Technical Summary: Hitachi HM5264805 64-Mbit SDRAM

Overview

The Hitachi HM5264805F is a high-performance 64-Mbit Synchronous DRAM (SDRAM) component designed for applications requiring high-speed data transfer and efficient memory management. Organized as 2,097,152 words × 8 bits × 4 banks, this SDRAM offers flexible memory configurations suitable for various computing and embedded systems. The device operates with a 3.3V power supply and features a LVTTL interface, making it compatible with modern digital systems. All inputs and outputs are synchronized to the rising edge of the clock, ensuring reliable data transfer at clock frequencies up to 133 MHz.

The HM5264805F is part of a family that includes the HM5264165F (16-bit organization) and HM5264405F (4-bit organization), providing designers with multiple options for different bus width requirements. The device is packaged in a standard 54-pin plastic TSOP II package, offering a compact footprint for space-constrained applications.

Key Features

• Memory Organization: 64-Mbit capacity organized as 2,097,152 words × 8 bits × 4 banks
• Power Supply: Single 3.3V ± 0.3V power supply
• Clock Frequency: Up to 133 MHz operation (also supports 100 MHz)
• Interface: LVTTL compatible inputs and outputs
• Bank Architecture: Four independent banks supporting concurrent operation
• Burst Operation: Programmable burst lengths (1, 2, 4, 8, or full page)
• Burst Sequences: Supports both sequential and interleave burst modes
• CAS Latency: Programmable CAS latency of 2 or 3 cycles
• Data Masking: Byte control via DQM (Data Input/Output Mask)
• Refresh: 4096 refresh cycles every 64ms with auto refresh and self refresh modes
• Package: 54-pin plastic TSOP II (Thin Small Outline Package)

Applications

The HM5264805F is suitable for a wide range of applications requiring high-speed memory access and efficient data handling:

• Desktop and laptop computer systems
• Workstations and servers
• Networking equipment (routers, switches)
• Telecommunications infrastructure
• Embedded systems and industrial controllers
• Graphics cards and display subsystems
• Consumer electronics (set-top boxes, digital TVs)
• Automotive infotainment systems

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: Commercial (0°C to +70°C)

DC Characteristics

• Input Leakage Current (II): ±1 μA max
• Output Leakage Current (IOZ): ±1 μA max
• Operating Current (IDD): 120 mA max (133 MHz operation)
• Standby Current (ISB): 20 mA max (CKE ≤ VIL, all banks idle)
• Self Refresh Current (ISSR): 4 mA max

AC Characteristics (133 MHz Operation)

• Clock Cycle Time (tCK): 7.5 ns min
• CAS Latency: 2 or 3 clock cycles
• Access Time from Clock (tAC): 5.4 ns max
• Row Address to Column Address Delay (tRCD): 20 ns max
• Row Precharge Time (tRP): 20 ns max
• Row Active Time (tRAS): 45 ns min, 120k ns max
• Refresh Period (tREF): 64 ms

Functional Description

Memory Architecture

The HM5264805F organizes its 64-Mbit memory space into four independent banks, each containing 2,097,152 addresses of 8-bit words. This architecture allows simultaneous activation of different banks, significantly improving memory access efficiency compared to conventional DRAM architectures.

Burst Operation

The device supports programmable burst lengths of 1, 2, 4, 8, or full page (256). Two burst sequence modes are available:

• Sequential: Address increments within the burst boundary
• Interleave: Uses a predefined interleaved address sequence

Refresh Modes

The HM5264805F incorporates two refresh methods to maintain data integrity:

• Auto Refresh: Requires external refresh control at regular intervals
• Self Refresh: Internal timer automatically maintains refresh when CKE is low

Package Information

54-pin TSOP II Package Dimensions

• Package Type: TSOP II (Type 1)
• Pin Count: 54
• Body Size: 22.2mm × 10.2mm
• Lead Pitch: 0.8mm
• Package Height: 1.2mm max
• Lead Width: 0.22mm
• Lead Length: 0.5mm

Pin Configuration

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

• Clock and Control: CLK, CKE, /CS, /RAS, /CAS, /WE
• Address Inputs: A0-A11 (row), A0-A8 (column), BA0-BA1 (bank select)
• Data I/O: DQ0-DQ7
• Data Mask: DQM
• Power: VDD, VDDQ, VSS, VSSQ

Ordering Information

The device is available in different speed grades and configurations:

• HM5264805F-75: 133 MHz operation
• HM5264805F-A60: 100 MHz operation
• HM5264805F-B60: 100 MHz operation (alternative)

Conclusion

The Hitachi HM5264805F 64-Mbit SDRAM provides a high-performance memory solution for systems requiring efficient data handling and high-speed operation. With its four-bank architecture, programmable burst modes, and flexible configuration options, this device offers designers a versatile memory component suitable for a wide range of applications. The 3.3V LVTTL interface and standard TSOP II package ensure compatibility with modern system designs while maintaining a compact footprint.