658512A

Technical Summary: Hitachi HM658512A CMOS Pseudo Static RAM

Overview

The Hitachi HM658512A is a high-performance CMOS pseudo-static RAM organized as 512K words × 8 bits. Utilizing a 0.8 µm Hi-CMOS process, this component achieves higher density, improved performance, and lower power consumption compared to conventional SRAM solutions. It is designed for applications requiring fast access times, low power operation, and simple interfacing with TTL-compatible systems. The HM658512A is ideal for embedded systems, industrial controls, and other memory-intensive applications.

Features

• Single 5V Power Supply (±10%) - Operates reliably within a standard voltage range.
• High-Speed Operation
  • CE Access Time: 70/80/100 ns (max)
  • Random Read/Write Cycle Time: 115/130/160 ns (min)
• Low Power Consumption
  • Active Mode: 250 mW (typical)
  • Standby Mode: 200 µW (typical)
• TTL Compatibility - All inputs and outputs are directly compatible with TTL logic levels.
• Non-Multiplexed Address Configuration - Simplifies interfacing with microprocessors.
• Refresh Cycle Support
  • 2048 refresh cycles within 32 ms
  • Supports address refresh, automatic refresh, and self-refresh modes.

Applications

The HM658512A is suitable for a wide range of applications, including:

• Embedded systems requiring fast, low-power memory
• Industrial control systems
• Data logging and acquisition systems
• Telecommunications equipment
• Consumer electronics with memory-intensive operations

Electrical Characteristics

The following table summarizes key electrical specifications:

• Operating Voltage: 5V ±10%
• Access Time (Max): 70 ns, 80 ns, or 100 ns (depending on variant)
• Cycle Time (Min): 115 ns, 130 ns, or 160 ns (depending on variant)
• Power Consumption:
  • Active: 250 mW (typical)
  • Standby: 200 µW (typical)
• Input/Output Compatibility: TTL levels

Package Information

The HM658512A is available in multiple package options to suit different design requirements:

• 600-mil 32-pin Plastic DIP (DP-32) - Designated as HM658512ALP-7, HM658512ALP-8, HM658512ALP-10 (varying access times).
• 525-mil 32-pin Plastic SOP (FP-32D) - Designated as HM658512ALFP-7, HM658512ALFP-8, HM658512ALFP-10.
• 400-mil 32-pin Plastic TSOP (TTP-32D) - Designated as HM658512ALTT-7, HM658512ALTT-8, HM658512ALTT-10.
• 400-mil 32-pin Plastic TSOP (TTP-32DR) - Designated as HM658512ALRR-7, HM658512ALRR-8, HM658512ALRR-10.

Pin Configuration

The HM658512A features a 32-pin layout with the following pin functions:

• A0-A18: Address inputs (A0-A10 for row, A11-A18 for column addressing).
• I/O0-I/O7: Bidirectional data input/output lines.
• CE: Chip Enable (active low).
• OE/RFSH: Output Enable / Refresh control.
• WE: Write Enable (active low).
• VCC: Power supply (5V).
• VSS: Ground.

Functional Block Diagram

The internal architecture of the HM658512A includes:

• Memory Matrix (2048 × 256 × 8)
• Row and Column Decoders
• Address Latch Control
• Refresh Control and Timing Pulse Generator
• Read/Write Control Logic

Operating Modes

The HM658512A supports several operational modes:

• Active Mode: When CE is low, the device is fully operational for read/write cycles.
• Standby Mode: When CE is high, power consumption is minimized.
• Refresh Mode: Supports multiple refresh methods to maintain data integrity.

Conclusion

The Hitachi HM658512A is a versatile and high-performance CMOS pseudo-static RAM, offering a balance of speed, power efficiency, and ease of integration. Its wide range of package options and robust feature set make it suitable for diverse applications in industrial, consumer, and embedded systems.