Cypress Semiconductor Corp CY62157ELL-55BVXE

Overview

CY62157ELL-55BVXE from Cypress Semiconductor is an 8-Mbit (512 K × 16) CMOS static RAM with 45 ns access time, 4.5–5.5 V supply range, and ultra-low standby current (2 µA typical). It supports byte-wide write enable via BHE/ BLE, automatic power-down on deselect, and operates across –40 °C to +85 °C for industrial applications. Used in portable instrumentation and embedded controllers requiring non-volatile data retention during low-power sleep.

For engineers reviewing the CY62157ELL-55BVXE datasheet, CY62157ELL-55BVXE pinout, CY62157ELL-55BVXE application, or CY62157ELL-55BVXE equivalent, key selection criteria include TSOP II package compatibility, TTL-level I/O interface requirements, CE1/CE2 dual-chip-enable logic, and sub-8 µA industrial standby current compliance.

Technical Context

The CY62157ELL-55BVXE implements a 512K × 16 asynchronous SRAM architecture with independent high- and low-byte enables (BHE/ BLE), dual chip enables (CE1 active-low, CE2 active-high), and automatic power-down triggered by CE or byte-enable deassertion. Its TTL-compatible input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V) require external level-shifting when interfacing with pure CMOS processors.

Timing is defined by overlapping control signals: read access requires CE1 LOW + CE2 HIGH + OE LOW + WE HIGH; write requires CE1 LOW + CE2 HIGH + WE LOW with BHE or BLE LOW. Data retention is guaranteed down to 2 V VCC, with tCDR = 0 ns and ICCDR ≤ 8 µA at VCC = 2 V.

Key Specifications

Pinout & Package

Package: 44-pin TSOP II (Thin Small Outline Package, Type II), 400 mil width, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IS62WV51216BLL-45NLI and AS6C4008-55TIN, the CY62157ELL-55BVXE uniquely combines 45 ns speed, 5 V TTL compatibility, and 44-pin TSOP II packaging - making it optimal for legacy 5 V controller upgrades without PCB redesign.

Availability

CY62157ELL-55BVXE is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, and automotive body control units requiring stable component supply across extended product lifecycles.

Supply support for CY62157ELL-55BVXE 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) designs high-reliability memory and programmable solutions for industrial, automotive, and IoT applications.

The CY62157E MoBL® SRAM product line targets battery-constrained portable electronics, emphasizing ultra-low standby current, TTL compatibility, and robust data retention - not general-purpose computing memory.

FAQ

Is CY62157ELL-55BVXE compatible with 3.3 V microcontrollers?

No. The CY62157ELL-55BVXE requires 4.5–5.5 V VCC and features TTL-level inputs (VIH ≥ 2.2 V, VIL ≤ 0.8 V), not 3.3 V CMOS thresholds. Interfacing with 3.3 V MCUs requires bidirectional level shifters such as TXB0108 or discrete MOSFET translators to avoid logic misreads and excessive input leakage.

What happens if both CE1 and CE2 are asserted simultaneously?

When CE1 is LOW and CE2 is HIGH, the device operates normally. If CE1 is LOW and CE2 is LOW, the device enters high-impedance standby regardless of OE or WE state. If CE1 is HIGH and CE2 is HIGH, the device remains deselected and draws ISB2 current. CE1 HIGH + CE2 LOW is an invalid state per datasheet truth table and must be avoided.

Can BHE and BLE be tied permanently LOW for full 16-bit operation?

Yes. Tying both BHE and BLE LOW enables full 16-bit data transfers on I/O0–I/O15. This configuration is valid and commonly used in 16-bit bus systems. However, doing so forfeits byte-select capability and increases active current slightly due to double the I/O capacitance being driven.

Does CY62157ELL-55BVXE support battery backup mode?

It supports data retention down to 2 V VCC with ICCDR ≤ 8 µA, but lacks built-in battery-switching circuitry. External diode-OR or ideal diode controllers (e.g., LTC4412) must be added to switch between main supply and backup battery. The device itself does not monitor VCC or initiate switchover.