RT9218APS Equivalent & Substitute Parts

Part Overview

The RT9218APS is a dual-output power management IC (PMIC) from Richtek USA Inc. designed for applications requiring synchronized step-down buck regulation combined with linear LDO output capability. This device integrates a 300kHz switching frequency controller with dual output topology in a 14-SOIC package, operating across a 5V to 12V supply range.

The RT9218APS is classified as obsolete. Identifying suitable substitute components is essential for design continuity, production planning, and long-term system reliability when original inventory becomes unavailable.

Substiute Parts

RT9218APS

Richtek USA Inc.In Stock: 1490RT9218APS Datasheet

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RT8120FGS

Richtek USA Inc.In Stock: 725RT8120FGS Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the RT9218APS is constrained by its dual-output topology combining synchronous buck and linear LDO regulation. The primary substitute identified is the RT8120FGS, which shares the following critical parameters with the main part:

Common Substitution Criteria:

• Manufacturer: Richtek USA Inc.
• Switching Frequency: 300kHz
• Supply Voltage Range: Overlapping operational window (RT8120FGS: 3V ~ 13.2V encompasses RT9218APS: 5V ~ 12V)
• Synchronous Rectifier: Present in both designs
• Package Family: Both use 8-SOIC or 14-SOIC surface-mount packages
• RoHS3 Compliance: Both devices meet ROHS3 requirements
• MSL Rating: Both rated MSL 3 (168 Hours)

Functional Differences: The RT8120FGS operates as a single-output buck controller with transistor driver output, whereas the RT9218APS provides dual outputs (one synchronous buck, one linear LDO). This represents a functional reduction rather than direct equivalence.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The RT9218APS is obsolete, making the RT8120FGS a necessary alternative for ongoing production and design updates. The RT8120FGS maintains active product status with Richtek USA Inc., ensuring continued availability and technical support.

Compliance & Certification: Both devices meet ROHS3 compliance requirements and carry identical MSL ratings (3, 168 Hours), satisfying environmental and moisture-handling standards for surface-mount assembly processes.

Operational Range: The RT8120FGS supply voltage range (3V ~ 13.2V) encompasses the RT9218APS operating window (5V ~ 12V), providing compatibility within the specified supply constraints. The RT8120FGS extends the lower supply limit to 3V and upper limit to 13.2V, offering broader operational flexibility.

Temperature Performance: The RT8120FGS operates across -40°C ~ 85°C, exceeding the RT9218APS range of 0°C ~ 70°C. This extended temperature capability supports applications requiring wider thermal operating windows.

Frequently Asked Questions (FAQ)

Q: Can the RT8120FGS directly replace the RT9218APS in existing designs?

A: Direct replacement requires design modification. The RT9218APS provides two independent outputs (synchronous buck and linear LDO), while the RT8120FGS provides single-output buck control. Applications requiring dual-output functionality must implement external linear regulation or alternative LDO solutions alongside the RT8120FGS.

Q: Are the package dimensions compatible?

A: Both devices use 8-SOIC and 14-SOIC packages with identical pitch (0.154", 3.90mm width). However, the RT9218APS uses 14-SOIC while the RT8120FGS uses 8-SOIC, requiring PCB layout modifications for pin-to-pin substitution.

Q: What is the significance of the 300kHz switching frequency match?

A: Identical switching frequency ensures compatible filter component selection and noise characteristics. External inductor and capacitor values designed for the RT9218APS remain applicable to the RT8120FGS buck stage, simplifying circuit adaptation.

Q: Does the RT8120FGS support the same supply voltage range?

A: The RT8120FGS supply range (3V ~ 13.2V) is broader than the RT9218APS (5V ~ 12V). Designs operating within the original 5V ~ 12V window are fully supported. Designs requiring operation below 5V or above 12V benefit from the extended range.

Q: Are there differences in synchronous rectification capability?

A: Both devices incorporate synchronous rectifier functionality at 300kHz switching frequency, maintaining equivalent efficiency characteristics for buck regulation stages.

Q: What compliance certifications apply to both parts?

A: Both the RT9218APS and RT8120FGS are ROHS3 compliant and carry MSL 3 (168 Hours) ratings, meeting standard environmental and moisture-sensitivity requirements for surface-mount manufacturing.