Infineon Technologies CY7C433-20JXC

Overview

CY7C433-20JXC from Cypress Semiconductor is a 4,096 × 9-bit asynchronous FIFO memory with independent 50 MHz read/write capability, TTL-compatible I/O, and dual flag control (Empty/Full/Half Full). It implements retransmit functionality in standalone mode and supports unlimited width/depth expansion via dedicated expansion logic. Used in high-speed data buffering between mismatched clock domains in industrial communication gateways.

For engineers reviewing the CY7C433-20JXC datasheet, CY7C433-20JXC pinout, CY7C433-20JXC application, or CY7C433-20JXC equivalent, key selection criteria include its 4K×9 depth, 20 ns access time, standalone retransmit support, and PLCC-28 package compatibility with legacy board layouts.

Technical Context

This FIFO uses dual-ported RAM cells fabricated in 0.65-µm P-well CMOS, enabling true asynchronous operation: read and write ports operate independently at up to 50 MHz regardless of depth or width configuration. The device includes dedicated expansion logic (XO/HF, FL/RT, MR) that eliminates serial propagation delay during depth expansion.

Flag generation is synchronous to respective control edges: EF asserts within 25 ns after a read on empty state, FF asserts within 25 ns after a write on full state, and HF toggles on midpoint crossing. Retransmit mode requires both R and W held HIGH while RT is pulsed LOW, enabling deterministic replay of buffered data without external sequencing logic.

Key Specifications

Pinout & Package

Package: 28-pin Plastic Leaded Chip Carrier (PLCC), 11.5 mm × 11.5 mm, J-lead, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar asynchronous FIFO applications.

Compared with IDT7204L20PFI and MC100E131FN, CY7C433-20JXC uniquely delivers 5V TTL compatibility, integrated retransmit, and drop-in PLCC-28 replacement for legacy Cypress/IDT designs-reducing validation effort and preserving board layout.

Availability

CY7C433-20JXC is available at Aetrix Electronics and suitable for industrial serial gateways, legacy bus bridges, video line buffering, and test equipment data capture requiring stable component supply across extended temperature ranges.

Supply support for CY7C433-20JXC 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

Cypress Semiconductor (now part of Infineon Technologies) is a fabless semiconductor company specializing in programmable system-on-chip, memory, and interface solutions for industrial, automotive, and consumer markets.

CY7C433 belongs to Cypress's legacy asynchronous FIFO product line, designed specifically for high-reliability, zero-software-overhead data buffering in mixed-signal and real-time embedded systems with strict timing constraints.

FAQ

What is the maximum clock frequency supported for read and write operations?

CY7C433-20JXC supports independent 50 MHz read and write operations, verified per datasheet switching characteristics (t_RC = 20 ns min). This is guaranteed across commercial temperature range (0°C to +70°C) with 5.0 V ±10% supply and 30 pF load capacitance. No external PLL or clock multiplier is required to achieve this rate.

Does the device support depth expansion, and how is it implemented?

Yes, depth expansion is supported using the XI (expansion input) and XO/HF (expansion out/half-full) pins. In depth-expansion mode, XO from one device connects to XI of the next, enabling pointer synchronization without serial delay stacking. The HF pin repurposes as XO, and flag logic is cascaded to maintain accurate Empty/Full status across the chain.

How does the retransmit (RT) function operate, and what conditions must be met?

Retransmit is activated by pulling FL/RT LOW while both R and W are held HIGH. The FIFO then outputs the last-read 9-bit word on Q0–Q8 upon subsequent R pulses. This mode requires no external address tracking or CPU involvement, making it ideal for protocol-level retry mechanisms in serial communications.

Is CY7C433-20JXC pin-compatible with earlier Cypress FIFOs like CY7C429?

Yes, CY7C433-20JXC shares identical PLCC-28 pinout and electrical behavior with CY7C429-20JXC and CY7C425-20JXC, differing only in memory depth (4K vs 2K vs 1K). All share identical timing parameters, flag definitions, and expansion logic-enabling direct upgrade in existing PCB layouts without redesign.