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KS8721B
Microchip Technology
IC TRANSCEIVER FULL 1/1 48SSOP
7296 Pcs New Original In Stock
1/1 Transceiver Full MII, RMII 48-SSOP
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Minimum 1
5.0 / 5.0
- (294 Ratings)
KS8721B
Product Overview
1339454
DiGi Electronics Part Number
KS8721B-DGManufacturer
Microchip Technology
KS8721B
Description
IC TRANSCEIVER FULL 1/1 48SSOPInventory
7296 Pcs New Original In Stock
1/1 Transceiver Full MII, RMII 48-SSOP
CAD Models - PCB Symbols & Footprints
Quantity
Minimum 1
Minimum 1
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KS8721B Technical Specifications
Category
Interface, Drivers, Receivers, Transceivers
Packaging
Tube
Series
-
Product Status
Discontinued at Digi-Key
Type
Transceiver
Protocol
MII, RMII
Number of Drivers/Receivers
1/1
Duplex
Full
Data Rate
-
Voltage - Supply
2.375V ~ 2.625V
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
48-BSSOP (0.295", 7.50mm Width)
Supplier Device Package
48-SSOP
Base Product Number
KS8721
Datasheet & Documents
Datasheets
Download KS8721B Product Specification (PDF)
HTML Datasheet
KS8721B-DG
Environmental & Export Classification
RoHS Status
ROHS3 Compliant
Moisture Sensitivity Level (MSL)
1 (Unlimited)
REACH Status
REACH Unaffected
ECCN
5A991B1
HTSUS
8542.39.0001
Additional Information
Standard Package
30
Alternative Parts
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MANUFACTURER
QUANTITY AVAILABLE
DiGi PART NUMBER
UNIT PRICE
SUBSTITUTE TYPE
Reviews
5.0/5.0-(Show up to 5 Ratings)
Dec 02, 2025
Hochwertige Verpackung und exakte Logistik – ein erstklassiges Einkaufserlebnis.
Dec 02, 2025
Dank des exzellenten Kundendienstes fühle ich mich bei DiGi Electronics bestens aufgehoben.
Dec 02, 2025
The quick shipping process made shopping very convenient, and packaging was excellent.
Dec 02, 2025
DiGi Electronics provides affordability without compromising on shipping safety and packaging quality.
Dec 02, 2025
Excellent customer care—answers to my questions were detailed and timely.
Dec 02, 2025
Customer support was supportive and attentive, helping me troubleshoot minor issues with ease.
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Frequently Asked Questions (FAQ)
Can the KS8721B be used as a drop-in replacement for the KSZ8721B in an existing Ethernet design, and what are the key compatibility risks?
The KS8721B and KSZ8721B are functionally similar and both support MII and RMII interfaces, but they are not guaranteed drop-in replacements. The KS8721B is an earlier version with subtle differences in register maps and power-up behavior that may affect auto-negotiation timing and link reliability. Designers should verify PHY initialization sequences in firmware and confirm compatibility with the host MAC, especially when migrating designs. Always compare errata and ensure clocking (25 MHz reference) and pin configurations match the KSZ8721B layout. Migration risk is moderate—perform full link-up and temperature testing before deployment.
What are the main design-in risks when using the KS8721B in new designs given its discontinued status at Digi-Key?
Using the KS8721B in new designs poses significant supply chain risks due to its discontinued status at major distributors. While current inventory exists (7209 pcs), long-term availability is uncertain, increasing end-of-life (EOL) exposure. Designers should assess lifetime requirements and consider qualifying a second-source PHY like the Microchip KSZ8721B or KSZ8851 now. Mitigation strategies include purchasing extended stock, verifying with suppliers on future availability, and designing with footprint compatibility for alternate SSOP-48 PHYs to reduce redesign costs later.
How does the KS8721B handle EMI and signal integrity in compact PCB layouts, and what layout practices minimize risk?
The KS8721B, packaged in a 48-BSSOP, is sensitive to PCB layout-induced noise in high-speed MII/RMII interfaces and analog PHY circuitry. To maintain signal integrity, keep XTAL traces short and guarded, route MDI differential pairs (if magnetics are external) with 100Ω impedance and minimal stubs, and isolate analog (AVDD) from digital (DVDD) supplies with separate planes and ferrite beads. Use a solid ground plane beneath the KS8721B and avoid routing high-speed signals under the device. Poor layout can cause failed link negotiation or degraded EMI performance—always follow Microchip's reference layout from the datasheet Appendix.
Is the KS8721B suitable for industrial temperature applications even though its rated operating temperature is 0°C to 70°C?
The KS8721B is specified for 0°C to 70°C operation, making it unsuitable for true industrial environments (-40°C to +85°C) without system-level risk. Extended temperature exposure outside the datasheet range can cause link instability, increased bit error rates, or long-term reliability degradation. If deploying in harsher environments, consider the KSZ8721BLXCA or other industrial-grade PHYs with extended temperature support. For limited over-temperature use, verify performance across temperature with burn-in testing and monitor supply voltage stability, but expect reduced design margin and potential compliance issues.
What are the key reliability concerns when using the KS8721B in high-humidity environments, even with its MSL 1 rating?
Although the KS8721B has an MSL 1 (unlimited) rating, indicating no moisture sensitivity during assembly, long-term reliability in high-humidity environments depends on proper board-level protection. Condensation or ionic contamination on the PCB can lead to leakage currents or corrosion, particularly on the analog section (AVDD, XTAL, and MDI pins). To mitigate risks, use conformal coating on the assembled board, ensure adequate ventilation or sealing in enclosures, and avoid exposing the KS8721B to persistent moisture. Additionally, maintain clean assembly processes to prevent electrochemical migration, which can compromise PHY functionality over time.
Quality Assurance (QC)
DiGi ensures the quality and authenticity of every electronic component through professional inspections and batch sampling, guaranteeing reliable sourcing, stable performance, and compliance with technical specifications, helping customers reduce supply chain risks and confidently use components in production.
KS8721B CAD Models
Microchip Technology KS8721B PCB symbols & footprints
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