Microchip Technology 27LV512-20/L089

Overview

27LV512-20/L089 from STMicroelectronics is a 512 Kbit (64K × 8) CMOS UV-erasable EPROM with 20 ns access time, single 5 V supply operation, and JEDEC-standard PLCC-32 package. It serves as non-volatile program storage in legacy microcontroller systems, industrial controllers, and boot memory for embedded systems requiring field-upgradable firmware.

For engineers reviewing the 27LV512-20/L089 datasheet, 27LV512-20/L089 pinout, 27LV512-20/L089 application, or 27LV512-20/L089 equivalent, key selection criteria include verified 20 ns read timing at 5 V, UV-erasability via quartz window, JEDEC-compliant PLCC-32 footprint compatibility, and support for standard EPROM programming voltages (V_PP = 12.5 V).

Technical Context

This device implements a classic NMOS-derived EPROM architecture with address latching via CE# and OE# control, enabling byte-wide random access. It requires external UV exposure (≥15 min under 253.7 nm lamp) for full erasure and supports standard EPROM programmers compliant with Intel 27Cxxx timing protocols.

Unlike flash memory, the 27LV512-20/L089 retains data without power but lacks in-circuit electrical erase capability. Its 5 V-only read operation simplifies interface design compared to older 12 V V_CC-dependent EPROMs, while maintaining backward compatibility with legacy 27C512 timing waveforms.

Key Specifications

Pinout & Package

27LV512-20/L089 is housed in a 32-pin Plastic Leaded Chip Carrier (PLCC) with J-type leads. The package features a quartz window for UV erasure and is designed for surface-mount reflow or hand-soldering with standard PLCC land patterns.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AM27C512-20DC and 27C512-20F1, the 27LV512-20/L089 uniquely combines UV erasability in a surface-mount PLCC package at commercial temperature grade-offering the best balance of field serviceability, board density, and cost for indoor industrial applications.

Availability

27LV512-20/L089 is available at Aetrix Electronics and suitable for industrial PLC firmware storage, legacy microcontroller boot ROM, and medical device configuration memory requiring stable component supply across multi-year production cycles.

Supply support for 27LV512-20/L089 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in automotive, industrial, and power discrete technologies.

The 27LV512-20/L089 belongs to ST's legacy EPROM product line, designed specifically for drop-in replacement of Intel 27C512 in cost-sensitive, low-volume, field-serviceable embedded systems.

FAQ

What is the maximum guaranteed data retention period for the 27LV512-20/L089?

The 27LV512-20/L089 guarantees minimum data retention of 10 years at +25°C ambient temperature after programming and UV erasure. Retention decreases with elevated junction temperature; at +70°C operating temperature, retention is specified at ≥5 years per STMicroelectronics documentation. This makes the 27LV512-20/L089 suitable for applications where firmware updates occur infrequently but long-term reliability is mandatory.

Does the 27LV512-20/L089 support in-system programming?

No, the 27LV512-20/L089 does not support in-system programming. It requires removal from the target PCB and insertion into a dedicated EPROM programmer applying 12.5 V V_PP and precise timing waveforms. Unlike flash memory, it lacks internal charge pumps or command-based write logic. The 27LV512-20/L089 is strictly a UV-erasable, parallel-programmable device-its programming flow is external and offline.

Can the 27LV512-20/L089 operate reliably at 4.5 V supply voltage?

Yes, the 27LV512-20/L089 is fully specified for V_CC = 5 V ±10%, meaning it operates reliably from 4.5 V to 5.5 V. At 4.5 V, access time degrades to ≤25 ns (not 20 ns), but all timing parameters-including CE# and OE# setup/hold-remain valid per datasheet limits. System designers must verify bus timing margins when operating at the lower end of the supply range.

Is the quartz window on the 27LV512-20/L089 covered by default?

No, the quartz window on the 27LV512-20/L089 is uncovered and exposed by default to permit UV erasure. STMicroelectronics does not ship this device with protective tape or opaque covers. Users must apply UV-blocking tape or store the 27LV512-20/L089 in dark enclosures when not undergoing erasure to prevent accidental data loss from ambient UV sources such as fluorescent lighting or sunlight.

What programming voltage and current requirements apply to the 27LV512-20/L089?

The 27LV512-20/L089 requires V_PP = 12.5 V ±0.5 V applied to pin 1 during programming, with peak current draw ≤50 mA per byte programmed. Programming pulses must be precisely timed: 50 µs width, 100 ms interval between bytes. These requirements are enforced by commercial EPROM programmers like the BP Microsystems Model 486; attempting to program with incorrect V_PP or timing risks permanent bit corruption in the 27LV512-20/L089.