AOZ1978AI LED Driver Controller Equivalent & Substitute Parts

Part Overview

The AOZ1978AI is an LED driver controller IC manufactured by Alpha & Omega Semiconductor Inc., designed for step-up (boost) topology applications in backlight systems. This device operates as a DC-DC controller with PWM and analog dimming capabilities across a 8V to 18V supply range at 200kHz switching frequency in a 20-SOIC package.

The AOZ1978AI is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support ongoing production or redesign requirements for applications currently utilizing this component.

Substiute Parts

AOZ1978AI

Alpha & Omega Semiconductor Inc.In Stock: 5442AOZ1978AI Datasheet

Current PartRFQ

LT3795IFE#TRPBF

Analog Devices Inc.In Stock: 1155LT3795IFE#TRPBF Datasheet

MFR RecommendedRFQ

MIC3231YTSE-TR

Microchip TechnologyIn Stock: 1229MIC3231YTSE-TR Datasheet

MFR RecommendedRFQ

MP4700GS

Monolithic Power SystemsIn Stock: 1024MP4700GS Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the AOZ1978AI are selected based on the following critical parameters that determine functional compatibility:

Primary Selection Criteria:

• Device type: DC DC Controller
• Number of outputs: 1
• Dimming support: Analog and/or PWM capability
• Application domain: LED driver control
• Mounting type: Surface Mount

Secondary Compatibility Factors:

• Supply voltage range overlap with 8V to 18V minimum requirement
• Switching frequency in the 100kHz to 1MHz range
• Operating temperature range of -40°C or lower minimum
• Internal switch configuration: No (external switching required)

The substitute parts identified maintain functional equivalence within the LED driver controller category while accommodating variations in package form factor, supply voltage range, and frequency specifications. Topology variations (step-up boost versus step-down buck) are noted as design-level considerations.

Parameter Comparison

Engineering Selection Recommendations

LT3795IFE#TRPBF (Analog Devices Inc.): This part is classified as active with ROHS3 compliance and REACH unaffected status. It supports the full 8V to 18V supply range of the AOZ1978AI with extended upper voltage capability to 110V. The device maintains both analog and PWM dimming modes and operates across -40°C to 125°C. The 28-TSSOP-EP package differs from the original 20-SOIC form factor and requires PCB layout redesign. Switching frequency range of 100kHz to 1MHz encompasses the 200kHz operation point.

MIC3231YTSE-TR (Microchip Technology): This part is active with ROHS3 compliance and REACH unaffected status. It maintains step-up (boost) topology matching the AOZ1978AI architecture. Supply voltage range spans 6V to 45V, covering the 8V to 18V requirement. PWM dimming is supported; analog dimming is not available. Operating temperature extends to 125°C. The 16-TSSOP-EP package requires PCB redesign. Moisture sensitivity level is 3 (168 hours), compared to level 1 for the original part.

MP4700GS (Monolithic Power Systems): This part is active with ROHS3 compliance and REACH unaffected status. It operates within the 8V to 18V supply range matching the AOZ1978AI exactly. The device includes automotive-grade qualification. Topology is step-down (buck) rather than step-up (boost), representing a fundamental circuit architecture change. PWM dimming is supported; analog dimming is not available. The 8-SOIC package is smaller than the original 20-SOIC, potentially simplifying PCB layout. Switching frequency is 160kHz, close to the original 200kHz specification.

Frequently Asked Questions (FAQ)

Q: Can the LT3795IFE#TRPBF directly replace the AOZ1978AI without circuit modifications?

A: No. While both devices are DC DC controllers with single outputs and support PWM dimming, the LT3795IFE#TRPBF uses a 28-TSSOP-EP package versus the 20-SOIC package of the AOZ1978AI. PCB layout and routing must be redesigned. Additionally, the LT3795IFE#TRPBF does not specify topology, requiring verification of internal circuit architecture compatibility with your boost converter design.

Q: Why is the MIC3231YTSE-TR listed as a substitute if it lacks analog dimming?

A: The MIC3231YTSE-TR maintains the step-up (boost) topology and single-output DC DC controller architecture of the AOZ1978AI. It supports PWM dimming across the required supply voltage range and operating temperature. If your application uses only PWM dimming (not analog dimming), this part provides functional equivalence. If analog dimming is required, this part is not suitable.

Q: What is the primary difference between the MP4700GS and the AOZ1978AI?

A: The MP4700GS uses step-down (buck) topology, while the AOZ1978AI uses step-up (boost) topology. These represent fundamentally different circuit architectures. The MP4700GS is suitable only if your application can accommodate a buck converter instead of a boost converter. Supply voltage and frequency specifications are otherwise compatible.

Q: Are all substitute parts RoHS compliant?

A: Yes. The LT3795IFE#TRPBF and MIC3231YTSE-TR are ROHS3 compliant. The MP4700GS is ROHS3 compliant. All three substitute parts are REACH unaffected.

Q: Does package size affect electrical performance?

A: Package size does not affect electrical performance of the controller IC itself. However, package selection impacts PCB layout, thermal management, and board space. The 28-TSSOP-EP (LT3795IFE#TRPBF) and 16-TSSOP-EP (MIC3231YTSE-TR) packages require different PCB footprints than the original 20-SOIC. The 8-SOIC (MP4700GS) is the smallest option.

Q: What is the significance of the moisture sensitivity level (MSL) difference?

A: The AOZ1978AI and LT3795IFE#TRPBF both have MSL 1 (unlimited shelf life). The MIC3231YTSE-TR has MSL 3 (168 hours), requiring controlled storage conditions and bake-out procedures before soldering if shelf life limits are exceeded. This affects supply chain handling and manufacturing processes.

Q: Can I use the MP4700GS in a boost converter application?

A: No. The MP4700GS is a step-down (buck) controller, not a step-up (boost) controller. It cannot be used in boost converter applications without complete circuit redesign using a different topology.