Overview
The M48T35-70PC1, produced by STMicroelectronics, is a highly integrated 32 Kb x 8 non-volatile static RAM and real-time clock solution. This monolithic chip is part of the TIMEKEEPER® family and is available in two special packages: the 28-pin, 600 mil DIP CAPHAT™ package and the 28-pin, 330 mil SOIC package. The CAPHAT™ package includes a quartz crystal and a long life lithium button cell in a single package, while the SOIC package allows for a separate SNAPHAT® housing containing the battery and crystal to be mounted after the surface mount process. This design ensures protection of the battery and crystal from high temperatures during device surface-mounting. The M48T35-70PC1 is pin and function compatible with JEDEC standard 32 Kb x 8 SRAMs and can easily fit into many ROM, EPROM, and EEPROM sockets, providing non-volatility without special WRITE timing or limitations on the number of WRITEs.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Memory Organization | 32 Kb x 8 | |
| Access Time | 70 ns | ns |
| Operating Voltage | 4.75 to 5.5 V (M48T35), 4.5 to 5.5 V (M48T35Y) | V |
| Power-Fail Deselect Voltage (VPFD) | 4.5 V ≤ VPFD ≤ 4.75 V (M48T35), 4.2 V ≤ VPFD ≤ 4.5 V (M48T35Y) | V |
| Battery Backup Switchover Voltage (VSO) | Below VPFD (min) | V |
| Package Types | 28-pin DIP CAPHAT™, 28-pin SOIC with SNAPHAT® housing | |
| Temperature Range | –40 to 85 °C | °C |
| Data Retention | At least 7 years with VCC below VSO | years |
Key Features
- Integrated ultra-low power SRAM, real-time clock, power-fail control circuit, and battery.
- BYTEWIDE™ RAM-like clock access with BCD coded year, month, day, date, hours, minutes, and seconds.
- Frequency test output for real-time clock.
- Automatic power-fail chip deselect and WRITE protection.
- Self-contained battery and crystal in the CAPHAT™ DIP package or separate SNAPHAT® housing for SOIC package.
- Pin and function compatible with JEDEC standard 32 Kb x 8 SRAMs.
- RoHS compliant – Lead-free second level interconnect.
Applications
- Embedded systems requiring non-volatile memory and real-time clock functionality.
- Industrial control systems where data integrity and timekeeping are critical.
- Automotive systems needing robust and reliable memory and clock solutions.
- Medical devices requiring precise timekeeping and non-volatile data storage.
- Consumer electronics such as set-top boxes, routers, and other network devices.
Q & A
- What is the memory organization of the M48T35-70PC1?
The M48T35-70PC1 has a memory organization of 32 Kb x 8.
- What are the operating voltage ranges for the M48T35 and M48T35Y?
The operating voltage ranges are 4.75 to 5.5 V for the M48T35 and 4.5 to 5.5 V for the M48T35Y.
- What is the purpose of the CAPHAT™ and SNAPHAT® packages?
The CAPHAT™ package includes a quartz crystal and a lithium button cell in a single package, while the SNAPHAT® housing contains the battery and crystal and is mounted on top of the SOIC package after surface mounting to protect the components from high temperatures.
- How does the power-fail protection work in the M48T35-70PC1?
The device has a power-fail detect circuit that write protects the SRAM when VCC falls within the VPFD window and switches to battery power when VCC drops below VSO, ensuring data integrity.
- What is the data retention period when VCC is below VSO?
The data retention period is at least 7 years when VCC is below VSO).
- Is the M48T35-70PC1 compatible with standard SRAMs?
Yes, it is pin and function compatible with JEDEC standard 32 Kb x 8 SRAMs).
- What is the temperature range for the M48T35-70PC1?
The operating temperature range is –40 to 85 °C).
- Does the M48T35-70PC1 support BCD coded timekeeping?
Yes, it supports BCD coded year, month, day, date, hours, minutes, and seconds).
- Is the M48T35-70PC1 RoHS compliant?
Yes, it is RoHS compliant with lead-free second level interconnect).
- What are some typical applications for the M48T35-70PC1?
Typical applications include embedded systems, industrial control systems, automotive systems, medical devices, and consumer electronics).
