Microchip Technology USB3250-ABZJ

Overview

USB3250-ABZJ from Microchip Technology is a USB 2.0 physical layer (PHY) transceiver IC designed for Hi-Speed USB device endpoints. It implements full USB 2.0 electrical compliance (480 Mbps HS / 12 Mbps FS), integrates 45 Ω and 1.5 kΩ termination resistors, supports UTMI+ interface (60 MHz 8-bit or 30 MHz 16-bit), and operates across –40°C to +85°C ambient. It serves as the analog front-end between a USB device controller (SIE) and the USB cable in bus-powered peripherals.

For engineers reviewing the USB3250-ABZJ datasheet, USB3250-ABZJ pinout, USB3250-ABZJ application, or USB3250-ABZJ equivalent, this page delivers verified technical context, validated pin functions, real-world timing and power behavior, and confirmed alternative transceivers - all aligned with Microchip's DS00002142A specification and industrial deployment requirements.

Technical Context

The USB3250-ABZJ implements a dual-mode PHY with independent HS/FS transceiver selection via XCVRSELECT and termination switching via TERMSELECT. Its clock recovery unit uses a 12 MHz crystal (XI/XO) to generate a stable 480 MHz internal clock, then derives CLKOUT at either 60 MHz (8-bit unidirectional mode) or 30 MHz (16-bit bidirectional mode), both synchronized to USB bit timing.

It performs full NRZI encoding/decoding, bit stuffing/unstuffing with error detection, SYNC/EOP generation and detection, and includes on-die short-circuit protection on DP/DM. Internal biasing (RBIAS = 12 kΩ) sets HS transmit current and termination impedance, while on-chip decoupling capacitance isolates analog and digital domains against switching noise.

Key Specifications

Pinout & Package

USB3250-ABZJ is housed in a 56-pin Very Thin Quad Flat No-Lead (VQFN) package with exposed thermal pad. All VSS and VSSA pins are bonded to the exposed pad, which must be connected to a solid ground plane per Microchip layout guidelines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar USB 2.0 PHY applications.

Compared with SMSC USB3317C-ABZT and ON Semi NB3N3020B, USB3250-ABZJ uniquely combines HS/FS dual-mode operation, integrated crystal oscillator, and UTMI+ interface in a single 56-pin VQFN - making it optimal for compact, bus-powered, industrial-grade USB device endpoints requiring full protocol compliance without external timing or termination components.

Availability

USB3250-ABZJ is available at Aetrix Electronics and suitable for digital cameras, external storage devices, POS terminals, and test equipment requiring stable component supply, long-term industrial availability, and guaranteed USB-IF certification compliance.

Supply support for USB3250-ABZJ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology is a global semiconductor company specializing in microcontrollers, analog devices, and connectivity solutions, with deep expertise in USB protocol implementation and industrial-grade mixed-signal ICs.

The USB3250-ABZJ belongs to Microchip's USB Physical Layer Transceiver product line, engineered specifically for robust, low-power, bus-powered USB 2.0 device endpoints in industrial, consumer, and embedded applications.

FAQ

What USB data rates does the USB3250-ABZJ support?

The USB3250-ABZJ supports both 480 Mbps High Speed (HS) and 12 Mbps Full Speed (FS) data transmission rates, maintaining full backward compatibility with USB 1.1 devices. It automatically detects and negotiates speed during USB reset and chirp sequences, and its dual-mode transceiver allows seamless switching between HS and FS operation without hardware reconfiguration. This dual-rate capability is implemented in silicon and verified per USB-IF Hi-Speed certification requirements.

Does USB3250-ABZJ require an external crystal?

Yes, USB3250-ABZJ requires a 12 MHz ±100 ppm fundamental-mode quartz crystal connected between XI and XO pins. The on-chip oscillator uses this crystal to generate the precise 480 MHz internal clock needed for HS timing compliance. Microchip specifies that resonators meeting ±500 ppm may also be used, but the 12 MHz crystal is the recommended and validated configuration for full USB 2.0 specification adherence in the USB3250-ABZJ.

What is the function of the TERMSELECT pin on USB3250-ABZJ?

The TERMSELECT pin on USB3250-ABZJ selects between High Speed (HS) and Full Speed (FS) termination networks: logic 0 enables the internal 45 Ω HS driver termination, while logic 1 enables the 1.5 kΩ FS pull-up resistor on DP. This pin operates independently from XCVRSELECT, allowing termination to be configured separately from transceiver selection - a key feature for reliable speed negotiation and compliance testing per USB 2.0 specification.

Can USB3250-ABZJ operate in bus-powered mode?

Yes, USB3250-ABZJ is explicitly designed for bus-powered operation, drawing a maximum of 72 mA (185 mW) in HS mode and as little as 240 µA in Suspend Mode 1. Its dual-supply architecture (1.8 V core / 3.3 V I/O) and integrated termination eliminate external power-hungry components, enabling full USB 2.0 functionality in self-contained, cable-powered peripherals such as portable HDDs and digital cameras without auxiliary power sources.

What package type is used for USB3250-ABZJ?

USB3250-ABZJ is packaged in a 56-pin Very Thin Quad Flat No-Lead (VQFN) with an exposed thermal pad. The package measures 8 mm × 8 mm × 0.9 mm and features perimeter I/O pads plus a center thermal pad bonded to all VSS and VSSA pins. Microchip mandates that the exposed pad be soldered to a solid PCB ground plane to ensure proper thermal dissipation and analog noise isolation - a requirement documented in DS00002142A, page 9.