LM1771TSD/NOPB Equivalent & Substitute Parts

Part Overview

The LM1771TSD/NOPB is a Buck Regulator Positive Output Step-Down DC-DC Controller IC manufactured by Texas Instruments in a 6-WSON (3x3) package. This component functions as a transistor driver for step-down topology applications with a single output phase. The part is currently classified as obsolete, making identification of suitable alternatives essential for ongoing design support and production continuity. Substitute parts must maintain electrical compatibility across supply voltage, switching frequency, and control feature specifications while accommodating packaging and availability constraints.

Substiute Parts

LM1771TSD/NOPB

Texas InstrumentsIn Stock: 3199LM1771TSD/NOPB Datasheet

Current PartRFQ

LM1770TMF/NOPB

Texas InstrumentsIn Stock: 2389LM1770TMF/NOPB Datasheet

MFR RecommendedRFQ

LM1771SSD/NOPB

Texas InstrumentsIn Stock: 6020LM1771SSD/NOPB Datasheet

Parametric EquivalentRFQ

LM1771USD/NOPB

Texas InstrumentsIn Stock: 2098LM1771USD/NOPB Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the LM1771TSD/NOPB is determined by strict alignment of the following critical parameters:

Electrical Compatibility Requirements:

• Supply voltage range: 2.8V ~ 5.5V
• Switching frequency range: 100kHz ~ 1MHz
• Output configuration: Positive, single output, single phase
• Synchronous rectifier capability: Yes
• Topology: Buck (step-down)

Packaging & Mechanical Requirements:

• Mounting type: Surface Mount
• Package compatibility: 6-WSON (3x3) or equivalent footprint

Compliance & Environmental Requirements:

• RoHS3 compliance
• MSL rating: 1 (Unlimited)
• Operating temperature: -40°C ~ 125°C

Substitute parts are categorized into two groups:

Parametric Equivalents (Same Package): Parts maintaining identical package, pinout, and all electrical specifications. These provide direct replacement capability.

Manufacturer Recommended Alternative (Different Package): Parts with identical electrical specifications but different package form factor, requiring PCB layout modification.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No PCB Modification):

LM1771SSD/NOPB and LM1771USD/NOPB are parametric equivalents with identical package specifications (6-WSON 3x3). Both parts maintain all electrical parameters, control features, and compliance certifications of the obsolete LM1771TSD/NOPB. Both are classified as Active products, ensuring long-term availability and supply chain stability. LM1771SSD/NOPB offers higher inventory availability (6002 units) compared to LM1771USD/NOPB (2013 units).

For Alternative Topology (PCB Layout Modification Required):

LM1770TMF/NOPB is the manufacturer-recommended alternative when package form factor change is acceptable. This part maintains electrical compatibility across all critical parameters (supply voltage, switching frequency, synchronous rectifier capability, and operating temperature range). The transition from 6-WSON (3x3) to SOT-23-5 packaging requires PCB layout redesign. LM1770TMF/NOPB is classified as Active with 2368 units in inventory. Note that this part does not specify Enable control features in the provided data.

Compliance & Certification:

All substitute parts maintain ROHS3 compliance and MSL rating of 1 (Unlimited), ensuring compatibility with standard manufacturing and storage protocols.

Frequently Asked Questions (FAQ)

Q: Can LM1771SSD/NOPB or LM1771USD/NOPB be used as direct replacements for the obsolete LM1771TSD/NOPB?

A: Yes. Both parts are parametric equivalents with identical package specifications (6-WSON 3x3), electrical parameters, and control features. No PCB modifications are required. Both are Active products with confirmed inventory availability.

Q: What is the difference between LM1771SSD/NOPB and LM1771USD/NOPB?

A: Both parts are electrically and mechanically identical. The primary difference is inventory availability: LM1771SSD/NOPB has 6002 units in stock versus 2013 units for LM1771USD/NOPB. Selection may be based on supply chain requirements and lead time considerations.

Q: Why is LM1770TMF/NOPB listed as an alternative if it has a different package?

A: LM1770TMF/NOPB is the manufacturer-recommended alternative when the 6-WSON package is not feasible. It maintains all critical electrical specifications (supply voltage, switching frequency, synchronous rectifier, and operating temperature). However, the SOT-23-5 package requires PCB layout redesign and is not a pin-for-pin replacement.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. LM1771SSD/NOPB, LM1771USD/NOPB, and LM1770TMF/NOPB are all ROHS3 compliant with MSL rating of 1 (Unlimited), meeting standard environmental and manufacturing requirements.

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

A: Supply voltage range (2.8V ~ 5.5V), switching frequency range (100kHz ~ 1MHz), synchronous rectifier capability, single-phase buck topology, and operating temperature range (-40°C ~ 125°C) are the critical parameters. All listed substitutes maintain these specifications.

Q: Does LM1770TMF/NOPB have the same control features as the main part?

A: LM1770TMF/NOPB does not specify Enable control features in the provided data, unlike LM1771TSD/NOPB, LM1771SSD/NOPB, and LM1771USD/NOPB. This should be verified against detailed datasheets if Enable functionality is required for the application.