Infineon Technologies CY7C433-20AXC

Overview

CY7C433-20AXC from Cypress Semiconductor is a 4,096 × 9-bit asynchronous FIFO memory with dual-port RAM architecture, supporting independent 50 MHz read/write operations, TTL-compatible I/O, and full/empty/half-full flag signaling. It operates at 5V ±10% across industrial temperature range (–40°C to +85°C) and is used in high-throughput data buffering between mismatched clock domains in telecom line cards and industrial PLC backplanes.

For engineers reviewing the CY7C433-20AXC datasheet, CY7C433-20AXC pinout, CY7C433-20AXC application, or CY7C433-20AXC equivalent, key selection criteria include its 4K×9 depth, 20 ns access time, standalone retransmit capability, and width/depth expandability without throughput penalty.

Technical Context

This FIFO implements a dual-ported static RAM cell array with separate read and write address pointers, enabling true asynchronous operation - read and write clocks may run at different frequencies or be completely independent. Control logic includes dedicated Master Reset (MR), Read Enable (R), Write Enable (W), and Retransmit (RT) inputs that directly govern pointer behavior and output state.

Flag generation is synchronous to respective control edges: EF (Empty) asserts when read pointer equals write pointer; FF (Full) asserts when write pointer wraps to read pointer; HF (Half Full) transitions at 2,048 words written. In depth expansion mode, the HF pin repurposes as Expansion Out (XO) to cascade control to downstream FIFOs.

Key Specifications

Pinout & Package

Package: 44-pin PLCC (Plastic Leaded Chip Carrier), 16.5 mm × 16.5 mm, JEDEC MS-026AC compliant. RoHS-compliant Pb-free finish available.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IDT7204L20PFI and AM7204-20JC, CY7C433-20AXC uniquely delivers industrial-grade thermal robustness (–40°C to +85°C) with native 5V TTL compatibility and proven retransmit functionality - making it the preferred choice for mission-critical embedded buffering where voltage stability and environmental resilience are non-negotiable.

Availability

CY7C433-20AXC is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLC backplanes, medical imaging pipelines, and automotive ADAS sensor aggregation requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CY7C433-20AXC 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 U.S.-based semiconductor company specializing in programmable system-on-chip (PSoC), memory, and interface solutions for industrial, automotive, and communications markets.

CY7C433 belongs to Cypress's legacy asynchronous FIFO product line, designed specifically for deterministic, low-latency data buffering in heterogeneous clock-domain systems where software-managed queues introduce unacceptable jitter or overhead.

FAQ

What is the function of the FL/RT pin on CY7C433-20AXC?

The FL/RT pin serves a dual role: when HIGH, it configures the device for standard flag logic (EF, FF, HF outputs active); when pulled LOW, it enables retransmit mode - allowing repeated reads of the last accessed word without advancing the read pointer. This is implemented in hardware and requires R and W to remain HIGH during retransmit activation.

Can CY7C433-20AXC operate with mixed 3.3V and 5V logic interfaces?

No - CY7C433-20AXC is a strictly 5V-only device: V_CC must be 5V ±10%, and all inputs require VIH ≥ 2.0V (commercial) or 2.2V (industrial). Its outputs swing rail-to-rail (0V–5V) and are not 3.3V-tolerant. Direct connection to 3.3V logic requires external level-shifting circuitry.

How does depth expansion work without degrading throughput?

Depth expansion uses parallel steering of control signals (W, R, MR) and data paths across multiple CY7C433 devices. The XO output of one device drives the MR input of the next, enabling synchronized pointer advancement without daisy-chaining delays. This preserves the full 50 MHz throughput because propagation delays do not accumulate serially.

Is the Half Full (HF) flag usable in all expansion configurations?

No - HF is valid only in standalone and width-expansion modes, where it asserts LOW at exactly 2,048 words stored. In depth-expansion mode, the HF pin becomes Expansion Out (XO) and outputs a cascading enable signal instead; using it as a half-full indicator would cause incorrect flag behavior and potential data loss.