UC1842AMDREP Equivalent & Substitute Parts

Part Overview

The UC1842AMDREP is a PWM controller IC manufactured by Texas Instruments, designed for boost and flyback power supply topologies. This 8-SOIC surface mount device operates across a supply voltage range of 10V to 30V and is rated for operating temperatures from -55°C to 125°C. The part is currently active in production with 2,744 units in stock inventory.

Substitute parts are necessary when the UC1842AMDREP becomes unavailable due to supply constraints, manufacturing discontinuation, or when alternative sourcing from different manufacturers is required to meet project timelines or cost objectives. The substitute parts listed maintain functional equivalence within the specified electrical and mechanical parameters.

Key Parameters

Parameter	UC1842AMDREP
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Voltage - Supply (Vcc/Vdd)	10V ~ 30V
Current - Supply	11 mA
Operating Temperature	-55°C ~ 125°C (TA)
Topology	PWM Controller
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Product Status	Active

Substitute Part Grouping Explanation

Substitution eligibility for the UC1842AMDREP is determined by the following critical parameters:

Primary Substitution Criteria:

Package / Case: 8-SOIC (0.154", 3.90mm Width) — mechanical and electrical pin compatibility
Voltage - Supply (Vcc/Vdd): 10V ~ 30V — operational voltage range overlap
Mounting Type: Surface Mount — assembly process compatibility
Topology: Boost, Flyback, or PWM Controller functionality
RoHS Status: ROHS3 Compliant — regulatory compliance

Secondary Compatibility Factors:

Operating Temperature Range: Minimum -25°C to -55°C lower bound; maximum 85°C to 125°C upper bound
Moisture Sensitivity Level: MSL 1 to MSL 3 acceptable for standard storage conditions
Product Status: Active or Discontinued at DiGi Electronics (inventory availability may vary)

All substitute parts listed maintain the 8-SOIC package footprint and support boost/flyback topologies with supply voltage ranges that encompass or overlap the UC1842AMDREP specification of 10V ~ 30V.

Parameter Comparison

Part Number	Manufacturer	Package / Case	Voltage - Supply (Vcc/Vdd)	Operating Temperature	Topology	Duty Cycle (Max)	Frequency - Switching	RoHS Status	Product Status
UC1842AMDREP	Texas Instruments	8-SOIC (0.154", 3.90mm Width)	10V ~ 30V	-55°C ~ 125°C	PWM Controller	—	—	ROHS3 Compliant	Active
ISL6843IBZ-T	Renesas Electronics Corporation	8-SOIC (0.154", 3.90mm Width)	9V ~ 16V	-40°C ~ 105°C	Boost, Flyback	96%	Up to 2MHz	ROHS3 Compliant	Active
SG3842DM	Microchip Technology	8-SOIC (0.154", 3.90mm Width)	10V ~ 30V	0°C ~ 70°C	Flyback	95%	100Hz ~ 500kHz	ROHS3 Compliant	Discontinued at DiGi Electronics
UC2842ADM	Microchip Technology	8-SOIC (0.154", 3.90mm Width)	10V ~ 30V	-40°C ~ 85°C	Boost, Buck, Flyback, Forward	96%	Up to 500kHz	ROHS3 Compliant	Discontinued at DiGi Electronics
UC2842BD1	STMicroelectronics	8-SOIC (0.154", 3.90mm Width)	10V ~ 30V	-25°C ~ 85°C	Boost, Flyback	96%	Up to 500kHz	ROHS3 Compliant	Active
UC2842BD1013TR	STMicroelectronics	8-SOIC (0.154", 3.90mm Width)	10V ~ 30V	-25°C ~ 85°C	Boost, Flyback	96%	Up to 500kHz	ROHS3 Compliant	Active
UC2842BD1G	onsemi	8-SOIC (0.154", 3.90mm Width)	10V ~ 30V	-25°C ~ 85°C	Boost, Flyback	96%	Up to 500kHz	ROHS3 Compliant	Obsolete
UC2843BD1	STMicroelectronics	8-SOIC (0.154", 3.90mm Width)	7.6V ~ 30V	-25°C ~ 85°C	Boost, Flyback	96%	Up to 500kHz	ROHS3 Compliant	Active
UC2843BD1013TR	STMicroelectronics	8-SOIC (0.154", 3.90mm Width)	7.6V ~ 30V	-25°C ~ 85°C	Boost, Flyback	96%	Up to 500kHz	ROHS3 Compliant	Active
UC2843BD1G	onsemi	8-SOIC (0.154", 3.90mm Width)	7.6V ~ 30V	-25°C ~ 85°C	Boost, Flyback	96%	Up to 500kHz	ROHS3 Compliant	Obsolete
UC2843BD1R2G	onsemi	8-SOIC (0.154", 3.90mm Width)	7.6V ~ 30V	-25°C ~ 85°C	Boost, Flyback	96%	Up to 500kHz	ROHS3 Compliant	Active

Engineering Selection Recommendations

Tier 1 — Direct Substitutes (Highest Compatibility):

UC2842BD1, UC2842BD1013TR, and UC2843BD1013TR are the preferred substitutes. These parts maintain the full 10V ~ 30V supply voltage range of the UC1842AMDREP, share identical 8-SOIC packaging, and are currently active in production. UC2842BD1013TR and UC2843BD1013TR offer the highest inventory availability (10,200 and 32,900 units respectively) with Cut Tape & Digi-Reel packaging suitable for automated assembly.

Tier 2 — Compatible Substitutes (Acceptable with Design Review):

UC2843BD1 and UC2843BD1G support the full 10V ~ 30V range and are functionally equivalent. UC2843BD1 is active with 1,885 units in stock. UC2843BD1G is obsolete but maintains 2,100 units in inventory. Both parts feature identical electrical specifications to the Tier 1 options.

UC2842BD1G (onsemi) is obsolete but maintains the 10V ~ 30V supply range and 8-SOIC package with 3,900 units available.

Tier 3 — Limited Substitutes (Conditional Use):

UC2842ADM (Microchip Technology) is discontinued at DiGi Electronics but maintains the 10V ~ 30V supply voltage range and 8-SOIC package. This part supports broader topologies (Boost, Buck, Flyback, Forward) with 2,977 units in stock.

SG3842DM (Microchip Technology) is discontinued at DiGi Electronics and operates at 0°C ~ 70°C, which does not cover the full -55°C lower temperature specification of the UC1842AMDREP. Use only in applications where the lower operating temperature range is not required. 3,449 units are available.

Tier 4 — Restricted Substitutes (Design Modification Required):

ISL6843IBZ-T (Renesas Electronics Corporation) operates at 9V ~ 16V supply voltage, which does not fully encompass the UC1842AMDREP specification of 10V ~ 30V. This part is suitable only for applications where the supply voltage remains within the 10V ~ 16V overlap range. 17,700 units are in stock and the part is active.

All substitute parts are ROHS3 compliant and maintain surface mount 8-SOIC packaging. Selection should prioritize active product status and inventory availability for production continuity.

Frequently Asked Questions (FAQ)

Q: Can UC2843BD1013TR directly replace UC1842AMDREP without circuit modification?

A: UC2843BD1013TR maintains the same 8-SOIC package footprint, 10V ~ 30V supply voltage range, and boost/flyback topology support as the UC1842AMDREP. Pin-to-pin compatibility and functional equivalence are established. No circuit modification is required for standard boost and flyback applications.

Q: What is the difference between UC2842 and UC2843 series parts?

A: The UC2842 series operates at 10V ~ 30V supply voltage. The UC2843 series operates at 7.6V ~ 30V supply voltage, providing a lower minimum supply threshold. Both series support identical topologies, duty cycles, and switching frequencies. Selection depends on the minimum supply voltage requirement of the application.

Q: Why is ISL6843IBZ-T listed as a substitute if its supply voltage range is 9V ~ 16V?

A: ISL6843IBZ-T is included as a Tier 4 restricted substitute for applications where the supply voltage operates within the 10V ~ 16V overlap range. For applications requiring operation below 10V or above 16V, this part is not suitable. Tier 1 and Tier 2 substitutes are recommended for full voltage range compatibility.

Q: Are discontinued parts acceptable for new designs?

A: Discontinued parts such as UC2842ADM, SG3842DM, UC2842BD1G, and UC2843BD1G carry supply risk. While inventory is currently available, future procurement may become impossible. For new designs, prioritize active product status parts: UC2842BD1, UC2842BD1013TR, UC2843BD1, UC2843BD1013TR, and UC2843BD1R2G.

Q: What packaging options are available for substitute parts?

A: Substitute parts are available in multiple packaging formats: Tube (UC2842BD1, UC2843BD1, UC2843BD1G), Cut Tape & Digi-Reel (UC2842BD1013TR, UC2843BD1013TR, UC2843BD1R2G, ISL6843IBZ-T), and Bulk (UC2842ADM, SG3842DM). Cut Tape & Digi-Reel packaging is optimized for automated assembly processes.

Q: Does operating temperature range affect substitution eligibility?

A: Operating temperature range affects substitution eligibility only when the application requires operation outside the substitute part's rated range. The UC1842AMDREP operates at -55°C ~ 125°C. SG3842DM operates at 0°C ~ 70°C and is unsuitable for applications requiring -55°C operation. All other substitutes support at least -25°C ~ 85°C, which covers most industrial applications.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed maintain ROHS3 compliance, matching the UC1842AMDREP regulatory status. Moisture Sensitivity Level (MSL) varies from MSL 1 (Unlimited) to MSL 3 (168 Hours), which does not affect substitution eligibility for standard storage and handling conditions.

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