A8740EEETR-T LED Driver IC Equivalent & Substitute Parts

Part Overview

The A8740EEETR-T is an LED Driver IC manufactured by Allegro MicroSystems, designed as a 1-output AC DC offline switcher with flyback topology for camera flash applications. The device operates across a supply voltage range of 1.5V to 5.5V and is housed in an 8-DFN (2x2) package with exposed pad. This part is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and production continuity.

Substiute Parts

A8740EEETR-T

Allegro MicroSystemsIn Stock: 1158A8740EEETR-T Datasheet

Current PartRFQ

HV9923N8-G

Microchip TechnologyIn Stock: 2693HV9923N8-G Datasheet

MFR RecommendedRFQ

LM3450MTX/NOPB

Texas InstrumentsIn Stock: 5425LM3450MTX/NOPB Datasheet

MFR RecommendedRFQ

MP4050AGS

Monolithic Power SystemsIn Stock: 872MP4050AGS Datasheet

MFR RecommendedRFQ

RT8497AGS

Richtek USA Inc.In Stock: 25338RT8497AGS Datasheet

MFR RecommendedRFQ

TPS92411DDA

Texas InstrumentsIn Stock: 1805TPS92411DDA Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the A8740EEETR-T is determined by the following critical parameters:

• Type: AC DC Offline Switcher (all candidates match)
• Number of Outputs: 1 (all candidates match)
• Mounting Type: Surface Mount (all candidates match)
• RoHS & Compliance: ROHS3 Compliant, REACH Unaffected, EAR99 classification (all candidates match)
• Topology Compatibility: Flyback topology preferred; alternatives with Step-Down (Buck) or multi-topology support are acceptable based on application requirements
• Internal Switch(s): Original part has no internal switch; substitutes with internal switches are acceptable if voltage and current ratings align
• Supply Voltage Range: Original operates 1.5V–5.5V; substitutes must support overlapping or compatible voltage ranges
• Package Form Factor: 8-pin surface mount packages (DFN, SOIC, SOP, TSSOP) are interchangeable with PCB layout adaptation

Five manufacturer-recommended substitute parts are identified, each offering different topology and electrical characteristics suitable for specific application contexts.

Parameter Comparison

Engineering Selection Recommendations

TPS92411DDA (Texas Instruments) — Active product status with extended operating temperature range (-40°C to 150°C TJ). Supports multiple topologies (Flyback, Step-Down, Step-Up) with internal switch and wide supply voltage range (7.5V–100V). MSL-2 rating requires controlled storage. Suitable for applications requiring topology flexibility and thermal headroom.

HV9923N8-G (Microchip Technology) — Active product with unlimited MSL rating. Operates across 20V–400V supply range with 30mA output current and Triac dimming capability. Topology is Step-Down (Buck) with internal switch. Requires higher input voltage than original part; suitable for high-voltage AC line applications.

LM3450MTX/NOPB (Texas Instruments) — Active product with extended temperature range (-40°C to 125°C TJ). Supports Flyback and Step-Up (Boost) topologies with internal switch. Supply range 8.5V–20V with 11.5V output voltage specification. 16-TSSOP package requires PCB layout modification. Unlimited MSL rating.

MP4050AGS (Monolithic Power Systems) — Active product with automotive-grade qualification. Supply range 4.1V–5V closely matches original part voltage window. Step-Down (Buck) topology with 22kHz switching frequency. 8-SOIC package compatible with original footprint. MSL-2 rating and -40°C to 125°C operating range.

RT8497AGS (Richtek USA Inc.) — Obsolete product status. Step-Down (Buck) topology with 1.4A output current and 10V–30V supply range. 8-SOP package compatible with original form factor. MSL-3 rating indicates moisture sensitivity requiring careful handling. Not recommended for new designs due to obsolescence.

For new designs, prioritize active products: TPS92411DDA, HV9923N8-G, LM3450MTX/NOPB, or MP4050AGS based on specific voltage, topology, and thermal requirements.

Frequently Asked Questions (FAQ)

Q: Can the A8740EEETR-T be directly replaced with any of these substitutes without PCB modification?

A: Direct pin-for-pin replacement is not guaranteed. While all substitutes are surface-mount 8-pin devices, package variants (DFN, SOIC, SOP, TSSOP, TO-243AA) have different footprints. MP4050AGS and RT8497AGS use 8-SOIC packages most compatible with the original 8-UFDFN form factor, though pad dimensions may differ. LM3450MTX/NOPB uses 16-TSSOP, requiring significant PCB layout changes. Verify pinout and thermal pad specifications before layout finalization.

Q: What is the primary reason the A8740EEETR-T is obsolete?

A: The part is classified as obsolete by the manufacturer. Active alternatives from major suppliers (Texas Instruments, Microchip, Monolithic Power Systems) offer equivalent or enhanced functionality with ongoing production support and availability.

Q: Which substitute is best for low-voltage applications below 10V?

A: MP4050AGS operates within 4.1V–5V, most closely matching the original part's 1.5V–5.5V range. However, the original part's 1.5V minimum is not matched by any substitute. For applications requiring sub-5V operation, verify that MP4050AGS meets specific load and efficiency requirements.

Q: Are all substitutes RoHS3 compliant?

A: Yes. All six parts (original and five substitutes) are ROHS3 Compliant, REACH Unaffected, and classified as EAR99 for export control purposes.

Q: What does MSL rating mean, and why does it vary among substitutes?

A: Moisture Sensitivity Level (MSL) indicates how long a component can be stored in standard conditions (23°C, 50% relative humidity) before requiring baking before reflow soldering. MSL-1 (unlimited) requires no time restriction. MSL-2 (1 year) and MSL-3 (168 hours) require controlled storage and pre-reflow baking. The original A8740EEETR-T has MSL-1; substitutes with higher MSL ratings require additional manufacturing process control.

Q: Can RT8497AGS be used in new production designs?

A: RT8497AGS is classified as obsolete. While inventory is available (25,300 pcs), it is not recommended for new designs. Active alternatives provide better long-term supply assurance and manufacturer support.

Q: What is the key difference between Flyback and Step-Down (Buck) topologies in these parts?

A: Flyback topology (A8740EEETR-T, TPS92411DDA, LM3450MTX/NOPB) uses transformer isolation and is suitable for isolated power conversion. Step-Down (Buck) topology (RT8497AGS, HV9923N8-G, MP4050AGS) provides non-isolated voltage reduction and is simpler but requires direct electrical connection between input and output. Application requirements determine topology suitability.