BSC059N03ST Equivalent & Substitute Parts Reference

Part Overview

The BSC059N03ST is an N-Channel 30V MOSFET manufactured by Infineon Technologies in the OptiMOS™ series. This device is rated for 19A continuous drain current (Ta) and 89A (Tc) in a surface mount PG-TDSON-8-1 package. The part is currently discontinued at DiGi Electronics, making equivalent substitutes necessary for ongoing design support and procurement.

The BSC059N03ST serves in applications requiring low on-resistance switching at 30V with moderate to high current handling. Equivalent parts must maintain electrical compatibility across drain-source voltage, continuous current ratings, on-resistance characteristics, and gate drive requirements while accommodating available packaging options.

Key Parameters

Parameter	BSC059N03ST	Unit
Drain to Source Voltage (Vdss)	30	V
Continuous Drain Current (Ta)	19	A
Continuous Drain Current (Tc)	89	A
Rds On (Max) @ Id, Vgs	5.5 mOhm @ 50A, 10V	mOhm
Gate Charge (Qg) @ Vgs	21 nC @ 5V	nC
Vgs(th) (Max) @ Id	2 V @ 35µA	V
Input Capacitance (Ciss) @ Vds	2670 pF @ 15V	pF
Operating Temperature Range	-55 to 150	°C (TJ)
Mounting Type	Surface Mount
Package	8-PowerTDFN (PG-TDSON-8-1)
RoHS Status	Non-compliant

Substitute Part Grouping Explanation

Substitution eligibility for the BSC059N03ST is determined by the following critical parameters:

Mandatory Compatibility Criteria:

Drain to Source Voltage (Vdss): 30V minimum
Continuous Drain Current (Ta): 19A minimum at 25°C
Gate Drive Voltage: 4.5V to 10V compatibility
Vgs(th) threshold voltage: within ±20V gate bias range
Operating Temperature: -55°C to 150°C (TJ)
Mounting: Surface Mount configuration
Package Class: 8-pin power package variants (PowerTDFN, VSONP, PowerFlat)

Secondary Compatibility Parameters:

On-resistance (Rds On): Lower or equivalent values acceptable
Gate Charge (Qg): Lower values preferred for reduced switching losses
Input Capacitance (Ciss): Comparable values for gate drive circuit design

The substitute parts listed below meet these criteria within the allowed electrical and mechanical parameter ranges for this MOSFET category.

Parameter Comparison

Parameter	BSC059N03ST (Infineon)	CSD17552Q5A (TI)	CSD17577Q5A (TI)	CSD17577Q5AT (TI)	FDMS7672 (Fairchild)	STL65N3LLH5 (ST)	Unit
Vdss	30	30	30	30	30	30	V
Id (Ta) @ 25°C	19	17	60	60	19	—	A
Id (Tc) @ 25°C	89	60	60	60	28	65	A
Rds On (Max) @ Id, Vgs	5.5 @ 50A, 10V	6.2 @ 15A, 10V	4.2 @ 18A, 10V	4.2 @ 18A, 10V	5.0 @ 19A, 10V	5.8 @ 9.5A, 10V	mOhm
Vgs(th) (Max) @ Id	2 @ 35µA	1.9 @ 250µA	1.8 @ 250µA	1.8 @ 250µA	3 @ 250µA	1 @ 250µA	V
Gate Charge (Qg) @ Vgs	21 @ 5V	12 @ 4.5V	35 @ 10V	35 @ 10V	44 @ 10V	12 @ 4.5V	nC
Ciss (Max) @ Vds	2670 @ 15V	2050 @ 15V	2310 @ 15V	2310 @ 15V	2960 @ 15V	1500 @ 25V	pF
Vgs (Max)	±20	±20	±20	±20	±20	±22	V
Operating Temp Range	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	-55 to 150	°C (TJ)
Package	8-PowerTDFN	8-VSONP (5x6)	8-VSONP (5x6)	8-VSONP (5x6)	Power56	PowerFlat (5x6)
Product Status	Discontinued	Active	Active	Active	Active	Obsolete
RoHS Status	Non-compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	Not specified	ROHS3 Compliant

Engineering Selection Recommendations

Primary Substitutes (Active Product Status):

CSD17577Q5A and CSD17577Q5AT (Texas Instruments NexFET™) are the preferred substitutes. Both devices exceed the BSC059N03ST current rating (60A Ta vs. 19A Ta) while maintaining 30V Vdss compatibility. The CSD17577Q5A is supplied in Tape & Reel packaging with 24,121 units in stock. The CSD17577Q5AT variant is supplied in Cut Tape & Digi-Reel® format with 3,764 units available. Both are ROHS3 compliant. The CSD17577Q5A carries REACH Unaffected status, while CSD17577Q5AT is REACH Affected. On-resistance is superior at 4.2 mOhm, and gate charge is specified at 35 nC @ 10V. The 8-VSONP (5x6) package is mechanically compatible with the original 8-PowerTDFN footprint for most applications.

CSD17552Q5A (Texas Instruments NexFET™) provides an intermediate current rating of 17A (Ta) and 60A (Tc), with on-resistance of 6.2 mOhm @ 15A, 10V. This device is ROHS3 compliant with 30,100 units in stock. Gate charge is reduced to 12 nC @ 4.5V, offering lower switching losses. The 8-VSONP (5x6) package maintains mechanical compatibility.

FDMS7672 (Fairchild Semiconductor PowerTrench®) matches the original 19A (Ta) current rating with 28A (Tc) capability. On-resistance is 5.0 mOhm @ 19A, 10V. This device is Active with 52,870 units in stock. Gate charge is elevated at 44 nC @ 10V. The Power56 package requires PCB layout verification for compatibility. RoHS compliance status is not specified in available data.

Secondary Substitute (Obsolete Status):

STL65N3LLH5 (STMicroelectronics STripFET™ V) is marked Obsolete and carries only 2,400 units in inventory. While it provides superior current handling at 65A (Tc) and lower gate charge at 12 nC @ 4.5V, its discontinued status limits long-term procurement viability. This device is ROHS3 compliant. The PowerFlat™ (5x6) package differs from the original footprint.

Recommendation Summary:

For new designs and ongoing production, select CSD17577Q5A or CSD17577Q5AT based on packaging requirements (Tape & Reel vs. Cut Tape). Both offer superior electrical performance, active product status, full RoHS3 compliance, and adequate inventory. For applications requiring exact current matching, FDMS7672 provides equivalent Ta rating with high stock availability. Avoid STL65N3LLH5 for new procurement due to obsolete status.

Frequently Asked Questions (FAQ)

Q: Can CSD17577Q5A directly replace BSC059N03ST in existing PCB layouts?

A: The CSD17577Q5A uses an 8-VSONP (5x6) package versus the original 8-PowerTDFN. While both are 8-pin power packages with similar thermal characteristics, PCB footprint verification is required. Pin assignments must be confirmed against both datasheets before board-level substitution.

Q: What is the difference between CSD17577Q5A and CSD17577Q5AT?

A: Both devices are electrically identical with matching electrical specifications. The primary difference is packaging format: CSD17577Q5A is supplied in Tape & Reel (TR), while CSD17577Q5AT is supplied in Cut Tape (CT) & Digi-Reel®. CSD17577Q5A has REACH Unaffected status; CSD17577Q5AT is REACH Affected. Select based on procurement and supply chain requirements.

Q: Why is FDMS7672 listed as a substitute if it has lower Tc current rating (28A vs. 89A)?

A: FDMS7672 matches the original Ta rating (19A) and maintains 30V Vdss compatibility. The lower Tc rating reflects different thermal measurement conditions. For applications operating within the 19A Ta envelope, FDMS7672 provides equivalent functionality with higher inventory availability (52,870 units).

Q: Is STL65N3LLH5 suitable for new production designs?

A: No. STL65N3LLH5 is marked Obsolete with limited inventory (2,400 units). While electrically capable, its discontinued status creates long-term supply risk. Use only for legacy product support or repair applications where no alternative exists.

Q: What are the key electrical parameters that determine substitution compatibility?

A: Substitution is determined by: (1) Drain-Source Voltage (Vdss) minimum 30V, (2) Continuous Drain Current (Ta) minimum 19A at 25°C, (3) Gate drive voltage compatibility (4.5V to 10V), (4) Vgs(th) within ±20V range, (5) Operating temperature -55°C to 150°C (TJ), and (6) Surface mount 8-pin power package configuration. On-resistance, gate charge, and input capacitance are secondary parameters that may vary within acceptable ranges.

Q: Does RoHS compliance affect substitution decisions?

A: Yes. The original BSC059N03ST is RoHS non-compliant. All active substitutes (CSD17577Q5A, CSD17577Q5AT, CSD17552Q5A, FDMS7672) are either ROHS3 compliant or have unspecified status. For applications subject to RoHS regulations, select ROHS3-compliant alternatives: CSD17577Q5A, CSD17577Q5AT, CSD17552Q5A, or STL65N3LLH5.

Q: Can I use CSD17552Q5A if my application requires higher current than 17A (Ta)?

A: CSD17552Q5A is rated for 17A (Ta), which is below the original 19A specification. Use only if your actual application current requirement is 17A or lower. For applications requiring 19A or higher Ta rating, select CSD17577Q5A (60A Ta) or FDMS7672 (19A Ta).

Q: What is the impact of different on-resistance values on circuit performance?

A: On-resistance directly affects power dissipation and thermal performance. Lower Rds On values reduce I²R losses. CSD17577Q5A at 4.2 mOhm provides superior efficiency compared to BSC059N03ST at 5.5 mOhm. For thermal-constrained applications, lower on-resistance substitutes improve reliability and reduce heatsinking requirements.

Q: Are gate charge differences significant for gate driver circuit design?

A: Yes. Gate charge (Qg) affects switching speed and gate driver power requirements. BSC059N03ST specifies 21 nC @ 5V. CSD17552Q5A and STL65N3LLH5 offer reduced gate charge at 12 nC, enabling faster switching and lower gate driver current. CSD17577Q5A and FDMS7672 have higher gate charge (35 nC and 44 nC respectively), requiring verification that existing gate drivers can supply adequate current.

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