Power inductors for an Indian SMPS design, sourced from Hong Kong, hit a footprint cliff at 4.7 µH. In Walsin’s inductor export the smallest part that carries 1 A is 3.2 mm² (2016); the smallest that carries 2 A is 16 mm² (4040), five times the board area. Among the 16 power-type series, at 10 µH nothing under 16 mm² carries even 0.5 A.
Venatech Limited, an authorised Walsin distributor in Hong Kong, holds the Walsin Technology (Walsin) inductor parametric export, Walsin_Inductor_ALL.xlsx: 5,410 real rows after we exclude the quality-assurance test row. This post is for a purchasing or design engineer at an Indian maker of meters, chargers, LED drivers or power supplies who has to fit a buck or flyback inductor into a fixed board area. Every part number is real and every count is ours. The one Indian statement below carries its source and the day we fetched it (23 October 2026).
What did India approve under the component scheme in August 2026?
A large pipeline, and it names coils. As reproduced on 18 August 2026 from a Ministry of Electronics and Information Technology release, the Electronics Component Manufacturing Scheme had approved 106 projects with 69,548 crore rupees of investment and about 74,628 direct jobs, after 31 new proposals worth 6,844 crore rupees were cleared on 17 August 2026.
The product categories listed include connectors, relays, antennas, coils, filters and capacitors. The release does not name an inductor product, a maker or a supplier, and we draw no conclusion about local supply of any part. The only point a buyer can take is that domestic component capacity is being planned; qualifying a second source is still your job.
| Point | What the source says | Source date | Match / mismatch |
|---|---|---|---|
| Projects approved | 106 in total, including 31 on 17 August 2026 | CXO Digital Pulse, 18 August 2026 (MeitY release) | Match for scale; mismatch with any part claim |
| Investment | 69,548 crore rupees overall; 6,844 crore for the 31 new proposals | CXO Digital Pulse, 18 August 2026 | Mismatch with a price: it is an investment total |
| Categories | Components include coils, filters and capacitors | CXO Digital Pulse, 18 August 2026 | Mismatch: no inductor part, size or current is named |
How much board area does each current step cost at each inductance?
At 4.7 µH it costs five times the area, and at 10 µH the ladder starts at 16 mm². We parsed the rated current and the length-by-width of every power-type row in the export: 403 rows in 16 series, of which 397 have a part number that agrees with the inductance column. For each inductance rung we took the smallest footprint that clears 1 A, 2 A and 3 A.
| Inductance | Rows, series | Smallest footprint at 1 A or more | At 2 A or more | At 3 A or more | Match / mismatch |
|---|---|---|---|---|---|
| 1 µH | 42, 15 | 1.28 mm² (1.6 × 0.8), MAP1608ST1R0MMPK |
2.4 mm² (2.0 × 1.2), WIP201210Y-1R0ML |
2.4 mm², same part | Match: the area barely moves |
| 2.2 µH | 44, 15 | 1.28 mm², MAP1608ST2R2MMPK |
3.2 mm² (2.0 × 1.6), WLPH201610M2R2PS |
8.0 mm² (3.2 × 2.5), WIP322512A-2R2ML |
Mismatch: 2.5 times at the third step |
| 4.7 µH | 42, 13 | 3.2 mm² (2.0 × 1.6), WLPH201610M4R7PS |
16.0 mm² (4.0 × 4.0), CSMM0420D-4R7M |
25.0 mm² (5.0 × 5.0), CSME0540D-4R7M |
Mismatch: 5 times at the second step |
| 10 µH | 17, 4 | 16.0 mm² (4.0 × 4.0), CSMM0420D-100M |
16.0 mm², same part | 46.15 mm² (7.1 × 6.5), VEFL2C0630-100MPA |
Mismatch: nothing smaller reaches 0.5 A |
| 22 µH | 15, 4 | 18.48 mm² (4.4 × 4.2), AIP0420MB-220M |
46.15 mm², VEFL2C0630-220MPA |
46.15 mm², same part | Mismatch: 2.5 times at the second step |
| 47 µH | 11, 3 | 35.4 mm² (6.0 × 5.9), CSME0645D-470M |
none | none | Mismatch: the ladder ends below 2 A |
We have not seen this counted anywhere: the 4.7 µH row jumps from 3.2 to 16.0 mm² with no part between, and the 10 µH row has no 1 A part below 16 mm². The current here is the published Rated Current, not a saturation figure, because only 146 of 5,410 rows publish a saturation current. Our post on rated current against saturation current explains why that matters for a switching converter.
Which worked parts show the 4.7 µH cliff?
Four parts show it, and each fails or passes on one named field. Take an incumbent 4.7 µH inductor that must carry 2 A. The Walsin parts that match on inductance and sit in a 2520 footprint carry 1.36 to 1.8 A; the first part that reaches 2 A is CSMM0420D-4R7M at 2.85 A rated and 4 A saturation, and it is 16 mm², 1.8 mm thick. The last column is yours.
| Walsin part | Size, thickness | Inductance, rated current | Match / mismatch against a 4.7 µH, 2 A line | Your incumbent |
|---|---|---|---|---|
WLPH252012M4R7PP |
2520, 1.2 mm | 4.7 µH, 1.61 A | Match on inductance; mismatch on current (below 2 A). Stocked as at 23 September 2026 | |
WIP252012S-4R7ML |
2520, 1.2 mm | 4.7 µH, 1.8 A | Match on inductance; mismatch on current (below 2 A) | |
WLPH201610M4R7PS |
2016, 1.0 mm | 4.7 µH, 1.3 A | Match on inductance; mismatch on current and footprint | |
CSMM0420D-4R7M |
4040, 1.8 mm | 4.7 µH, 2.85 A | Match on inductance and current; mismatch on footprint (16 mm²) | |
AIP0518MB-4R7M |
5452, 1.6 mm | 4.7 µH, 3.5 A | Match on inductance and current; mismatch on footprint (28.08 mm²) |
We excluded six rows because their part numbers contradict the inductance column, for example WLPH201610MR47PP and WIP201610P-R47ML, whose code reads 0.47 µH and whose column reads 4.0 µH. A second defect sits in the footprint column: 14 of the 397 rows, 7 WPA and 7 WQPH, are coded 2520(1008) but list 2.0 × 1.6 mm, so their area reads 3.2 mm² instead of 5.0. None is the only part in any cell of the table above. Our post on power inductors above 1 A lists the higher-current families.
What does the Hong Kong shelf hold for SMPS inductors?
Two lines, both 2520. Of the 1,125 part numbers in our 23 September 2026 stock list, 2 are inductors: WLPH252012M2R2PP (2.2 µH, 2.27 A) and WLPH252012M4R7PP (4.7 µH, 1.61 A), each 5.0 mm² and 1.2 mm thick. At 2.2 µH the stocked part clears 2 A, against a 3.2 mm² minimum in the export; at 4.7 µH it does not clear 2 A. The shelf is a dated snapshot, never live-synced, and we give no quantity or lead-time promise.
What does the export not publish?
Saturation current for 253 of the 397 rows, and any datasheet. The 397 rows hold a published saturation current on 144; the other 253 publish only a rated current. We hold no datasheet for any inductor series, so every figure above is the export’s, not a document we have read.
What will we not tell you about India?
Anything about Indian import, standards or approval of power supplies. We hold no office, entity or stock in India; our locations are Hong Kong, Shenzhen, Singapore and Jiangmen, with Chengdu in preparation. We state no duty rate, no certification requirement and no transit time. Confirm with your compliance team.
How Venatech helps
We start with the cross-reference. Paste your incumbent inductor into the free cross-reference tool, which decodes 18 manufacturers’ part numbers across 800,000+ crossable parts and shows Walsin candidates with match and mismatch fields, or upload a bill of materials to the BOM checker, up to 500 part numbers. The Hong Kong ready-stock list is a dated snapshot, 23 September 2026, never live-synced. Walsin is the only line we are authorised for; Stackpole and Viking are lines we supply. We work from Hong Kong, in small lots, and you can request a quote through the site. The tables above came from our own export; the inductor range lists the families. ISO 9001 and IATF 16949 are not held by Venatech. Qualification stays with you: confirm against both datasheets and qualify in your own circuit.
The short version
For an Indian SMPS board, the inductance is rarely the hard field; the current and the area are. At 4.7 µH Walsin’s smallest 2 A part is five times the area of its smallest 1 A part, at 10 µH nothing under 16 mm² carries 0.5 A, and the shelf holds two 2520 lines.
Send us one inductor from a power-supply bill of materials, with the current and the area you can spare, and we will return the Walsin rows with the differences stated. If your layout allows 3 mm² and your current is 2 A, what is the plan?
Sources
Fetched 23 October 2026. The Indian statement comes from this page; the part data comes from our own Walsin export and stock list.
- CXO Digital Pulse, “106 ECMS Projects Approved, Set to Generate around 75 thousand Direct Jobs with 69,548 Crore Rupees Investment”, dated 18 August 2026, reproducing a MeitY release: https://www.cxodigitalpulse.com/?p=60677
Frequently asked questions
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What did India approve under its component scheme in August 2026?
As reproduced on 18 August 2026 from a MeitY release, 106 projects with 69,548 crore rupees of investment, after 31 new proposals were cleared on 17 August 2026. The categories include coils, filters and capacitors. No inductor part or supplier is named, so we draw no sourcing conclusion.
How much larger is a 2 A, 4.7 µH Walsin inductor than a 1 A one?
Five times in board area. The smallest part at 4.7 µH that carries 1 A is 3.2 mm² (2016); the smallest that carries 2 A is 16 mm² (4040). We parsed 397 power-type rows to find it. No part sits between the two.
Can a 10 µH Walsin power inductor be smaller than 16 mm²?
Not within the 16 power-type series we parsed. The 10 µH rung has 17 rows in 4 series, and the smallest that clears 0.5 A is 4.0 by 4.0 mm. Other inductor families in the export offer smaller 10 µH parts, which we did not rate as power parts.
Which inductors are on the Hong Kong shelf?
Two, as at 23 September 2026: WLPH252012M2R2PP at 2.2 µH and 2.27 A, and WLPH252012M4R7PP at 4.7 µH and 1.61 A. Both are 2520 and 1.2 mm thick. The shelf is a snapshot, not live stock, and carries no quantity or lead-time promise.
Does the export publish a saturation current?
Only on 146 of 5,410 rows; among the 397 rows we used, 144 carry one and 253 do not. We hold no inductor datasheet. A switching design needs the saturation limit, so take it from Walsin in writing.
Do you state Indian import rules or approvals?
No. We hold no Indian customs or product-approval content, and no office or stock in India. We give no legal or customs advice; confirm with your compliance team. We supply parts, lot and date-code traceability and, on request, a certificate of conformity per shipment.