The DO-201AD package is the JEDEC axial outline used for 3 A to 5 A through-hole rectifiers. Body: 7.2 mm to 9.5 mm long, 4.8 mm to 5.3 mm in diameter. Leads: 1.22 mm to 1.32 mm in diameter, 25.4 mm minimum at each end. Those four numbers set your footprint, your insertion tooling and your thermal margin. Here is what the datasheets and the IPC rules actually require.
Key takeaways
- Vishay document 88516 (rev. 19-Dec-2025) gives 7.2 mm to 9.5 mm body length, 4.8 mm to 5.3 mm body diameter, 1.22 mm to 1.32 mm lead diameter, 25.4 mm minimum lead length.
- DO-27 is a different drawing: Diodes Incorporated permits a 5.60 mm body diameter, so a part sold as “DO-201AD (DO-27)” can be 0.3 mm fatter than your library model.
- A 1.60 mm finished hole with a 2.15 mm pad covers the 1.32 mm worst-case lead at IPC-2222 Level A.
- The 20 °C/W thermal resistance is conditional: 9.5 mm lead length, PCB mounted, 20 mm × 20 mm copper at each lead.
- Vishay still maintains the 1N5400 series. Diodes Incorporated discontinued its version and ST has put STPS5L40 on last-time-buy.
DO-201AD dimensions and what they constrain
DO-201AD is a JEDEC axial through-hole diode outline with a molded epoxy body 7.2 mm to 9.5 mm long and 4.8 mm to 5.3 mm in diameter, and two 1.22 mm to 1.32 mm leads at least 25.4 mm long. It houses 3 A to 5 A rectifiers such as the 1N5408.
[IMAGE 1: Dimensioned side view of a DO-201AD axial rectifier with body length, body diameter, lead diameter and lead length called out in millimetres | alt: “DO-201AD package dimensions diagram showing 9.5 mm body length, 5.3 mm body diameter and 1.32 mm lead diameter”]
The outline is loose: a 2.3 mm window on length, 0.5 mm on diameter. Design to the largest value any approved source allows.
Table 1. DO-201AD outline dimensions by source, plus the DO-27 drawing often quoted alongside it
| Dimension | Vishay 88516 (DO-201AD) | onsemi CASE 267-05 | Diodes Inc. (DO-27) |
| Body length | 7.2–9.5 mm | 7.30–9.50 mm | 8.50–9.50 mm |
| Body diameter | 4.8–5.3 mm | 4.80–5.30 mm | 5.00–5.60 mm |
| Lead diameter | 1.22–1.32 mm | 1.20–1.30 mm | 1.20–1.30 mm |
| Lead length (each end) | 25.4 mm min. | 25.40 mm min. | 25.40 mm min. |
| Unit weight | 1.1 g | 1.1 g (approx.) | not stated |
| Polarity | Colour band = cathode | Style 1: pin 1 = cathode | Colour band = cathode |
DO-201AD versus DO-27: the 0.3 mm nobody checks
Distributors and rectifier houses routinely write “DO-27/DO-201AD” as though the two were one part. The drawings disagree. Diodes Incorporated publishes DO-201AD at 4.80 mm to 5.30 mm body diameter and DO-27 at 5.00 mm to 5.60 mm.
That matters twice. Axial inserters are set up from a body-diameter window, and a 5.6 mm body in tooling jogged for 5.3 mm will jam. Second-source datasheets inherit the confusion: Won-Top Electronics prints 5.0 mm to 5.6 mm diameter under a DO-201AD heading. Set the body keep-out at 5.6 mm by 9.5 mm.
What the outline actually carries
DO-201AD is not a 3 A package. It is the package the industry standardised on for 3 A silicon rectifiers, then kept using as the die improved. Schottky and fast-recovery parts rated 5 A ship in the same outline.
Table 2. Representative devices in DO-201AD
| Part (manufacturer) | Type | VRRM | IF(AV) | VF max. | trr | Lifecycle |
| 1N5400–1N5408 (Vishay) | Standard recovery | 50–1000 V | 3.0 A | 1.2 V at 3.0 A | > 500 ns | Active |
| 1N5820–1N5822 | Schottky | 20–40 V | 3.0 A | not compared | n/a | Active |
| SBYV28-200-E3/54 (Vishay) | Fast recovery | 200 V | 3.5 A | 1.1 V at 3.5 A | 20 ns | Active |
| HER308 (HVCA) | High efficiency | 1000 V | 3.0 A | not stated | 75 ns | Active |
| HER503GP-TP (MCC) | Fast recovery | 200 V | 5.0 A | 1.0 V at 5.0 A | 50 ns | Not for new designs |
| STPS5L40 (STMicroelectronics) | Schottky | 40 V | 5.0 A | 0.50 V at 5.0 A | n/a | Last-time-buy |
Forward voltage across the outline spans 0.50 V to 1.7 V, so the package says nothing about conduction loss.
Footprint: hole size, pad size and lead spacing
Start from the worst-case lead diameter of 1.32 mm, not the 1.20 mm minimum. IPC-2222 sets the minimum finished hole as maximum lead diameter plus 0.25 mm at Level A, plus 0.20 mm at Level B, plus 0.15 mm at Level C.
- Level A finished hole: 1.32 + 0.25 = 1.57 mm. Specify 1.60 mm.
- Level B: 1.52 mm. Level C: 1.47 mm.
- Preferred pad is finished hole plus 0.53 mm, so 2.13 mm. Specify 2.15 mm.
- That leaves a 0.27 mm annular ring, comfortable for any Class 2 fabricator.
[INTERNAL LINK: through-hole land pattern rules in IPC-2222 → plated through-hole and annular ring design]
Lead spacing is where the common library footprint quietly breaks the rules. IPC-A-610 requires the lead to run straight for at least one lead diameter, and never less than 0.8 mm, before the bend starts. Its bend table calls for a minimum inside radius of two lead diameters once the lead exceeds 1.2 mm.
[IMAGE 2: Top-down footprint sketch showing hole diameter, pad diameter, and the straight-lead and bend-radius allowances that set minimum hole pitch | alt: “DO-201AD PCB footprint showing 1.60 mm finished hole, 2.15 mm pad and lead bend allowances”]
Run the arithmetic for a worst-case body. Hole pitch equals body length plus twice the straight lead run plus twice the sum of bend radius and half the lead diameter: 9.5 + 2(1.32) + 2(2.64 + 0.66) = 18.7 mm. The widely mirrored library footprint DIOAD1270W100L812D508 uses 12.70 mm spacing and assumes an 8.12 mm body and a 1.00 mm lead, below the JEDEC minimum of 1.20 mm.
That footprint assumes a nominal part and a tight bend. Use 15.24 mm as a working minimum, and 20.32 mm for Class 3 lead forming on a worst-case body. If you inherit a 12.70 mm footprint, check the hole diameter first.
Thermal: read the footnote before you trust 20 °C/W
Vishay quotes a typical junction-to-ambient thermal resistance of 20 °C/W for the 1N5400 series. The footnote qualifies it: 0.375 in (9.5 mm) lead length, PCB mounted, with 0.8 in × 0.8 in (20 mm × 20 mm) copper heat sinks. The leads are the heat path; that copper is part of the spec.
A conservative first pass at 3.0 A, using the datasheet maximum forward voltage of 1.2 V:
- Dissipation: 3.0 A × 1.2 V = 3.6 W (worst case; real loss depends on conduction angle and form factor).
- Rise: 3.6 W × 20 °C/W = 72 °C.
- Junction at 25 °C ambient: 97 °C. At 55 °C ambient: 127 °C.
- Against a 150 °C junction limit that is 23 °C of margin in a warm enclosure, before you shrink the copper.
[INTERNAL LINK: rectifier thermal derating → how to read forward-current derating curves]
The 3.0 A rating itself is referenced to 105 °C lead temperature at 12.5 mm lead length, and Vishay publishes separate derating curves for 6.4 mm, 7.9 mm and 12.7 mm leads. Cropping leads to fit a tight footprint moves you onto a different curve entirely.
Where DO-201AD sits among axial packages
Table 3. Axial rectifier packages compared
| Package | Body length × diameter | Lead diameter | Typical IF(AV) | Typical IFSM | Example part |
| DO-41 (DO-204AL) | 4.1–5.2 × 2.0–2.7 mm | 0.72–0.86 mm | 1.0 A | 30 A | 1N4007 |
| DO-15 (DO-204AC) | 5.9–7.6 × 2.7–3.6 mm | 0.69–0.88 mm | 1.5–2 A class | not compared | 1N5399 |
| DO-201AD | 7.2–9.5 × 4.8–5.3 mm | 1.22–1.32 mm | 3.0–5.0 A | 200 A | 1N5408 |
| P600 (R-6) | approx. 9.1 mm diameter | not compared | 6.0 A | 400 A | P600M |
| SMC (DO-214AB) | Surface mount | J-lead | 3.0 A | not compared | S3M |
DO-41 to DO-201AD buys three times the average current and six times the surge; P600 doubles surge again for twice the board area.
[INTERNAL LINK: DO-41 (DO-204AL) package guide → DO-41 axial rectifier outline and footprint]
Soldering, packaging and compliance
Vishay specifies solder dip at 275 °C maximum for 10 s per JESD 22-B106, matte tin leads solderable per J-STD-002 and JESD 22-B102, an E3 suffix meeting JESD 201 class 1A whisker testing, and molding compound to UL 94 V-0.
onsemi specifies 260 °C maximum for 10 s on the same generic part number, so build the wave profile to the tighter limit if you dual-source a 1N5408. Catalogue text drifts further: one RS listing for the Vishay part quotes 245 °C. Use the datasheet revision you approved.
Axial tape follows EIA RS-296-E. Vishay code /54 is 1400 pieces on a 330 mm (13 in) reel at 10.0 mm pitch and 52.4 mm tape width; code /73 is a 1000-piece ammo pack. Diodes Incorporated shipped 500-piece bulk or 1.2 k on a 13 in reel. Neither datasheet assigns a moisture sensitivity level, since these parts are not reflow mounted. For automotive work, check qualification explicitly: earlier Vishay revisions stated these devices are not AEC-Q101 qualified, and the current one claims nothing.
Lifecycle and sourcing reality check
The outline is healthy. Several of the parts inside it are not.
- Vishay 1N5400-1N5408: datasheet revised 19 December 2025. Active.
- Diodes Incorporated 1N5400-1N5408: DS28007 rev. 8-3 (Sept 2014) carried “not recommended for new design, use S3A-S3M series”; rev. 9-4 (Aug 2019) is marked obsolete. The replacement is a surface-mount family, which tells you where the volume went.
- ST STPS5L40 (40 V, 5 A Schottky): listed at DigiKey as last-time-buy, about 5,378 pieces in stock when checked in July 2026.
- MCC HER503GP-TP: not for new designs.
[INTERNAL LINK: second-sourcing discrete semiconductors → AVL strategy and EOL risk on discretes]
Price is not the constraint. At DigiKey in July 2026 a Vishay SBYV28-200-E3/54 runs about USD 0.47 in ones and USD 0.215 at 1,400 on reel. Availability of the specific die is, so add a second manufacturer part number at design time.
Frequently asked questions
What size is a DO-201AD package?
Vishay gives 7.2 mm to 9.5 mm body length and 4.8 mm to 5.3 mm body diameter, with 1.22 mm to 1.32 mm leads at least 25.4 mm long at each end. The onsemi CASE 267-05 drawing is within 0.1 mm of that on every dimension. A finished part weighs about 1.1 g.
Is DO-201AD the same as DO-27?
Not quite. Vendors use the names interchangeably, but the Diodes Incorporated DO-27 drawing allows a 5.00 mm to 5.60 mm body diameter and an 8.50 mm minimum body length, against 4.80 mm to 5.30 mm and 7.20 mm for DO-201AD. Design mechanical clearance to the DO-27 maximum if you accept both.
What hole size should I use for a DO-201AD footprint?
Use a 1.60 mm finished hole with a 2.15 mm pad. IPC-2222 Level A sets the minimum finished hole at maximum lead diameter plus 0.25 mm: 1.32 + 0.25 = 1.57 mm, rounded up to a standard drill. Tighter Level B and C rules allow 1.52 mm and 1.47 mm.
How much current can a DO-201AD diode handle?
Three amps is the classic rating, referenced to 105 °C lead temperature at 12.5 mm lead length, with a 200 A single-cycle surge rating for the 1N5400 series. Five-amp parts exist in the same outline, including the ST STPS5L40 Schottky and the MCC HER503 fast-recovery family.
What is the difference between DO-201AD and DO-41?
DO-41 is roughly half the length and half the diameter, with 0.72 mm to 0.86 mm leads instead of 1.22 mm to 1.32 mm. Electrically that is the difference between a 1 A, 30 A-surge 1N4007 and a 3 A, 200 A-surge 1N5408. The larger leads are the reason: they carry the heat out.
What to do next
Stay on DO-201AD when you need 3 A with real surge headroom, the assembly is already through-hole, and board area is not binding. Move to SMC (DO-214AB) for volume manufacturing, since that is where the silicon vendors pointed their replacements. Step up to P600 when you need 6 A or a 400 A surge.
[INTERNAL LINK: SMC (DO-214AB) surface-mount rectifiers → SMC package dimensions and thermal pad design]
Either way, do three things before release. Set the finished hole to 1.60 mm and confirm the inherited footprint is not still on a 1.00 mm lead assumption. Check whether the copper at each lead is near the 20 mm × 20 mm the thermal number assumes, and re-derate if not. Then pull lifecycle status on every approved part number: at least three common devices in this outline are already obsolete or on last-time-buy.
Sources
- Vishay 1N5400-1N5408 datasheet (document 88516) – https://www.vishay.com/docs/88516/1n5400.pdf
- Diodes Incorporated DO-201AD package outline – https://www.diodes.com/assets/Package-Files/DO-201AD.pdf
- Diodes Incorporated DO-27 package outline – https://www.diodes.com/assets/Package-Files/DO-27.pdf
- onsemi 1N5400-1N5408 (CASE 267-05) – https://media.digikey.com/pdf/Data%20Sheets/ON%20Semiconductor%20PDFs/1N5400-5408%20Series%20Rev5.pdf
- Vishay packaging information (document 88869) – https://www.vishay.com/docs/88869/packaging.pdf
JEDEC JEP95 registered outlines – https://www.jedec.org/standards-documents/technology-focus-areas/registered-outlines-jep95
