TL3845BDR-8 Equivalent & Substitute Parts

Part Overview

The TL3845BDR-8 is a DC-DC controller IC manufactured by Texas Instruments, designed for boost, flyback, and forward converter topologies. It functions as a transistor driver for step-up and step-up/step-down applications with positive output configuration. The device operates across a supply voltage range of 7.6V to 30V with a 100kHz switching frequency and 48% maximum duty cycle. Currently in active product status with 17,222 units in stock, this component is widely used in power management applications requiring multi-topology regulation.

Substitute parts are necessary when the original TL3845BDR-8 becomes unavailable, when alternative packaging formats are required for manufacturing processes, or when design specifications allow for functionally equivalent controllers from other manufacturers that meet the same electrical and mechanical parameters.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Package / Case	8-SOIC (0.154", 3.90mm Width)
Topology	Boost, Flyback, Forward Converter
Function	Step-Up, Step-Up/Step-Down
Output Configuration	Positive
Voltage - Supply (Vcc/Vdd)	7.6V ~ 30V
Frequency - Switching	100kHz
Duty Cycle (Max)	48%
Operating Temperature	0°C ~ 70°C (TA)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the TL3845BDR-8 is determined by strict adherence to the following critical parameters:

Mandatory Matching Parameters:

Package / Case: 8-SOIC (0.154", 3.90mm Width)
Voltage - Supply (Vcc/Vdd): 7.6V ~ 30V
Duty Cycle (Max): 48%
Output Configuration: Positive
Mounting Type: Surface Mount
RoHS Status: ROHS3 Compliant or equivalent
Moisture Sensitivity Level (MSL): 1 (Unlimited)

Functionally Compatible Parameters:

Topology: Boost, Flyback, Forward Converter (or subset thereof)
Function: Step-Up, Step-Up/Step-Down (or subset thereof)
Output Type: Transistor Driver
Control Features: Frequency Control

Substitute parts are grouped into two categories: parametric equivalents (identical electrical specifications and packaging) and manufacturer-recommended alternatives (functionally compatible with allowable parameter variations in switching frequency and operating temperature range).

Parameter Comparison

Part Number	Manufacturer	Packaging	Vcc/Vdd (V)	Switching Frequency	Duty Cycle (Max)	Operating Temp (TA/TJ)	Topology	Output Config	Product Status
TL3845BDR-8	Texas Instruments	Tape & Reel (TR)	7.6 ~ 30	100kHz	48%	0°C ~ 70°C	Boost, Flyback, Forward	Positive	Active
TL3845DR-8	Texas Instruments	Cut Tape (CT) & Digi-Reel®	7.6 ~ 30	100kHz	48%	0°C ~ 70°C	Boost, Flyback, Forward	Positive	Active
UC3844BD1013TR	STMicroelectronics	Cut Tape (CT) & Digi-Reel®	10 ~ 30	Up to 500kHz	48%	0°C ~ 70°C	Boost, Flyback	Positive, Isolation Capable	Active
UC3845ADM-TR	Microchip Technology	Cut Tape (CT)	7.6 ~ 30	Up to 500kHz	48%	0°C ~ 70°C	Boost, Buck, Flyback, Forward	Positive, Isolation Capable	Discontinued at DiGi Electronics
UC3845BD1013TR	STMicroelectronics	Cut Tape (CT) & Digi-Reel®	7.6 ~ 30	Up to 500kHz	48%	-40°C ~ 150°C	Boost, Flyback	Positive, Isolation Capable	Active
UC3845BD1G	onsemi	Tube	7.6 ~ 30	Up to 500kHz	48%	0°C ~ 70°C	Boost, Flyback	Positive, Isolation Capable	Active
UC3845BD1R2G	onsemi	Cut Tape (CT) & Digi-Reel®	7.6 ~ 30	Up to 500kHz	48%	0°C ~ 70°C	Boost, Flyback	Positive, Isolation Capable	Active
UC3845BVD1R2G	onsemi	Tape & Reel (TR)	7.6 ~ 30	Up to 500kHz	48%	-40°C ~ 105°C	Boost, Flyback	Positive, Isolation Capable	Active

Engineering Selection Recommendations

Parametric Equivalent (Identical Specifications): TL3845DR-8 is the direct parametric equivalent to TL3845BDR-8, differing only in packaging format (Cut Tape & Digi-Reel® versus Tape & Reel). Both maintain identical electrical specifications, operating temperature range, and switching frequency. Selection between these two depends solely on manufacturing process requirements and packaging compatibility with assembly equipment.

Manufacturer-Recommended Alternatives: The following parts are functionally compatible substitutes that meet all mandatory electrical and mechanical parameters while offering extended capabilities or alternative sourcing:

UC3845BD1013TR (STMicroelectronics) and UC3845BD1R2G (onsemi) provide identical supply voltage range and duty cycle specifications with enhanced switching frequency capability (up to 500kHz). Both are in active product status with substantial inventory availability. UC3845BD1013TR offers extended operating temperature range (-40°C to 150°C), suitable for industrial and automotive applications.

UC3845BVD1R2G (onsemi) provides Tape & Reel packaging matching the original TL3845BDR-8 format with extended operating temperature range (-40°C to 105°C) and active product status.

UC3844BD1013TR (STMicroelectronics) operates within a minimum supply voltage of 10V (versus 7.6V for the primary part) and supports boost and flyback topologies only. This part is suitable only when minimum input voltage requirements exceed 10V.

UC3845ADM-TR (Microchip Technology) is discontinued at DiGi Electronics and should not be selected for new designs despite meeting electrical specifications.

Frequently Asked Questions (FAQ)

Q: Can TL3845DR-8 be used as a direct replacement for TL3845BDR-8? A: Yes. TL3845DR-8 is a parametric equivalent with identical electrical specifications. The only difference is packaging format (Cut Tape & Digi-Reel® versus Tape & Reel). Selection depends on manufacturing process compatibility.

Q: What is the key difference between TL3845BDR-8 and UC3845BD1013TR? A: Both operate at 7.6V to 30V supply voltage with 48% maximum duty cycle. UC3845BD1013TR offers higher switching frequency capability (up to 500kHz versus 100kHz) and extended operating temperature range (-40°C to 150°C). UC3845BD1013TR supports boost and flyback topologies, while TL3845BDR-8 also supports forward converter topology.

Q: Is UC3844BD1013TR compatible with TL3845BDR-8? A: UC3844BD1013TR is functionally compatible for applications where minimum input voltage is 10V or higher. It does not support the full 7.6V minimum supply voltage of the original part and lacks forward converter topology support. Use only when design specifications permit these limitations.

Q: Why is UC3845ADM-TR listed if it is discontinued? A: UC3845ADM-TR meets all electrical and mechanical substitution criteria but is discontinued at DiGi Electronics. It is included for reference in legacy design reviews. New designs should not specify this part.

Q: What packaging options are available for substitutes? A: Substitutes are available in Tape & Reel (TR), Cut Tape (CT) & Digi-Reel®, and Tube packaging formats. All maintain the 8-SOIC (0.154", 3.90mm Width) package case. Selection depends on manufacturing assembly process requirements.

Q: Do all substitute parts meet RoHS3 compliance? A: Yes. All listed substitute parts are ROHS3 Compliant with Moisture Sensitivity Level 1 (Unlimited), matching the environmental compliance of TL3845BDR-8.

Q: Which substitute offers the widest operating temperature range? A: UC3845BD1013TR (STMicroelectronics) provides the widest operating temperature range at -40°C to 150°C, suitable for extended industrial and automotive temperature environments.

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