NXP Semiconductors SC18IS603IPW,128

Overview

SC18IS603IPW,128 from NXP Semiconductors is an I²C-to-SPI bridge IC operating as an I²C-bus slave and SPI master, supporting up to 4 Mbit/s SPI data rate with external clock input (0–18 MHz), 200-byte internal buffer, and four programmable slave select outputs. It enables microcontrollers with only I²C interfaces to control multiple SPI peripherals in industrial sensor hubs and embedded control systems.

For engineers reviewing the SC18IS603IPW,128 datasheet, SC18IS603IPW,128 pinout, SC18IS603IPW,128 application, or SC18IS603IPW,128 equivalent, key selection criteria include external clock dependency, absence of SS2/SS3 support, GPIO reconfiguration capability, and 2.4–3.6 V supply operation - all critical for deterministic timing and multi-device SPI bus expansion.

Technical Context

The SC18IS603IPW,128 implements a dedicated hardware bridge architecture: its I²C interface operates strictly as a slave (up to 400 kHz) with 7-bit address + R/W bit decoding, while its SPI master supports all four SPI modes (CPOL/CPHA configurable) and dynamic clock scaling via F0h command using CLKIN-derived dividers (f_osc/4, /16, /64, /128). No internal oscillator is present - CLKIN is mandatory.

It uses a 200-byte FIFO buffer to decouple I²C transaction timing from SPI burst execution; SPI transfers are initiated only after full STOP condition detection on I²C, and interrupt (INT) signals completion. All four SSn pins (SS0–SS3) are functional, but SS2 is GPIO-only and SS3 is absent - confirmed by pin mapping and block diagram Fig 2.

Key Specifications

Pinout & Package

SC18IS603IPW,128 is housed in a 16-pin TSSOP package (SOT403-1), 4.4 mm body width, lead pitch 0.65 mm. Pin 13 is CLKIN (input only); SS2 (Pin 10) is GPIO-only; SS3 is not implemented - confirmed by Fig 2 and Table 2 footnotes.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C-to-SPI bridge applications.

Compared with SC18IS602IPW and MAX14483, the SC18IS603IPW,128 uniquely delivers externally controlled high-speed SPI (up to 4 Mbit/s) with full GPIO configurability, making it optimal for timing-critical, multi-peripheral industrial bridges where clock precision and pin reuse are design priorities.

Availability

SC18IS603IPW,128 is available at Aetrix Electronics and suitable for industrial sensor interfaces, legacy MCU peripheral expansion, modular PLC I/O subsystems, and automotive body control gateways requiring stable component supply and long-term manufacturability.

Supply support for SC18IS603IPW,128 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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in interface bridging and mixed-signal integration.

The SC18IS603IPW,128 belongs to NXP's I²C-to-SPI bridge product line, engineered specifically to extend legacy or resource-limited microcontrollers into SPI-based peripheral ecosystems without firmware-level protocol emulation.

FAQ

Does SC18IS603IPW,128 require an external clock source, and what is the supported frequency range?

Yes, SC18IS603IPW,128 requires an external clock applied to the CLKIN pin (Pin 13) for all operation - it has no internal oscillator. The supported frequency range is DC to 18 MHz, enabling SPI master speeds up to 4 Mbit/s (f_CLKIN/4). This external dependency ensures precise timing control but mandates careful clock source selection and PCB layout for jitter-sensitive applications.

Can SC18IS603IPW,128 support more than two SPI slave devices simultaneously?

SC18IS603IPW,128 provides four SSn pins (SS0–SS3), but only SS0 and SS1 are functional as active-low SPI slave select outputs. SS2 is GPIO-only, and SS3 is not implemented - confirmed in Fig 2 and Table 2 footnotes. Therefore, it natively supports up to two independent SPI slaves; additional devices require external logic or multiplexing.

What is the purpose and behavior of the INT pin on SC18IS603IPW,128?

The INT pin (Pin 9) is an active-low open-drain interrupt output that asserts after every completed SPI transaction - whether read or write. It remains asserted until cleared via the F1h "Clear Interrupt" command or automatically upon the next valid I²C address match. This signal enables event-driven host polling and eliminates continuous status register checking.

How does the 200-byte data buffer in SC18IS603IPW,128 affect I²C-to-SPI transaction flow?

The 200-byte FIFO buffer in SC18IS603IPW,128 decouples I²C and SPI timing: all bytes received over I²C (after address and Function ID) are stored before any SPI activity begins. SPI transmission starts only after the I²C STOP condition is detected, ensuring atomic payload delivery and preventing partial transfers due to I²C bus contention or clock stretching.

Is SC18IS603IPW,128 compatible with 5 V I²C or SPI systems?

No, SC18IS603IPW,128 operates strictly from 2.4 V to 3.6 V and is not 5 V tolerant on any pin when configured in quasi-bidirectional mode - applying 5 V causes excessive current flow from pin to VDD. For 5 V systems, level-shifting circuitry is mandatory on SDA, SCL, MOSI, MISO, and SSn lines to prevent damage and ensure signal integrity.