FZT949TC Equivalent & Substitute Parts

Part Overview

The FZT949TC is a PNP bipolar junction transistor manufactured by Diodes Incorporated, rated for 30 V collector-emitter breakdown voltage and 5.5 A maximum collector current in a surface mount SOT-223-3 package. This device is classified as obsolete, indicating discontinuation from the manufacturer. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this transistor topology.

Key Parameters

Parameter	FZT949TC Value	Unit
Transistor Type	PNP	—
Current - Collector (Ic) (Max)	5.5	A
Voltage - Collector Emitter Breakdown (Max)	30	V
Vce Saturation (Max) @ Ib, Ic	440 mV @ 500 mA, 5.5 A	—
Current - Collector Cutoff (Max)	50	nA
DC Current Gain (hFE) (Min) @ Ic, Vce	100 @ 1 A, 1 V	—
Power - Max	3	W
Frequency - Transition	100	MHz
Operating Temperature	−55 to 150	°C
Mounting Type	Surface Mount	—
Package / Case	TO-261-4, TO-261AA	—
Supplier Device Package	SOT-223-3	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—
Product Status	Obsolete	—

Substitute Part Grouping Explanation

Substitution of the FZT949TC is determined by electrical and mechanical compatibility across the following critical parameters:

Electrical Compatibility Criteria:

Transistor type must be PNP
Collector-emitter breakdown voltage (VCEO) must be ≥ 30 V
Maximum collector current (Ic) must be ≥ 5.5 A
Power dissipation capability must be ≥ 3 W
Operating temperature range must encompass −55 to 150 °C
DC current gain (hFE) must be ≥ 100 at specified test conditions

Mechanical Compatibility Criteria:

Surface mount package type (SOT-223-3 or equivalent)
Pin configuration compatible with TO-261-4 or TO-261AA footprints

Regulatory Compliance:

RoHS3 compliance required
MSL rating of 1 (Unlimited) preferred

Substitute parts are grouped into three categories based on substitution relationship: direct manufacturer equivalents (same base product number with different packaging), parametric equivalents (identical electrical specifications with different packaging), and manufacturer-recommended alternatives (different manufacturers with comparable or superior electrical ratings).

Parameter Comparison

Part Number	Manufacturer	Ic (Max) [A]	VCEO (Max) [V]	Vce Sat (Max) [mV]	Power (Max) [W]	Frequency [MHz]	Product Status	Packaging
FZT949TC	Diodes Incorporated	5.5	30	440	3	100	Obsolete	SOT-223-3
ZX5T949GTA	Diodes Incorporated	5.5	30	210	3	110	Active	SOT-223-3
ZXTP2008GTA	Diodes Incorporated	5.5	30	210	3	110	Active	SOT-223-3
FZT949TA	Diodes Incorporated	5.5	30	440	3	100	Active	SOT-223-3
PBSS303PZ,135	Nexperia USA Inc.	5.3	30	265	2	130	Active	SOT-223
PBSS4032PZ,115	Nexperia USA Inc.	4.4	30	400	2	130	Active	SOT-223
PZT2907AT1G	onsemi	0.6	60	1600	1.5	200	Active	SOT-223
PZT2907AT3G	onsemi	0.6	60	1600	1.5	200	Active	SOT-223
STN790A	STMicroelectronics	3	30	700	1.6	100	Active	SOT-223

Engineering Selection Recommendations

Tier 1 - Direct Replacement (Recommended):

FZT949TA is the primary substitute for FZT949TC. Both parts share identical electrical specifications (5.5 A collector current, 30 V breakdown voltage, 3 W power rating, 100 MHz transition frequency, 440 mV saturation voltage). FZT949TA is manufactured by Diodes Incorporated and maintains active product status, ensuring long-term availability. The part is supplied in Tape & Reel packaging and is RoHS3 compliant with MSL 1 rating. This substitution requires no circuit redesign and maintains full electrical equivalence.

Tier 2 - Enhanced Performance Alternatives (Diodes Incorporated):

ZX5T949GTA and ZXTP2008GTA are direct electrical equivalents with improved performance characteristics. Both maintain 5.5 A collector current and 30 V breakdown voltage ratings. These parts feature reduced saturation voltage (210 mV versus 440 mV), higher transition frequency (110 MHz versus 100 MHz), and lower collector cutoff current (20 nA versus 50 nA). Both are active products with established supply availability. ZX5T949GTA is supplied in Cut Tape packaging, while ZXTP2008GTA is supplied in Tape & Reel format. These substitutes are suitable for applications where improved switching performance and reduced power dissipation are beneficial.

Tier 3 - Manufacturer-Recommended Alternatives (Nexperia):

PBSS303PZ,135 and PBSS4032PZ,115 are manufacturer-recommended alternatives from Nexperia USA Inc. PBSS303PZ,135 provides 5.3 A collector current (within 96% of FZT949TC rating) with improved transition frequency (130 MHz) and reduced saturation voltage (265 mV). PBSS4032PZ,115 provides 4.4 A collector current with 130 MHz transition frequency. Both parts are AEC-Q100 qualified automotive-grade devices with active product status. These alternatives are suitable for applications requiring automotive qualification or enhanced frequency performance, though they exhibit reduced maximum collector current and power dissipation compared to the original part.

Tier 4 - Limited Compatibility (Not Recommended for Direct Substitution):

PZT2907AT1G and PZT2907AT3G (onsemi) and STN790A (STMicroelectronics) do not meet the electrical requirements of FZT949TC. PZT2907 series devices are rated for only 600 mA collector current (11% of FZT949TC rating) and 1.5 W power dissipation (50% of FZT949TC rating), making them unsuitable for applications requiring the full 5.5 A current capability. STN790A is rated for 3 A collector current and 1.6 W power dissipation, both below FZT949TC specifications. These parts are listed as manufacturer-recommended alternatives but do not provide electrical equivalence and should only be considered for applications with reduced current and power requirements.

Frequently Asked Questions (FAQ)

Q: Can FZT949TA be used as a direct replacement for FZT949TC without circuit modification?

A: Yes. FZT949TA is electrically identical to FZT949TC across all critical parameters: 5.5 A maximum collector current, 30 V breakdown voltage, 3 W power rating, 100 MHz transition frequency, and 440 mV saturation voltage at specified test conditions. Both parts use the same SOT-223-3 package and footprint. The only difference is product status (FZT949TA is active; FZT949TC is obsolete) and packaging format (Tape & Reel versus unspecified for FZT949TC).

Q: What is the advantage of using ZX5T949GTA or ZXTP2008GTA over FZT949TA?

A: ZX5T949GTA and ZXTP2008GTA offer improved switching characteristics compared to FZT949TA. Both parts feature reduced saturation voltage (210 mV versus 440 mV), resulting in lower power dissipation during saturation. Transition frequency is increased to 110 MHz (versus 100 MHz), and collector cutoff current is reduced to 20 nA (versus 50 nA). These improvements are beneficial in high-frequency switching applications or designs where thermal management is critical. Electrical current and voltage ratings remain identical at 5.5 A and 30 V.

Q: Are PBSS303PZ,135 and PBSS4032PZ,115 suitable replacements for FZT949TC?

A: PBSS303PZ,135 and PBSS4032PZ,115 are partial substitutes with reduced current ratings. PBSS303PZ,135 provides 5.3 A collector current (96% of FZT949TC) and is suitable for applications not requiring the full 5.5 A capability. PBSS4032PZ,115 provides only 4.4 A collector current (80% of FZT949TC) and should only be used in applications with reduced current requirements. Both parts offer improved frequency performance (130 MHz) and are AEC-Q100 qualified for automotive applications. Power dissipation is reduced to 2 W for both parts (67% of FZT949TC rating). These alternatives are not recommended for designs requiring the full 5.5 A current or 3 W power capability of the original part.

Q: Why are PZT2907AT1G and STN790A listed as alternatives if they do not meet FZT949TC specifications?

A: PZT2907AT1G and STN790A are listed as manufacturer-recommended alternatives in the provided substitute list but do not provide electrical equivalence to FZT949TC. PZT2907AT1G is rated for only 600 mA collector current and 1.5 W power dissipation, making it unsuitable for applications requiring 5.5 A current handling. STN790A is rated for 3 A collector current and 1.6 W power dissipation, both significantly below FZT949TC specifications. These parts should only be considered for applications with substantially reduced current and power requirements or where the higher voltage rating (60 V for PZT2907) provides additional design margin.

Q: What packaging formats are available for substitute parts?

A: Substitute parts are available in multiple packaging formats. FZT949TA, ZX5T949GTA, and ZXTP2008GTA are supplied in SOT-223-3 packages matching the original FZT949TC footprint. ZX5T949GTA is available in Cut Tape (CT) format, while ZXTP2008GTA is supplied in Tape & Reel (TR) format. PBSS303PZ,135, PBSS4032PZ,115, PZT2907AT1G, PZT2907AT3G, and STN790A are supplied in SOT-223 packages (equivalent to SOT-223-3 in pin configuration). All parts use the same TO-261-4 or TO-261AA footprint and are compatible with existing PCB designs.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All substitute parts listed are RoHS3 compliant and carry MSL 1 (Unlimited) moisture sensitivity ratings, matching the compliance profile of FZT949TC. This ensures compatibility with modern manufacturing processes and environmental regulations.

Q: Which substitute part offers the best overall performance improvement?

A: ZX5T949GTA and ZXTP2008GTA offer the best overall performance improvement while maintaining full electrical equivalence. Both parts provide identical current (5.5 A) and voltage (30 V) ratings with reduced saturation voltage (210 mV versus 440 mV), higher transition frequency (110 MHz versus 100 MHz), and lower leakage current (20 nA versus 50 nA). These improvements result in lower power dissipation, faster switching speed, and improved reliability. Both parts are active products with established supply availability.

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