AT-41533-TR1G RF Transistor NPN Equivalent & Substitute Parts

Part Overview

The AT-41533-TR1G is an RF transistor NPN manufactured by Broadcom Limited, designed for RF applications operating at 12V with a maximum collector current of 50mA and power dissipation of 225mW. This surface mount device in SOT-23 packaging is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The part operates across the 900MHz to 2.4GHz frequency range with specified noise figure and gain characteristics suitable for RF signal amplification in mobile and wireless communication systems.

Key Parameters

Parameter	Value	Unit
Transistor Type	NPN	—
Voltage - Collector Emitter Breakdown (Max)	12V	V
Current - Collector (Ic) (Max)	50mA	mA
Power - Max	225mW	mW
Noise Figure (Typ @ f)	1dB ~ 1.6dB @ 900MHz ~ 2.4GHz	dB
Gain	9dB ~ 14.5dB	dB
DC Current Gain (hFE) (Min) @ Ic, Vce	30 @ 5mA, 5V	—
Operating Temperature (TJ)	150°C	°C
Mounting Type	Surface Mount	—
Package / Case	TO-236-3, SC-59, SOT-23-3	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the AT-41533-TR1G is determined by the following critical parameters:

Electrical Compatibility Criteria:

Transistor type must be NPN
Voltage rating must equal or exceed 12V collector-emitter breakdown voltage
Maximum collector current must be sufficient for 50mA operation
Power dissipation capability must support 225mW
Noise figure and gain characteristics must fall within or near the specified ranges for RF applications at 900MHz to 2.4GHz

Mechanical Compatibility Criteria:

Mounting type must be surface mount
Package must be compatible with SOT-23-3 footprint or equivalent small outline packages

Compliance Criteria:

Moisture sensitivity level should be MSL 1 (Unlimited) for optimal handling
REACH and RoHS compliance status should be documented

The substitute parts are grouped into two categories: RF-optimized substitutes (2SC5646A-TL-H, BFP540ESDH6327XTSA1, BFP760H6327XTSA1, HFA3102BZ) designed for high-frequency RF applications, and general-purpose NPN substitutes (MMBT2484LT1G, MMBT2484LT3G, MMBT6429LT1G) suitable for lower-frequency or non-RF applications where the full RF performance of AT-41533-TR1G is not required.

Parameter Comparison

Parameter	AT-41533-TR1G	2SC5646A-TL-H	BFP540ESDH6327XTSA1	BFP760H6327XTSA1	HFA3102BZ	MMBT6429LT1G
Transistor Type	NPN	NPN	NPN	NPN	6 NPN	NPN
Voltage - Collector Emitter Breakdown (Max)	12V	4V	5V	4V	12V	45V
Current - Collector (Ic) (Max)	50mA	30mA	80mA	70mA	30mA	200mA
Power - Max	225mW	100mW	250mW	240mW	250mW	225mW
Frequency - Transition	900MHz ~ 2.4GHz	10GHz ~ 12.5GHz	30GHz	45GHz	10GHz	700MHz
Noise Figure (Typ @ f)	1dB ~ 1.6dB @ 900MHz ~ 2.4GHz	1.5dB @ 2GHz	0.9dB ~ 1.4dB @ 1.8GHz	0.5dB ~ 0.95dB @ 900MHz ~ 5.5GHz	1.8dB ~ 2.1dB @ 500MHz ~ 1GHz	—
Gain	9dB ~ 14.5dB	9.5dB ~ 10.5dB @ 2GHz	21.5dB	16.5dB ~ 29dB	12.4dB ~ 17.5dB	—
DC Current Gain (hFE) (Min) @ Ic, Vce	30 @ 5mA, 5V	100 @ 5mA, 1V	50 @ 20mA, 3.5V	160 @ 35mA, 3V	40 @ 10mA, 3V	500 @ 100µA, 5V
Operating Temperature (TJ)	150°C	150°C	150°C	150°C	150°C	150°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	SOT-23-3	3-SSFP	SOT-343	SOT-343	14-SOIC	SOT-23-3
Product Status	Obsolete	Obsolete	Active	Active	Active	Active
RoHS Status	—	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	3 (168 Hours)	1 (Unlimited)

Engineering Selection Recommendations

For RF Applications (900MHz to 2.4GHz Band):

BFP760H6327XTSA1 is the primary substitute for AT-41533-TR1G in RF applications. This Infineon Technologies part is active in production status, ROHS3 compliant, and offers superior noise figure (0.5dB ~ 0.95dB @ 900MHz ~ 5.5GHz) and gain characteristics (16.5dB ~ 29dB) compared to the original part. The 45GHz transition frequency provides significant headroom for 2.4GHz operation. Collector current capability of 70mA exceeds the 50mA requirement, and power dissipation of 240mW is within specification. The SOT-343 package is a compact surface mount alternative to SOT-23-3. MSL 1 rating ensures unlimited shelf life.

BFP540ESDH6327XTSA1 serves as a secondary RF substitute with 30GHz transition frequency and active production status. This part provides 21.5dB gain and noise figure of 0.9dB ~ 1.4dB @ 1.8GHz. The 80mA collector current and 250mW power rating provide operational margin. SOT-343 packaging and ROHS3 compliance are documented.

For Lower-Frequency or Non-RF Applications:

MMBT6429LT1G is suitable when RF performance requirements are relaxed. This onsemi part is active in production, ROHS3 compliant, and offers 700MHz transition frequency with 225mW power dissipation matching the original specification. The 200mA collector current and 45V voltage rating provide significant operational margin. SOT-23-3 packaging maintains footprint compatibility with AT-41533-TR1G. MSL 1 rating ensures unlimited shelf life.

MMBT2484LT1G and MMBT2484LT3G are general-purpose NPN alternatives with 60V voltage rating and 100mA collector current. These parts are active in production and ROHS3 compliant but lack RF performance specifications. They are suitable only for non-RF switching or amplification applications.

Compliance and Production Status:

All recommended active substitutes (BFP760H6327XTSA1, BFP540ESDH6327XTSA1, MMBT6429LT1G, MMBT2484LT1G, MMBT2484LT3G) are ROHS3 compliant and REACH unaffected. The original AT-41533-TR1G is obsolete; therefore, transition to an active substitute is necessary for new designs and ongoing production support.

Frequently Asked Questions (FAQ)

Q: Can BFP760H6327XTSA1 directly replace AT-41533-TR1G in existing designs?

A: BFP760H6327XTSA1 is electrically compatible for RF applications operating at 900MHz to 2.4GHz. The 4V voltage rating is lower than the original 12V specification; verify that your circuit operates at or below 4V collector-emitter voltage. The SOT-343 package is physically smaller than SOT-23-3; PCB layout modification may be required. Noise figure and gain characteristics are superior, providing improved RF performance.

Q: What is the key difference between RF-optimized substitutes and general-purpose substitutes?

A: RF-optimized substitutes (BFP760H6327XTSA1, BFP540ESDH6327XTSA1, 2SC5646A-TL-H, HFA3102BZ) are specified with transition frequency, noise figure, and gain parameters optimized for high-frequency RF signal amplification. General-purpose substitutes (MMBT6429LT1G, MMBT2484LT1G, MMBT2484LT3G) lack RF performance specifications and are suitable only for low-frequency switching or audio-frequency amplification.

Q: Why does HFA3102BZ contain 6 NPN transistors in a 14-SOIC package?

A: HFA3102BZ is an integrated RF transistor array containing six independent NPN transistors in a single 14-SOIC package. This part is suitable only if your application requires multiple transistor functions or if the array configuration matches your circuit topology. For single-transistor replacement, this part is not recommended.

Q: Is MMBT2484LT1G suitable for RF applications?

A: No. MMBT2484LT1G lacks RF performance specifications (no transition frequency, noise figure, or gain data provided). This part is a general-purpose NPN transistor suitable for low-frequency switching or audio amplification only. For RF applications at 900MHz to 2.4GHz, use BFP760H6327XTSA1 or BFP540ESDH6327XTSA1.

Q: What does MSL 1 (Unlimited) mean for moisture sensitivity?

A: MSL 1 (Unlimited) indicates that the component has no moisture sensitivity restrictions. The part can be stored indefinitely without desiccant packaging or environmental controls. This is superior to MSL 3 (168 Hours), which requires desiccant storage and limits shelf life to 168 hours after opening the moisture barrier bag.

Q: Can I use MMBT6429LT1G as a direct footprint replacement for AT-41533-TR1G?

A: Yes. MMBT6429LT1G uses the same SOT-23-3 (TO-236-3) package as AT-41533-TR1G, enabling direct PCB footprint compatibility. However, electrical performance differs: MMBT6429LT1G operates at 700MHz transition frequency and lacks RF noise figure specifications. Use this substitute only if your application does not require RF performance at 900MHz to 2.4GHz.

Q: Why is the voltage rating of BFP760H6327XTSA1 (4V) lower than AT-41533-TR1G (12V)?

A: BFP760H6327XTSA1 is optimized for low-voltage RF applications with superior high-frequency performance. The 4V rating reflects the design target for modern RF systems operating at reduced supply voltages. Verify that your circuit design operates at or below 4V collector-emitter voltage before selecting this substitute. If your application requires 12V operation, use HFA3102BZ (12V rating) or MMBT6429LT1G (45V rating).

Q: Are 2SC5646A-TL-H and MRF317 suitable substitutes?

A: 2SC5646A-TL-H is listed in the original AT-41533-TR1G substitute list but is classified as obsolete. This part is not recommended for new designs. MRF317 is a high-power RF transistor (100W, 12A, 35V) designed for chassis mount applications and is not suitable as a direct replacement for the surface mount AT-41533-TR1G. MRF317 is intended for power amplifier applications requiring significantly higher current and power handling.

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