Hitachi HM62256B Series 32Kx8 CMOS Static RAM

Overview

The Hitachi HM62256B Series is a high-performance CMOS static RAM organized as 32,768 words × 8 bits (32Kx8). Manufactured using advanced 0.8 µm Hi-CMOS process technology, this component delivers superior performance while maintaining low power consumption. The device is particularly well-suited for applications requiring battery backup due to its extremely low standby power dissipation.

The HM62256B is available in multiple package options including various TSOP, SOP, and DIP configurations, making it versatile for different mounting density requirements. Its completely static operation eliminates the need for clock signals or complex timing strobes, simplifying system design.

Key Features

• Single 5V Power Supply: Operates at 5.0V ± 10%
• High-Speed Operation: Multiple speed grades available with maximum access times of 55ns, 70ns, and 85ns
• Low Power Consumption:
  • Active mode: 25mW typical (at 1MHz operation)
  • Standby mode: 1.0µW typical (battery backup operation)
• Fully Static Design: No refresh requirements or clock signals needed
• Equal Access and Cycle Times: Simplifies timing considerations
• Three-State Outputs: Common data input/output with TTL compatibility
• Wide Temperature Range: Suitable for industrial applications
• Multiple Package Options: Supports various mounting requirements

Applications

The HM62256B is designed for use in a wide range of applications including:

• Battery-backed memory systems
• Industrial control systems
• Embedded systems
• Telecommunications equipment
• Automotive electronics
• Medical devices
• Point-of-sale terminals
• Data loggers
• Consumer electronics

Its combination of low power consumption, high reliability, and flexible packaging makes it particularly suitable for portable and battery-operated devices where power efficiency is critical.

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (Vcc): -0.3V to +7.0V
• Input Voltage (Vin): -0.3V to Vcc + 0.3V
• Operating Temperature Range (Topr): -40°C to +85°C
• Storage Temperature Range (Tstg): -55°C to +125°C

DC Characteristics (TA = -40°C to +85°C, Vcc = 5V ± 10%)

• Input High Voltage (VIH): 2.2V min
• Input Low Voltage (VIL): 0.8V max
• Output High Voltage (VOH): 2.4V min (Ioh = -2.0mA)
• Output Low Voltage (VOL): 0.4V max (Iol = 2.1mA)
• Supply Current (Active):
  • 55ns version: 40mA max (f=1MHz)
  • 70ns version: 35mA max (f=1MHz)
  • 85ns version: 30mA max (f=1MHz)
• Supply Current (Standby): 10µA max (CMOS level)

AC Characteristics

• Read Cycle Time (tRC): Equal to access time for each speed grade
• Write Cycle Time (tWC): Equal to access time for each speed grade
• Address Access Time (tAA):
  • 55ns version: 55ns max
  • 70ns version: 70ns max
  • 85ns version: 85ns max
• Chip Enable to Output Valid (tCE): Equal to access time
• Output Enable to Output Valid (tOE): 20ns max
• Write Pulse Width (tWP): 45ns min (55ns version), 55ns min (70ns version), 65ns min (85ns version)

Package Information

The HM62256B is available in multiple package options to suit various application requirements:

TSOP Packages

• 8 × 14 mm TSOP: Standard thin small outline package
• 8 × 13.4 mm TSOP (1.2mm thickness): Reduced thickness version for space-constrained applications

SOP Packages

• 450 mil SOP: Standard small outline package with 450 mil footprint pitch width

DIP Packages

• 600 mil Plastic DIP: Standard dual in-line package
• 300 mil Plastic DIP: Narrow body dual in-line package

Package Dimensions (Typical)

• TSOP (Type I): 14.0mm × 8.0mm × 1.0mm
• TSOP (Type II): 13.4mm × 8.0mm × 1.2mm
• SOP: 19.2mm × 10.3mm × 3.5mm
• 600 mil DIP: 32.8mm × 15.2mm × 4.7mm
• 300 mil DIP: 32.8mm × 7.8mm × 4.7mm

Ordering Information

The HM62256B is available in different speed grades and package options. The complete ordering part number is constructed as follows:

HM62256B[Speed][Package][Option]

• [Speed]:
  • 55: 55ns version
  • 70: 70ns version
  • 85: 85ns version
• [Package]:
  • L: TSOP (Type I)
  • P: TSOP (Type II)
  • F: SOP
  • D: 600 mil DIP
  • N: 300 mil DIP

Quality and Reliability

The HM62256B series meets stringent quality and reliability standards:

• High-temperature operating life tested
• Temperature cycling tested
• Humidity testing performed
• ESD protection on all pins
• Latch-up tested

The device is suitable for use in industrial and automotive applications where reliability under harsh conditions is required.