TL3843D-8 Equivalent & Substitute Parts

Part Overview

The TL3843D-8 is a Power Management IC (PMIC) manufactured by Texas Instruments, functioning as a multi-topology DC-DC controller for boost, flyback, and forward regulator applications. This device operates as a transistor driver with positive output configuration and is classified as Last Time Buy, indicating discontinuation from the original manufacturer. Substitute parts are necessary to maintain design continuity and ensure long-term supply availability for applications requiring equivalent control functionality.

Substiute Parts

TL3843D-8

Texas InstrumentsIn Stock: 1510TL3843D-8 Datasheet

Current PartRFQ

UC3843BD1G

onsemiIn Stock: 2327UC3843BD1G Datasheet

MFR RecommendedRFQ

UC3843BD1R2G

onsemiIn Stock: 88979UC3843BD1R2G Datasheet

MFR RecommendedRFQ

UC3843BVD1R2G

onsemiIn Stock: 5000486UC3843BVD1R2G Datasheet

MFR RecommendedRFQ

UC3844BD1013TR

STMicroelectronicsIn Stock: 2203UC3844BD1013TR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the TL3843D-8 is determined by the following critical parameters:

Primary Compatibility Criteria:

• Package / Case: 8-SOIC form factor (0.154", 3.90mm Width)
• Voltage - Supply (Vcc/Vdd): 7.6V ~ 30V minimum range
• Frequency - Switching: Up to 500kHz capability
• Output Type: Transistor Driver
• Mounting Type: Surface Mount
• RoHS Status: ROHS3 Compliant

Secondary Considerations:

• Topology support: Boost and Flyback minimum requirement
• Duty Cycle (Max): 96% or higher
• Operating Temperature: 0°C ~ 70°C or extended range

The substitute parts listed below meet or exceed the primary compatibility criteria. Variations in duty cycle maximum (96% vs. 97%), extended operating temperature ranges, and output configuration enhancements (isolation capability) do not preclude substitution when the core electrical and mechanical parameters align.

Parameter Comparison

Engineering Selection Recommendations

UC3843BD1G and UC3843BD1R2G (onsemi): Both parts are active products with full parameter alignment to the TL3843D-8 across voltage supply, switching frequency, and package specifications. UC3843BD1R2G offers significantly higher inventory availability (88,872 pcs) compared to UC3843BD1G (2,300 pcs), making it the preferred choice for volume applications. Both maintain ROHS3 compliance and identical operating temperature ranges.

UC3843BVD1R2G (onsemi): This variant extends the operating temperature range to -40°C ~ 105°C, providing enhanced thermal performance for applications requiring extended temperature operation. Inventory availability is substantially higher (5,000,400 pcs). This part is suitable as a direct substitute when extended temperature capability is beneficial or required.

UC3844BD1013TR (STMicroelectronics): This part exhibits a reduced maximum duty cycle (48% vs. 97%), which represents a functional limitation for applications requiring high duty cycle operation. The minimum supply voltage is also elevated to 10V, narrowing the input voltage range. This part is suitable only for applications that do not require the full duty cycle capability of the original TL3843D-8 and operate within the 10V ~ 30V supply range.

Recommendation Priority:

1. UC3843BD1R2G for standard applications with high availability requirements
2. UC3843BVD1R2G for extended temperature operation
3. UC3843BD1G as secondary option when specific packaging (Tube) is required
4. UC3844BD1013TR only when duty cycle and supply voltage limitations are acceptable

Frequently Asked Questions (FAQ)

Q: Can UC3844BD1013TR directly replace TL3843D-8 in all applications?

A: No. UC3844BD1013TR has a maximum duty cycle of 48% compared to TL3843D-8's 97%, and a minimum supply voltage of 10V versus 7.6V. It is suitable only for applications that operate within these reduced specifications.

Q: What is the primary difference between UC3843BD1R2G and UC3843BD1G?

A: Both parts are electrically identical. The difference is packaging: UC3843BD1R2G is supplied in Cut Tape (CT) & Digi-Reel format with significantly higher inventory (88,872 pcs), while UC3843BD1G is supplied in Tube format with lower inventory (2,300 pcs).

Q: Is UC3843BVD1R2G suitable for applications operating at 0°C to 70°C?

A: Yes. UC3843BVD1R2G operates across -40°C ~ 105°C, which encompasses the 0°C ~ 70°C range. It is a compatible substitute with enhanced thermal capability.

Q: Are all substitute parts in the same 8-SOIC package?

A: Yes. All substitute parts use the 8-SOIC (0.154", 3.90mm Width) package, ensuring mechanical and electrical pin compatibility with the TL3843D-8.

Q: Do all substitute parts support the same topologies as TL3843D-8?

A: The UC3843 variants (UC3843BD1G, UC3843BD1R2G, UC3843BVD1R2G) support Boost and Flyback topologies. The TL3843D-8 additionally supports Forward topology. For Forward regulator applications, verify circuit compatibility or consider alternative controllers.

Q: What is the significance of "Last Time Buy" status for TL3843D-8?

A: Last Time Buy indicates that Texas Instruments has discontinued this part and will not manufacture additional units beyond existing inventory. Substitution with active products (UC3843 or UC3844 variants) is necessary for long-term design continuity and future production requirements.