ZXLD381FHTA LED Driver IC Equivalent & Substitute Parts

Part Overview

The ZXLD381FHTA is a LED Driver IC manufactured by Diodes Incorporated, designed as a 1-output DC DC controller with step-up (boost) topology for backlight applications. This device operates with a 320mA switch current output and features an integrated internal switch. The part is classified as obsolete, making substitute parts necessary for new designs and ongoing production requirements.

Substiute Parts

ZXLD381FHTA

Diodes IncorporatedIn Stock: 5114ZXLD381FHTA Datasheet

Current PartRFQ

ZXLD383ET5TA

Diodes IncorporatedIn Stock: 1467ZXLD383ET5TA Datasheet

MFR RecommendedRFQ

ZXLD381FHTA

Diodes IncorporatedIn Stock: 5114ZXLD381FHTA Datasheet

Parametric EquivalentRFQ

AT9932TS-G

Microchip TechnologyIn Stock: 12440AT9932TS-G Datasheet

MFR RecommendedRFQ

IS31LT3354-STLS2-TR

Lumissil MicrosystemsIn Stock: 15130IS31LT3354-STLS2-TR Datasheet

MFR RecommendedRFQ

NCP1370BDR2G

onsemiIn Stock: 3251NCP1370BDR2G Datasheet

MFR RecommendedRFQ

TPS92690Q1PWP/NOPB

Texas InstrumentsIn Stock: 1111TPS92690Q1PWP/NOPB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the ZXLD381FHTA are selected based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

• Topology: Step-Up (Boost) capability
• Number of Outputs: 1 output configuration
• Internal Switch: Presence of integrated switch
• Voltage Supply Range: Compatibility with 0.9V to 2.2V input
• Output Voltage: 20V capability
• Current Output: 320mA switch current
• Switching Frequency: Proximity to 350kHz operation
• Applications: Backlight functionality
• RoHS Compliance: ROHS3 Compliant

Substitute Categories:

Direct Functional Replacement (Recommended):

• ZXLD383ET5TA (Diodes Incorporated) – Same manufacturer, active product status, enhanced supply voltage range (0.9V to 3.3V), identical topology and output specifications

Alternative Topologies with Boost Capability:

• TPS92690Q1PWP/NOPB (Texas Instruments) – Flyback/SEPIC/Step-Up topology, no internal switch, higher voltage supply range (4.5V to 75V)
• NCP1370BDR2G (onsemi) – Flyback/SEPIC/Step-Down/Step-Up topology, no internal switch, higher voltage supply range (9.5V to 26V)

Buck Topology Alternatives:

• IS31LT3354-STLS2-TR (Lumissil Microsystems) – Step-Down (Buck) topology, no internal switch, higher voltage supply range (6V to 40V)

Multi-Topology Controller:

• AT9932TS-G (Microchip Technology) – Step-Down/Step-Up topology, no internal switch, higher voltage supply range (5.3V to 40V), automotive grade

Parameter Comparison

Engineering Selection Recommendations

ZXLD383ET5TA (Recommended Primary Substitute)

The ZXLD383ET5TA is the preferred substitute for the obsolete ZXLD381FHTA. Both devices are manufactured by Diodes Incorporated and share identical topology (step-up boost), output configuration (1 output), and internal switch architecture. The ZXLD383ET5TA maintains the same 320mA switch current and 20V output voltage specifications. The primary enhancement is an expanded supply voltage range (0.9V to 3.3V versus 0.9V to 2.2V), providing greater design flexibility. The ZXLD383ET5TA is in active product status with ROHS3 compliance and unlimited moisture sensitivity level (MSL 1), ensuring long-term availability and supply chain stability. Operating temperature range extends to -20°C, improving low-temperature performance. Package migration from SOT-23-3 to TSOT-23-5 requires PCB layout adjustment but maintains surface mount compatibility.

TPS92690Q1PWP/NOPB (Alternative for Higher Voltage Applications)

The TPS92690Q1PWP/NOPB from Texas Instruments provides step-up (boost) capability within a multi-topology controller (Flyback/SEPIC/Step-Up). This device lacks an internal switch, requiring external switching components. The supply voltage range (4.5V to 75V) exceeds the ZXLD381FHTA requirements, making it suitable for applications requiring higher input voltages. The device operates at 350kHz–490kHz, aligning with the original 350kHz specification. It carries automotive grade qualification (AEC-Q100) and operates across -40°C to 125°C, providing enhanced temperature performance. ROHS3 compliance and MSL 1 rating ensure regulatory compliance. The 16-PowerTSSOP package requires significant PCB redesign compared to the original SOT-23-3.

NCP1370BDR2G (Alternative for Multi-Topology Flexibility)

The NCP1370BDR2G from onsemi is a multi-topology LED driver controller supporting Flyback, SEPIC, step-down, and step-up configurations. Without an internal switch, external switching components are required. The supply voltage range (9.5V to 26V) positions this device for higher-voltage input applications. The controller supports both analog and PWM dimming, providing enhanced functionality. Operating temperature range of -40°C to 125°C and ROHS3 compliance meet regulatory requirements. The 8-SOIC package is more compact than the 16-PowerTSSOP alternative but still requires PCB layout modification from the original SOT-23-3.

IS31LT3354-STLS2-TR (Alternative for Buck Topology Applications)

The IS31LT3354-STLS2-TR from Lumissil Microsystems implements step-down (buck) topology, fundamentally different from the boost topology of the ZXLD381FHTA. This device is applicable only when buck conversion is acceptable for the application. It lacks an internal switch and operates across 6V to 40V supply range. The 1MHz switching frequency is higher than the original 350kHz. Automotive grade qualification and -40°C to 85°C operating temperature provide robust performance. ROHS3 compliance and MSL 3 rating are standard. The SOT-23-5 package is similar in size to the ZXLD383ET5TA alternative.

AT9932TS-G (Alternative for Automotive Multi-Topology Applications)

The AT9932TS-G from Microchip Technology is a multi-topology controller supporting step-down and step-up configurations without an internal switch. The supply voltage range (5.3V to 40V) accommodates higher input voltages. Automotive grade qualification (AEC-Q100) and extended operating temperature (-40°C to 150°C) provide robust performance for automotive environments. PWM dimming capability is supported. ROHS3 compliance and MSL 3 rating meet regulatory standards. The 24-TSSOP package requires substantial PCB redesign.

Frequently Asked Questions (FAQ)

Q: Can ZXLD383ET5TA directly replace ZXLD381FHTA without circuit modifications?

A: The ZXLD383ET5TA maintains functional equivalence in topology, output configuration, and current specifications. However, the package change from SOT-23-3 to TSOT-23-5 requires PCB footprint modification. The expanded supply voltage range (0.9V to 3.3V) is backward compatible with designs operating within the original 0.9V to 2.2V range. Circuit topology remains unchanged.

Q: Why do alternative substitutes lack internal switches?

A: The ZXLD381FHTA integrates an internal switch, reducing external component count and PCB area. Alternative controllers from Texas Instruments, onsemi, Lumissil, and Microchip implement controller-only architectures, requiring external MOSFETs or switching transistors. This design approach provides greater flexibility for custom topologies and higher power applications but increases component count and design complexity.

Q: What are the package compatibility implications?

A: The original ZXLD381FHTA uses SOT-23-3 (3-pin), the smallest package among substitutes. ZXLD383ET5TA uses TSOT-23-5 (5-pin), requiring additional PCB traces. Alternative controllers use larger packages: 16-PowerTSSOP (TPS92690Q1PWP/NOPB), 8-SOIC (NCP1370BDR2G), SOT-23-5 (IS31LT3354-STLS2-TR), and 24-TSSOP (AT9932TS-G). Package selection impacts PCB layout, thermal management, and board space allocation.

Q: Are all substitutes RoHS3 compliant?

A: Yes, all listed substitutes carry ROHS3 compliance certification, meeting regulatory requirements for hazardous substance restrictions. Moisture sensitivity levels vary: ZXLD381FHTA and ZXLD383ET5TA are MSL 1 (unlimited), while TPS92690Q1PWP/NOPB is MSL 1, and NCP1370BDR2G, IS31LT3354-STLS2-TR, and AT9932TS-G are MSL 3 (168 hours).

Q: Which substitute is best for automotive applications?

A: TPS92690Q1PWP/NOPB, IS31LT3354-STLS2-TR, and AT9932TS-G carry automotive grade qualifications. TPS92690Q1PWP/NOPB and AT9932TS-G hold AEC-Q100 certification. AT9932TS-G provides the widest operating temperature range (-40°C to 150°C) and multi-topology flexibility, making it suitable for demanding automotive environments.

Q: What is the frequency difference impact between 350kHz and 330kHz?

A: ZXLD383ET5TA operates at 330kHz versus the original 350kHz. This 20kHz difference (5.7% variation) has minimal impact on inductor and capacitor selection for most backlight applications. Component values may require minor adjustment, but the frequency proximity ensures compatibility with existing passive component designs.

Q: Can I use a buck topology substitute in a boost application?

A: No. IS31LT3354-STLS2-TR implements step-down (buck) topology, which reduces voltage. The ZXLD381FHTA requires step-up (boost) topology to increase voltage from 0.9V–2.2V input to 20V output. Buck topology substitutes are applicable only for applications requiring voltage reduction, not voltage elevation.