LM2991S Linear Voltage Regulator IC Negative Adjustable

Part Overview

The LM2991S is a linear voltage regulator IC designed for negative adjustable output applications. It delivers 1A output current in a surface-mount TO-263 (DDPAK-5) package. The device features adjustable negative voltage regulation with integrated over-temperature and short-circuit protection, making it suitable for power management circuits requiring negative rail generation.

The LM2991S carries a Last Time Buy product status, indicating limited availability from the original manufacturer. Identifying equivalent substitute parts ensures design continuity and supply chain reliability for ongoing production and maintenance applications.

Substiute Parts

LM2991S

Texas InstrumentsIn Stock: 12391LM2991S Datasheet

Current PartRFQ

LM2991S/NOPB

Texas InstrumentsIn Stock: 5217LM2991S/NOPB Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM2991S is determined by strict equivalence across the following critical parameters:

• Output configuration (negative polarity)
• Output type (adjustable voltage regulation)
• Number of regulators (single output)
• Output current rating (1A minimum)
• Input voltage range (-26V maximum)
• Output voltage adjustment range (-3V to -24V)
• Package type (TO-263 DDPAK-5)
• Mounting technology (surface mount)
• Protection features (over-temperature and short-circuit)
• Operating temperature range (-40°C to 125°C)
• Compliance certifications (ROHS3, REACH Unaffected)

The LM2991S/NOPB variant qualifies as a direct substitute based on identical electrical specifications and package configuration. The primary distinction is product status and lead-free plating designation (NOPB = No Plumbum/Lead-Free).

Parameter Comparison

Engineering Selection Recommendations

The LM2991S/NOPB is the direct functional equivalent for the LM2991S. Both devices meet ROHS3 compliance and REACH Unaffected status, ensuring regulatory alignment for industrial and commercial applications.

The LM2991S/NOPB carries Active product status, providing superior long-term availability compared to the Last Time Buy designation of the LM2991S. For new designs or production continuity, the LM2991S/NOPB is the preferred selection. Both parts are pin-compatible and electrically identical, requiring no circuit modifications for substitution.

Current inventory levels show 5200 units of LM2991S/NOPB available, supporting immediate procurement requirements.

Frequently Asked Questions (FAQ)

Q: Can LM2991S/NOPB replace LM2991S in existing designs?

A: Yes. Both devices are electrically and mechanically identical. The /NOPB designation indicates lead-free plating and active product status. No circuit changes are required.

Q: What does Last Time Buy status mean for the LM2991S?

A: Last Time Buy indicates the manufacturer will discontinue production. Existing inventory is available, but future availability is not guaranteed. Transitioning to LM2991S/NOPB ensures supply chain continuity.

Q: Are there package compatibility concerns between these parts?

A: No. Both use the TO-263 (DDPAK-5) package with identical pinout and thermal characteristics. PCB layouts and thermal management designs require no modification.

Q: Do these parts meet current compliance requirements?

A: Yes. Both LM2991S and LM2991S/NOPB are ROHS3 compliant and REACH Unaffected, meeting current regulatory standards for industrial and commercial applications.

Q: What is the MSL rating, and why does it matter?

A: Both parts carry MSL 3 (168 Hours), indicating moderate moisture sensitivity. Standard moisture control during storage and handling is required. Reflow soldering must occur within 168 hours of package opening under controlled humidity conditions.