Mfr Part #:

KS8721B

Q: What Ethernet speeds does the KS8721B support?

The KS8721B supports 10BaseT, 100BaseTX, and 100BaseFX speeds.

Q: Does the KS8721B support auto-negotiation?

Yes, the KS8721B supports auto-negotiation for 10/100Mbps speed and full/half-duplex mode.

Q: What interfaces does the KS8721B support?

The KS8721B supports Media Independent Interface (MII) and Reduced Media Independent Interface (RMII).

Q: What is the commercial operating temperature range for the KS8721B?

The commercial operating temperature range is 0°C to +70°C.

Q: What packages is the KS8721B available in?

The KS8721B is available in 48-pin SSOP and 48-pin TQFP packages.

Available from 1 distributors

Mfr Name: Micrel Inc.

The Micrel Inc. KS8721B is a 2.5V Physical Layer Transceiver offering 10/100BaseTX/FX Ethernet speeds. It supports MII and RMII interfaces, auto-negotiation, and various duplex modes.

✓ Total Stock: 4,596 pcs

$ Price Range: $1.67

KS8721B Available from 1 distributor

✓ Authorised

✓ Non-Authorised

Distributor		Stock	Pricing	MOQ	PKG	Lead Time	Date Code	On Order Quantity	On Order Delivery
Optech Co.,Limited ✓ Non-Authorised Inventory information	4,596 pcs On Request	4596 pcs	On Request	1	On Request	On Request	05+	On Request	On Request

KS8721B Specifications Quick View

Most important parameters for selection – full specs in datasheet.

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Category	New Products
Manufacturer Name	Micrel Inc.
Interface	MII/RMII
Operating Temperature	0°C to +70°C
Power Consumption	<200mW
Speed	10/100Mbps
Voltage	2.5V

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KS8721B Description

Short technical summary and product information.

The KS8721B from Micrel Inc. is a single-chip 10/100BaseTX/FX MII Physical Layer Transceiver designed for low voltage and low power applications. Operating at 2.5V, it integrates PMA, PMD, and PCS functions, providing an MII interface for data transmission and reception.

This transceiver fully complies with the IEEE 802.3u standard and supports both MII and Reduced MII (RMII) interfaces. It features auto-negotiation for automatic configuration of 10 or 100 Mbps speeds and full or half duplex operation. The KS8721B also includes on-chip filtering for 10BaseT, eliminating the need for external filters and allowing a single set of line magnetics for both 100BaseTX and 10BaseT.

Key features include support for Far-End Fault Detection, power down and power saving modes, and configurable management through MII serial ports or external pins. It provides LED outputs for link status, activity, duplex mode, collision, and speed indication. The device is available in 48-pin SSOP and TQFP packages and operates within commercial (0°C to +70°C) and industrial (-40°C to +85°C) temperature ranges.

KS8721B Quick Information

Product Type: Physical Layer Transceiver

Canonical Name: KS8721B 10/100BaseTX/FX MII Physical Layer Transceiver

Subcategory: PHY Transceiver

KS8721B Compliance

RoHS Status: RoHS Compliant

Moisture Sensitivity Level (MSL): 1 Unlimited

REACH Status: REACH Unaffected

KS8721B Estimated Pricing

Qty	Low	High
1+	$1.67	$1.67

Estimated market price range - modelled values for guidance only, not live distributor offers.

KS8721B Features

Single chip 10/100BaseTX/FX PHY solution.
2.5V CMOS design with low power consumption.
Supports MII and RMII interfaces.
Auto-negotiation for speed and duplex modes.
On-chip filtering for 10BaseT.

KS8721B Applications

Ideal for 100BaseTX/10BaseT applications.
Suitable for media converter applications.
Used in data communication systems.
Supports MAC integration via MII port.

KS8721B FAQs

6 frequently asked questions generated from this part’s specifications.

What Ethernet speeds does the KS8721B support?

The KS8721B supports 10BaseT, 100BaseTX, and 100BaseFX speeds.

What is the operating voltage for the KS8721B?

The KS8721B operates at 2.5V.

Does the KS8721B support auto-negotiation?