Renesas X1288V14-2.7AT1

Overview

X1288V14-2.7AT1 from Intersil is a 14-pin TSSOP real-time clock/calendar with integrated 32K × 8 EEPROM, CPU supervisor (power-on reset, programmable low-voltage sense, and watchdog timer), oscillator compensation circuitry, and battery backup switch. It operates from 2.7V to 5.5V main supply and retains timekeeping down to 1.8V on VBACK, delivers 1.25µA typical timekeeping current, supports 400kHz I²C-compatible 2-wire interface, and provides software-selectable frequency output (1Hz/100Hz/32.768kHz) or alarm interrupt on PHZ/IRQ - deployed in utility meters and HVAC equipment.

For engineers reviewing the X1288V14-2.7AT1 datasheet, X1288V14-2.7AT1 pinout, X1288V14-2.7AT1 application, or X1288V14-2.7AT1 equivalent, key selection considerations include its dual nonvolatile alarms with repeat mode, on-chip digitally controlled trim capacitor (±30ppm adjustment), BlockLock™ EEPROM protection, and VTRIP programmability across 1.7–5.0V - critical for industrial power monitoring and battery-backed timing integrity.

Technical Context

The X1288V14-2.7AT1 integrates a 32.768kHz crystal oscillator with internal feedback resistor and 64-position digital trim capacitor, enabling precise frequency calibration without external components. 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.

CPU supervision includes a user-programmable reset threshold (VTRIP = 2.85V ±100mV), three watchdog timeout options (0.25s/0.75s/1.75s), and open-drain RESET output with 5kΩ recommended pull-up. The device switches autonomously between VCC and VBACK based on voltage thresholds (VCB = VBACK −0.2V, VBC = VBACK +0.2V), ensuring uninterrupted timekeeping during main power loss.

Key Specifications

Pinout & Package

Package: 14-lead TSSOP (RoHS-compliant, Pb-free plus anneal option available).

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, the X1288V14-2.7AT1 uniquely combines wide VCC range (2.7–5.5V), programmable VTRIP, on-die oscillator trimming, dual repeat-mode alarms, and 32KB BlockLock™ EEPROM - making it optimal for industrial systems requiring robust timekeeping, configurability, and data integrity under variable power conditions.

Availability

X1288V14-2.7AT1 is available at Aetrix Electronics and suitable for utility metering, HVAC control, and industrial test equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for X1288V14-2.7AT1 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 (now part of Renesas Electronics) is a semiconductor manufacturer 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, EEPROM, and CPU supervision into a single compact package - targeting applications demanding autonomous timekeeping, secure nonvolatile storage, and reliable power monitoring in space-constrained environments.

FAQ

What is the backup supply voltage range supported by the X1288V14-2.7AT1?

The X1288V14-2.7AT1 accepts VBACK from 1.8V to 5.5V. When VCC falls below VBACK − 0.2V, the device automatically switches to VBACK to maintain RTC and SRAM operation. At VBACK = 1.8V, timekeeping current is 1.25µA typical, enabling multi-year operation on standard lithium coin cells or supercapacitors - a key design advantage for battery-backed instrumentation.

Does the X1288V14-2.7AT1 support I²C Fast Mode?

Yes, the X1288V14-2.7AT1 fully supports I²C Fast Mode at 400kHz. Its SCL and SDA pins meet timing requirements including tLOW ≥ 1.3µs, tHIGH ≥ 0.6µs, and tSU:STA ≥ 0.6µs. The SDA output incorporates slope-controlled pull-down to ensure signal integrity under capacitive bus loads up to 400pF - verified in the FN8102 datasheet AC specifications section.

How is the reset threshold (VTRIP) programmed on the X1288V14-2.7AT1?

The X1288V14-2.7AT1 allows user programming of VTRIP from 1.7V to 5.0V using a dedicated 15V programming voltage applied to VCC during a specific SCL/SDA sequence (AEh, 03h/01h). The programmed value has ±25mV variation after programming at 25°C. This feature enables custom brown-out response without external resistor dividers - a capability not found in most legacy RTCs like the DS1307 or PCF8563.

What is the EEPROM endurance and data retention specification for the X1288V14-2.7AT1?

The X1288V14-2.7AT1 provides 100,000 write/erase cycles per byte and 100-year data retention at +25°C. These values are guaranteed under specified operating conditions (VCC = 2.7–5.5V, TA = −40°C to +85°C) and reflect actual characterization - not typical estimates. The BlockLock™ protection architecture further enhances reliability by preventing accidental overwrites of critical configuration sectors.

Can the X1288V14-2.7AT1 generate a 1Hz output while simultaneously asserting an alarm interrupt?

No - the PHZ/IRQ pin is functionally exclusive: it operates either as a frequency output (1Hz/100Hz/32.768kHz/off) or as an active-low alarm interrupt (AL0/AL1), selected via FO1/FO0 bits in address 0011h. When configured as IRQ, the pin asserts low on alarm match and remains low until cleared by reading the status register; frequency output is disabled during this mode.