Texas Instruments USBN9603-28M/NOPB

Overview

USBN9603-28M/NOPB from National Semiconductor is a full-speed USB 1.1 node controller IC integrating transceiver, 3.3V regulator, Serial Interface Engine (SIE), seven endpoint FIFOs (1×8-byte control + 6×64-byte data), 8-bit parallel interface, and enhanced DMA support. It operates at 5V or 3.3V, uses a 24 MHz crystal, and targets embedded host-peripheral bridge applications in industrial controllers and legacy PC peripherals.

For engineers reviewing the USBN9603-28M/NOPB datasheet, USBN9603-28M/NOPB pinout, USBN9603-28M/NOPB application, or USBN9603-28M/NOPB equivalent, key selection criteria include its pin-to-pin compatibility with USBN9602-28M, non-multiplexed/multiplexed CPU interface modes, automatic DMA (ADMA) for bulk/ISO transfers, and integrated 3.3V transceiver supply regulation.

Technical Context

The USBN9603-28M/NOPB implements a complete USB 1.1-compliant Media Access Controller (MAC) and Physical Layer Interface (PHY), including NRZI decoding, bit stuffing/unstuffing, CRC generation/checking, and clock recovery from 48 MHz (doubled from 24 MHz XIN). Its SIE handles all USB protocol states-NodeReset, NodeSuspend, NodeResume-and generates ACK/NAK/STALL handshakes per endpoint configuration.

Endpoint Pipe Controller (EPC) manages seven dedicated pipes: one bidirectional control endpoint (EP0) and six unidirectional endpoints (three TX, three RX), each with independent FIFOs and status registers. The programmable interrupt output supports active-high, active-low, or open-drain signaling via Main Control Register (MCNTRL) configuration.

Key Specifications

Pinout & Package

USBN9603-28M/NOPB is housed in a 28-pin SOIC package (suffix -28M), pin-to-pin compatible with USBN9602-28M. Package dimensions: 17.9 mm × 7.5 mm × 2.3 mm, standard JEDEC MS-013AC footprint.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar USB node controller applications.

Compared with USBN9604-28M/NOPB, USBN9603-28M/NOPB offers identical feature set and pinout but omits DLL-synchronized reset-making it suitable for cost-sensitive, non-phase-critical applications. Versus ISP1181BD, USBN9603-28M/NOPB provides legacy compatibility and lower system-level integration effort despite smaller FIFOs and USB 1.1 limitation.

Availability

USBN9603-28M/NOPB is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy printer controllers, medical data loggers, and embedded test equipment requiring stable component supply across long-lifecycle programs.

Supply support for USBN9603-28M/NOPB 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

National Semiconductor was a U.S.-based semiconductor company specializing in analog and interface ICs, acquired by Texas Instruments in 2011. Its legacy USB controller portfolio remains widely deployed in industrial and embedded systems.

The USBN9603-28M/NOPB belongs to National's USB Node Controller product line, designed specifically for cost-effective, low-pin-count USB peripheral implementations in resource-constrained microcontroller systems.

FAQ

What USB specification versions does the USBN9603-28M/NOPB support?

The USBN9603-28M/NOPB supports USB Specification versions 1.0 and 1.1 at full speed (12 Mbps). It does not support USB 2.0 High-Speed (480 Mbps) or later revisions. Its Serial Interface Engine (SIE) implements all required protocol layers-including bit stuffing, CRC checking, and handshake generation-to ensure full compliance with USB 1.1 electrical and functional requirements. This makes USBN9603-28M/NOPB suitable for legacy and cost-sensitive peripheral designs where USB 2.0 bandwidth is unnecessary.

Is the USBN9603-28M/NOPB pin-to-pin compatible with the USBN9602-28M?

Yes, the USBN9603-28M/NOPB is explicitly documented as pin-to-pin compatible with the USBN9602-28M in standard package (-28M). This compatibility allows direct replacement in existing designs without PCB modification. The USBN9603-28M/NOPB improves upon the USBN9602-28M with enhanced DMA support, larger endpoint FIFOs (64 bytes vs. smaller prior allocation), and updated register mapping-while retaining identical pin functions, timing, and package footprint.

Does the USBN9603-28M/NOPB require an external crystal, and what are the specifications?

Yes, the USBN9603-28M/NOPB requires a 24 MHz fundamental-mode AT-cut crystal connected between XIN and XOUT pins. Recommended crystal parameters: 24 MHz ±2500 ppm tolerance, maximum series resistance 50 Ω, shunt capacitance ≤10 pF, and load capacitance 20 pF. External capacitors C1 and C2 (typically 15 pF each) must be used per the oscillator circuit in the datasheet. An external 24 MHz clock may alternatively drive XIN, with XOUT left unconnected.

How does the integrated 3.3V regulator on the USBN9603-28M/NOPB function?

The USBN9603-28M/NOPB's integrated 3.3V regulator outputs on the V3.3 pin and is powered from VCC (5V or 3.3V). It supplies regulated 3.3V to the internal USB transceiver and can also power the mandatory 1.5 kΩ D+ pull-up resistor. A 1 µF tantalum capacitor is required between V3.3 and AGND. The regulator may be disabled in software to allow operation in pure 3.3V systems where external regulation is already provided-ensuring flexibility across 5V and 3.3V host environments.

What interface modes does the USBN9603-28M/NOPB support, and how are they selected?

The USBN9603-28M/NOPB supports three interface modes selected by hard-wiring MODE1 and MODE0 pins: non-multiplexed parallel (00), multiplexed Intel-compatible parallel (01), and MICROWIRE serial (10). In non-multiplexed mode, A0 and D0–D7 operate as separate address/data lines; in multiplexed mode, AD0–AD7 carry time-multiplexed address/data with ALE strobe; MICROWIRE mode uses SK, SI, and SO for serial communication. Mode 11 is reserved and should not be used.