LB1935FA-BH Equivalent & Substitute Parts

Part Overview

The LB1935FA-BH is a bipolar motor driver IC manufactured by onsemi, designed for stepper motor applications with integrated control and power stage functionality. This device operates across a 2.2V to 7.5V supply range and features a half-bridge output configuration with parallel interface control. The product is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

LB1935FA-BH

onsemiIn Stock: 903LB1935FA-BH Datasheet

Current PartRFQ

TC78H621FNG,EL

Toshiba Semiconductor and StorageIn Stock: 24238TC78H621FNG,EL Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The TC78H621FNG,EL qualifies as a substitute based on the following alignment criteria:

Functional Compatibility:

• Both devices provide bipolar motor driver functionality with integrated control and power stage architecture
• Both support half-bridge output configuration suitable for stepper motor applications
• Both are surface-mount devices with ROHS3 compliance and EAR99 classification

Electrical Parameter Alignment:

• Supply voltage range overlap: LB1935FA-BH operates 2.2V–7.5V; TC78H621FNG,EL operates 2.7V–5.5V (compatible within 2.7V–5.5V window)
• Load voltage compatibility: TC78H621FNG,EL supports 2.5V–15V, encompassing the LB1935FA-BH range
• Operating temperature: TC78H621FNG,EL range of -30°C–85°C exceeds the LB1935FA-BH specification of -20°C–75°C

Substitution Limitations:

• Interface difference: LB1935FA-BH uses parallel control; TC78H621FNG,EL uses PWM control (requires interface adaptation)
• Output configuration: LB1935FA-BH provides 4 half-bridges; TC78H621FNG,EL provides 2 half-bridges (reduced channel count)
• Package difference: LB1935FA-BH is 10-pin; TC78H621FNG,EL is 16-pin (different pinout and footprint)

Parameter Comparison

Engineering Selection Recommendations

The TC78H621FNG,EL is available as an active product with current manufacturing support, addressing the obsolescence status of the LB1935FA-BH. Both devices maintain ROHS3 compliance and EAR99 classification, satisfying regulatory and export requirements.

Substitution feasibility depends on system-level design constraints:

Direct substitution is not possible without circuit modification due to interface protocol differences (parallel vs. PWM control) and reduced output channel count (4 half-bridges vs. 2 half-bridges). The TC78H621FNG,EL requires control logic redesign and PCB layout changes due to different package geometry (16-TSSOP vs. 10-TFSOP/MSOP).

Electrical compatibility exists within the overlapping supply voltage range (2.7V–5.5V). The substitute's load voltage specification (2.5V–15V) and extended operating temperature range (-30°C–85°C) provide operational margin beyond the original device.

Selection should prioritize applications where PWM-based motor control is acceptable and dual-channel operation meets functional requirements. Systems requiring four independent half-bridge channels or parallel control interface require alternative component evaluation.

Frequently Asked Questions (FAQ)

Q: Can TC78H621FNG,EL replace LB1935FA-BH without PCB modification?

A: No. The devices differ in package type (16-TSSOP vs. 10-TFSOP/MSOP), pinout, and control interface (PWM vs. parallel). PCB redesign and control firmware modification are required.

Q: What is the primary functional difference between these devices?

A: The LB1935FA-BH provides four half-bridge outputs with parallel control logic, while TC78H621FNG,EL provides two half-bridge outputs with PWM control. This affects motor channel capacity and control methodology.

Q: Are the supply voltage ranges compatible?

A: Partial compatibility exists. Both devices operate within the 2.7V–5.5V window. The LB1935FA-BH extends to 2.2V minimum and 7.5V maximum, which the TC78H621FNG,EL does not support.

Q: Does the TC78H621FNG,EL support stepper motor applications?

A: Yes. The TC78H621FNG,EL is specified for bipolar motor driver applications and supports stepper motor control through its half-bridge output configuration, though with reduced channel count.

Q: What compliance certifications apply to both devices?

A: Both devices are ROHS3 compliant, REACH unaffected, and classified as EAR99 for export control purposes.

Q: Is the TC78H621FNG,EL actively manufactured?

A: Yes. The TC78H621FNG,EL is classified as active product status with current manufacturing availability, unlike the obsolete LB1935FA-BH.