M48T02-70PC1 - 5V 16Kbit TimeKeeper SRAM RTC | STMicroelectronics
MPN: M48T02-70PC1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $17.55 | $17.55 |
| 10 | $16.2 | $162.00 |
| 100 | $14.8 | $1,480.00 |
| 500 | $13.5 | $6,750.00 |
| 1,000 | $12.4 | $12,400.00 |
M48T02-70PC1 Overview
A real-time clock (RTC) is a dedicated integrated circuit that tracks seconds, minutes, hours, days, dates, months, and years with automatic leap-year compensation. The M48T02 family combines RTC functionality with a non-volatile static RAM, forming a TIMEKEEPER (utility) hybrid module that retains data and time without external backup hardware. Such modules sit in the system hierarchy as Memory ICs > Non-volatile SRAM > RTC + SRAM combination modules, and are widely used when a host MCU needs both configuration storage and wall-clock time across power cycles.
Key features include a parallel address/data bus interface (multiplexed to match a standard 2K x 8 SRAM pinout), BCD-formatted clock registers, automatic leap-year correction through 2099, programmable square-wave output, and built-in power-fail write protection that locks the SRAM when VCC drops below the lithium backup threshold. The TIMEKEEPER (utility) architecture means the user simply reads and writes the SRAM address space - clock information is mapped into the upper RAM addresses - so existing SRAM software drivers work with no modification.
Typical applications include industrial controllers, point-of-sale terminals, data loggers, metering equipment, security and access-control systems, and any embedded design that needs both battery-backed parameter memory and a calendar-clock. Designers should observe the VCC power-up ramp specifications in the datasheet to ensure the battery switchover circuit latches correctly, and avoid applying external bias to the backup cell. The through-hole DIP-24 module remains popular for legacy boards, prototypes, and field-replaceable designs where socketed parts are desirable.
Drop-in alternatives for M48T02-70PC1 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with M48T02-70PC1 (same form factor and footprint) — differing in Memory Size, Operating Temperature, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
M48T02-150PC1
✅ Drop-In📋 Reference alternative (not in catalog)
M48T12-70PC1
✅ Drop-In📋 Reference alternative (not in catalog)
M48Z02-70PC1
✅ Drop-In📋 Reference alternative (not in catalog)
M48T02-70PC1 Maximum Ratings & Electrical Characteristics
| Memory Type | Non-volatile TimeKeeper SRAM (NV-SRAM + RTC) |
| Memory Size | 16 Kbit (2 Kb x 8) |
| Interface | Parallel (asynchronous) |
| Access Time | 70 ns |
| Operating Voltage (VCC) | 5.0 V (4.75 V to 5.5 V) |
| Backup Cell | Integrated lithium coin cell (internal) |
| Data Retention | Minimum 10 years without VCC |
| Clock Functions | Sec/Min/Hr/Day/Date/Month/Year, BCD format, leap-year compensation to 2099 |
| Package | 24-pin DIP Module (PC1), 0.600 inch / 15.24 mm row spacing |
| Pinout Compatibility | Pin and function compatible with JEDEC 2 Kb x 8 SRAM |
| Power-Fail Write Protection | Yes (internal, battery-backed) |
| Programmable Output | Square-wave output (selectable) |
| Operating Temperature | 0C to +70C (commercial grade) |
| Mounting Type | Through-Hole (DIP Module) |
M48T02-70PC1 Pin Configuration
| Pin 1 | A0 — Address input A0 (LSB) |
| Pin 2 | A1 — Address input A1 |
| Pin 3 | A2 — Address input A2 |
| Pin 4 | A3 — Address input A3 |
| Pin 5 | A4 — Address input A4 |
| Pin 6 | A5 — Address input A5 |
| Pin 7 | A6 — Address input A6 |
| Pin 8 | A7 — Address input A7 |
| Pin 9 | DQ0 — Data I/O bit 0 |
| Pin 10 | DQ1 — Data I/O bit 1 |
| Pin 11 | A8 — Address input A8 |
| Pin 12 | A9 — Address input A9 |
| Pin 13 | A10 — Address input A10 |
| Pin 14 | A11 — Address input A11 (MSB) |
| Pin 15 | /CE1 — Chip Enable 1 (active low) |
| Pin 16 | CE2 — Chip Enable 2 (active high) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | GND — Ground |
| Pin 19 | DQ7 — Data I/O bit 7 |
| Pin 20 | DQ6 — Data I/O bit 6 |
| Pin 21 | DQ5 — Data I/O bit 5 |
| Pin 22 | DQ4 — Data I/O bit 4 |
| Pin 23 | DQ3 — Data I/O bit 3 |
| Pin 24 | DQ2 — Data I/O bit 2 |
Typical Applications
M48T02-70PC1 is suitable for 7 applications: Industrial PLC Parameter Backup, Point-of-Sale (POS) Terminal, Data Logger / Environmental Recorder, Utility Metering (Electricity / Water / Gas), Security and Access Control Panel, Medical Device Configuration Memory, Vending Machine / Kiosk Controller.
Industrial PLC Parameter Backup
The M48T02-70PC1 fits industrial PLC designs because its 2 Kb x 8 non-volatile SRAM stores PLC ladder-logic parameters, setpoints, and runtime counters across power cycles, while the on-board RTC timestamps alarms and event logs. With 70 ns access time the part interfaces directly to 8051-class host CPUs without wait states, and the JEDEC-standard 2K x 8 SRAM pinout lets engineers drop it onto existing SRAM footprints. The integrated lithium cell delivers 10-year retention per the ST datasheet, eliminating the need for an external supercapacitor or battery and simplifying UL/CE certification for long-life industrial equipment.
Recommended
Point-of-Sale (POS) Terminal
POS terminals need to retain transaction logs, configuration, and the current date/time across accidental power loss, which the M48T02-70PC1 handles directly through its battery-backed SRAM and RTC. The 70 ns access time supports the typical 8-bit host bus of an entry-level POS terminal, and the through-hole DIP-24 package suits socketed designs where field replacement of the timekeeping module is desirable. The leap-year-corrected calendar through 2099 ensures accurate date stamping for fiscal records without firmware intervention, and the 10-year lithium retention exceeds typical POS refresh cycles.
Recommended
Data Logger / Environmental Recorder
The M48T02-70PC1 stores the most recent configuration and provides a hardware time-stamp channel for battery-powered data loggers measuring temperature, humidity, or vibration. Its 5 V VCC and very low battery-only standby current let the system sleep for long intervals while preserving accurate wall-clock time and recorded parameter buffers. The parallel bus simplifies write cycles during burst sampling, and the internal lithium cell means designers do not need to budget external battery space on small-form-factor logger PCBs. RTC second/minute granularity is sufficient for hourly or daily sample logging.
Recommended
Utility Metering (Electricity / Water / Gas)
Electricity, water, and gas meters use the M48T02-70PC1 to keep cumulative consumption registers and tariff schedules intact during power-line brownouts or battery replacement, while supplying a precise calendar for time-of-use billing windows. The integrated lithium cell provides the long data-retention period specified in metering certification tests, and the 70 ns SRAM access time is plenty for the slow microcontroller typically used in meter designs. Because the part is pin-compatible with a JEDEC 2K x 8 SRAM, retrofitting an existing meter PCB from discrete RTC + SRAM to the M48T02 is a near-zero-effort migration.
Recommended
Security and Access Control Panel
Access-control panels store authorized user lists, event logs, and the current schedule in the M48T02-70PC1's 2 Kb x 8 non-volatile SRAM, while the RTC drives time-stamping of door events and lockout windows. The internal lithium backup ensures credentials survive facility power loss without an external supercapacitor, simplifying enclosure design and reducing BOM. The through-hole DIP Module package is easy to service in the field, which matters for commercial security installations where downtime translates directly to customer impact. 70 ns access matches typical 8-bit access-controller MCUs.
Recommended
Medical Device Configuration Memory
In medical instrumentation, the M48T02-70PC1 retains calibration constants, patient log entries, and device configuration across power cycles, while the integrated RTC provides a tamper-resistant real-time clock for audit trails. The internal lithium cell removes the service burden of replacing an external backup battery, which is critical in devices intended for multi-year deployment. The 70 ns access time is more than adequate for the slow, low-noise MCUs common in medical designs, and the JEDEC SRAM footprint lets engineers repurpose legacy calibration-board layouts. Pin-and-function compatibility with standard 2K x 8 SRAM simplifies FDA documentation by referencing an industry-standard interface.
Recommended
Vending Machine / Kiosk Controller
Vending machines and unattended kiosks keep inventory counts, pricing tables, and the last-known state of the bill validator in the M48T02-70PC1's non-volatile SRAM, while the RTC drives time-of-day promotions and scheduled restocking reports. The internal lithium cell ensures no service call is needed if the kiosk is unplugged for weeks, and the 70 ns access time pairs cleanly with 8051-class kiosk controllers. The DIP Module package simplifies service technician swaps because the part is socketable, and the 10-year data retention comfortably outlasts the typical service interval.
Recommended
Recommended Products Summary
Engineering reference data for M48T02-70PC1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | M48T02-150PC1 | M48T12-70PC1 | M48Z02-70PC1 |
|---|---|---|---|---|
| Brand | STMicroelectronics | STMicroelectronics | STMicroelectronics | STMicroelectronics |
| Package | 24-pin DIP Module (PC1) | 24-pin DIP Module (PC1) - same | 24-pin DIP Module (PC1) - same | 24-pin DIP Module (PC1) - same |
| Memory Density | 16 Kbit (2 Kb x 8) | 16 Kbit (2 Kb x 8) | 16 Kbit (2 Kb x 8) | 16 Kbit (2 Kb x 8) |
| Access Time | 70 ns | 150 ns (+80 ns slower) | 70 ns (same) | 70 ns (same) |
| Operating Voltage | 5.0 V (4.75 V to 5.5 V) | 5.0 V | 5.0 V | 5.0 V |
| Data Retention | 10 years minimum | 10 years minimum | 10 years minimum | 10 years minimum |
| Integrated Backup Cell | Yes (internal lithium coin cell) | Yes (internal lithium) | Yes (internal lithium) | Yes (internal lithium) |
| Interface | Parallel (JEDEC 2K x 8 SRAM compatible) | Parallel (JEDEC 2K x 8 SRAM compatible) | Parallel (JEDEC 2K x 8 SRAM compatible) | Parallel (JEDEC 2K x 8 SRAM compatible) |
| Operating Temperature | 0C to +70C (commercial) | 0C to +70C (commercial) | 0C to +70C (commercial) | 0C to +70C (commercial) |
| Lifecycle Status | Active | Active | Active | Active |
Key Differentiators
- 70 ns access time vs 150 ns for the slower -150 speed grade (vs M48T02-150PC1)
- Drop-in same-footprint same-density alternative (vs M48Z02-70PC1)
- Integrated lithium backup with 10-year data retention (vs M48T12-70PC1)
Design Notes
The M48T02-70PC1 operates from a single 5.0 V VCC rail and draws typical operating current from VCC during SRAM reads and writes; during power-down the internal lithium cell takes over clock and SRAM retention. VCC ramp-up time must respect the datasheet specification to ensure the power-fail switchover logic latches correctly - too-fast or too-slow VCC rises can cause SRAM corruption or premature battery drain. Place a 0.1 uF decoupling capacitor close to the VCC pin and follow ST's recommended power-rail sequencing for designs where VCC may collapse briefly during sleep/wake cycles.
The 24-pin DIP Module has a 0.600 inch / 15.24 mm row spacing and is intended for through-hole soldering on a standard DIP-24 land pattern, ideally socketed for field serviceability. Address and data lines should be length-matched within a few millimetres to avoid skew on the parallel bus at 70 ns access cycles, and the /CE1, /OE, and /WE control lines should be guarded with 10 kohm pull-ups so the chip does not enter a random state at power-up. Keep switching DC-DC nodes and high-current traces physically separated from the address/data bus to limit injected noise.
Do not attempt to recharge, replace, or externally bias the internal lithium cell - the backup cell is sealed and any external voltage on the backup pin will permanently damage the device. Do not place the M48T02-70PC1 above 70C ambient for sustained periods, as elevated temperature rapidly reduces the lithium cell's effective capacity and shortens the 10-year retention figure. Ensure firmware reads time using BCD conversion per the ST datasheet, not as raw binary, or the calendar registers will be misinterpreted. Finally, when migrating designs to the M48Z02-70PC1, verify the chip-enable polarity matches the host MCU's external memory interface, because the M48Z02 family uses a slightly different CE configuration.
Compliance Information
M48T02-70PC1 contains an internal lithium coin cell; this typically places the DIP Module variant outside RoHS scope under the battery-exemption rules historically applied in the EU. Confirm exact compliance status with the manufacturer datasheet or your distributor. The M48T02 family is not AEC-Q100 qualified - it targets industrial and commercial temperature grades only.
