LB1939T-TLM-E Equivalent & Substitute Parts

Part Overview

The LB1939T-TLM-E is a half-bridge motor driver IC manufactured by onsemi, designed for DC motors, general-purpose applications, and bipolar stepper motors. This device operates with a supply voltage range of 1.9V to 6.5V and delivers 400mA per output channel. The part is classified as obsolete, making identification of suitable substitute components essential for ongoing design support and production continuity.

Substiute Parts

LB1939T-TLM-E

onsemiIn Stock: 3365LB1939T-TLM-E Datasheet

Current PartRFQ

TC78H621FNG,EL

Toshiba Semiconductor and StorageIn Stock: 24238TC78H621FNG,EL Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the LB1939T-TLM-E is determined by the following critical parameters:

• Output Configuration: The main part features a half-bridge (4) configuration. Substitute parts must support motor driver functionality with compatible output topology.
• Current Rating: The 400mA per-channel specification establishes the minimum current delivery requirement for equivalent operation.
• Supply Voltage Range: Operating range of 1.9V to 6.5V defines the input voltage compatibility window.
• Load Voltage Range: The 1.6V to 7.5V load voltage specification constrains acceptable substitute devices.
• Technology & Interface: Bipolar technology with logic interface determines signal compatibility and switching characteristics.
• Package Compatibility: Surface mount 20-TSSOP packaging is required for direct board-level substitution.
• Compliance & Status: RoHS3 compliance and active product status ensure long-term availability and regulatory alignment.

The TC78H621FNG,EL from Toshiba Semiconductor and Storage qualifies as a substitute based on shared motor driver functionality, surface-mount packaging, and overlapping electrical specifications within the defined parameter constraints.

Parameter Comparison

Engineering Selection Recommendations

The TC78H621FNG,EL is an active product with confirmed long-term availability, addressing the obsolescence status of the LB1939T-TLM-E. Both devices maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment across manufacturing environments.

The TC78H621FNG,EL delivers higher current capability (1.1A versus 400mA) and operates across an extended load voltage range (2.5V to 15V), providing design margin for applications requiring increased power delivery. The DMOS technology offers improved efficiency characteristics compared to the bipolar approach of the original part.

Package differences exist: the substitute uses 16-TSSOP versus the original 20-TSSOP. PCB layout modifications are required to accommodate the reduced pin count and package footprint. The lower moisture sensitivity level (MSL 1 versus MSL 3) of the substitute part reduces handling and storage constraints during manufacturing.

Frequently Asked Questions (FAQ)

Q: Can the TC78H621FNG,EL directly replace the LB1939T-TLM-E without circuit modifications?

A: Direct pin-for-pin replacement is not possible due to package differences (16-TSSOP versus 20-TSSOP). PCB layout redesign is required. Circuit topology may require adjustment based on the PWM interface of the substitute versus the logic interface of the original part.

Q: What are the key electrical differences between these devices?

A: The TC78H621FNG,EL provides higher output current (1.1A versus 400mA), extended load voltage range (2.5V to 15V versus 1.6V to 7.5V), and DMOS technology versus bipolar. Supply voltage overlap exists between 2.7V and 5.5V, establishing the common operating window.

Q: Does the substitute part support the same motor types?

A: Both devices support brushed DC motors and bipolar stepper motors. The TC78H621FNG,EL is explicitly rated for general-purpose applications, matching the original part's application scope.

Q: What are the packaging and handling implications?

A: The substitute part features MSL 1 (unlimited moisture exposure) versus MSL 3 (168-hour limit) for the original. This reduces moisture-sensitive device handling requirements during assembly and storage.

Q: Are both parts compliant with current regulatory standards?

A: Both devices are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic component manufacturing and distribution.