HM5251405B

HM5251405B 512-Mbit SDRAM Technical Summary

Overview

The Hitachi HM5251405B is a high-performance 512-Mbit Synchronous DRAM (SDRAM) organized as 33,554,432 words × 4 bits × 4 banks. This component is part of a family of 512-Mbit SDRAMs that includes variations with different word/bit configurations to suit various application requirements. The HM5251405B features a fully synchronous operation with all inputs and outputs referenced to the rising edge of the clock input. The device is packaged in a space-efficient 54-pin plastic TSOP II package, making it suitable for applications where board space is at a premium.

This SDRAM is designed for applications requiring high-density memory with fast access times and efficient data management. The 4-bank architecture allows for simultaneous and independent operation of different memory sections, improving overall system performance. With its 3.3V power supply and LVTTL interface, the HM5251405B is compatible with modern low-voltage systems while maintaining robust signal integrity.

Key Features

• Memory Organization: 33,554,432 words × 4 bits × 4 banks (512 Mbit)
• Power Supply: 3.3V ±0.3V operation
• Clock Frequency: Up to 133 MHz (75 ns) or 100 MHz (6 ns) operation
• Interface: LVTTL compatible inputs and outputs
• Bank Architecture: 4 independent banks supporting concurrent operations
• Burst Operation: Supports burst read/write and burst read/single write operations
• Programmable Burst Length: 1, 2, 4, or 8 with sequential or interleave sequencing options
• CAS Latency: Programmable to 2 or 3 clock cycles
• Data Masking: Byte control via DQM (Data Input/Output Mask)
• Refresh Requirements: 8,192 refresh cycles every 64 ms
• Refresh Modes: Supports both auto refresh and self refresh modes
• Package: 54-pin plastic TSOP II (Thin Small Outline Package)

Applications

The HM5251405B is designed for use in a wide range of electronic systems requiring high-density, high-speed memory. Typical applications include:

• Computer systems and workstations
• Networking equipment (routers, switches, gateways)
• Telecommunications infrastructure
• Consumer electronics (HDTVs, set-top boxes, gaming systems)
• Industrial control systems
• Embedded systems requiring reliable memory solutions
• Test and measurement equipment
• Medical imaging systems

Electrical Characteristics

Absolute Maximum Ratings

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

Recommended Operating Conditions

• Supply Voltage (VDD): 3.3V ±0.3V
• Input High Voltage (VIH): 2.0V min (VDD = 3.0V)
• Input Low Voltage (VIL): 0.8V max (VDD = 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
• Operating Current (IDD): 120 mA max (133 MHz operation)
• Standby Current (IDD1): 30 mA max (CKE ≤ VIL, all banks idle)
• 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, 120k ns max

Package Information

The HM5251405B is available in a 54-pin plastic TSOP II package with the following dimensions:

• Package Type: TSOP II (Thin Small Outline Package)
• Pin Count: 54 pins
• Package Width: 10.16 mm (nominal)
• Package Length: 22.22 mm (nominal)
• Package Height: 1.2 mm (max)
• Lead Pitch: 0.8 mm
• Lead Width: 0.22 mm (nominal)
• Lead Length: 0.6 mm (nominal)

Functional Description

The HM5251405B operates with a fully synchronous interface where all operations are referenced to the rising edge of the clock signal. The device features four independent memory banks that can be accessed simultaneously, allowing for efficient memory management and improved system performance.

The SDRAM supports programmable burst lengths of 1, 2, 4, or 8 with two burst sequence options: sequential and interleaved. The CAS latency is programmable to either 2 or 3 clock cycles, providing flexibility in system timing requirements. Data masking is implemented through the DQM pin, which controls the input/output buffers during read and write operations.

Refresh operations can be performed either through auto refresh commands or by entering self refresh mode, which maintains data integrity while minimizing power consumption. The device requires 8,192 refresh cycles every 64 ms to maintain data integrity, with options for distributed or burst refresh modes.

Ordering Information

The HM5251405B is available in different speed grades and package options. The complete ordering information includes:

• HM5251405B-75: 133 MHz operation (7.5 ns cycle time)
• HM5251405B-A6: 100 MHz operation (10 ns cycle time)
• HM5251405B-B6: Alternate 100 MHz operation version

Each variant is available in the standard 54-pin TSOP II package. For specific ordering codes and additional options, consult the manufacturer's latest datasheet or contact authorized distributors.