RT9218GS Equivalent & Substitute Parts

Part Overview

The RT9218GS is a dual-output power management IC (PMIC) manufactured by Richtek USA Inc., featuring integrated step-down (buck) synchronous and linear (LDO) regulators in a 14-SOP package. This device operates at 300kHz switching frequency and supports 5V and 12V supply voltages across an operating temperature range of -40°C to 85°C. The RT9218GS is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing design support and component procurement.

Substiute Parts

RT9218GS

Richtek USA Inc.In Stock: 5335RT9218GS 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 RT9218GS is constrained by the following critical parameters:

• Topology Requirements: The main part integrates both synchronous buck and linear (LDO) regulation in a single package. Substitute parts must provide equivalent functional output configurations.
• Number of Outputs: The RT9218GS provides 2 independent outputs. Substitutes must match or exceed this output capability.
• Switching Frequency: Fixed at 300kHz, a standard frequency for power management applications.
• Supply Voltage Range: Operates from 5V and 12V supplies; substitutes must support compatible input voltage ranges.
• Operating Temperature: -40°C to 85°C industrial range; substitutes must maintain this specification.
• Package Compatibility: 14-SOIC form factor; substitutes in alternative packages require board redesign.
• Compliance: RoHS3 compliance and MSL 3 rating are mandatory for equivalent substitution.

The RT8120FGS is evaluated as a partial functional alternative based on shared switching frequency, supply voltage compatibility, and compliance certifications, though with reduced output configuration.

Parameter Comparison

Engineering Selection Recommendations

The RT9218GS is obsolete and no longer in active production. The RT8120FGS is an active product from the same manufacturer with matching switching frequency (300kHz), compatible supply voltage range (3V ~ 13.2V encompasses the 5V and 12V requirements), and identical operating temperature specifications (-40°C ~ 85°C).

Both devices maintain ROHS3 compliance and MSL 3 ratings, ensuring equivalent environmental and reliability standards. However, the RT8120FGS is a single-output buck controller, whereas the RT9218GS integrates dual outputs (synchronous buck and linear LDO). Direct substitution requires circuit redesign to accommodate the reduced output configuration and different package pin count (8-SOP versus 14-SOP).

Selection of the RT8120FGS as a substitute is appropriate only when the application requires a single buck regulation output and can accommodate board-level modifications for the smaller package footprint.

Frequently Asked Questions (FAQ)

Q: Can the RT8120FGS directly replace the RT9218GS without circuit modification?

A: No. The RT8120FGS is a single-output buck controller in an 8-SOP package, while the RT9218GS is a dual-output PMIC (buck + LDO) in a 14-SOP package. Direct pin-for-pin substitution is not possible. Circuit redesign is required.

Q: What are the key differences in output capability?

A: The RT9218GS provides two independent regulated outputs: one synchronous buck output and one linear (LDO) output. The RT8120FGS provides only a single buck controller output. Applications requiring dual-output regulation cannot use the RT8120FGS without additional external components.

Q: Are the switching frequencies compatible?

A: Yes. Both devices operate at 300kHz switching frequency, ensuring compatible EMI characteristics and external component sizing for applications that can accommodate the reduced output configuration.

Q: Do both devices support the same supply voltage range?

A: The RT9218GS operates from 5V and 12V supplies. The RT8120FGS supports a broader range of 3V ~ 13.2V, which encompasses the RT9218GS supply requirements. Supply voltage compatibility is not a limiting factor for substitution.

Q: Are compliance and reliability ratings equivalent?

A: Yes. Both devices are ROHS3 compliant with MSL 3 (168 Hours) moisture sensitivity ratings, ensuring equivalent environmental and reliability standards for industrial applications.

Q: What package considerations apply to substitution?

A: The RT9218GS uses a 14-SOIC package while the RT8120FGS uses an 8-SOIC package. Both maintain the same 0.154" (3.90mm) width, but the pin count and layout differ significantly. PCB redesign is mandatory for any substitution attempt.