MCP79510T-I/MS - SPI RTCC 1Kb EE 64B SRAM | Microchip
MPN: MCP79510T-I/MS ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.92 | $5.92 |
| 10 | $5.4 | $54.00 |
| 100 | $4.78 | $478.00 |
| 500 | $4.21 | $2,105.00 |
| 1,000 | $3.72 | $3,720.00 |
| 2,500 | $3.31 | $8,275.00 |
MCP79510T-I/MS Overview
A Real-Time Clock (RTC) is a dedicated integrated circuit that maintains accurate time and date information independently of the host processor, typically counting seconds, minutes, hours, days, months and years. RTCs sit beneath clock & timing ICs in the broader semiconductor hierarchy: RTC -> clock & timing -> timing IC -> power management/interface IC. Battery-backed RTCs retain time during main power loss, making them essential for any system that must log events with wall-clock timestamps across power cycles.
Key features of the MCP79510T-I/MS include digital trimming for improved long-term accuracy, software-controlled block write-protect for the EEPROM, a power-fail timestamp that captures the moment of main power loss, and a 64-byte SRAM that retains user data during backup. The integrated battery switchover automatically routes power from an external backup cell when VCC drops below the threshold, eliminating external MOSFETs and comparator circuits. Its event-detection input and configurable alarm provide a flexible wake-up mechanism for low-duty-cycle battery applications.
The MCP79510 family shares a common register map and SPI command set across the MCP79510, MCP79511, MCP79512 and MCP79520/21/22 variants, allowing firmware reuse. The MCP79510T-I/MS is the 1 Kbit EEPROM member with 64 B SRAM, while the MCP79511/12 double the EEPROM and SRAM, and the MCP79520/21/22 add a unique 64-bit EUI-48/EUI-64 MAC ID for network-connected designs. Designers should consult the Microchip MCP79510 product page and the family datasheet (DS22078D) for the precise register differences.
Typical applications include industrial data loggers, smart meters, medical monitoring devices, point-of-sale terminals, security alarm panels, and IoT edge nodes. The wide operating voltage and integrated battery switchover make the part drop-in compatible with both regulated 3.3V rails and direct Li-ion battery stacks. For designs that need higher accuracy, the digital trimming register allows sub-ppm adjustment against a known reference such as a GPS-disciplined oscillator.
When designing with the MCP79510T-I/MS, place a 1 uF to 10 uF decoupling capacitor close to VCC and route the 32.768 kHz crystal traces symmetrically to minimize load-capacitance mismatch. The backup battery input should be decoupled with a small ceramic cap to absorb inrush during switchover; do not exceed the absolute maximum VCC or BAT voltage or the on-chip battery switchover circuit will be damaged.
Drop-in alternatives for MCP79510T-I/MS — 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 MCP79510T-I/MS (same form factor and footprint) — differing in Interface, Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MCP79511T-I/MS
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$0.99 / Unit
View Datasheet →MCP79512T-I/MS
✅ Drop-In📋 Reference alternative (not in catalog)
MCP79520T-I/MS
✅ Drop-In📋 Reference alternative (not in catalog)
MCP79522T-I/MS
✅ Drop-In📋 Reference alternative (not in catalog)
MCP79510T-I/MS Specifications
| Function | Real-Time Clock / Calendar (RTCC) |
| Interface | SPI (4-wire, mode 0/3) |
| Supply Voltage (VCC) | 1.8 V to 3.6 V |
| Backup Battery Voltage (VBAT) | 1.3 V to 3.6 V |
| Operating Temperature | -40 C to +85 C (Industrial) |
| EEPROM Memory | 1 Kbit (128 x 8) |
| SRAM (Battery-Backed) | 64 bytes |
| Timekeeper Registers | Bcd seconds, minutes, hours, day, date, month, year, century |
| On-Chip Oscillator | 32.768 kHz, digital trimming |
| Battery Switchover | Integrated, automatic |
| Alarms / Event Input | Configurable alarm and event-detection input |
| Write Protection | Software block write-protect for EEPROM |
| Package | 10-MSOP (3.00 mm width) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (Unlimited, per JEDEC J-STD-020) |
| RoHS Status | Compliant |
MCP79510T-I/MS Pin Configuration
| Pin 1 | VCC — Primary supply voltage (1.8 V to 3.6 V) |
| Pin 2 | VBAT — Backup battery input (1.3 V to 3.6 V) |
| Pin 3 | NC — Not connected (per datasheet) |
| Pin 4 | X1 — 32.768 kHz crystal input |
| Pin 5 | X2 — 32.768 kHz crystal output |
| Pin 6 | MFP — Multi-function pin (alarm / event / square-wave output) |
| Pin 7 | SO — SPI serial data output |
| Pin 8 | SI — SPI serial data input |
| Pin 9 | CS — SPI chip-select (active low) |
| Pin 10 | GND — Ground |
Typical Applications
MCP79510T-I/MS is suitable for 6 applications: Industrial Data Logger, Smart Meter / Energy Monitor, Medical Monitoring Device, Point-of-Sale Terminal, Security and Alarm Panel, IoT Edge Node / Sensor Hub.
Industrial Data Logger
The MCP79510T-I/MS fits industrial data loggers because its 1.8-3.6 V supply, 64-byte battery-backed SRAM and integrated battery switchover timestamp every record even across brownouts and main-power failures. Engineers place the part on the always-on power rail with a CR2032 backup, log events via SPI into the 1 Kbit EEPROM with software block write-protect, and use the digital trimming register to keep time within +/-2 ppm against a GPS reference. This combination eliminates external RTC supervisor circuitry, reduces BOM cost by 30-40%, and preserves audit-grade timestamps for SCADA, PLC, and remote-monitoring deployments in factory automation.
Recommended
Smart Meter / Energy Monitor
The MCP79510T-I/MS suits smart electricity, water and gas meters because its integrated battery switchover keeps wall-clock time during tamper events and AC-power outages, while the 1 Kbit EEPROM stores calibration constants, tariff schedules and tamper-event timestamps. Used with a CR2032 backup cell, the part delivers industrial -40 to +85 C operation, +72 dB PSRR-style supply-noise rejection typical of RT families, and the MFP event-detection pin can flag cover-open or magnetic-tamper events directly. Compared with discrete RTC + supervisor IC designs, this integration reduces the BOM by one IC and shrinks PCB area, which is critical for the form factor of ANSI C12.20 / IEC 62053-compliant metering modules.
Recommended
Medical Monitoring Device
The MCP79510T-I/MS fits portable medical devices such as glucose meters, pulse oximeters and infusion pumps because it provides regulatory-grade timestamps on patient measurements and medication logs from a single 1.8-3.6 V rail with a Li-ion or coin-cell backup. Its 64-byte SRAM retains the most recent sample and device state during power loss, while the 1 Kbit EEPROM can store up to 128 patient-event records with software write-protect, supporting FDA 21 CFR Part 11 audit trails. Industrial temperature operation to +85 C covers body-worn and bedside use cases without thermal derating, and the integrated switchover removes an extra supervisor IC that would otherwise consume board space and increase battery drain in wearable designs.
Recommended
Point-of-Sale Terminal
The MCP79510T-I/MS is ideal for point-of-sale (POS) terminals and payment terminals because it provides cryptographic timestamps for EMV transactions, audit logs and tax records with battery-backed retention across power cycles. The 4-wire SPI interface runs up to several MHz and shares the bus with secure EEPROMs and display controllers, while the configurable MFP pin can drive a beeper or interrupt line on scheduled events. Combined with the 10-MSOP small-footprint package, the part keeps the BOM compact and reduces the failure surface by replacing discrete RTC + supervisor + crystal load-cap designs, which is critical for PCI PTS-compliant hardware with strict reliability and tamper-detection requirements.
Recommended
Security and Alarm Panel
The MCP79510T-I/MS serves wired and wireless security/alarm panels because its event-detection input on the MFP pin can be triggered directly by a PIR sensor, glass-break detector or door switch, timestamping the event in the battery-backed SRAM with millisecond accuracy across mains-power interruptions. The integrated battery switchover preserves the schedule for arm/disarm routines during AC failure, and the EEPROM stores up to 128 event log entries with software block write-protect so installers cannot tamper with history. Industrial -40 to +85 C operation supports unheated garage and outdoor control-box installations, and the SPI bus enables simple firmware upgrades that add new alarm-tone schedules or wireless-sensor pairing codes.
Recommended
IoT Edge Node / Sensor Hub
The MCP79510T-I/MS is a strong fit for IoT edge nodes (LoRa, BLE, NB-IoT, Wi-Fi sensor hubs) where wall-clock timestamps on every telemetry packet simplify time-series ingestion and allow battery-powered devices to wake on a precise schedule. Its 1.8-3.6 V operation matches directly with coin-cell or Li-ion stacks, while the 1 Kbit EEPROM can store LoRaWAN credentials, BLE pairing keys or the last N sensor readings with software write-protect. The integrated battery switchover keeps the timekeeper running during deep-sleep wake-ups, and the MFP pin can wake the host MCU on a scheduled alarm, eliminating one external interrupt source and reducing standby current by tens of microamps for years of battery life.
Recommended
Recommended Products Summary
Engineering reference data for MCP79510T-I/MS — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MCP79511T-I/MS | MCP79512T-I/MS | MCP79520T-I/MS | MCP79522T-I/MS | M41T81SM6F |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | STMicroelectronics |
| Package | 10-MSOP | 10-MSOP - same | 10-MSOP - same | 10-MSOP - same | 10-MSOP - same | 8-SO (different footprint, not drop-in) |
| Interface | SPI (4-wire) | SPI (4-wire) - same | SPI (4-wire) - same | SPI (4-wire) - same | SPI (4-wire) - same | I2C (different) |
| EEPROM Memory | 1 Kbit | 2 Kbit | 4 Kbit | 1 Kbit | 2 Kbit | None (no integrated EEPROM) |
| Battery-Backed SRAM | 64 B | 128 B | 128 B | 64 B | 128 B | 8 B |
| Unique ID / MAC | None | None | None | EUI-48 | EUI-64 | None |
| Supply Voltage | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 2.7 V to 5.5 V (different) |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
Key Differentiators
- Integrated battery switchover removes external supervisor MOSFET and comparator (vs M41T81SM6F)
- Same 10-MSOP package and register map across the MCP7951x family (vs MCP79511T-I/MS)
- Optional EUI-48 / EUI-64 unique MAC ID member of the same family (vs MCP79520T-I/MS)
- Wider supply voltage range than many legacy RTCs (vs M41T81SM6F)
Design Notes
Place a 1 uF to 10 uF decoupling capacitor on VCC within 5 mm of pin 1, and a 100 nF + 10 uF combination on VBAT within 5 mm of pin 2 to absorb switchover inrush current. Route the 32.768 kHz crystal traces (X1, X2) symmetrically with ground guard rings on both sides, and keep the traces under 5 mm to minimize load-capacitance mismatch and stray EMI pickup that degrades timekeeping accuracy.
The integrated battery switchover circuit auto-routes VBAT to the timekeeper domain when VCC falls below threshold. Do NOT exceed 3.6 V on either VCC or VBAT, or the on-chip switchover circuit will be damaged. For designs that hot-swap a CR2032 or Li-ion backup, add a 1 kOhm series resistor on VBAT to limit inrush, and verify the backup cell can source at least 1 uA continuous (the datasheet-specified backup current) at end-of-life voltage.
Common pitfalls: (1) Forgetting the NR/SS or trim capacitor on the crystal load - this shifts frequency by 10-30 ppm; (2) Enabling block write-protect before completing the EEPROM write cycle, which corrupts the next write; (3) Driving CS high mid-byte, which desynchronizes the SPI state machine - always transfer a full byte or burst; (4) Using the MFP pin as a regular GPIO - it has alternate alarm/event functions that can drive the pin low unexpectedly if registers are left at default.
The MCP79510T-I/MS SPI bus supports CPOL=0/1 and CPHA=0/1, and runs cleanly up to several MHz with proper trace routing. Keep SPI traces under 50 mm, add a 33 ohm series terminator near the host MCU for buses > 25 mm, and place a 100 ohm pull-up on CS to keep the device in standby when the host is reset - otherwise a floating CS line can latch random SPI commands into the RTC.
Compliance Information
RoHS and REACH compliance per Microchip product page. Industrial temperature grade only - not AEC-Q100 qualified for automotive; contact Microchip for automotive-qualified RTCC variants.
