Hitachi HM5251165B 512-Mbit SDRAM Technical Summary

Overview

The Hitachi HM5251165B is a high-performance 512-Mbit Synchronous Dynamic Random Access Memory (SDRAM) component designed for applications requiring high-speed data access and large memory capacity. This device is organized as 8,388,608 words × 16 bits × 4 banks, offering flexible memory configuration options. The HM5251165B operates with a 3.3V power supply and features a fully synchronous operation with all inputs and outputs referenced to the rising edge of the clock signal.

This SDRAM is part of a family that includes two additional configurations: the HM5251805B (16,777,216 words × 8 bits × 4 banks) and HM5251405B (33,554,432 words × 4 bits × 4 banks). All variants share similar core architecture and performance characteristics while offering different word width options to suit various system requirements.

Key Features

• Memory Organization: 512-Mbit capacity organized as 8M × 16 × 4 banks
• Power Supply: 3.3V ±0.3V operation
• High-Speed Operation: Supports clock frequencies up to 133 MHz (7.5 ns cycle time)
• Interface: LVTTL compatible inputs and outputs
• Bank Architecture: Four independent banks supporting concurrent operation
• Burst Operation: Programmable burst lengths (1, 2, 4, or 8) with sequential or interleave addressing
• CAS Latency: Programmable CAS latency of 2 or 3 clock cycles
• Refresh: Supports both auto refresh and self refresh modes with 8,192 refresh cycles every 64 ms
• Data Control: Byte control via DQMU/DQML signals (for ×16 configuration)
• Package: 54-pin plastic TSOP II (Thin Small Outline Package)

Applications

The HM5251165B is suitable for a wide range of applications requiring high-density, high-speed memory solutions:

• Computer systems and workstations
• Networking equipment (routers, switches)
• Telecommunications infrastructure
• High-performance embedded systems
• Graphics and video processing
• Industrial control systems
• Test and measurement equipment

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (VDD, VDDQ): -0.5V to +4.6V
• Input Voltage (VI): -0.5V to VDDQ +0.5V
• Output Voltage (VO): -0.5V to VDDQ +0.5V
• Operating Temperature Range: 0°C to +70°C
• Storage Temperature Range: -55°C to +125°C

Recommended Operating Conditions

• Supply Voltage (VDD, VDDQ): 3.3V ±0.3V
• Input High Voltage (VIH): 2.0V min (VDDQ = 3.0V)
• Input Low Voltage (VIL): 0.8V max (VDDQ = 3.0V)
• Operating Temperature: 0°C to +70°C

DC Characteristics

• Input Leakage Current (II): ±1 μA max
• Output Leakage Current (IOZ): ±1 μA max
• Active Current (IDD): 180 mA max (133 MHz operation)
• Standby Current (IDD2): 30 mA max (CKE = LOW, CS = HIGH)
• Self Refresh Current (IDD6): 2 mA max

AC Characteristics

• Clock Cycle Time (tCK): 7.5 ns min (133 MHz) / 10 ns min (100 MHz)
• Access Time from Clock (tAC): 5.4 ns max
• CAS Latency: 2 or 3 clock cycles (programmable)
• RAS to CAS Delay (tRCD): 20 ns max
• Row Precharge Time (tRP): 20 ns max
• Row Active Time (tRAS): 45 ns min, 120 μs max

Functional Description

Memory Architecture

The HM5251165B features a four-bank architecture that allows each bank to operate independently. This enables efficient memory access pipelining and concurrent operations across different banks. The memory array is divided into rows and columns, with each bank containing 8,388,608 addressable 16-bit words.

Burst Operation

The device supports programmable burst lengths of 1, 2, 4, or 8, with two addressing sequences available:

• Sequential: Linear address incrementing within the burst
• Interleave: Addresses follow a predefined interleaved sequence

Refresh Modes

The HM5251165B incorporates two refresh modes to maintain data integrity:

• Auto Refresh: Requires external refresh control at regular intervals
• Self Refresh: Internal timer maintains refresh cycles during low-power operation

Package Information

54-pin TSOP II Package

• Package Dimensions: 22.2mm × 10.2mm × 1.2mm (typical)
• Pin Count: 54
• Pin Pitch: 0.8mm
• Package Material: Plastic
• Lead Finish: Matte tin

Pin Configuration

The 54-pin TSOP II package includes the following key signal groups:

• Clock and control signals (CLK, CKE, CS, RAS, CAS, WE)
• Address inputs (A0-A11)
• Bank address inputs (BA0, BA1)
• Data input/output (DQ0-DQ15)
• Data mask controls (DQMU, DQML)
• Power and ground (VDD, VSS, VDDQ, VSSQ)

Ordering Information

The HM5251165B is available in different speed grades and configurations:

• HM5251165B-75: 133 MHz operation (7.5 ns cycle time)
• HM5251165B-A6: 100 MHz operation (10 ns cycle time)
• HM5251165B-B6: Alternate 100 MHz version

Conclusion

The Hitachi HM5251165B 512-Mbit SDRAM provides a high-performance memory solution for demanding applications. With its 3.3V operation, four-bank architecture, and flexible burst modes, it offers system designers an optimal balance of performance, power efficiency, and density. The device's programmable features and standard TSOP II package make it suitable for a wide range of applications in computing, networking, and embedded systems.