Renesas X1288V14Z-2.7T1

Overview

X1288V14Z-2.7T1 from Intersil is a 14-pin TSSOP real-time clock/calendar with integrated 32K × 8 EEPROM, CPU supervisor (power-on reset, low-voltage sense, watchdog timer), and oscillator compensation circuitry. It operates from 2.7V to 5.5V main supply and retains timekeeping down to 1.8V on VBACK, supports 400kHz I²C-compatible 2-wire interface, and delivers ±30ppm digital frequency adjustment via 64-position trim capacitor - used in utility meters and HVAC equipment for accurate timestamping and configuration storage.

For engineers reviewing the X1288V14Z-2.7T1 datasheet, X1288V14Z-2.7T1 pinout, X1288V14Z-2.7T1 application, or X1288V14Z-2.7T1 equivalent, key selection considerations include its dual non-volatile alarms, battery-switch architecture, programmable 1Hz/100Hz/32.768kHz PHZ/IRQ output, 100-year EEPROM data retention, and Pb-free TSSOP packaging compliant with RoHS and lead-free reflow profiles.

Technical Context

The X1288V14Z-2.7T1 integrates a 32.768kHz crystal oscillator with on-chip digitally controlled trim capacitors (64 positions) and six discrete frequency adjustment settings enabling ±30ppm calibration. Its RTC maintains time in hundredths-of-a-second resolution with automatic leap-year correction through 2099 and stores calendar data in BCD format across dedicated SSEC, SC, MN, HR, DT, MO, YR, and DW registers.

Supervisor functionality includes a user-programmable VTRIP threshold (2.55V–2.95V for -2.7 variant), open-drain RESET output with 250ms typical power-up delay, and selectable watchdog timeout periods (0.25s/0.75s/1.75s/off). The device switches autonomously between VCC and VBACK based on voltage differentials (VCB = VBACK − 0.2V, VBC = VBACK + 0.2V) and remains fully operational during nonvolatile EEPROM writes.

Key Specifications

Pinout & Package

Package: 14-lead TSSOP (RoHS-compliant Pb-free plus anneal finish, MSL Level 3).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar real-time clock/supervisor applications.

Compared with DS1339U-33+T&R and PCF8583P/03,118, the X1288V14Z-2.7T1 uniquely combines wide VCC range (2.7–5.5V), autonomous VBACK switchover, on-die oscillator trimming, and 32KB EEPROM - reducing component count and enabling single-chip timekeeping, supervision, and data retention in space-constrained industrial designs.

Availability

X1288V14Z-2.7T1 is available at Aetrix Electronics and suitable for utility metering, HVAC control systems, and industrial network routers requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for X1288V14Z-2.7T1 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

Intersil Corporation (now part of Renesas Electronics) is a U.S.-based semiconductor company specializing in precision analog, power management, and timing solutions for industrial, communications, and computing markets.

The X1288 product line was designed to integrate real-time clock, nonvolatile memory, and CPU supervision into a single compact package for embedded systems needing reliable timekeeping, configuration persistence, and fail-safe reset behavior under variable power conditions.

FAQ

What is the primary function of the X1288V14Z-2.7T1?

The X1288V14Z-2.7T1 is a multifunction integrated circuit combining real-time clock/calendar, 32K × 8 EEPROM, CPU supervisor (with power-on reset, low-voltage detection, and watchdog timer), and oscillator compensation. It serves as a single-chip timing, memory, and system supervision solution for industrial and consumer electronics where accuracy, data retention, and power resilience are critical. The X1288V14Z-2.7T1 operates across 2.7V–5.5V and maintains timekeeping down to 1.8V on VBACK.

Does the X1288V14Z-2.7T1 support I²C communication?

Yes, the X1288V14Z-2.7T1 features a 2-wire serial interface fully interoperable with standard I²C protocols at up to 400kHz. Its SDA and SCL pins implement open-drain and always-enabled input buffers respectively, with slope-controlled fall times and defined timing parameters (tLOW = 1.3µs, tHIGH = 0.6µs) ensuring robust bus operation. The X1288V14Z-2.7T1 responds to slave address 0xD0 (1101000x) and supports sequential reads and page writes to both clock/control registers and EEPROM array.

How does the oscillator compensation work in the X1288V14Z-2.7T1?

The X1288V14Z-2.7T1 incorporates an on-die digitally controlled trim capacitor with 64 discrete positions and six coarse frequency adjustment settings, enabling total oscillator calibration of ±30ppm. This eliminates the need for external load capacitors and manual tuning. Compensation is applied to the internal feedback network driving the external 32.768kHz crystal connected between X1 and X2. The X1288V14Z-2.7T1 datasheet specifies that this circuitry achieves stable oscillation using recommended crystals like the Citizen CFS206-32.768KDZF.

What are the backup power capabilities of the X1288V14Z-2.7T1?

The X1288V14Z-2.7T1 features a dedicated VBACK pin supporting backup voltages from 1.8V to 5.5V, allowing operation from coin cells, supercaps, or regulated auxiliary supplies. When VCC drops below VBACK − 0.2V, the internal power switch seamlessly transfers operation to VBACK without time loss or register corruption. Timekeeping current drops to 1.25µA at 1.8V, enabling multi-year battery life. The X1288V14Z-2.7T1 retains full RTC, alarm, and SRAM functionality during backup mode.

Can the X1288V14Z-2.7T1 generate multiple frequency outputs?

Yes, the X1288V14Z-2.7T1's PHZ/IRQ pin is software-configurable to output 32.768kHz, 100Hz, or 1Hz signals - or remain inactive. This selection is controlled by FO1 and FO0 bits in the INT register (address 0011h). Unlike dedicated clock generators, this output derives directly from the internal oscillator divider chain and is synchronized to the RTC timebase. The X1288V14Z-2.7T1 does not support arbitrary frequencies or phase-adjustable outputs; its frequency options are fixed and intended for UI clocks, LED blink timing, or system synchronization triggers.