An RTC family name is not a purchasable identity. A released BOM should carry the complete manufacturer part number, including temperature, package, compliance and supported packing characters. Analog Devices currently lists four models each for DS3231 and DS3232, because commercial and industrial grades are available in tube and tape-and-reel forms. Dropping even one character can change the approved item or create an ambiguous quotation.
This checklist turns the manufacturer ordering table into controls for engineering, sourcing and incoming inspection. Use it after choosing the RTC architecture in the real-time clock IC selection guide. Then confirm every code against the latest Analog Devices product page, data sheet, package drawing and supplier label before purchase.
What counts as a complete RTC orderable code?
Analog Devices lists four DS3231 models on its official product page: DS3231S#, DS3231S#T&R, DS3231SN# and DS3231SN#T&R (Analog Devices, DS3231 Product Page, retrieved 2026). A complete orderable code is one exact listed model, not the shorter DS3231 family name or a distributor-created abbreviation.
The BOM should separate three fields that often become mixed: manufacturer part number, approved package or footprint, and purchasing pack. Keep the full code in the first field. Record the package drawing and land pattern in controlled engineering fields. Record tube or reel and any minimum pack requirement in sourcing data. Why risk asking a free-text description to preserve identity?
| Family | Complete models currently listed by Analog Devices | Do not release as |
|---|---|---|
| DS3231 | DS3231S#; DS3231S#T&R; DS3231SN#; DS3231SN#T&R | DS3231 |
| DS3232 | DS3232S#; DS3232S#T&R; DS3232SN#; DS3232SN#T&R | DS3232 |
| DS1307 | DS1307+; DS1307N+; DS1307Z+; DS1307Z+T&R; DS1307ZN+; DS1307ZN+T&R | DS1307 |
For exact device records, review the DS3231S# product page, DS3231SN# product page, DS3232S# product page and DS3232SN# product page. The current manufacturer page remains the authority for orderability.
How do S and SN temperature grades differ?
The 2015 DS3231 data sheet specifies DS3231S# for 0°C to +70°C and DS3231SN# for -40°C to +85°C (Analog Devices, DS3231 Data Sheet, Rev. 10, 2015). S and SN share a 16-pin SO package, but they do not carry the same temperature qualification.
The same temperature pattern applies to DS3232. DS3232S# is the commercial-grade 0°C to +70°C model, while DS3232SN# covers -40°C to +85°C. Both use a 20-pin, 300-mil SO package. Therefore, changing S to SN is a qualification and sourcing decision, not a PCB-footprint redesign within that family.
A wider temperature grade may appear electrically preferable, but substitution still requires change control. Approved vendor list status, customer qualification, traceability, cost, availability and packing can differ. Use the detailed DS3231S# versus DS3231SN# comparison or DS3232S# versus DS3232SN# comparison before approving a grade change.
Why are PDIP and SOIC RTC packages not interchangeable?
Analog Devices lists six DS1302 base package and grade combinations across 8-pin, 300-mil PDIP, 208-mil SO and 150-mil SO packages (Analog Devices, DS1302 Data Sheet, Rev. 4, 2015). Identical pin counts do not make these through-hole and surface-mount bodies footprint-compatible.
DS1302+ and DS1302N+ are 8-pin, 300-mil PDIP models. DS1302S+ and DS1302SN+ use 208-mil SO packages. DS1302Z+ and DS1302ZN+ use narrower 150-mil SO packages. The N marks the industrial temperature option in each pairing. Current Analog Devices product tables also list T&R variants for the S, SN, Z and ZN surface-mount models.
| Package choice | Commercial code | Industrial code | PCB and purchasing check |
|---|---|---|---|
| 8 PDIP, 300 mil | DS1302+ | DS1302N+ | Through-hole pitch, row spacing and tube handling |
| 8 SO, 208 mil | DS1302S+ / DS1302S+T&R | DS1302SN+ / DS1302SN+T&R | Wide SO body, land pattern and packing |
| 8 SO, 150 mil | DS1302Z+ / DS1302Z+T&R | DS1302ZN+ / DS1302ZN+T&R | Narrow SO body, land pattern and packing |
What do +, # and T&R mean on RTC part numbers?
The DS1302 data sheet defines + as a lead-free, RoHS-compliant package, while the DS3231 data sheet defines # as RoHS compliant with possible exempt lead and a JESD97 e3 finish (Analog Devices, DS3231 Data Sheet, Rev. 10, 2015). These marks are not interchangeable decoration.
T&R means the manufacturer lists a tape-and-reel purchasing model. Current Analog Devices pages explicitly show DS3231S#T&R, DS3231SN#T&R, DS3232S#T&R and DS3232SN#T&R. They also show selected DS1302 and DS1307 SOIC reel models. Don’t append T&R merely because an assembly line prefers reels. Confirm the exact model first.
What should procurement verify before releasing an RTC BOM?
The current DS3232 page lists four models covering 2 temperature grades and 2 packing forms (Analog Devices, DS3232 Product Page, retrieved 2026). Procurement should verify the exact code, manufacturer status, package evidence, packing, AVL approval and quotation match before releasing any RTC line.
A practical AVL should use one row per complete manufacturer code. If both DS3231SN# and DS3231SN#T&R are acceptable, list both and give each its packing constraint. This structure prevents an approved reel code from silently authorizing a different grade, package or compliance mark. It also makes quotation comparison far easier.
How should labels and footprints be verified at receipt?
The DS3231 data sheet identifies a 16 SO package, package code W16#H2, outline 21-0042 and land pattern 90-0107 (Analog Devices, DS3231 Data Sheet, Rev. 10, 2015). Incoming inspection should connect the supplier label to this controlled engineering evidence before stock release.
Start with the outer label. Compare manufacturer name, complete orderable code, quantity, lot or batch identifier, date code, country information and packing type against the purchase order and traceability requirements. Then inspect a sample only under the approved procedure. Top marking can be shorter than the orderable code, so use the data sheet’s top-mark table rather than expecting the full BOM string on the package.
Next, verify physical compatibility. Check pin count, lead pitch, body width, pin-one indicator and package dimensions against the approved drawing. DS3231’s 16-pin wide SO and DS3232’s 20-pin wide SO are plainly different despite similar family names. A generic footprint library name is supporting information, not manufacturer evidence.
Frequently asked questions
These answers address recurring purchasing questions about package breadth, temperature letters, compliance characters, reel availability and label verification.
Can I put only “DS3231” on the BOM?
No. Use one complete manufacturer-listed model: DS3231S#, DS3231S#T&R, DS3231SN# or DS3231SN#T&R, as applicable. A family-only entry does not preserve temperature grade or packing form.
Are DS3231S# and DS3231SN# footprint-compatible?
Both use the same 16-pin SO package in the manufacturer ordering table, but their specified temperature grades differ. Treat substitution as a controlled grade and AVL change even when no PCB edit is required.
Can purchasing add T&R to any SOIC RTC?
No. Add T&R only when the manufacturer lists that exact orderable model. Package shape alone does not authorize a tape-and-reel purchasing code.
Does # mean exactly the same thing as +?
No. Keep the manufacturer-published character exactly. The cited data sheets define the compliance and finish conventions for each family, so the marks should not be normalized into one internal part number.
Should incoming inspection expect the full orderable code on the IC body?
Not necessarily. Verify the official top-mark table, package form, supplier label and traceability records together. A shortened body mark alone cannot establish packing identity.
Final BOM release rule
Across DS3231 and DS3232, Analog Devices lists 8 complete models spanning 2 grades and 2 packing forms per family (Analog Devices, DS3231 Product Page, retrieved 2026). Release the exact listed code, then bind it to verified package, footprint, AVL, label and packing evidence.
Verification method and freshness policy
ICEARTH checked the seven official Analog Devices resources listed below on July 27, 2026. The review compared manufacturer product-model tables with data-sheet ordering tables, temperature specifications, package drawings, land-pattern references and top-mark guidance. It is a documentation review for BOM and sourcing control; it does not claim laboratory testing, authenticity testing or drop-in qualification.
Statements that use “currently lists” are time-sensitive. Recheck the manufacturer product page before every BOM release, after any PCN or PDN notice, and at least quarterly while a part remains on an active AVL. Record the access date and the exact approved orderable code in the change record.
Editorial responsibility: This guide is published and maintained by ICEARTH. Send documentation corrections or source discrepancies to [email protected]; reported issues should be checked against the cited manufacturer documents before the article is revised.
Sources
This checklist uses 7 official Analog Devices resources: 4 product pages and 3 manufacturer data sheets, all checked on July 27, 2026. Product pages establish currently listed models, while data sheets establish temperature ranges, package identities, top marks and the manufacturer’s + and # conventions.
- Analog Devices, DS3231 Product Page, retrieved 2026-07-27.
- Analog Devices, DS3231: Extremely Accurate I2C-Integrated RTC/TCXO/Crystal Data Sheet, Rev. 10, retrieved 2026-07-27.
- Analog Devices, DS3232 Product Page, retrieved 2026-07-27.
- Analog Devices, DS3232: Extremely Accurate I2C RTC with Integrated Crystal and SRAM Data Sheet, Rev. 5, retrieved 2026-07-27.
- Analog Devices, DS1302 Product Page, retrieved 2026-07-27.
- Analog Devices, DS1302: Trickle-Charge Timekeeping Chip Data Sheet, Rev. 4, retrieved 2026-07-27.
- Analog Devices, DS1307 Product Page, retrieved 2026-07-27.
This article supports BOM and sourcing review. Confirm the latest manufacturer documentation and your organization’s qualification rules before release.
Continue the engineering review
From this guide to exact component data
Related component comparisons
These comparisons contain an exact product record linked in this article.
Browse product recordsAll engineering guidesSourcing resources
