Winbond Electronics Corporation W29C020CP90B

Overview

W29C020CP90B from Winbond is a 2-Mbit (256K × 8) 5V-only CMOS flash memory with 90 ns read access time, JEDEC-standard byte-wide pinout, and dual 8 KB boot blocks with lockout capability. It supports in-system programming using only 5V V_DD, requires no 12V V_PP, and delivers fast page-write (10 ms) and chip-erase (50 ms) cycles - ideal for embedded firmware storage in legacy industrial controllers and BIOS boot modules.

For engineers reviewing the W29C020CP90B datasheet, W29C020CP90B pinout, W29C020CP90B application, or W29C020CP90B equivalent, key selection criteria include boot-block programmability, software/hardware write protection, 20-year data retention, low active current (25 mA typ.), and compatibility with standard EPROM programmers and 5V microcontroller buses.

Technical Context

The W29C020CP90B implements a single-supply flash architecture with internal V_PP generation, enabling erase/program operations without external high-voltage circuitry. Its 128-byte page-write buffer and toggle-bit (DQ6)/data-polling (DQ7) status detection support efficient firmware updates in resource-constrained systems.

It features two independently lockable 8 KB boot blocks - one at address 0x00000–0x01FFF and another at 0x3E000–0x3FFFF - controlled via 7-byte command sequences. The device operates across 0°C to +70°C ambient and maintains 10K write/erase cycles with 20-year data retention under JEDEC conditions.

Key Specifications

Pinout & Package

W29C020CP90B is housed in a 32-pin PLCC (Plastic Leaded Chip Carrier) package with 0.50-inch body width, JEDEC MS-026 compliant footprint, and surface-mount soldering compatibility. Pin 1 is marked by corner notch; pin numbering follows counterclockwise sequence starting from top-left.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar flash memory applications.

Compared with AM29F020B-90JC and SST39SF020-90-4C-NHE, the W29C020CP90B uniquely combines dual 8 KB lockable boot sectors, 5V-only operation, JEDEC pinout, and 20-year retention - making it optimal for legacy system upgrades requiring both security and socket compatibility.

Availability

W29C020CP90B is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy PC BIOS replacement, embedded network router bootloaders, and medical device configuration storage requiring stable component supply across extended product lifecycles.

Supply support for W29C020CP90B 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

Winbond Electronics Corporation is a Taiwan-based semiconductor manufacturer specializing in memory ICs, including NOR flash, DRAM, and specialty memory solutions for industrial, computing, and communications markets.

The W29C020CP90B belongs to Winbond's legacy 5V-only parallel flash family, designed specifically for drop-in replacement of EPROMs in cost-sensitive, long-lifecycle embedded systems where high-voltage programming is impractical.

FAQ

What is the maximum read access time for the W29C020CP90B?

The W29C020CP90B has a guaranteed maximum read access time of 90 ns under specified conditions (V_DD = 5.0 V ±10 %, T_A = 0°C to +70°C). This value is validated across all production lots and reflects worst-case propagation delay from address valid to stable data output on DQ0–DQ7. The W29C020CP90B achieves this timing without wait-state insertion when interfaced with 10–12 MHz 8-bit microcontrollers.

Does the W29C020CP90B require a 12V supply for programming?

No, the W29C020CP90B does not require a 12V supply for programming. It operates with a single 5.0 V ±10 % supply for all functions - read, erase, and program - using on-chip charge pump circuitry to generate internal high voltage. This eliminates the need for external V_PP circuitry, simplifying design and reducing bill-of-materials cost compared to older EPROM-compatible flash devices like the AM29F020B.

How many write/erase cycles is the W29C020CP90B rated for?

The W29C020CP90B is rated for 10,000 typical write/erase cycles per memory location, as specified in the official Winbond datasheet (Revision A4, February 2002). This endurance rating applies across the full operating temperature range (0°C to +70°C) and is validated using standard JEDEC test methods. The W29C020CP90B also guarantees 20-year data retention at 25°C, ensuring long-term reliability in infrequently updated applications.

Can the W29C020CP90B be used as a direct replacement for 27C020 EPROMs?

Yes, the W29C020CP90B is designed as a JEDEC-standard byte-wide pinout-compatible replacement for 27C020 EPROMs. It shares identical 32-pin PLCC packaging, address/data bus layout (A0–A17, DQ0–DQ7), and control signal assignments (#CE, #OE, #WE). However, unlike EPROMs, the W29C020CP90B requires specific software command sequences for programming and supports in-system erase - so UV-eraser sockets cannot be reused without firmware adaptation.

What boot block protection options does the W29C020CP90B support?

The W29C020CP90B supports independent software lockout of two 8 KB boot blocks: one at the lowest address range (0x00000–0x01FFF) and one at the highest (0x3E000–0x3FFFF). Lockout is enabled via a 7-byte command sequence and verified by reading address 0x00002 or 0x3FFF2 - outputting "FF" hex indicates activation. Once locked, those blocks resist erasure or programming, while remaining memory remains fully writable. This feature is integral to the W29C020CP90B's secure bootloader architecture.