Quick Summary for Buyers
The PM-DB2798S+ is a MIL-STD-1553 data bus interface transformer manufactured by Holt Integrated Circuits in partnership with Premier Magnetics. It is a dual ratio device with both 1:2.5 and 1:1.79 secondary winding options, packaged in a compact 8-pin surface-mount form factor. The part is widely specified in military and aerospace 1553 data bus designs.
For procurement teams, the practical reality is that this transformer family sits outside mainstream catalog distribution. Buyers searching for stock typically encounter long lead times, limited unit counts per source, and an aftermarket of mixed traceability. Inspection, lot consistency, and original packaging verification matter more here than in commodity component categories.
ZZX Electronics currently holds 513 pcs of PM-DB2798S+ in date code 2115 (2021 Week 15), supported by lot traceability documentation and inspection photos on request. This article covers what the part is, what to confirm before purchasing legacy MIL-STD-1553 transformers, and how ZZX supports buyers sourcing this component.
What Is PM-DB2798S+?
PM-DB2798S+ is a pulse transformer designed for MIL-STD-1553 data bus interface circuits. Holt Integrated Circuits introduced the PM-DB2790S / PM-DB2791S / PM-DB2795S / PM-DB2798S family in partnership with Premier Magnetics as reduced-footprint surface-mount alternatives to traditional through-hole 1553 interface magnetics.
Within this family, PM-DB2798S+ is the dual ratio variant. It combines the functions of the PM-DB2791S and PM-DB2795S into a single component, allowing the designer to select either a transformer coupled or direct coupled turns ratio from the secondary winding. The two available ratios are 1:2.5 and 1:1.79, matching the standard 1553 transceiver coupling configurations.
Key electrical and physical attributes:
| Attribute | Value |
|---|---|
| Function | MIL-STD-1553 data bus interface transformer |
| Configuration | Dual ratio (1:2.5 and 1:1.79) |
| Primary DCR | 2 Ω |
| Secondary DCR | 3.5 Ω |
| Package | 8-pin gull-wing SMD |
| Body size | 0.40″ × 0.40″ × 0.185″ (approximately 10.16 × 10.16 × 4.7 mm) |
| Manufacturer | Holt Integrated Circuits (in partnership with Premier Magnetics) |
| Lead finish | Pb-free (RoHS), as indicated by the “+” suffix |
For technical performance characteristics, designers should refer to Holt’s official datasheet. ZZX does not redistribute manufacturer documentation beyond the link provided on the product page.
Lifecycle Considerations
Holt Integrated Circuits continues to list the PM-DB transformer family in its catalog at the time of writing. However, distribution availability for individual PM-DB series part numbers varies significantly across authorized channels. Several distributors who carry adjacent parts in the family do not carry PM-DB2798S+ specifically, and stock depth on aftermarket channels is often shallow and inconsistent.
For buyers, the practical takeaway is that long-term supply for any specific PM-DB series ordering code should be confirmed directly with Holt Integrated Circuits or authorized distributors before committing to a multi-year procurement plan. Manufacturer lifecycle status can change, and Holt may issue product change notices that affect individual ordering codes within the family.
ZZX does not make formal lifecycle declarations on behalf of original component manufacturers. We treat PM-DB2798S+ as a legacy / hard-to-find sourcing target rather than a stable, in-production catalog item, and we recommend buyers approach it that way for procurement planning purposes.
Buyers placing large or repeat orders should:
- Confirm current lifecycle status with Holt Integrated Circuits or an authorized distributor.
- Document the date codes received in each shipment for traceability.
- Plan reserve inventory for sustainment projects where redesign is not feasible.
Lifecycle uncertainty is the norm rather than the exception for legacy avionics and military-grade interface magnetics, and procurement frameworks should reflect that.
Current Sourcing Challenges
Sourcing PM-DB2798S+ involves several recurring challenges that buyers should plan for:
Limited authorized distribution. Major broadline distributors that stock the broader Holt portfolio do not consistently list PM-DB2798S+ as an active catalog item. This pushes most buyers toward independent distributors, brokers, and the aftermarket — channels with widely varying quality controls.
Shallow stock depth. Where the part does appear on third-party listings, the quantities offered are typically in the single-digit to low-double-digit pcs range, with significant price variation between sources. Buyers requiring quantities of 100 pcs or more often need to aggregate across multiple sources, which complicates lot consistency.
Date code spread. Surviving inventory pools tend to span several production years. For applications that require consistent magnetic characteristics across a build, the variation in date codes across shipments is a real consideration, and buyers should request date code disclosure before purchase.
Counterfeit and remarked risk. The combination of a specialized aerospace customer base, low-volume production, and aftermarket pricing creates incentives for counterfeit and remarked product to enter the supply chain. Visual inspection alone is rarely sufficient; lot and packaging verification is essential.
Documentation gaps. Aftermarket sourcing channels frequently cannot provide complete traceability documentation back to the manufacturer. For programs with quality requirements (AS9100, ISO 9001 with traceability annexes, etc.), this can disqualify otherwise functional inventory.
A disciplined sourcing process — clear date code requirements, inspection before payment, documented packaging condition — addresses most of these challenges.
ZZX Inventory Information
At the time of publication, ZZX Electronics holds verified inventory of PM-DB2798S+ with the following characteristics:
| Attribute | Value |
|---|---|
| Quantity available | 513 pcs |
| Lot No. | 2115 |
| Date code | 2115 (2021 Week 15) |
| Country of origin | China |
| Manufacturer | Holt Integrated Circuits |
Lot and date code consistency across all 513 pcs is documented, which is useful for buyers who require a single-lot build for engineering qualification or production consistency. Inspection photos showing the actual chip silkscreen, label, and packaging are available on request before any order commitment.
Stock quantities and pricing reflect the position at the time this article was published. Both can change without notice as inventory moves. Buyers should request a current availability check by quoting the part number and required quantity. ZZX can also coordinate inspection of a sample unit shipped ahead of a production order, which is the standard practice we recommend for first-time buyers of legacy components.
How Buyers Can Verify Authenticity
Authenticity verification is the single most important step when sourcing legacy MIL-STD-1553 transformers from any channel other than the original manufacturer. The following checklist reflects the verification steps ZZX uses internally and recommends to buyers.
1. Request inspection photos before paying. A reputable supplier will share high-resolution photos of the actual lot in stock, not generic product photos. Photos should clearly show the component silkscreen, the packaging label, and the overall packaging condition. Compare the part number, lot code, and date code visible in the photos against what the supplier is quoting in writing.
2. Verify silkscreen markings. The silkscreen on the transformer body should show the part number (“PM-DB2798S+”) and a date code in a format consistent with Holt’s published convention. Markings that are partially worn, off-center, or printed in an inconsistent font are warning signs. Genuine Holt parts use consistent industrial laser or pad-print marking; remarked parts often show solvent residue, slight ghosting under the new mark, or surface texture inconsistencies.
3. Verify the packaging label. The original Holt / Premier Magnetics packaging includes a printed label with the part number, lot number, date code, country of origin, and quantity. The label should also include barcode encoding of the part number and reference number. A handwritten or hand-applied label, or a label that does not match the silkscreen lot/date code, is a major red flag.
4. Confirm lot and date code consistency. All units within a single shipment should share the same lot number and date code. Mixed lots within a single tray or bag almost always indicate aftermarket repackaging rather than original factory packaging. For programs requiring single-lot builds, this verification is a hard requirement, not a preference.
5. Inspect packaging condition. Original factory packaging for surface-mount transformers typically uses anti-static trays or moisture barrier bags. Loose units in generic ESD bags, units wrapped in tape, or packaging that shows signs of having been opened and re-sealed warrant additional scrutiny.
6. Request documentation. Where available, buyers should request a Certificate of Conformance (CoC) or inspection report from the supplier. ZZX can provide such documentation for inventory we hold under verified lot traceability.
7. Order a sample before production quantity. For first-time purchases or new suppliers, ordering a small sample for engineering inspection before committing to production volumes is inexpensive insurance. ZZX coordinates sample orders for buyers who request them.
These steps, applied consistently, address the great majority of counterfeit and quality risks in the legacy MIL-STD-1553 transformer market.
Procurement Strategies for Legacy Components
For PM-DB2798S+ and similar legacy interface magnetics, three procurement strategies cover most real-world scenarios:
For active production at known volumes, place orders at the cadence the program demands, but specify lot and date code requirements in writing on each purchase order. Use multiple qualified suppliers to reduce single-source risk, while accepting that lot consistency may not be maintainable across suppliers. Document everything for traceability audits.
For long-term sustainment programs (10 years and beyond), consider a one-time buy strategy to secure sufficient inventory for the program’s expected life, plus a reasonable reserve for field replacement. Storage conditions matter — transformers should be kept in anti-static, low-humidity environments with periodic inventory rotation if humidity-sensitive packaging is used. The economics of a one-time buy compared to repeated aftermarket purchases often favor consolidation, even accounting for the carrying cost of inventory.
For repair, refurbishment, and field replacement, smaller-quantity purchases from a verified source are usually the most practical path. The verification overhead (inspection, documentation) is proportionally higher per unit, but the total exposure is small. Buyers in this scenario benefit most from suppliers who can offer documentation and inspection support for small orders.
In all three scenarios, the constant is documentation. Lot and date code traceability, inspection records, and verified supplier provenance reduce risk at every downstream step.
A Note on Engineering Migration
For long-term designs, customers may need to evaluate newer interface transformer or magnetic-module options based on official manufacturer documentation. ZZX Electronics does not provide engineering migration certification. Any replacement, redesign, or qualification decision should be verified by the customer’s engineering team. Please refer to the manufacturer’s official lifecycle and migration documentation for technical guidance.
How ZZX Electronics Can Support
ZZX Electronics serves as an independent sourcing partner for hard-to-find and obsolete electronic components, including legacy MIL-STD-1553 interface transformers like PM-DB2798S+. Our services for this category include:
- Sourcing of verified inventory with lot and date code traceability
- Inspection photos of actual stock provided before order commitment
- Sample order coordination for engineering qualification
- Documentation support, including Certificates of Conformance where available
- Procurement risk consultation for legacy and obsolete component programs
We do not act as an authorized distributor for Holt Integrated Circuits and do not certify components on behalf of the original manufacturer. Our role is to verify what we hold, document it, and support the buyer’s own qualification process.
If you are sourcing PM-DB2798S+ or related parts in the Holt PM-DB series, three next steps are available:
- Request a stock availability check for the quantity you need: PM-DB2798S+ on ZZX Electronics.
- Request inspection photos of our current lot 2115 inventory before any order commitment.
- Request a sample for engineering evaluation ahead of a production purchase.
Other Holt parts and related integrated circuits are available through the same sourcing channel.
Disclaimer
This article is based on publicly available manufacturer documentation and ZZX Electronics’ sourcing experience. It does not constitute engineering certification or a guarantee of component compatibility.
ZZX Electronics serves as an independent sourcing partner for obsolete and hard-to-find components. We do not certify replacements on behalf of original component manufacturers. Any decisions regarding component selection, redesign, migration, or qualification must be made and verified by the customer’s engineering team under their specific application conditions.
Inventory quantities, lot codes, and date codes referenced in this article reflect verified information at the time of publication and are subject to change.
