TL3842BP Equivalent & Substitute Parts

Part Overview

The TL3842BP is a boost, flyback, and forward regulator controller IC manufactured by Texas Instruments, designed for positive output step-up and step-up/step-down DC-DC conversion applications. This 8-PDIP through-hole component operates across a 10V to 30V supply voltage range with switching frequencies up to 500kHz and a maximum duty cycle of 96%. The part is currently in Last Time Buy status, making equivalent and substitute parts necessary for ongoing design support and procurement planning.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Part Number	TL3842BP
Category	Power Management (PMIC)
Package / Case	8-DIP (0.300", 7.62mm)
Mounting Type	Through Hole
Topology	Boost, Flyback, Forward
Output Configuration	Positive
Voltage - Supply (Vcc/Vdd)	10V ~ 30V
Frequency - Switching	Up to 500kHz
Duty Cycle (Max)	96%
Operating Temperature	0°C ~ 70°C (TA)
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution for the TL3842BP is determined by strict alignment of the following electrical and mechanical parameters:

Critical Substitution Criteria:

Package / Case: 8-DIP (0.300", 7.62mm) form factor
Mounting Type: Through Hole
Voltage - Supply (Vcc/Vdd): 10V ~ 30V minimum range
Frequency - Switching: Up to 500kHz capability
Duty Cycle (Max): 96% or greater
Topology: Boost and/or Flyback support
Output Configuration: Positive output
RoHS3 Compliance

Substitute parts are grouped into two categories:

Upgrade Parts (Enhanced specifications or extended availability):

SG2842M, UC2842BN, UC2842BNG, UC2843BN

Manufacturer Recommended Parts (Direct functional equivalents with active status):

UC2842AM, UC3842AM, UC3842BN, UC3842BNG, UC3843AM, UC3843BN

All listed substitutes maintain the 8-DIP through-hole package, support boost and flyback topologies, and operate within the 10V to 30V supply range with up to 500kHz switching frequency.

Parameter Comparison

Part Number	Manufacturer	Package	Topology	Vcc/Vdd Range	Switching Freq	Duty Cycle Max	Temp Range	Product Status
TL3842BP	Texas Instruments	8-DIP	Boost, Flyback, Forward	10V ~ 30V	Up to 500kHz	96%	0°C ~ 70°C	Last Time Buy
SG2842M	Microchip Technology	8-DIP	Flyback	10V ~ 30V	100Hz ~ 500kHz	95%	-25°C ~ 85°C	Discontinued at DiGi Electronics
UC2842BN	STMicroelectronics	8-DIP	Boost, Flyback	10V ~ 30V	Up to 500kHz	96%	-25°C ~ 85°C	Active
UC2842BNG	onsemi	8-DIP	Boost, Flyback	10V ~ 30V	Up to 500kHz	96%	-25°C ~ 85°C	Active
UC2843BN	STMicroelectronics	8-DIP	Boost, Flyback	7.6V ~ 30V	Up to 500kHz	96%	-25°C ~ 85°C	Active
UC2842AM	Microchip Technology	8-DIP	Boost, Buck, Flyback, Forward	10V ~ 30V	Up to 500kHz	96%	-40°C ~ 85°C	Discontinued at DiGi Electronics
UC3842AM	Microchip Technology	8-DIP	Boost, Buck, Flyback, Forward	10V ~ 30V	Up to 500kHz	96%	0°C ~ 70°C	Discontinued at DiGi Electronics
UC3842BN	STMicroelectronics	8-DIP	Boost, Flyback	10V ~ 30V	Up to 500kHz	96%	0°C ~ 70°C	Active
UC3842BNG	onsemi	8-DIP	Boost, Flyback	10V ~ 30V	Up to 500kHz	96%	0°C ~ 70°C	Active
UC3843AM	Microchip Technology	8-DIP	Boost, Buck, Flyback, Forward	7.6V ~ 30V	Up to 500kHz	96%	0°C ~ 70°C	Discontinued at DiGi Electronics
UC3843BN	STMicroelectronics	8-DIP	Boost, Flyback	7.6V ~ 30V	Up to 500kHz	96%	0°C ~ 70°C	Active

Engineering Selection Recommendations

For Active Production and New Designs:

UC3842BN (STMicroelectronics) and UC3842BNG (onsemi) are the primary recommended substitutes. Both parts maintain identical electrical specifications to the TL3842BP, including 10V to 30V supply voltage, 500kHz switching frequency capability, and 96% maximum duty cycle. Both are in active production status with substantial inventory availability (55,100 and 2,400 units respectively) and maintain ROHS3 compliance. The operating temperature range matches the TL3842BP at 0°C to 70°C.

UC3843BN (STMicroelectronics) and UC3843AM (Microchip Technology) provide extended lower supply voltage support (7.6V minimum) while maintaining all other critical parameters. UC3843BN is actively produced with 60,300 units in stock.

For Extended Temperature Range Applications:

UC2842BN (STMicroelectronics) and UC2842BNG (onsemi) extend the operating temperature range to -25°C to 85°C while maintaining all core electrical specifications. Both are in active production with high inventory levels (2,612 and 5,140 units respectively).

For Discontinued Product Replacement:

UC2842AM and UC3842AM (Microchip Technology) are manufacturer-recommended alternatives but are discontinued at DiGi Electronics. These should be considered only if existing inventory is available and long-term supply is not a concern.

All substitute parts are ROHS3 compliant and maintain the 8-DIP through-hole package format required for direct PCB compatibility.

Frequently Asked Questions (FAQ)

Q: Can UC3843BN replace TL3842BP directly on the PCB?

A: Yes. UC3843BN maintains the 8-DIP through-hole package, identical pin configuration, and all critical electrical parameters including 10V to 30V supply voltage range, 500kHz switching frequency, and 96% duty cycle. The lower minimum supply voltage (7.6V vs 10V) does not prevent substitution in designs operating at 10V or higher.

Q: What is the difference between UC2842 and UC3842 series parts?

A: Both series support boost and flyback topologies with identical switching frequency and duty cycle specifications. The primary difference is operating temperature range: UC2842 series extends to -25°C to 85°C, while UC3842 series operates at 0°C to 70°C. Select based on your application's temperature requirements.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts maintain ROHS3 compliance, matching the TL3842BP specification.

Q: Why is SG2842M listed as an upgrade part if it has a lower duty cycle (95% vs 96%)?

A: SG2842M is included as a functional substitute because 95% duty cycle remains within acceptable operating parameters for most boost and flyback applications. However, designs requiring the full 96% duty cycle should select alternatives with matching specifications.

Q: Can I use UC2843BN in a design originally specified for TL3842BP?

A: Yes, with verification. UC2843BN supports the required 10V to 30V supply range and 500kHz switching frequency. The lower minimum supply voltage (7.6V) is not a limitation for designs operating at 10V or above. Confirm your application does not require the forward topology, as UC2843BN supports only boost and flyback.

Q: Which substitute has the best long-term availability?

A: UC3843BN (STMicroelectronics) and UC3843AM (Microchip Technology) show the highest inventory levels (60,300 and 3,500 units respectively) and active production status, providing the strongest long-term supply assurance.

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