KS8721BL Equivalent & Substitute Parts

Part Overview

The KS8721BL is a 1/1 transceiver with full-duplex capability supporting MII and RMII protocols, packaged in a 48-LQFP (7x7) surface mount configuration. This part is discontinued at DiGi Electronics, necessitating identification of functionally equivalent alternatives for ongoing design requirements and production needs. The KS8721BL operates at a supply voltage of 2.375V to 2.625V across an industrial temperature range of 0°C to 70°C.

Substiute Parts

KS8721BL

Microchip TechnologyIn Stock: 1408KS8721BL Datasheet

Current PartRFQ

KSZ8721BL

Microchip TechnologyIn Stock: 6898KSZ8721BL Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

The KSZ8721BL qualifies as a direct substitute based on the following alignment of critical parameters:

• Protocol Compatibility: Both parts support identical MII and RMII protocols with 1/1 driver/receiver configuration and full-duplex operation
• Package Equivalence: Both use 48-LQFP (7x7) surface mount packaging, ensuring PCB layout compatibility
• Functional Classification: Both are classified as transceivers within the interface category
• Thermal Range: Both operate across 0°C to 70°C, meeting identical temperature specifications
• Moisture Sensitivity: Both maintain MSL 3 rating (168 Hours)
• Base Product Lineage: Both share the KSZ8721 base product number, indicating design continuity within the Microchip Technology product family

The primary distinction lies in supply voltage specification and product status, detailed in the parameter comparison section below.

Parameter Comparison

Engineering Selection Recommendations

The KSZ8721BL is the direct substitute for the discontinued KS8721BL based on functional equivalence across all protocol, package, and thermal specifications. Selection between these parts depends on system-level requirements:

KSZ8721BL Selection Criteria: Choose this substitute when active product status and regulatory compliance are required. The KSZ8721BL maintains ROHS3 compliance and is currently in active production with significantly higher inventory availability (6816 Pcs vs. 1305 Pcs). This part is suitable for new designs and ongoing production requiring modern compliance certifications.

Supply Voltage Consideration: The KSZ8721BL operates at 3V to 3.6V, compared to the KS8721BL's 2.375V to 2.625V specification. Circuit design must accommodate this voltage differential through appropriate power supply configuration and signal level management.

Legacy System Compatibility: For systems currently operating with KS8721BL at 2.375V to 2.625V supply voltage, substitution requires power supply redesign or voltage regulation modification to meet the KSZ8721BL's 3V to 3.6V requirement.

Frequently Asked Questions (FAQ)

Q: Are KS8721BL and KSZ8721BL pin-compatible? A: Both parts use the 48-LQFP (7x7) package with identical pinout configuration, ensuring direct PCB compatibility without layout modifications.

Q: Can KSZ8721BL replace KS8721BL in existing designs without circuit modification? A: Protocol and package compatibility are confirmed. However, the supply voltage specification differs (3V ~ 3.6V vs. 2.375V ~ 2.625V). Circuit redesign is necessary if the existing system operates at the lower voltage range.

Q: What is the significance of the voltage difference between these parts? A: The KSZ8721BL requires a higher supply voltage range. Designs must verify that power supply infrastructure can deliver 3V to 3.6V and that all connected signal interfaces operate within this voltage domain.

Q: Why is KS8721BL discontinued while KSZ8721BL remains active? A: Product lifecycle decisions are manufacturer-determined. The KSZ8721BL represents the current production equivalent with updated compliance certifications (ROHS3).

Q: Are there any RoHS compliance implications for substitution? A: The KS8721BL is RoHS non-compliant, while KSZ8721BL is ROHS3 compliant. Systems requiring RoHS compliance must use the KSZ8721BL substitute.

Q: Do both parts support identical MII and RMII protocol implementations? A: Yes. Both parts provide 1/1 transceiver configuration with full-duplex operation across MII and RMII protocols, ensuring functional equivalence at the protocol level.

Q: What packaging format differences exist between these parts? A: KSZ8721BL is supplied in Tray packaging format. Both parts maintain identical 48-LQFP (7x7) component packaging for PCB assembly.