UC2845AD Equivalent & Substitute Parts

Part Overview

The UC2845AD is a current mode PWM controller manufactured by Microchip Technology, designed for boost, buck, flyback, and forward regulator topologies. This integrated circuit functions as a transistor driver for step-up and step-down DC-DC conversion applications with positive, isolation-capable output configuration. The UC2845AD is classified as obsolete, necessitating identification of equivalent and substitute components for ongoing design support and procurement continuity. Alternative parts must maintain electrical compatibility across supply voltage, switching frequency, duty cycle, and thermal operating ranges while preserving the 14-SOIC package form factor.

Substiute Parts

UC2845AD

Microchip TechnologyIn Stock: 1441UC2845AD Datasheet

Current PartRFQ

UC2845AD

UnitrodeIn Stock: 1498UC2845AD Datasheet

DirectRFQ

UC2845ADTR

Texas InstrumentsIn Stock: 6377UC2845ADTR Datasheet

DirectRFQ

UC2845D

onsemiIn Stock: 1673UC2845D Datasheet

DirectRFQ

TL2845BD

Texas InstrumentsIn Stock: 2031TL2845BD Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the UC2845AD is determined by strict alignment with the following electrical and mechanical parameters:

Primary Substitution Criteria:

• Supply voltage range: 7.6V to 30V
• Maximum switching frequency: 500 kHz
• Maximum duty cycle: 48%
• Operating temperature range: -40°C to 85°C
• Package specification: 14-SOIC (0.154", 3.90mm Width)
• Mounting type: Surface Mount
• Output configuration: Single output, single phase, transistor driver topology

Substitution Categories:

Direct Equivalents maintain identical electrical specifications, package form factor, and functional topology. These parts are pin-compatible and functionally interchangeable within the specified parameter envelope.

Functional Equivalents support the same topologies and parameter ranges but may originate from different manufacturers or carry different product status classifications. Electrical performance remains equivalent across all critical operating conditions.

Similar Parts support overlapping but not identical topology sets. The TL2845BD supports boost, flyback, and forward topologies but does not explicitly support buck topology, representing a functional subset of the UC2845AD capability.

Parameter Comparison

Engineering Selection Recommendations

Recommended Primary Substitutes:

UC2845ADTR (Texas Instruments) is the preferred substitute for new designs and procurement. This part carries active product status, ensuring long-term availability and manufacturing support. The UC2845ADTR is supplied in Tape & Reel packaging with ROHS3 compliance and MSL 1 rating, meeting modern supply chain and environmental requirements. Supply voltage range (7.6V to 30V) and operating temperature range (-40°C to 85°C) align with the original UC2845AD specification. Current supply specification of 11 mA is documented for this variant.

UC2845AD (Unitrode) provides direct functional equivalence with active product status. This variant maintains identical part number designation and supports the full parameter envelope of the original component. Unitrode manufacturing ensures compatibility with existing designs.

Alternative Substitutes:

UC2845D (onsemi) offers functional equivalence but carries obsolete product status classification, limiting its suitability for new procurement. RoHS non-compliance status restricts application in regulated industries and regions with environmental restrictions.

TL2845BD (Texas Instruments) functions as a partial substitute, supporting boost, flyback, and forward topologies with identical supply voltage (7.6V to 30V), switching frequency (500 kHz), duty cycle (48%), and operating temperature ranges. This part does not explicitly support buck topology, making it unsuitable for applications requiring step-down conversion capability. TL2845BD carries Last Time Buy status, indicating limited future availability.

Selection Criteria Summary:

For applications requiring full topology support (boost, buck, flyback, forward), select UC2845ADTR or UC2845AD (Unitrode). For applications limited to boost, flyback, and forward topologies, TL2845BD provides equivalent performance with active or extended availability status. Avoid UC2845D for new designs due to obsolete status and RoHS non-compliance.

Frequently Asked Questions (FAQ)

Q: Can UC2845ADTR replace UC2845AD in existing designs?

A: Yes. UC2845ADTR maintains electrical compatibility across all specified parameters: supply voltage (7.6V to 30V), switching frequency (500 kHz), duty cycle (48%), operating temperature (-40°C to 85°C), and 14-SOIC package form factor. Pin configuration and functional topology support are identical. The primary difference is packaging format (Tape & Reel versus Tube) and active product status.

Q: What is the difference between UC2845AD and UC2845ADTR?

A: Both parts share identical electrical specifications and pin configuration. UC2845ADTR is supplied in Tape & Reel format for automated assembly, while UC2845AD is supplied in Tube format for manual handling. UC2845ADTR carries active product status with documented long-term availability, whereas UC2845AD (Microchip) is classified as obsolete.

Q: Is TL2845BD a complete substitute for UC2845AD?

A: TL2845BD is a partial substitute. It supports boost, flyback, and forward topologies with identical electrical parameters (7.6V to 30V supply, 500 kHz switching frequency, 48% duty cycle). However, TL2845BD does not explicitly support buck topology. Applications requiring step-down conversion capability must use UC2845ADTR or UC2845AD (Unitrode). TL2845BD carries Last Time Buy status, indicating limited future procurement availability.

Q: Are all substitute parts available in 14-SOIC package?

A: Yes. All listed substitutes conform to 14-SOIC (0.154", 3.90mm Width) package specification with surface mount mounting type. Package compatibility ensures direct PCB layout compatibility without redesign.

Q: What is the significance of RoHS compliance for UC2845 selection?

A: UC2845ADTR and TL2845BD carry ROHS3 compliance certification, meeting environmental and regulatory requirements in the European Union and other regulated markets. UC2845D is RoHS non-compliant, restricting its use in applications subject to environmental regulations. For new designs and regulated applications, select ROHS3-compliant variants.

Q: Does operating temperature range differ among substitutes?

A: All listed substitutes maintain the -40°C to 85°C operating temperature range specified for the original UC2845AD. Temperature performance is equivalent across all variants.

Q: What does "Last Time Buy" status mean for TL2845BD?

A: Last Time Buy indicates that Texas Instruments has announced end-of-life for TL2845BD production. Existing inventory remains available for purchase, but no new manufacturing will occur after the specified cutoff date. For long-term design support, UC2845ADTR (active status) is the preferred selection.

Q: Can UC2845D be used as a substitute despite obsolete status?

A: UC2845D maintains electrical compatibility with the original UC2845AD across all specified parameters. However, obsolete product status indicates discontinued manufacturing and limited future availability. RoHS non-compliance further restricts application in regulated environments. UC2845D is suitable only for legacy system maintenance where existing inventory is available and regulatory compliance is not required.