Renesas 7164L55DB

Overview

7164L55DB from Renesas Electronics is a military-grade 64K (8K × 8-bit) CMOS static RAM with 55 ns maximum access time, TTL-compatible I/O, three-state outputs, and battery backup data retention down to 2 V. It operates from a single 5 V supply and supports standby power reduction via dual chip select control (CS1/CS2). Used in avionics, radar processors, and hardened embedded controllers requiring non-volatile SRAM persistence under brownout.

For engineers reviewing the 7164L55DB datasheet, 7164L55DB pinout, 7164L55DB application, or 7164L55DB equivalent, key selection criteria include military temperature range (–55°C to +125°C), CERDIP-28 package compatibility, 2 V data retention capability, and dual-CS standby power management for mission-critical systems.

Technical Context

The 7164L55DB implements fully static asynchronous operation-no clocks or refresh required-and uses dual chip select logic where CS1 HIGH or CS2 LOW forces automatic entry into low-power standby mode. Its L-version architecture enables data retention at VCC as low as 2 V while maintaining full read/write functionality at 5 V ±10%.

It features TTL-compatible input thresholds (VIH ≥ 2.2 V, VIL ≤ 0.8 V), output drive capability of 8 mA sink / –4 mA source, and supports both WE-controlled and CS-controlled write timing modes. The device complies with MIL-STD-883 Class B for high-reliability military deployment.

Key Specifications

Pinout & Package

7164L55DB is housed in a 28-pin ceramic dual in-line package (CERDIP), designated CD28, with 0.600-inch body width and through-hole mounting. Pin 1 is marked by a dot on the top surface.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 7164S55DB, the 7164L55DB delivers critical 2 V data retention and 40× lower standby current-essential for battery-backed avionics. Against IS61LV25616AL-10TLI, it trades speed and density for guaranteed military reliability, hermetic packaging, and 5 V interoperability without level shifting.

Availability

7164L55DB is available at Aetrix Electronics and suitable for avionics flight control, radar signal processing, hardened industrial PLCs, and military communications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 7164L55DB 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

Renesas Electronics Corporation is a global semiconductor leader specializing in microcontrollers, analog, power, and memory solutions for automotive, industrial, and infrastructure markets.

The IDT7164 family-now part of Renesas' legacy high-reliability memory portfolio-was designed specifically for military and aerospace applications demanding MIL-STD-883 qualified static RAM with battery backup and wide-temperature operation.

FAQ

What is the minimum supply voltage required to retain data in the 7164L55DB?

The 7164L55DB guarantees data retention down to 2.0 V (VDR), as specified in Table 10 of the Renesas datasheet. This applies across the full military temperature range (–55°C to +125°C) and enables operation during brownout conditions without data loss. The 7164L55DB maintains this specification only in its L-version configuration; the S-version does not support sub-4.5 V retention.

Does the 7164L55DB require an external clock or refresh circuitry?

No, the 7164L55DB uses fully static CMOS architecture and requires no clock input or periodic refresh cycles. All operations-including read, write, and standby-are controlled solely by address, data, and control signals (CS1, CS2, WE, OE). This eliminates timing-critical clock distribution and reduces system-level EMI, making the 7164L55DB ideal for deterministic real-time systems like flight control computers.

How does the dual chip select (CS1/CS2) logic affect power consumption in the 7164L55DB?

In the 7164L55DB, asserting CS1 HIGH or CS2 LOW automatically places the device into low-power standby mode (ISB), reducing supply current to ≤5 µA over the full military temperature range. This dual-path control allows flexible system-level power gating-e.g., CS2 can be held HIGH while CS1 is toggled for burst access, or CS1 held LOW while CS2 manages background sleep. The 7164L55DB's ISB current is 40× lower than the standard-power 7164S55DB variant.

Is the 7164L55DB pin-compatible with other members of the IDT7164 family?

Yes, the 7164L55DB shares identical pinout and footprint with all IDT7164 variants in the CD28 (28-pin CERDIP) package, including 7164S55DB, 7164L25DB, and 7164S20DB. Signal assignments for A0–A12, I/O0–I/O7, CS1, CS2, WE, OE, VCC, GND, and NC are functionally and physically identical. This allows drop-in replacement within the same speed grade and package type without PCB modification.

What packaging and screening standards apply to the 7164L55DB?

The 7164L55DB is supplied in a 28-pin hermetically sealed CERDIP (CD28) package and is fully screened to MIL-STD-883 Class B requirements, including Method 1015 (steady-state life test), Method 2003 (thermal shock), and Method 2017 (hermeticity). It meets temperature cycling (–55°C to +125°C), mechanical shock, and vibration specifications defined for high-reliability defense electronics. The 7164L55DB carries no RoHS exemption markings and complies with Renesas' green materials policy.