ProductsDiscrete SemiconductorsTIP121
PACKAGE REFERENCETO-220Confirm case, pinout and ordering suffix before purchase.
MANUFACTURER PART RECORD

TIP121

STMicroelectronics

TIP121 is an ST NPN power Darlington transistor in TO-220, tube — for driving motors, relays and solenoids directly from MCU outputs. The Darlington pair is the selection point: minimum DC current gain of 1000, so a few milliamps of base drive switches 5 A loads — no separate driver stage needed. Selection advice: ST lists the TIP121 as Active (in volume production). Its complement is the TIP126 (PNP) — for push-pull stages specify the pair together. Note the Darlington VCE(sat) of ~2 V at full load: at 5 A it dissipates ~10 W, so a heatsink is mandatory, and it is not a low-dropout switch — for efficient switching consider a MOSFET instead. Evidence: ST data confirms Active status, NPN Darlington, TO-220. Match the full TIP121 code — the TIP122 (100 V) and TIP120 (60 V) are different voltage grades. State quantity, packing and date-code requirements in your RFQ; we reconfirm the offered lot before quotation and reply within 24 hours.

Discrete SemiconductorsNPN Darlington transistorTO-220
MPN
TIP121
Manufacturer
STMicroelectronics
Family
NPN Darlington transistor
Package
TO-220
Manufacturer channel coverage
Checked by RFQ
Data last checked
Commercial check required
PROCUREMENT DATA

Identity and sourcing requirements.

Manufacturer part number
TIP121
Manufacturer
STMicroelectronics
Product family
NPN Darlington transistor
Category
Discrete Semiconductors
Package reference
TO-220
Manufacturer-channel report
Confirmed on request
Sourceics price status
Quoted for required quantity
Sourceics sourcing status
Supplier and stock verified during RFQ
Required order checks
Suffix, package, date code, lot, source and traceability
SELECTION GUIDANCE

TIP121 selection guidance

TIP121 is a NPN Darlington transistor from STMicroelectronics in TO-220. Discrete selection is a ratings exercise: polarity, voltage, current and thermal limits at your worst-case point, with the ordering code fixing the exact qualified device.

One message is enough to start: the TIP121 order code in full, the volume, reel/tube/tray choice and acceptable date codes. Before we put numbers on paper we re-validate the available lot line by line; expect our answer inside 24 hours.

QUOTE WORKFLOW

Four checks before a commercial offer.

01

Identity

Exact MPN, manufacturer and suffix

02

Supply

Supplier type, quantity and freshness

03

Evidence

Lot, labels, photos and documents

04

Terms

Price, lead time, payment and shipping

RELATED REFERENCES

Explore more Discrete Semiconductors records

Browse existing catalog records — same series first, then the same category and manufacturer. These are not confirmed replacements; compatibility requires engineering review.

COMMON QUESTIONS

TIP121 FAQ

What do the suffixes in TIP121 mean?

Every suffix in a manufacturer ordering code identifies one exact orderable device — package, temperature grade, packing format or a revision. TIP121 names the TO-220 configuration; a code that differs by even one suffix character may be a different device. Always quote the complete code exactly as it appears on your BOM.

What is the difference between package and packing for TIP121?

The package (TO-220) is the physical form of the device itself. Packing describes how the devices are delivered — reel, tube, tray or cut tape. The same ordering code can ship in different packing formats depending on the lot, so confirm the required packing format when you submit your RFQ.

Can you provide traceability documents for TIP121?

Traceability evidence — lot and date-code information, labels and photos — is confirmed per lot at quotation time, because it depends on the actual lot offered. Tell us which documents your receiving inspection requires when you submit the RFQ, and we will confirm what can be provided for the offered lot.

How do I request a quotation for TIP121?

To request a quotation for TIP121, send the full ordering code, manufacturer (STMicroelectronics), quantity, packing format and date-code needs in one RFQ. Every RFQ gets a reply within 24 hours.