STS8DNF3LL Equivalent & Substitute Parts

Part Overview

The STS8DNF3LL is a dual N-channel MOSFET array manufactured by STMicroelectronics, rated for 30V drain-to-source voltage and 8A continuous drain current. This device is part of the STripFET™ II series and is packaged in an 8-SOIC surface mount configuration. The part is designated as "Not For New Designs," indicating that STMicroelectronics has discontinued active development for this model. Equivalent and substitute parts are necessary for applications requiring continued supply, design flexibility, or performance optimization within the specified electrical and mechanical parameters.

Key Parameters

Parameter	Value	Unit
Drain to Source Voltage (Vdss)	30	V
Continuous Drain Current (Id) @ 25°C	8	A
On-Resistance (Rds On) @ Id, Vgs	20 mOhm @ 4A, 10V	mOhm
Gate Threshold Voltage (Vgs(th)) @ Id	1	V @ 250µA
Gate Charge (Qg) @ Vgs	17	nC @ 5V
Input Capacitance (Ciss) @ Vds	800	pF @ 25V
Maximum Power Dissipation	1.6	W
Operating Temperature (TJ)	150	°C
Configuration	2 N-Channel (Dual)	—
Package / Case	8-SOIC (0.154", 3.90mm Width)	—
Mounting Type	Surface Mount	—
FET Feature	Logic Level Gate	—
Technology	MOSFET (Metal Oxide)	—
RoHS Status	ROHS3 Compliant	—
Moisture Sensitivity Level (MSL)	1 (Unlimited)	—

Substitute Part Grouping Explanation

Substitution of the STS8DNF3LL is determined by strict adherence to the following electrical and mechanical parameters:

Primary Substitution Criteria:

Drain to Source Voltage (Vdss): 30V (exact match required)
Configuration: 2 N-Channel (Dual) (exact match required)
Package / Case: 8-SOIC surface mount (exact match required)
Continuous Drain Current (Id) @ 25°C: 8A minimum
On-Resistance (Rds On): 20 mOhm or lower at rated conditions
Operating Temperature: 150°C maximum junction temperature
Technology: MOSFET (Metal Oxide)
RoHS Status: ROHS3 Compliant

Secondary Compatibility Parameters:

Gate Threshold Voltage (Vgs(th)): Logic level gate operation
Gate Charge (Qg): Lower values preferred for switching efficiency
Input Capacitance (Ciss): Lower values preferred for gate drive requirements
Maximum Power Dissipation: 1.6W or higher
Moisture Sensitivity Level (MSL): 1 (Unlimited) preferred

Substitute parts are grouped into two categories: Direct Equivalents (matching all primary criteria) and Compatible Alternatives (meeting primary criteria with minor parameter variations that do not affect functional performance in standard applications).

Parameter Comparison

Manufacturer Part Number	Manufacturer	Vdss (V)	Id @ 25°C (A)	Rds On (mOhm)	Vgs(th) (V)	Qg (nC)	Ciss (pF)	Power Max (W)	Tj Max (°C)	Package	Product Status
STS8DNF3LL	STMicroelectronics	30	8	20 @ 4A, 10V	1 @ 250µA	17 @ 5V	800 @ 25V	1.6	150	8-SOIC	Not For New Designs
AO4818B	Alpha & Omega Semiconductor Inc.	30	8	19 @ 8A, 10V	2.4 @ 250µA	18 @ 10V	888 @ 15V	2	150	8-SOIC	Active
AO4822	Alpha & Omega Semiconductor Inc.	30	8	19 @ 8A, 10V	2.4 @ 250µA	18 @ 10V	888 @ 15V	2	150	8-SOIC	Active
AO4822A	Alpha & Omega Semiconductor Inc.	30	8	19 @ 8A, 10V	2.4 @ 250µA	18 @ 10V	888 @ 15V	2	150	8-SOIC	Active
AO4842	Alpha & Omega Semiconductor Inc.	30	—	22 @ 7.5A, 10V	2.6 @ 250µA	11 @ 10V	448 @ 15V	2	150	8-SOIC	Not For New Designs
AO4854	Alpha & Omega Semiconductor Inc.	30	8	19 @ 8A, 10V	2.4 @ 250µA	18 @ 10V	888 @ 15V	2	150	8-SOIC	Active
BSO150N03MDGXUMA1	Infineon Technologies	30	8	15 @ 9.3A, 10V	2 @ 250µA	17 @ 10V	1300 @ 15V	1.4	150	8-SOIC	Active
DMG4822SSD-13	Diodes Incorporated	30	10	20 @ 8.5A, 10V	3 @ 250µA	10.5 @ 10V	478.9 @ 16V	1.42	150	8-SOIC	Active
DMN3018SSD-13	Diodes Incorporated	30	6.7	22 @ 10A, 10V	2.1 @ 250µA	13.2 @ 10V	697 @ 15V	1.5	150	8-SOIC	Active
DMN3033LSD-13	Diodes Incorporated	30	6.9	20 @ 6.9A, 10V	2.1 @ 250µA	13 @ 10V	725 @ 15V	2	150	8-SOIC	Active
DMN3033LSDQ-13	Diodes Incorporated	30	6.9	20 @ 6.9A, 10V	2.1 @ 250µA	13 @ 10V	725 @ 15V	2	150	8-SOIC	Active

Engineering Selection Recommendations

Direct Equivalents (Recommended for Replacement):

The following parts satisfy all primary substitution criteria and are designated as Active products:

AO4818B (Alpha & Omega Semiconductor Inc.): Matches 30V, 8A, 8-SOIC configuration with 19 mOhm on-resistance. Active product status ensures continued availability and support. Tape & Reel packaging available.
AO4822 (Alpha & Omega Semiconductor Inc.): Identical electrical specifications to AO4818B with 30V, 8A rating and 19 mOhm on-resistance. Active product status. Highest inventory availability (18,643 pcs).
AO4822A (Alpha & Omega Semiconductor Inc.): Functionally equivalent to AO4822 with Logic Level Gate feature. Active product status with highest inventory level (210,100 pcs). Recommended for new procurement.
AO4854 (Alpha & Omega Semiconductor Inc.): Meets all primary criteria with 30V, 8A, 19 mOhm on-resistance. Active product status. Available in Bulk packaging.

Compatible Alternatives (Performance-Optimized):

BSO150N03MDGXUMA1 (Infineon Technologies OptiMOS™ series): Exceeds primary criteria with superior 15 mOhm on-resistance at 9.3A. Active product status. Lower power dissipation (1.4W) compared to main part. MSL rating of 3 (168 Hours) requires moisture control during storage and handling.
DMG4822SSD-13 (Diodes Incorporated): Exceeds 8A requirement with 10A continuous drain current. Matches 30V voltage rating and 8-SOIC package. Active product status. Lower gate charge (10.5 nC) improves switching efficiency.

Functional Alternatives (Current-Reduced Applications):

DMN3018SSD-13 (Diodes Incorporated): Rated for 6.7A continuous drain current, below the 8A specification. Suitable for applications with reduced current requirements. Active product status. Lower input capacitance (697 pF) reduces gate drive power.
DMN3033LSD-13 and DMN3033LSDQ-13 (Diodes Incorporated): Both rated for 6.9A continuous drain current. Active product status. Suitable for applications operating below 8A. Tape & Reel packaging available.

Not Recommended for New Designs:

AO4842 (Alpha & Omega Semiconductor Inc.): Designated as "Not For New Designs." Continuous drain current specification not provided. Higher on-resistance (22 mOhm) and lower gate charge (11 nC) indicate different performance profile.

Frequently Asked Questions (FAQ)

Q: Can I use a substitute part with lower continuous drain current rating than the STS8DNF3LL?

A: Substitution with lower current ratings (such as DMN3018SSD-13 at 6.7A or DMN3033LSD-13 at 6.9A) is permissible only if the application circuit operates below the substitute part's rated current. The substitute must not be operated at or above its maximum continuous drain current specification. Verify application current requirements before selection.

Q: What is the significance of the on-resistance (Rds On) parameter in substitution?

A: On-resistance directly affects power dissipation and heat generation. The STS8DNF3LL specifies 20 mOhm at 4A, 10V. Substitute parts with equal or lower on-resistance (such as BSO150N03MDGXUMA1 at 15 mOhm) provide improved efficiency. Higher on-resistance values increase power loss and thermal stress.

Q: Are all substitute parts compatible with the same PCB layout and footprint?

A: All listed substitute parts use the 8-SOIC (0.154", 3.90mm Width) package, ensuring mechanical and footprint compatibility. However, verify pinout configuration in device datasheets before PCB design or rework. Pin assignments may differ between manufacturers.

Q: What is the impact of gate threshold voltage (Vgs(th)) differences?

A: The STS8DNF3LL specifies 1V gate threshold voltage, while most substitutes specify 2.1V to 2.4V. Higher threshold voltages require higher gate drive voltages for full on-state operation. Verify gate driver circuit capability to supply required gate voltage before substitution.

Q: Why does BSO150N03MDGXUMA1 have a different Moisture Sensitivity Level (MSL)?

A: BSO150N03MDGXUMA1 is rated MSL 3 (168 Hours), compared to MSL 1 (Unlimited) for the STS8DNF3LL. MSL 3 requires moisture control during storage and handling. Parts must be stored in dry conditions and baked before reflow soldering if exposed to moisture. MSL 1 parts have no moisture sensitivity restrictions.

Q: Can I substitute the STS8DNF3LL with a part rated for higher voltage (e.g., 40V or 60V)?

A: Substitution with higher voltage-rated parts is not recommended. The 30V rating is a design specification for the application circuit. Using higher voltage-rated devices may introduce unnecessary cost, size, or performance trade-offs without functional benefit.

Q: What does "Not For New Designs" status mean for the STS8DNF3LL?

A: "Not For New Designs" indicates that STMicroelectronics has discontinued active development and marketing of this part. Existing inventory may be available, but long-term supply is not guaranteed. New designs should select from Active-status alternatives such as AO4822A, AO4854, or BSO150N03MDGXUMA1.

Q: Are all substitute parts RoHS3 compliant?

A: All listed substitute parts are RoHS3 compliant, matching the compliance status of the STS8DNF3LL. All parts are also REACH Unaffected and classified as EAR99 for export control purposes.

Q: How do I determine which substitute part is best for my application?

A: Selection depends on application requirements: (1) For direct replacement with maximum availability, select AO4822A; (2) For improved efficiency and lower power dissipation, select BSO150N03MDGXUMA1; (3) For applications with reduced current requirements below 8A, select DMN3033LSD-13 or DMN3018SSD-13; (4) Verify gate drive circuit compatibility with substitute gate threshold voltage before final selection.

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