LM2831YSDX Equivalent & Substitute Parts

Part Overview

The LM2831YSDX is a buck switching regulator IC from Texas Instruments designed for positive adjustable output applications. It delivers 1.5A output current with an adjustable output range from 0.6V to 4.5V, operating from a 3V to 5.5V input supply at a switching frequency of 550kHz. The device is housed in a 6-WSON package with exposed pad for surface mount applications.

The LM2831YSDX is classified as obsolete. Identifying suitable substitute components is necessary to maintain design continuity and ensure component availability for new production runs and legacy system support.

Substiute Parts

LM2831YSDX

Texas InstrumentsIn Stock: 1062LM2831YSDX Datasheet

Current PartRFQ

ST1S09IPUR

STMicroelectronicsIn Stock: 6799ST1S09IPUR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute components for the LM2831YSDX must satisfy the following core electrical and mechanical criteria:

Functional Requirements:

• Buck topology with positive adjustable output configuration
• Single output channel
• Surface mount package with exposed pad

Electrical Compatibility Parameters:

• Input voltage range must encompass or exceed 3V to 5.5V
• Output voltage range must support 0.6V minimum and extend to at least 4.5V
• Output current capability must meet or exceed 1.5A
• Operating temperature range must cover -40°C to 125°C or be acceptable for the target application

Mechanical Compatibility:

• Package footprint must be compatible with 6-pin DFN/WSON form factors
• Exposed pad configuration required for thermal management

The ST1S09IPUR from STMicroelectronics meets these substitution criteria with enhanced specifications in several areas, including higher output current capability (2A), wider input voltage range (2.7V to 6V), and active product status with full RoHS3 compliance.

Parameter Comparison

Engineering Selection Recommendations

The ST1S09IPUR is a direct functional substitute for the LM2831YSDX with superior specifications and compliance status. Key advantages include:

Product Availability & Compliance: The ST1S09IPUR maintains active product status with full RoHS3 compliance and REACH unaffected designation, ensuring long-term supply chain stability and regulatory alignment for new designs.

Electrical Performance: The substitute provides higher output current capability (2A versus 1.5A) and extended input voltage range (2.7V to 6V versus 3V to 5.5V), offering greater design flexibility. The integrated synchronous rectifier improves efficiency compared to the asynchronous design of the original part.

Thermal & Reliability Characteristics: The ST1S09IPUR features superior moisture sensitivity (MSL 1 versus MSL 3), reducing handling and storage risks. The higher switching frequency (1.5MHz) enables smaller external component sizing.

Package Compatibility: Both devices use 6-pin DFN packages with exposed pads. Physical footprints are compatible, though PCB layout optimization may be beneficial to leverage the improved thermal characteristics of the substitute.

Application Considerations: The ST1S09IPUR output voltage minimum of 0.8V (versus 0.6V) is suitable for most adjustable regulator applications. Applications requiring output voltages below 0.8V require design verification or alternative components.

Frequently Asked Questions (FAQ)

Q: Can the ST1S09IPUR directly replace the LM2831YSDX without PCB modifications?

A: The ST1S09IPUR is functionally compatible and uses a compatible 6-pin DFN package footprint. However, the substitute has different electrical characteristics (higher current, higher switching frequency, integrated synchronous rectifier). PCB layout optimization is recommended to fully leverage the improved performance, particularly for thermal management and feedback network design.

Q: What is the minimum output voltage difference between these parts?

A: The LM2831YSDX supports output voltages down to 0.6V, while the ST1S09IPUR minimum is 0.8V. Applications requiring sub-0.8V outputs must verify alternative solutions or confirm that 0.8V operation is acceptable.

Q: How do the switching frequencies affect circuit design?

A: The LM2831YSDX operates at 550kHz while the ST1S09IPUR operates at 1.5MHz. Higher switching frequency allows smaller inductor and capacitor values in the ST1S09IPUR design, reducing board space and component cost. External component values must be recalculated for the substitute based on the manufacturer's design guidelines.

Q: Are there temperature range limitations when substituting?

A: The LM2831YSDX operates to 125°C junction temperature, while the ST1S09IPUR maximum is 85°C. Applications requiring operation above 85°C must confirm the substitute is suitable or identify alternative components rated for higher temperatures.

Q: What is the significance of the synchronous rectifier in the ST1S09IPUR?

A: The integrated synchronous rectifier in the ST1S09IPUR replaces the internal diode with a low-resistance MOSFET, reducing conduction losses and improving efficiency compared to the asynchronous design of the LM2831YSDX. This is particularly beneficial in high-current or low-output-voltage applications.

Q: Does the higher moisture sensitivity level (MSL) of the LM2831YSDX affect substitution?

A: The LM2831YSDX has MSL 3 (168-hour limit) while the ST1S09IPUR has MSL 1 (unlimited). The substitute offers superior moisture tolerance, reducing handling and storage constraints. This is an advantage when transitioning to the ST1S09IPUR.