Diodes Incorporated PI7C9X1170CZDEX

Overview

PI7C9X1170CZDEX from Diodes Incorporated is an I²C-bus/SPI-to-UART bridge controller implementing a single-channel full-duplex UART with 64-byte TX/RX FIFOs, backward-compatible register set (16C450), and support for RS-232/RS-485/RS-422/IrDA physical layers. It operates across 1.62–3.6V supply, supports up to 16 Mbit/s UART baud rate (4× sampling) and 33 Mbit/s SPI clock, and integrates eight programmable GPIOs. Used in industrial computing and battery-operated embedded systems requiring protocol translation between microcontroller buses and serial peripherals.

For engineers reviewing the PI7C9X1170CZDEX datasheet, PI7C9X1170CZDEX pinout, PI7C9X1170CZDEX application, or PI7C9X1170CZDEX equivalent, key selection considerations include I²C/SPI interface select logic, RTS/CTS hardware flow control timing behavior, IrDA SIR mode enablement, GPIO multiplexing options, and 16C450 register compatibility for legacy driver reuse.

Technical Context

The PI7C9X1170CZDEX implements a dual-mode serial bridge: I²C-bus slave (fast-mode, up to 400 kHz) or SPI slave (mode 0, up to 33 MHz), selectable via dedicated I2C/SPI# pin. Its UART core features fractional baud rate generation using a programmable divisor (1–65535) referenced to XTAL1/XTAL2 (up to 24 MHz crystal) or external clock (up to 64 MHz).

It supports automatic RS-485 half-duplex direction control via RTS#, with polarity inversion capability, and built-in IrDA encoder/decoder for SIR-compliant operation at 115.2 kbit/s or optional 1.152 Mbit/s. Flow control includes independent Auto-RTS (RX FIFO level-triggered) and Auto-CTS (transmit gating), plus software Xon/Xoff with dual-character support and special character detection.

Key Specifications

Pinout & Package

PI7C9X1170CZDEX is housed in a 24-pin TQFN package (ZD suffix), 4 mm × 4 mm × 0.75 mm, with exposed thermal pad (non-electrical, must be soldered to PCB ground plane). Pin numbering follows top-side view, counterclockwise from top-left corner (Pin 1 = VCC).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar UART bridge applications.

Compared with SC16IS752IPW and MAX3107ETJ+, the PI7C9X1170CZDEX uniquely combines I²C/SPI dual-interface flexibility, RS-485 auto-direction, IrDA SIR, and eight GPIOs in a single 24-pin TQFN - reducing board area and enabling compact, multi-protocol edge nodes without external glue logic.

Availability

PI7C9X1170CZDEX is available at Aetrix Electronics and suitable for industrial automation gateways, portable medical devices, smart energy metering hubs, and IoT edge node controllers requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for PI7C9X1170CZDEX 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and integrated circuits, specializing in high-performance analog, logic, and power management solutions for industrial, computing, and consumer markets.

The PI7C9X1170 belongs to Diodes' serial interface bridge product line, designed specifically to simplify protocol translation between resource-constrained microcontrollers and legacy or specialized serial peripherals in space- and power-sensitive embedded systems.

FAQ

What interface modes does the PI7C9X1170CZDEX support, and how is mode selection implemented?

The PI7C9X1170CZDEX supports I²C-bus slave mode (fast-mode, up to 400 kHz) and SPI slave mode (mode 0, up to 33 MHz). Mode selection is controlled by the logic level on the dedicated I2C/SPI# pin: HIGH selects I²C, LOW selects SPI. This pin must be stable before power-up or reset to ensure correct initialization of internal interface logic and register mapping.

How does the PI7C9X1170CZDEX handle RS-485 half-duplex direction control without external components?

The PI7C9X1170CZDEX uses its RTS# output to directly drive the DE/RE pins of an RS-485 transceiver. When Auto-RTS is enabled, RTS# asserts before TX starts and de-asserts after TX completes, synchronized to FIFO state. Direction polarity can be inverted via register bit to match transceiver logic; no external gates or timers are required for compliant RS-485 operation.

Can the PI7C9X1170CZDEX operate with a 1.8 V supply while interfacing to 3.3 V peripherals?

Yes - the PI7C9X1170CZDEX operates from 1.62 V to 3.6 V and has input thresholds scaled to VDD. At 1.8 V supply, all digital inputs (SCL, SDA, SCLK, CS#, etc.) recognize >0.7×VDD as HIGH and <0.3×VDD as LOW, ensuring reliable operation with 3.3 V peripherals when appropriate series resistors or level translators are used on outputs driving 3.3 V inputs.

What happens to the UART's register state during a software reset versus hardware RESET# assertion?

A software reset (via register bit) and hardware RESET# (≥40 ns low pulse) both clear most registers to default states (e.g., LCR = 0x1D, FCR = 0x00), but preserve DLL, DLH, XON1, XON2, XOFF1, and XOFF2 values. This allows baud rate and flow control character settings to persist across resets, enabling faster reinitialization without reloading critical configuration.