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FT441AA Buck Switching Regulator IC Equivalent & Substitute Parts
Part Overview
The FT441AA is a buck switching regulator IC manufactured by Fremont Micro Devices Ltd, classified as a Power Management (PMIC) device. This component functions as a step-down converter with positive adjustable output, delivering up to 900mA at 0.6V to 5.5V output range from a 2.5V to 5.5V input supply. The device operates at 1.5MHz switching frequency with integrated synchronous rectification and is packaged in SC-74A (SOT-753) surface mount configuration.
The FT441AA carries an Obsolete product status. Identifying functionally equivalent substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production requirements for applications currently utilizing this component.
Substiute Parts
Key Parameters
| Parameter | Value |
|---|---|
| Manufacturer Part Number | FT441AA |
| Manufacturer | Fremont Micro Devices Ltd |
| Category | Power Management (PMIC) |
| Function | Step-Down (Buck) |
| Output Configuration | Positive Adjustable |
| Voltage Input Range | 2.5V to 5.5V |
| Voltage Output Range | 0.6V to 5.5V |
| Output Current | 900mA |
| Switching Frequency | 1.5MHz |
| Synchronous Rectifier | Yes |
| Operating Temperature | -40°C to 85°C (TA) |
| Package / Case | SC-74A, SOT-753 |
| Mounting Type | Surface Mount |
| Product Status | Obsolete |
| RoHS Status | ROHS3 Compliant |
| Moisture Sensitivity Level | 1 (Unlimited) |
Substitute Part Grouping Explanation
Substitute parts for the FT441AA are identified based on strict electrical and mechanical parameter alignment. The primary substitution criteria are:
Critical Matching Parameters:
- Input voltage range: 2.5V to 5.5V
- Output voltage range: 0.6V to 5.5V
- Output configuration: Positive adjustable
- Topology: Buck (step-down)
- Synchronous rectification: Present
- Package type: SOT-23-5 surface mount (compatible with SOT-753 footprint requirements)
- RoHS3 compliance
- Moisture sensitivity level: 1
Secondary Consideration:
- Output current capacity: Substitute parts rated at 600mA represent a reduced current specification compared to the 900mA FT441AA. These parts are functionally equivalent for applications requiring ≤600mA output current.
All identified substitute parts are manufactured by Analog Devices Inc. under the LTC3406 product family. These devices maintain identical input/output voltage specifications, switching frequency (1.5MHz or 2.25MHz variants), and regulatory compliance as the FT441AA while offering active product status and improved supply availability.
Parameter Comparison
| Parameter | FT441AA | LTC3406ABES5-2#TRMPBF | LTC3406ABES5-2#TRPBF | LTC3406AES5#TRMPBF | LTC3406AES5#TRPBF | LTC3406AIS5#TRMPBF | LTC3406AIS5#TRPBF | LTC3406B-2ES5#TRMPBF | LTC3406B-2ES5#TRPBF | LTC3406BES5#TRMPBF | LTC3406BES5#TRPBF |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Manufacturer | Fremont Micro Devices Ltd | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. | Analog Devices Inc. |
| Function | Step-Down | Step-Down | Step-Down | Step-Down | Step-Down | Step-Down | Step-Down | Step-Down | Step-Down | Step-Down | Step-Down |
| Output Configuration | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable | Positive Adjustable |
| Voltage Input (Min) | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V | 2.5V |
| Voltage Input (Max) | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V |
| Voltage Output (Min/Fixed) | 0.6V | 0.6V | 0.6V | 0.6V | 0.6V | 0.6V | 0.6V | 0.6V | 0.6V | 0.6V | 0.6V |
| Voltage Output (Max) | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V | 5.5V |
| Output Current | 900mA | 600mA | 600mA | 600mA | 600mA | 600mA | 600mA | 600mA | 600mA | 600mA | 600mA |
| Frequency - Switching | 1.5MHz | 1.5MHz | 1.5MHz | 1.5MHz | 1.5MHz | 1.5MHz | 1.5MHz | 2.25MHz | 2.25MHz | 1.5MHz | 1.5MHz |
| Synchronous Rectifier | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Operating Temperature | -40°C to 85°C (TA) | -40°C to 85°C (TA) | -40°C to 85°C (TA) | -40°C to 85°C (TA) | -40°C to 85°C (TA) | -40°C to 125°C (TJ) | -40°C to 125°C (TJ) | -40°C to 85°C (TA) | -40°C to 85°C (TA) | -40°C to 85°C (TA) | -40°C to 85°C (TA) |
| Package / Case | SC-74A, SOT-753 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 | SOT-23-5 Thin, TSOT-23-5 |
| Mounting Type | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount | Surface Mount |
| Product Status | Obsolete | Active | Active | Active | Active | Active | Active | Active | Active | Active | Active |
| RoHS Status | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant |
| Moisture Sensitivity Level | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) | 1 (Unlimited) |
Engineering Selection Recommendations
All identified LTC3406 variants from Analog Devices Inc. are suitable substitutes for the obsolete FT441AA based on electrical parameter equivalence and regulatory compliance alignment. The following factors support substitution decisions:
Product Status Advantage: All substitute parts carry Active product status, ensuring long-term availability and continued manufacturer support compared to the Obsolete FT441AA.
Regulatory Compliance: All substitute parts maintain ROHS3 compliance and MSL Level 1 rating, matching the FT441AA's environmental and handling specifications.
Output Current Consideration: Substitute parts are rated at 600mA maximum output current, compared to the FT441AA's 900mA rating. Selection of substitute parts is appropriate for applications requiring output currents up to 600mA. Applications requiring sustained output currents exceeding 600mA require alternative component selection outside the LTC3406 family.
Switching Frequency Variants: LTC3406B-2ES5 variants operate at 2.25MHz switching frequency, compared to 1.5MHz for other LTC3406 options and the FT441AA. Higher switching frequency may reduce external component size in applications where this characteristic is beneficial.
Temperature Range Variants: LTC3406AIS5 variants support extended operating temperature range to 125°C (TJ), compared to 85°C (TA) for other options. Extended temperature rating is applicable for high-temperature environment applications.
Packaging Compatibility: SOT-23-5 (TSOT-23-5) packages are mechanically and electrically compatible with SC-74A (SOT-753) footprints in standard PCB designs.
Frequently Asked Questions (FAQ)
Q: Can LTC3406 parts directly replace FT441AA in existing designs?
A: LTC3406 variants are electrically equivalent for applications requiring output currents up to 600mA. The 900mA FT441AA is rated for higher current delivery. Verify your application's maximum output current requirement before substitution. Package footprints are compatible for standard PCB layouts.
Q: What is the primary difference between FT441AA and LTC3406 substitutes?
A: The FT441AA is rated for 900mA output current, while all LTC3406 variants are rated for 600mA. All other electrical parameters—input/output voltage ranges, switching frequency, topology, and synchronous rectification—are identical.
Q: Are there differences between LTC3406A and LTC3406B variants?
A: LTC3406B-2ES5 variants operate at 2.25MHz switching frequency compared to 1.5MHz for LTC3406A variants. Both families maintain identical voltage specifications and output current ratings. Switching frequency selection depends on application requirements for component size and EMI characteristics.
Q: What does the temperature rating difference mean (TA vs. TJ)?
A: TA represents ambient temperature rating, while TJ represents junction temperature rating. LTC3406AIS5 variants specify -40°C to 125°C (TJ), providing extended high-temperature operation capability compared to -40°C to 85°C (TA) for other variants. Application thermal environment determines which rating is appropriate.
Q: Are all LTC3406 variants ROHS3 compliant?
A: Yes. All identified LTC3406 substitute parts carry ROHS3 compliance certification, matching the FT441AA's regulatory status.
Q: What packaging options are available for LTC3406 substitutes?
A: All LTC3406 variants identified are packaged in SOT-23-5 Thin (TSOT-23-5) surface mount configuration. Tape & Reel (TR) and Cut Tape (CT) & Digi-Reel® packaging options are available depending on part number suffix and supplier inventory.
Q: Which LTC3406 variant should I select for new designs?
A: For applications requiring output currents up to 600mA with standard operating temperature range (-40°C to 85°C), LTC3406AES5 or LTC3406BES5 variants are appropriate. For extended temperature applications, select LTC3406AIS5. For applications benefiting from higher switching frequency, select LTC3406B-2ES5 variants. All maintain identical voltage specifications and regulatory compliance.
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