastes efficiency. 0.75V on a 3.3V rail is 23% loss — use the 30V MBRS130LT3G (0.395V) or synchronous rectification.

Above ~100V buses, a Schottky is no longer the efficiency winner. Ultrafast diodes match or beat Schottky VF above 100V while leaking 100x less at temperature. For 150V+ rails, look at ultrafast or SiC.

Pinout & Layout Notes

All four parts carry the cathode band on pin 1. Reversed mounting conducts through the body diode in the wrong direction — the rail never blocks. Check the band against the silkscreen before reflow.

Thermal note: SMB dissipation depends on PCB copper area and vias, not just the package. In a dense layout, a 100V part running at 0.75V needs a larger pad than the footprint minimum — give the cathode pad room or derate the current.

Other Alternatives Worth Knowing

VS-MBRS1100TRPBF (Vishay) — the same part cross-referenced by Vishay, 780mV at 1A. A direct drop-in on paper, but marked Obsolete in some channels — confirm availability before designing it in.

STPS1H100A (ST, SMA) — the same ST die in the smaller SMA package with 620mV forward drop. Lower VF and smaller size, but the footprint differs from SMB — a PCB change, not a swap.

10BQ100PBF (Vishay) — 100V/1A SMB with 890mV drop and 50A surge. Functionally equivalent, slightly higher VF, often cheaper in box packaging.

MBRS3100T3G (onsemi, 3A) — the same 100V class in SMC with 3A of current. The upgrade path if your load outgrows 1A; we stock both in the same shipment.

MBRS3200T3G (onsemi, 200V) — for environments that stress even 100V: harsh load-dump, long battery strings, snubber circuits with big spikes. Costs 90mV more VF, buys 2x the margin.

Route by constraint: second-sourcing the exact spec goes to STPS1H100U; price pressure or future current growth goes to SS110 or B2100; a change in bus voltage class pulls you to the 30V MBRS130 (below 10V) or the 200V MBRS3200 (harsh environments).

The package and the surge rating are the two details that kill a swap — check both before re-spinning the BOM.

Frequently Asked Questions About MBRS1100T3G Replacements

Q1: What is the direct replacement for MBRS1100T3G?

A: STPS1H100U (ST) is the closest same-spec drop-in. 100V/1A in the same SMB package, 770mV vs 750mV VF, same 50A surge and 175°C junction rating. No layout change, no thermal re-qualification needed.

Q2: Is SS110 the same as MBRS1100T3G?

A: Same voltage/current class, not the same part. SS110 is 100V/1A with 0.80-0.85V VF (50-100mV higher), 30-40A surge (vs 50A), and 125-150°C junction (vs 175°C). It also ships in both SMA and SMB packages — verify the package before ordering.

Q3: Can I replace MBRS1100T3G with MBRS130LT3G?

A: Only if your bus stays at or below ~10V. The MBRS130 is 30V/1A with 395mV VF — a great efficiency upgrade on 3.3V/5V rails, but on 24V it runs at 1.25x margin, one transient from breakdown. The 30V rating decides this, not the footprint.

Q4: What's the best 2A upgrade?

A: B2100-13-F (Diodes Inc.) or MBRS3100T3G (onsemi). B2100 keeps the SMB footprint with 2A at 0.79V, 50A surge, 150°C. MBRS3100 moves to SMC for 3A with the same 100V class — bigger pad, more copper, more current.

Q5: Is VS-MBRS1100TRPBF a direct drop-in?

A: Electrically yes — it's the Vishay cross-reference of the same part (780mV, 100V/1A SMB). But it's marked Obsolete in some distribution channels. Confirm stock and date codes before designing it into a new BOM; STPS1H100U is the safer second source.

Q6: Can I use a 100V ultrafast diode instead?

A: Yes, with a higher VF in exchange for 100x lower leakage. A 100V ultrafast (e.g., US1B-class) drops ~0.95V at 1A but leaks microamps instead of hundreds of microamps at temperature. In hot high-bias applications, the leakage savings can beat the VF penalty — above 100V it's often the better choice entirely.

Q7: Do SMA and SMB versions swap?

A: No — the footprints are different sizes. SMA (DO-214AC) pads are ~4.0 x 2.3mm; SMB (DO-214AA) pads ~4.6 x 2.6mm. An SMA part on an SMB layout leaves pads exposed and lifts during thermal cycling. Always match the package suffix.

Q8: Which alternative has the lowest forward voltage?

A: STPS1H100A (ST) at 620mV, in the smaller SMA package. If you can accept the footprint change, it cuts 130mV per amp versus the MBRS1100T3G. Among SMB-package parts, the original's 750mV is already near the floor — 10BQ100PBF is 890mV, so the original wins the SMB class.