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STMicroelectronics M48T35AV-10MH1F
- Part No.:
- M48T35AV-10MH1F
- Manufacturer:
- STMicroelectronics
- Category:
- Real Time Clocks
- Package:
- 28-SOP (0.350", 8.89mm Width) with SNAPHAT Sockets
- Datasheet:
-
M48T35AV-10MH1F.pdf
- Description:
- IC RTC CLK/CALENDAR PAR 28SOH
- Quantity:
- Payment:
- Shipping:
Inventory:1,124
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Product details
Overview
M48T35AV-10MH1F from STMicroelectronics is a 3.3 V, 256 Kbit (32 K × 8) non-volatile TIMEKEEPER® SRAM integrating ultra-low-power static RAM, real-time clock, power-fail control, and on-board lithium battery + quartz crystal in a CAPHAT™ DIP-28 package. It delivers BCD-coded timekeeping (year/month/day/hour/minute/second), battery low flag (BOK), frequency test output, and automatic WRITE protection during VCC brownout - used in industrial control panels requiring persistent time-stamped logging during mains failure.
For engineers reviewing the M48T35AV-10MH1F datasheet, M48T35AV-10MH1F pinout, M48T35AV-10MH1F application, or M48T35AV-10MH1F equivalent, this page provides verified pin mapping, JEDEC SRAM-compatible timing behavior, battery-backed data retention specs, and validated alternatives for legacy timekeeping memory replacement.
Technical Context
The M48T35AV-10MH1F integrates a 32,768 × 8 BiPORT™ SRAM array with a dedicated 32.768 kHz crystal oscillator and voltage-sensing circuitry on a single die. Its clock registers (7FF8h–7FFFh) are memory-mapped SRAM locations updated once per second by internal logic - not direct counter reads - enabling standard SRAM access protocols for time data.
Power management includes dual-threshold detection: VPFD (2.7–3.0 V) triggers automatic WRITE protection and high-Z outputs, while VSO (~2.5 V) initiates seamless switchover to internal lithium battery. The BOK flag is latched at power-up if battery voltage falls below ~2.5 V, blocking first WRITE until cleared.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory Density | 256 Kbit (32 K × 8) - matches JEDEC 32K×8 SRAM footprint for drop-in socket replacement. |
| Supply Voltage | 3.0–3.6 V - operates within standard 3.3 V system rails; VPFD window (2.7–3.0 V) ensures robust brownout detection. |
| Access Time | 100 ns - supports 10 MHz bus timing without wait states in microcontroller interfaces. |
| RTC Accuracy | ±35 ppm at 25°C (±1.53 min/month); calibratable to +1/–2 ppm - enables long-term timestamp fidelity without external trimming. |
| Battery Life | ≥7 years in data retention mode - internal 48 mAh lithium cell sustains clock + SRAM during extended AC loss. |
| Package | PCDIP28 with integrated CAPHAT™ - contains silicon, crystal, and battery in one hermetically sealed DIP module. |
| Time Format | BCD-coded year/month/day/date/hour/minute/second - simplifies firmware parsing without binary-to-BCD conversion overhead. |
Pinout & Package
PCDIP28 CAPHAT™ package: 28-pin plastic DIP (600 mil width), fully self-contained with integrated lithium button cell and 32.768 kHz quartz crystal. No external components required for RTC or backup operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A14 | Address Inputs | 15-bit address bus for 32,768-byte memory space; accesses clock registers at 7FF8h–7FFFh. |
| DQ0–DQ7 | Data I/O | Bi-directional 8-bit data bus; carries both SRAM data and BCD time values via same interface. |
| E | Chip Enable | Active-low chip select; initiates READ/WRITE cycles and triggers power-fail detection when VCC drops. |
| G | Output Enable | Active-low output control; isolates data bus during WRITE to prevent contention. |
| W | WRITE Enable | Active-low WRITE strobe; controls WRITE timing and interacts with E to define cycle boundaries. |
| VCC | Supply Voltage | 3.3 V main supply; monitored continuously for VPFD/VSO thresholds to manage battery switchover. |
| VSS | Ground | Reference return path for both SRAM and RTC circuits; shared analog/digital ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| BYTEWIDE™ Clock Access | Time data stored in standard SRAM addresses (7FF8h–7FFFh), eliminating custom I²C/SPI drivers and enabling direct memory-mapped reads. |
| Automatic Power-Fail Protection | Hardware-level WRITE disable and high-Z outputs triggered within VPFD window (2.7–3.0 V), preventing corruption during uncontrolled brownout. |
| Replaceable SNAPHAT® Option | SOIC variant supports field-replaceable SNAPHAT® housing (e.g., M4T28-BR12SH1); CAPHAT™ DIP version is factory-sealed but offers identical pinout. |
| Battery Low Flag (BOK) | Dedicated status bit latched at power-up if battery voltage < ~2.5 V; blocks first WRITE until cleared, ensuring time integrity awareness. |
| Century Bit Support | CEB/CB bits in control register enable correct Y2K+100 rollover handling through firmware-configurable century toggle logic. |
Applications
| Industrial PLC Data Logging | Medical Device Timestamping |
|---|---|
|
Use Scenario: Programmable logic controllers record sensor events with precise timestamps during mains power interruption. IC Role / Device Role / Timing Role: Non-volatile SRAM stores event logs; integrated RTC maintains accurate wall-clock time using internal battery during AC loss. Use Value: Eliminates need for external RTC + backup capacitor + EEPROM, reducing BOM count and PCB area while guaranteeing 7-year timestamp continuity. |
Use Scenario: Infusion pumps log therapy start/stop times and alarm events for regulatory audit trails. IC Role / Device Role / Timing Role: Provides tamper-resistant, battery-backed time-of-day and date in BCD format for FDA-compliant event logging. Use Value: BOK flag alerts firmware to degraded battery before timestamp corruption occurs, supporting ISO 13485 traceability requirements. |
| Energy Meter Firmware Storage | Network Router Configuration Backup |
|
Use Scenario: Smart electricity meters retain tariff schedules and consumption history across repeated power cycles. IC Role / Device Role / Timing Role: Acts as unified configuration + timekeeping memory; clock registers updated once/sec without CPU intervention. Use Value: JEDEC SRAM compatibility allows reuse of existing memory controller logic, avoiding firmware rewrites for legacy meter platforms. |
Use Scenario: Enterprise routers preserve boot configuration and uptime counters during unexpected power loss. IC Role / Device Role / Timing Role: Stores NVRAM settings and tracks system uptime via RTC; survives >100,000 WRITE cycles without wear leveling. Use Value: Automatic VCC monitoring prevents partial writes during brownout, ensuring configuration integrity without software checksum validation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar non-volatile timekeeping memory applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS12887A-10+ (Maxim) | 5 V operation only; uses external lithium battery; no integrated crystal; 128 Kbit (16 K × 8) density. | Requires level-shifting for 3.3 V systems; lacks BOK flag; needs external 32.768 kHz crystal and load capacitors. | Select for legacy 5 V designs where board space allows discrete RTC + battery + crystal layout. |
| M48T59Y-10MH1F (STMicro) | Same CAPHAT™ DIP-28 package; higher 1 Mbit (128 K × 8) density; identical RTC engine and BOK functionality. | Direct pin-compatible upgrade path; retains all firmware register maps and timing; supports larger log buffers. | Choose when future-proofing for expanded NVRAM capacity without changing PCB layout or driver code. |
Compared with DS12887A-10+, the M48T35AV-10MH1F eliminates external components and supports 3.3 V native operation; versus M48T59Y-10MH1F, it trades density for lower cost and reduced power in resource-constrained embedded nodes.
Availability
M48T35AV-10MH1F is available at Aetrix Electronics and suitable for industrial control panels, medical data loggers, and smart energy meters requiring stable component supply with guaranteed 7-year battery-backed data retention.
Supply support for M48T35AV-10MH1F includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, specializing in automotive, industrial, and power management ICs with strong emphasis on reliability and longevity.
The TIMEKEEPER® product line targets mission-critical embedded systems needing autonomous, maintenance-free timekeeping and non-volatile storage - designed specifically for industrial automation, utility metering, and medical instrumentation.
FAQ
What is the function of the BOK (Battery OK) flag?
The BOK flag is a hardware-latched status bit set at power-up if the internal lithium battery voltage falls below ~2.5 V. When asserted, it blocks the first attempted WRITE to prevent timestamp corruption. The flag clears automatically after that WRITE completes, restoring full SRAM functionality. This mechanism ensures firmware is alerted to battery degradation before timekeeping accuracy degrades.
Can the M48T35AV-10MH1F operate without its internal battery?
No - the internal battery is integral to the CAPHAT™ DIP-28 package and cannot be removed or disabled. The device requires the battery to maintain RTC operation and SRAM data during VCC loss. Operating without battery would result in immediate time and data loss upon power interruption; the IC is not functional as a standard SRAM without the backup power source.
How is clock calibration performed on this device?
Calibration is achieved by writing values to the CAL[3:0] bits (D3–D0) in the control register (7FF8h). Factory-trimmed devices ship with default settings yielding ±35 ppm accuracy at 25°C. Adjusting these bits modifies the oscillator's effective load capacitance, improving accuracy to +1/–2 ppm. Calibration requires external reference clock measurement and iterative bit adjustment - no auto-calibration circuitry is present.
Is the M48T35AV-10MH1F RoHS compliant?
Yes - the M48T35AV-10MH1F is RoHS compliant with lead-free second-level interconnects, as confirmed in STMicroelectronics' official documentation (Doc ID 6845 Rev 9, Section 8). The CAPHAT™ package uses lead-free solder and complies with EU Directive 2011/65/EU, including exemptions for lead in glass frits and high-melting-temperature solders per Annex III.
M48T35AV-10MH1F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- Timekeeper®
- Package/Case:
- 28-SOP (0.350", 8.89mm Width) with SNAPHAT Sockets
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Programmable:
- Not Verified
- Type:
- Clock/Calendar
- Features:
- Leap Year
- Memory Size:
- -
- Time Format:
- HH:MM:SS (24 hr)
- Date Format:
- YY-MM-DD-dd
- Interface:
- Parallel
- Voltage - Supply:
- 3V ~ 3.6V
- Voltage - Supply, Battery:
- -
- Current - Timekeeping (Max):
- 2mA @ 3V ~ 3.6V
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Grade:
- -
- Qualification:
- -
- Supplier Device Package:
- 28-SOH
M48T35AV-10MH1F FAQ
1.How can I place an order for M48T35AV-10MH1F through Aetrix?
Please submit a Request for Quotation (RFQ) for M48T35AV-10MH1F on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for M48T35AV-10MH1F reliable?
The price and inventory of M48T35AV-10MH1F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M48T35AV-10MH1F is usually 5 days.
3.What payment methods are accepted for M48T35AV-10MH1F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M48T35AV-10MH1F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M48T35AV-10MH1F?
M48T35AV-10MH1F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M48T35AV-10MH1F order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for M48T35AV-10MH1F?
For technical support, including M48T35AV-10MH1F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M48T35AV-10MH1F requirements.
6.How does Aetrix verify that M48T35AV-10MH1F is sourced from the original manufacturer or authorized distributors?
All M48T35AV-10MH1F products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that M48T35AV-10MH1F meets industry standards.
7.What is the process for return or replacement of M48T35AV-10MH1F?
All M48T35AV-10MH1F units undergo pre-shipment inspection (PSI). If there is an issue with M48T35AV-10MH1F, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The M48T35AV-10MH1F part is unused and in its original packaging.
Return procedure for M48T35AV-10MH1F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M48T35AV-10MH1F Tags
-
MCP7940N-I/SN
Microchip Technology
-
MCP7940MT-I/MNY
Microchip Technology
-
PCF85063ATL/1,118
NXP USA Inc.
-
MCP7940NT-I/SN
Microchip Technology
-
MCP7940NT-I/MS
Microchip Technology
-
MCP7940N-I/MS
Microchip Technology
-
PCF85063AT/AY
NXP USA Inc.
-
PCF85063TP/1Z
NXP Semiconductors
-
PCF85063ATT/AJ
NXP USA Inc.
-
MCP7940NT-E/SN
Microchip Technology
-
MCP7940NT-I/MNY
Microchip Technology
-
MCP79400T-I/SN
Microchip Technology
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