CROSS-REFERENCE ALTERNATIVE
COS3842BD is a Chinese-manufactured PWM Controller from COSINE (科山芯创) that cross-references to UC3842, and also to ST3842.
It is a SOP8 device positioned as a domestic-supply option against the imported: shorter lead times, no allocation risk and a stable price for volume production. Because the parts are not pin-identical in every case, the engineering checklist below lists what to verify before you commit.
Cross-reference · Before you substitute · Related parts · FAQ · Request a quote
COS3842BD — PWM Controller, alternative to UC3842
COS3842BD is supplied by Shenzhen Jingteng Electronics (JTDZ Tech) as a domestically sourced option for UC3842, ST3842 (KA3842). Imported parts in this class are frequently subject to allocation, long lead times and steep price swings. A Chinese-manufactured equivalent removes that exposure: the parts are production-validated in industrial, consumer and automotive designs and ship from stock on a short lead time.
Cross-reference chart — which imported parts does COS3842BD replace?
Every imported part number that COS3842BD is published as a cross-reference alternative to, per the COSINE (科山芯创) 2025 selection table:
| imported part number | brand | Replaced by (this part) |
|---|---|---|
| UC3842 | — | COS3842BD |
| ST3842 | KA3842 | COS3842BD |
Cross-reference means functional equivalence in the same application role. It is not a blanket claim of pin-for-pin identity — confirm package, pinout and the parameters listed below before you release a design change.
Device information
| Part number | COS3842BD |
| Manufacturer | COSINE (科山芯创) |
| Device class | PWM Controller |
| Package | SOP8 |
| Pin Count | 8 |
| Verified and new, traceable date code | |
| Stock | In stock, ships within 24 hours |
| Description | PWM Controller, SOP8 package. |
What to verify before substituting COS3842BD
These are the parameters that decide whether a cross-reference works in practice. Run through the list against the datasheet before releasing a change:
- Supported topologies and the oscillator/timing network the used — the R/C values set your frequency
- Maximum duty cycle and current-mode vs voltage-mode control
- Reference voltage accuracy and the feedback divider it feeds
- Start-up current and UVLO thresholds, which decide the start-up resistor value
- Gate-drive output current and whether an external driver is needed for your MOSFET
- Current-sense comparator threshold and blanking time
- Package and pinout
Typical applications
- Offline and DC-DC switch-mode power supplies
- Flyback, forward and push-pull topologies
- Battery chargers and adapters
- LED drivers and ballasts
- Inverters and UPS stages
- Industrial power conversion
Related COSINE parts and alternatives
Other {BRAND} parts in the same device family or the same device class — useful when you are cross-referencing a whole BOM rather than a single line item.
| COSINE part | Package | Cross-references to | Relation |
|---|---|---|---|
| COS3525AP | SOP16 | SG3525AP, KA3525A, UC1525A | PWM Controller |
| COS3525ADW | WSOP16 | SG3525ADW | PWM Controller |
Frequently asked questions
What does COS3842BD replace?
According to the COSINE (科山芯创) 2025 cross-reference table, COS3842BD is published as an alternative to UC3842, ST3842 (KA3842).
Is COS3842BD a pin-to-pin drop-in for UC3842?
Cross-reference means the part is intended for the same application role; it is not a blanket guarantee of pin-for-pin identity. Check package, pinout and the parameters listed under “What to verify” above, or send us your BOM and we will confirm before you commit.
Can you supply the UC3842 as well?
Yes. We source both the imported and the Chinese-manufactured alternative, so you can compare price, lead time and availability on the same quote.
What is the MOQ and lead time for COS3842BD?
MOQ 1 pc. COS3842BD is held in stock and ships within 24 hours; quotes are returned within 2 business hours. We ship worldwide including India, Vietnam and the Middle East.
Request a quote for COS3842BD
Send us the part number and target quantity — we reply within 2 business hours with price, stock and a cross-reference confirmation.
Request a quote More Power Management Chips
Genuine original parts guaranteed — traceable lot & date code, X-ray / visual inspection and third-party test supported before shipment.
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