HM62W16255H - 4-Mbit High-Speed Static RAM

Overview

The HM62W16255H is a high-performance 4-Mbit static RAM organized as 256K words × 16 bits. Designed using advanced CMOS process technology (4-transistor + 2-poly resistor memory cell) and high-speed circuit design techniques, this SRAM delivers exceptional performance for applications requiring fast access times, high density, and wide bit-width configurations. The device is particularly well-suited for cache and buffer memory applications in various computing systems.

Available in both 44-pin SOJ and 44-pin plastic TSOPII packages, the HM62W16255H offers flexibility in high-density PCB designs while maintaining excellent electrical characteristics and reliability.

Features

• Single 3.3V Power Supply: Operates at 3.3V ± 0.3V
• High-Speed Access: 12ns or 15ns maximum access time options
• Fully Static Operation: No clock or timing strobe required
• Symmetric Performance: Equal access and cycle times
• TTL Compatibility: All inputs and outputs directly compatible with TTL levels
• Low Power Consumption:
  • Operating current: 180mA/160mA (max)
  • TTL standby current: 60mA/50mA (max)
  • CMOS standby current: 5mA (max), 1mA (max) for L-version
• Data Retention:
  • Data retention current: 0.6mA (max) for L-version
  • Data retention voltage: 2.0V (min) for L-version
• Versatile Packaging: Available in 400-mil 44-pin SOJ and TSOPII packages
• Byte Control: Features upper and lower byte select (UB/LB) for flexible data access

Applications

The HM62W16255H is designed for high-performance applications including:

• Cache memory in computing systems
• High-speed buffer memory
• Networking equipment
• Telecommunications systems
• Industrial control systems
• Embedded systems requiring fast SRAM
• Graphics and video processing
• Data acquisition systems

Electrical Characteristics

Absolute Maximum Ratings

• Supply Voltage (VCC): -0.5V to +4.6V
• Input Voltage (VIN): -0.5V to VCC + 0.5V
• Output Voltage (VOUT): -0.5V to VCC + 0.5V
• Operating Temperature: 0°C to +70°C
• Storage Temperature: -55°C to +125°C

DC Characteristics (TA = 0°C to 70°C, VCC = 3.3V ± 0.3V)

• Input High Voltage (VIH): 2.0V min
• Input Low Voltage (VIL): 0.8V max
• Output High Voltage (VOH): 2.4V min (IOH = -4.0mA)
• Output Low Voltage (VOL): 0.4V max (IOL = 8.0mA)
• Input Leakage Current (IIN): ±1μA max
• Output Leakage Current (IOZ): ±1μA max

AC Characteristics

• Read Cycle Time (tRC): 12ns/15ns max
• Address Access Time (tAA): 12ns/15ns max
• Chip Select Access Time (tACS): 12ns/15ns max
• Output Enable to Output Valid (tOE): 6ns max
• Write Cycle Time (tWC): 12ns/15ns max
• Write Pulse Width (tWP): 10ns/12ns min
• Byte Write Pulse Width (tBWP): 10ns/12ns min

Package Information

Available Packages

• 44-pin Plastic SOJ (CP-44D): 400-mil body width
• 44-pin Plastic TSOPII (TTP-44DE): 400-mil body width

Ordering Information

• HM62W16255HJP-12: 12ns, 44-pin SOJ
• HM62W16255HJP-15: 15ns, 44-pin SOJ
• HM62W16255HLJP-12: 12ns, 44-pin SOJ (Low-power version)
• HM62W16255HLJP-15: 15ns, 44-pin SOJ (Low-power version)
• HM62W16255HTT-12: 12ns, 44-pin TSOPII
• HM62W16255HTT-15: 15ns, 44-pin TSOPII
• HM62W16255HLTT-12: 12ns, 44-pin TSOPII (Low-power version)
• HM62W16255HLTT-15: 15ns, 44-pin TSOPII (Low-power version)

Pin Configuration

The HM62W16255H features a center VCC and VSS type pinout for improved power distribution. The pin arrangement is as follows:

• Address Inputs: A0-A17 (18 address lines)
• Data I/O: I/O1-I/O16 (16-bit bidirectional data bus)
• Control Signals:
  • CS: Chip Select (active low)
  • OE: Output Enable (active low)
  • WE: Write Enable (active low)
  • UB: Upper Byte Select (active low)
  • LB: Lower Byte Select (active low)
• Power: VCC (3.3V), VSS (Ground)
• No Connection: NC (Pin 23)

Functional Description

The HM62W16255H is organized as a 256K × 16-bit memory array with advanced control features. The memory matrix consists of 256 rows × 8 columns × 128 blocks, totaling 4,194,304 bits (4Mb). The device features:

• Byte Control: The UB and LB pins allow for individual byte (upper and lower) access or full 16-bit word access
• Asynchronous Operation: All inputs are level-triggered with no clock requirement
• Three-State Outputs: Outputs enter high-impedance state when OE is high or CS is high
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