Hitachi HM628128D Series 1-Mbit Static RAM

Overview

The Hitachi HM628128D Series is a high-performance 1-Mbit static RAM organized as 131,072 words × 8 bits. Manufactured using advanced Hi-CMOS process technology, this SRAM series achieves higher density, improved performance, and reduced power consumption. The HM628128D is particularly well-suited for battery backup systems due to its low standby power dissipation. The series is available in multiple package options, including a standard 32-pin plastic DIP, 32-pin plastic SOP, and 32-pin plastic TSOPI, providing flexibility for various design requirements.

Features

• Single 5V Supply: Operates at 5V ± 10%, ensuring compatibility with standard power sources.
• High-Speed Access Time: Maximum access times of 55 ns and 70 ns, catering to high-performance applications.
• Low Power Consumption:
  • Active mode: 30 mW/MHz (typical)
  • Standby mode: 10 µW (typical), ideal for battery-operated systems.
• Completely Static Memory: No clock or timing strobe required, simplifying system design.
• Equal Access and Cycle Times: Ensures consistent performance for read and write operations.
• Common Data Input and Output: Three-state output for easy interfacing with bus systems.
• TTL Compatibility: All inputs are directly TTL compatible, facilitating integration with existing logic circuits.
• Battery Backup Operation: Features two chip selection inputs for efficient battery backup management.

Applications

The HM628128D Series is designed for a wide range of applications, particularly where low power consumption and high reliability are critical. Key application areas include:

• Battery Backup Systems: Due to its ultra-low standby power, the HM628128D is ideal for portable and battery-powered devices.
• Embedded Systems: Suitable for microcontroller-based systems requiring fast and reliable static RAM.
• Industrial Control Systems: Robust performance makes it a good fit for industrial automation and control applications.
• Telecommunications Equipment: High-speed access and low power dissipation are beneficial for networking and communication devices.
• Consumer Electronics: Used in devices such as digital cameras, gaming consoles, and smart appliances.

Electrical Characteristics

The following table summarizes the key electrical characteristics of the HM628128D Series:

• Supply Voltage (V_CC): 5V ± 10%
• Operating Temperature Range: Commercial (0°C to +70°C) or Industrial (-40°C to +85°C), depending on the variant.
• Input/Output Levels: TTL-compatible inputs and outputs.
• Active Power Dissipation: 30 mW/MHz (typical) at 5V.
• Standby Power Dissipation: 10 µW (typical) with CMOS-level inputs.
• Access Time: 55 ns (fastest grade) and 70 ns (standard grade).
• Data Retention Voltage: As low as 2V for battery backup operation.

Timing Characteristics

• Read Cycle Time: Equal to access time (55 ns or 70 ns).
• Write Cycle Time: Matches read cycle time for uniform performance.
• Chip Select to Output Valid: Typically within the access time specification.
• Output Hold Time: Minimum of 0 ns, ensuring data integrity during transitions.

Package Information

The HM628128D Series is available in three industry-standard packages, providing designers with flexibility for different PCB layouts and space constraints.

32-Pin Plastic DIP (Dual In-line Package)

• Package Type: DIP-32
• Dimensions: Approximately 42.0 mm × 10.16 mm (length × width).
• Pin Pitch: 2.54 mm (standard DIP spacing).
• Mounting: Through-hole technology, suitable for prototyping and breadboarding.

32-Pin Plastic SOP (Small Outline Package)

• Package Type: SOP-32
• Dimensions: Approximately 20.0 mm × 7.5 mm (length × width).
• Pin Pitch: 1.27 mm, enabling higher PCB density.
• Mounting: Surface-mount technology (SMT), ideal for compact designs.

32-Pin Plastic TSOPI (Thin Small Outline Package I)

• Package Type: TSOPI-32
• Dimensions: Approximately 18.4 mm × 8.1 mm (length × width).
• Pin Pitch: 0.8 mm, optimized for space-constrained applications.
• Mounting: Surface-mount technology (SMT), commonly used in portable electronics.

Ordering Information

The HM628128D Series offers multiple variants to meet different performance and environmental requirements. The ordering part number typically includes the following information:

• Speed Grade: 55 (55 ns) or 70 (70 ns).
• Temperature Range: C (Commercial) or I (Industrial).
• Package Type: DIP, SOP, or TSOPI.

Example part number: HM628128D-55 (55 ns access time, commercial temperature range, default package).

Conclusion

The Hitachi HM628128D Series is a versatile and high-performance 1-Mbit static RAM solution, offering a balance of speed, power efficiency, and reliability. Its low standby power makes it particularly suitable for battery-backed applications, while its multiple package options ensure compatibility with a wide range of designs. Whether used in industrial control systems, consumer electronics, or telecommunications, the HM628128D Series provides a robust and efficient memory solution.