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KST2222AMTF Equivalent & Substitute Parts
Part Overview
The KST2222AMTF is an NPN bipolar junction transistor manufactured by onsemi, housed in a SOT-23-3 surface mount package. This device is rated for 40 V collector-emitter breakdown voltage with a maximum collector current of 600 mA and 350 mW power dissipation. The transistor operates at a transition frequency of 300 MHz with a minimum DC current gain of 100 at 150 mA collector current and 10 V collector-emitter voltage.
The KST2222AMTF is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this component.
Substiute Parts
Key Parameters
| Parameter | Value | Unit |
|---|---|---|
| Transistor Type | NPN | — |
| Voltage - Collector Emitter Breakdown (Max) | 40 | V |
| Current - Collector (Ic) (Max) | 600 | mA |
| Power - Max | 350 | mW |
| Frequency - Transition | 300 | MHz |
| DC Current Gain (hFE) (Min) @ Ic, Vce | 100 @ 150mA, 10V | — |
| Vce Saturation (Max) @ Ib, Ic | 1V @ 50mA, 500mA | — |
| Current - Collector Cutoff (Max) | 10 | nA |
| Package / Case | SOT-23-3 (TO-236) | — |
| Mounting Type | Surface Mount | — |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) | — |
Substitute Part Grouping Explanation
Substitute parts for the KST2222AMTF are classified into two categories based on electrical and mechanical compatibility:
Direct Substitutes (Electrical and Mechanical Equivalence): Direct substitutes maintain identical or superior electrical ratings across all critical parameters: collector-emitter breakdown voltage (40 V), maximum collector current (600 mA), transition frequency (300 MHz), DC current gain minimum (100 @ 150mA, 10V), and saturation voltage characteristics. These parts are housed in the same SOT-23-3 package and share the same base product number or equivalent lineage. Direct substitutes include MMBT2222ALT1G, MMBT2222ALT3G, SMMBT2222ALT1G, and SMMBT2222ALT3G.
Similar Substitutes (Functional Compatibility with Parameter Variations): Similar substitutes operate within the same functional class but exhibit variations in one or more electrical parameters. The BC817 series variants (BC817-16LT1G, BC817-16LT3G, BC817-25LT1G, BC817-25LT3G, BC817-40LT1G, BC817-40LT3G) maintain the SOT-23-3 package and NPN configuration but differ in collector-emitter breakdown voltage (45 V versus 40 V), maximum collector current (500 mA versus 600 mA), transition frequency (100 MHz versus 300 MHz), and saturation voltage (700 mV versus 1 V). These parts are suitable for applications where the KST2222AMTF specifications exceed design requirements.
Substitution logic is based strictly on the following key parameters:
- Transistor type (NPN)
- Package type (SOT-23-3)
- Collector-emitter breakdown voltage rating
- Maximum collector current rating
- Power dissipation capability
- Transition frequency
- DC current gain characteristics
- Saturation voltage performance
Parameter Comparison
| Part Number | Manufacturer | Ic (Max) mA | Vce Breakdown (Max) V | Power (Max) mW | Frequency MHz | hFE (Min) | Product Status | Package |
|---|---|---|---|---|---|---|---|---|
| KST2222AMTF | onsemi | 600 | 40 | 350 | 300 | 100 | Obsolete | SOT-23-3 |
| MMBT2222ALT1G | onsemi | 600 | 40 | 225 | 300 | 100 | Active | SOT-23-3 |
| MMBT2222ALT3G | onsemi | 600 | 40 | 300 | 300 | 100 | Active | SOT-23-3 |
| SMMBT2222ALT1G | onsemi | 600 | 40 | 225 | 300 | 100 | Active | SOT-23-3 |
| SMMBT2222ALT3G | onsemi | 600 | 40 | 300 | 300 | 100 | Active | SOT-23-3 |
| BC817-16LT1G | onsemi | 500 | 45 | 300 | 100 | 100 | Active | SOT-23-3 |
| BC817-16LT3G | onsemi | 500 | 45 | 300 | 100 | 100 | Active | SOT-23-3 |
| BC817-25LT1G | onsemi | 500 | 45 | 300 | 100 | 160 | Active | SOT-23-3 |
| BC817-25LT3G | onsemi | 500 | 45 | 300 | 100 | 160 | Active | SOT-23-3 |
| BC817-40LT1G | onsemi | 500 | 45 | 300 | 100 | 250 | Active | SOT-23-3 |
| BC817-40LT3G | onsemi | 500 | 45 | 300 | 100 | 250 | Active | SOT-23-3 |
Engineering Selection Recommendations
Direct Substitutes - Recommended for Pin-Compatible Replacement:
MMBT2222ALT3G and SMMBT2222ALT3G are the primary recommended direct substitutes. Both maintain the full electrical specification set of the KST2222AMTF with 600 mA maximum collector current, 40 V breakdown voltage, and 300 MHz transition frequency. Both parts are in active production status, ensuring long-term supply availability. SMMBT2222ALT3G carries AEC-Q101 automotive qualification and is suitable for automotive-grade applications. MMBT2222ALT3G is suitable for general industrial and consumer applications. Both are RoHS3 compliant.
MMBT2222ALT1G and SMMBT2222ALT1G are secondary direct substitutes with identical electrical specifications except for reduced maximum power dissipation (225 mW versus 350 mW). These parts are appropriate for applications where thermal constraints limit power dissipation to 225 mW or less.
Similar Substitutes - Conditional Compatibility:
The BC817 series (BC817-16LT1G, BC817-16LT3G, BC817-25LT1G, BC817-25LT3G, BC817-40LT1G, BC817-40LT3G) are suitable substitutes only when application requirements do not demand the full performance envelope of the KST2222AMTF. These parts operate at reduced maximum collector current (500 mA versus 600 mA) and reduced transition frequency (100 MHz versus 300 MHz). The BC817 series is appropriate for low-frequency switching and amplification circuits where 100 MHz bandwidth is sufficient. All BC817 variants are in active production and RoHS3 compliant.
Frequently Asked Questions (FAQ)
Q: Can MMBT2222ALT1G replace KST2222AMTF in all applications?
A: MMBT2222ALT1G is electrically equivalent to KST2222AMTF in all parameters except maximum power dissipation. It is suitable for applications where power dissipation does not exceed 225 mW. For applications requiring the full 350 mW power rating, MMBT2222ALT3G or SMMBT2222ALT3G are required.
Q: What is the difference between MMBT2222ALT3G and SMMBT2222ALT3G?
A: Both parts are electrically identical with 600 mA maximum collector current, 40 V breakdown voltage, 300 MHz transition frequency, and 300 mW power dissipation. SMMBT2222ALT3G carries AEC-Q101 automotive qualification and is intended for automotive applications. MMBT2222ALT3G is suitable for general industrial and consumer applications. Both are RoHS3 compliant and in active production.
Q: Can BC817-40LT1G replace KST2222AMTF?
A: BC817-40LT1G is a functional substitute only for applications where the reduced specifications are acceptable. It provides 500 mA maximum collector current (versus 600 mA), 45 V breakdown voltage (versus 40 V), and 100 MHz transition frequency (versus 300 MHz). It is suitable for low-frequency switching applications but not for high-frequency circuits requiring 300 MHz bandwidth.
Q: Are all substitute parts available in the same SOT-23-3 package?
A: Yes. All substitute parts listed are housed in the SOT-23-3 (TO-236) surface mount package, ensuring mechanical and pin compatibility with the KST2222AMTF.
Q: What is the product status of the KST2222AMTF?
A: The KST2222AMTF is classified as obsolete. All recommended direct substitutes (MMBT2222ALT1G, MMBT2222ALT3G, SMMBT2222ALT1G, SMMBT2222ALT3G) are in active production status, ensuring continued availability and support.
Q: Are the substitute parts RoHS compliant?
A: Yes. All substitute parts listed are RoHS3 compliant. The KST2222AMTF does not specify RoHS status in the provided data.
Q: What is the difference between Cut Tape (CT) and Tape & Reel (TR) packaging?
A: Cut Tape (CT) and Digi-Reel® packaging is suitable for manual assembly and small-volume production. Tape & Reel (TR) packaging is optimized for automated pick-and-place assembly in high-volume manufacturing. Both formats contain the same electronic component; the difference is in the physical delivery and handling format.
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