62V16256B
Hitachi HM62V16256B Series 4-Mbit Static RAM
Overview
The Hitachi HM62V16256B Series is a high-performance 4-Mbit static RAM organized as 262,144 words × 16 bits. Manufactured using advanced Hi-CMOS process technology, this SRAM offers a combination of high density, high speed, and low power consumption. The device is particularly well-suited for battery backup applications due to its ultra-low standby power dissipation. The HM62V16256B is available in a standard 44-pin plastic TSOPII package, making it suitable for space-constrained applications.
Features
- Single 3.0V Power Supply: Operates from 2.7V to 3.6V, making it compatible with low-voltage systems
- High-Speed Operation: Fast access times of 70ns and 85ns (max) versions available
- Low Power Consumption:
- Active mode: 9mW typical power dissipation
- Standby mode: 3μW typical power dissipation (ideal for battery backup)
- Fully Static Design: No clock or refresh required, simplifying system design
- Equal Access and Cycle Times: Provides consistent performance for read and write operations
- Three-State Outputs: Common data input/output with high impedance state
- Battery Backup Operation: Dual chip select (CS1 and CS2) for efficient power management
- Byte Control: Independent upper and lower byte control (UB and LB pins)
Applications
The HM62V16256B is designed for a wide range of applications requiring reliable, non-volatile memory with battery backup capability:
- Portable and battery-powered devices
- Industrial control systems
- Telecommunications equipment
- Medical instrumentation
- Automotive electronics
- Data loggers and measurement equipment
- Embedded systems requiring fast, non-volatile memory
- Cache memory applications
Electrical Characteristics
Absolute Maximum Ratings
- Supply Voltage (VCC): -0.5V to +4.6V
- Input Voltage (VI): -0.5V to VCC +0.5V
- Output Voltage (VO): -0.5V to VCC +0.5V
- Operating Temperature: -40°C to +85°C
- Storage Temperature: -65°C to +150°C
Recommended Operating Conditions
- Supply Voltage (VCC): 2.7V to 3.6V
- Input High Voltage (VIH): 2.0V to VCC +0.3V
- Input Low Voltage (VIL): -0.3V to 0.8V
- Operating Temperature: -40°C to +85°C
DC Characteristics
- Active Current (ICC): 3mA typical at 70ns access time
- Standby Current (ISB): 1μA typical (CS1 ≥ VCC -0.2V, CS2 ≤ 0.2V)
- Input Leakage Current (II): ±1μA maximum
- Output Leakage Current (IOZ): ±1μA maximum
AC Characteristics
- Access Time (tAA): 70ns/85ns maximum
- Chip Select to Output Delay (tACS): 70ns/85ns maximum
- Output Enable to Output Valid (tOE): 25ns maximum
- Write Pulse Width (tWP): 60ns minimum
- Data Setup Time (tDS): 30ns minimum
- Data Hold Time (tDH): 0ns minimum
Package Information
44-Pin TSOPII Package (TTP-44DB)
- Package Type: Plastic Thin Small Outline Package (TSOPII)
- Pin Count: 44
- Pitch: 0.8mm
- Package Width: 10.16mm (400 mil)
- Package Height: 1.2mm maximum
- Lead Style: Normal-bend type
- Moisture Sensitivity Level (MSL): 3 (standard for TSOP packages)
Pin Configuration (Top View)
The 44-pin TSOPII package has the following pin arrangement:
| Pin Number | Pin Name | Function |
|---|---|---|
| 1-5, 20-23, 38-44 | A0-A17 | Address Inputs |
| 6, 37 | CS1, CS2 | Chip Select Inputs |
| 7-10, 13-16, 28-35 | I/O0-I/O15 | Data Input/Output |
| 11, 12, 17, 18, 36 | VCC | Power Supply |
| 19, 27 | VSS | Ground |
| 24 | WE | Write Enable |
| 25 | OE | Output Enable |
| 26 | LB | Lower Byte Select |
| 27 | UB | Upper Byte Select |
Functional Description
The HM62V16256B is a fully static RAM that does not require clock signals or refresh cycles. The memory array is organized as 262,144 words of 16 bits each. The device features two chip select inputs (CS1 and CS2) that allow for easy memory expansion and power management. When both chip selects are inactive, the device enters a low-power standby mode.
The byte control function (UB and LB) allows for individual access to the upper and lower bytes of the 16-bit word. The output enable (OE) controls the three-state outputs, while the write enable (WE) controls write operations. The device offers equal access and cycle times, providing consistent performance for both read and write operations.
