DS1248W-120+

Overview

The DS1248W-120+ is a nonvolatile SRAM integrated with a real-time clock, manufactured by Analog Devices Inc./Maxim Integrated. It provides 128K x 8 bits of memory and operates within a voltage range of 2.97V to 3.63V. The device utilizes a parallel interface and features a phantom clock mechanism for timekeeping without dedicated pins. It includes an embedded lithium energy cell that maintains calendar operation and retains RAM data when VCC is absent. The component supports automatic leap year compensation up to the year 2100 and ensures over 10 years of data retention in battery-backup mode.

Feature Summary

• Integrates 128K x 8 NV SRAM with a built-in real-time clock tracking hundredths of seconds through years.
• Features a phantom clock interface using serial bit stream pattern recognition on DQ0 for time register access.
• Includes an embedded lithium energy source electrically disconnected until first power application to preserve freshness.
• Provides automatic leap year compensation valid up to 2100 and write protection during power failures.

Applications

• Direct replacement for volatile static RAM or EEPROM in systems requiring persistent timekeeping.
• Embedded applications needing nonvolatile data storage alongside calendar functions.
• Industrial equipment requiring reliable time-stamping and data retention during power outages.

Procurement Notes

Verify the specific ordering suffix to confirm package type and temperature grade. The 'W' suffix indicates a 3.3V supply version in a 32-pin EDIP package. Confirm RoHS compliance status via the '+' suffix designation. Ensure compatibility with existing board layouts designed for standard 32-pin DIP modules. Check for any recent product change notices regarding manufacturing updates.

Selection Notes

Select this model for designs requiring 3.3V logic levels and a 120ns access time. The 32-pin EDIP package is suitable for through-hole mounting. Compare against the DS1248Y-70+ if a 5V supply or faster 70ns speed is required. Consider the DS1248WP-120+ variant if surface-mount assembly with a separate PowerCap module is preferred. Verify operating temperature requirements against the commercial 0°C to +70°C range specified for this part number.

Part Context

This component belongs to the DS1248 series of nonvolatile SRAMs with phantom clocks. It is pin-for-pin compatible with the DS1244P and DS1251P devices. The series offers various voltage options (3.3V and 5V) and speed grades (70ns and 120ns). The DS1248W-120+ specifically targets 3.3V applications with a slower access time compared to the Y-70 variants.

Replacement Considerations

Pin-for-pin compatible substitutes include the DS1244P and DS1251P families. For 5V applications, the DS1248Y-70+ serves as a higher-speed alternative. Surface-mount equivalents are available in the PowerCap module format, such as the DS1248WP-120+. Ensure voltage levels and access times match system requirements when selecting replacements.