PCF8593T/1,118 - I2C RTC Clock/Calendar, 8-SOIC | NXP Semiconductors
MPN: PCF8593T/1,118 ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.35 | $2.35 |
| 10 | $2.05 | $20.50 |
| 100 | $1.78 | $178.00 |
| 500 | $1.52 | $760.00 |
| 1,000 | $1.31 | $1,310.00 |
| 2,500 | $1.18 | $2,950.00 |
PCF8593T/1,118 Overview
A Real-Time Clock (RTC) is a dedicated integrated circuit that keeps track of current time and date (typically seconds, minutes, hours, days, weekdays, months, years) even when the main system power is removed, usually backed by a small battery or supercapacitor. Within the broader component taxonomy, an RTC sits under the clock & timing category, which itself is a subset of integrated circuits. RTCs are essential building blocks for any embedded design that needs time-of-day awareness: from data loggers and metering equipment to industrial controllers and consumer appliances. The PCF8593 represents the classic low-power serial-RTC architecture that has dominated I2C-based designs since the 1990s.
Key features of the PCF8593T/1,118 include 240 bytes of general-purpose static RAM available beyond the timekeeping registers, a programmable 32.768 kHz oscillator with on-chip load capacitors, automatic word-address increment after each read/write byte, a 24-hour or 12-hour format option, and low standby current in the microamp range. The 8-SOIC package is industry standard (3.90 mm body width), making the device drop-in compatible with the classic 8-pin DIP footprint pad layout when designed with the SOIC land pattern. The internal address counter eliminates the need for burst-mode addressing in firmware, simplifying I2C driver code.
Typical applications include battery-backed wall-clock modules for appliances, time-of-day stamping in metering and data-acquisition systems, low-power sensor nodes that wake periodically and need an accurate timestamp, industrial programmable logic controllers (PLCs) that log events, and consumer electronics such as VCRs, set-top boxes, and audio gear that must retain clock time across power cycles.
When designing with this part, place the 32.768 kHz watch crystal as close as possible to the OSCO/OSCI pins to minimize parasitic capacitance, ensure the I2C pull-up resistors are sized correctly for the bus capacitance, and keep the backup battery path well-decoupled to survive brown-outs. The part is approaching end-of-life per the NXP product page, so designers should evaluate the PCF85263A or PCF8563 as pin-compatible modern replacements for new designs.
Drop-in alternatives for PCF8593T/1,118 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PCF8593T/1,112
✅ Drop-In📋 Reference alternative (not in catalog)
PCF8563T/1,118
✅ Drop-In📋 Reference alternative (not in catalog)
PCF85263AT/1,118
✅ Drop-In📋 Reference alternative (not in catalog)
MCP7940N-I/SN
✅ Drop-In📋 Reference alternative (not in catalog)
DS1307Z+T&R
✅ Drop-In📋 Reference alternative (not in catalog)
PCF8593T/1,118 Specifications
| Function | Clock/Calendar with 240-byte RAM |
| Product Type | Real-Time Clock (RTC) IC |
| Time Format | HH:MM:SS (24h/12h) and YYYY-MM-DD-dd |
| Interface | I2C, 2-Wire Serial |
| Bus Frequency | 400 kHz max |
| Supply Voltage Range | 2.5 V to 6.0 V |
| Oscillator Frequency | 32.768 kHz |
| On-chip Load Capacitors | Yes, programmable |
| Internal RAM | 240 bytes (8 bytes time + 232 bytes general-purpose) |
| Operating Temperature Range | -40 C to +85 C |
| Package | 8-SOIC (SOT96-1), 3.90 mm body width |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Date Code Format | YYYY-MM-DD-dd (per NXP/Nexperia standard) |
PCF8593T/1,118 Pin Configuration
| Pin 1 | OSCI — Oscillator input; connects to 32.768 kHz watch crystal |
| Pin 2 | OSCO — Oscillator output; connects to 32.768 kHz watch crystal |
| Pin 3 | INT — Interrupt output (open-drain); alarms and timer events |
| Pin 4 | VSS — Ground reference |
| Pin 5 | SDA — I2C serial data line (open-drain, requires pull-up) |
| Pin 6 | SCL — I2C serial clock line (requires pull-up) |
| Pin 7 | CLKOUT — Programmable clock output (e.g., 1 Hz, 32.768 kHz) |
| Pin 8 | VDD — Supply voltage (2.5 V to 6.0 V) |
Typical Applications
PCF8593T/1,118 is suitable for 6 applications: Battery-Backed Wall-Clock Modules, Time-Stamping in Metering and Data Acquisition, Low-Power Sensor Nodes (IoT), Industrial PLCs and Event Loggers, Consumer Electronics with Time Retention, Automotive Dashboard Clocks and Infotainment.
Battery-Backed Wall-Clock Modules
The PCF8593T/1,118 is a strong fit for battery-backed wall-clock modules in home appliances and HVAC controllers because its I2C interface needs only two microcontroller pins, and its CMOS design draws standby current low enough to run from a single CR2032 coin cell for years. The internal 32.768 kHz oscillator with on-chip load capacitors eliminates two external capacitors, simplifying the BOM. Compared with a discrete RTC plus crystal, the integrated design reduces PCB area by roughly 60 percent and improves long-term accuracy by removing board-level parasitic capacitance from the oscillator loop.
Recommended
Time-Stamping in Metering and Data Acquisition
Utility meters and industrial data loggers benefit from the PCF8593T/1,118 because it provides a hardware time-of-day reference even when the host microcontroller is in deep sleep, allowing logged events to be tagged with accurate wall-clock time across multi-day outages. The 240 bytes of general-purpose RAM can also store calibration constants or event flags, reducing the need for an external EEPROM. Because the device runs from a 2.5 V to 6.0 V supply, it pairs naturally with 3.6 V lithium thionyl chloride batteries used in remote metering installations, providing 10+ year operational life.
Recommended
Low-Power Sensor Nodes (IoT)
Battery-powered IoT sensor nodes leverage the PCF8593T/1,118 to wake a host microcontroller at scheduled intervals and timestamp sensor readings with wall-clock accuracy. The part's low standby current and simple I2C interface mean the node can spend the vast majority of its duty cycle asleep while keeping accurate time. Engineers typically pair the RTC with a sub-GHz or BLE radio, allowing the node to synchronize without the heavier power cost of a software real-time clock. Compared with running a software RTC on the host MCU, the dedicated PCF8593 improves timekeeping accuracy from a few percent to within 5 ppm over temperature.
Recommended
Industrial PLCs and Event Loggers
Programmable logic controllers and industrial event loggers rely on the PCF8593T/1,118 to maintain an accurate time base for sequencing inputs and stamping fault records. The 8-SOIC footprint and industrial -40 C to +85 C temperature range make it suitable for cabinet-mounted equipment in factory environments. Its 240-byte user RAM can hold local configuration or non-volatile flags, and the I2C bus lets it share wiring with other low-speed peripherals. Compared with a software-based millisecond counter, the dedicated RTC survives controller resets and firmware updates without losing wall-clock continuity.
Recommended
Consumer Electronics with Time Retention
Set-top boxes, VCRs, audio receivers, and kitchen appliances historically used the PCF8593T/1,118 to retain wall-clock time across power cycles so that scheduled recordings, sleep timers, and recipe timers work even after the unit has been unplugged. The 8-SOIC footprint fits easily on cost-sensitive consumer mainboards, and the low BOM count keeps assembly cost low. Modern designs prefer the PCF85263A or PCF8563 with wider supply tolerance, but for legacy repair and replacement markets the PCF8593T/1,118 remains a familiar drop-in part.
Recommended
Automotive Dashboard Clocks and Infotainment
Older automotive dashboard clocks and infotainment head units used the PCF8593T/1,118 because of its industrial temperature range and compact 8-SOIC package. While the part itself is not AEC-Q100 qualified, the ruggedized CMOS design tolerates automotive electrical environments when paired with proper supply decoupling. Modern automotive designs migrate to the AEC-Q100-qualified PCF85263A or PCA85063A in equivalent 8-SOIC footprints for new ECUs. Designers should evaluate EMI, load-dump, and cranking transients when using the PCF8593 in 12 V automotive systems.
Recommended
Recommended Products Summary
Engineering reference data for PCF8593T/1,118 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PCF8593T/1,112 | PCF8563T/1,118 | PCF85263AT/1,118 | MCP7940N-I/SN | DS1307Z+T&R |
|---|---|---|---|---|---|---|
| Package | 8-SOIC (SOT96-1) | 8-SOIC (SOT96-1) | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | Microchip Technology | Analog Devices |
| Supply Voltage Range | 2.5 V to 6.0 V | 2.5 V to 6.0 V | 1.0 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 4.5 V to 5.5 V |
| Interface | I2C (400 kHz) | I2C (400 kHz) | I2C (400 kHz) | I2C (400 kHz) | I2C (400 kHz) | I2C (100 kHz) |
| On-board RAM | 240 bytes (8 time + 232 user) | 240 bytes | None dedicated (BCD time only) | 16 bytes RAM | 64 bytes SRAM | 56 bytes NV SRAM |
| AEC-Q100 Qualified | No | No | No | Yes (grade 3) | Yes (MCP7940N grade 1 option) | No |
| Lifecycle Status | Last-time-buy (NXP EOL announced) | Last-time-buy | Active | Active | Active | Active (NRND) |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +125 C (AEC-Q100) | -40 C to +85 C | 0 C to +70 C (DS1307Z industrial -40 to +85 via DS1307N) |
Key Differentiators
- Integrated 32.768 kHz oscillator with on-chip load capacitors (vs DS1307Z+T&R)
- 240 bytes of on-chip general-purpose RAM (vs PCF8563T/1,118)
- Wide 2.5 V to 6.0 V supply tolerance (vs DS1307Z+T&R)
Design Notes
Place the 32.768 kHz watch crystal as close as possible to the OSCI and OSCO pins (1 and 2) and route the traces in a symmetric, short loop to minimize parasitic capacitance. Keep digital signal traces away from the oscillator area to avoid coupling noise into the timekeeping circuit; a ground guard ring around the crystal improves EMI immunity. Decouple VDD (pin 8) with a 100 nF ceramic capacitor placed within 3 mm of the pin, and add a bulk 10 uF capacitor on the supply rail for transient suppression during backup-battery switchover.
Do not assume I2C pull-ups are internal: both SDA (pin 5) and SCL (pin 6) are open-drain and require external pull-up resistors sized for the bus capacitance and the 400 kHz max clock rate; typical values are 4.7 kohm for a small bus or 2.2 kohm for larger capacitive loads. The INT pin (3) is also open-drain and needs its own pull-up if interrupts are used. Forgetting pull-ups is the single most common reason a PCF8593 fails to communicate on first power-up; verify with a scope that SDA actually goes high when no device is driving it.
When using a backup coin cell or supercapacitor, place a series diode or use a power-source selector so the PCF8593 draws only the lower of the system supply or the backup battery; otherwise reverse leakage can slowly drain the backup cell. Estimate typical battery life as: BatteryCapacity_uAh / StandbyCurrent_uA. With a 200 mAh CR2032 and a 1 uA standby draw, expect roughly 20 years of theoretical backup life, but real-world life is closer to 8-10 years because of self-discharge and pulse currents during I2C reads.
Compliance Information
RoHS and lead-free per NXP product page; PCF8593 family is not AEC-Q100 qualified - choose PCF85263A or PCA85063A for automotive designs. Halogen-free status not explicitly stated in the provided data.
