NXP Semiconductors PCA8565BS/1,118

Overview

PCA8565BS/1,118 from NXP Semiconductors is a low-power CMOS real-time clock/calendar IC with integrated 32.768 kHz oscillator, programmable clock output (32.768 kHz/1.024 kHz/32 Hz/1 Hz), open-drain interrupt, and voltage-low detection. It operates from 0.9 V to 5.5 V, supports −40 °C to +125 °C, and communicates via 400 kbit/s I²C-bus (slave address A2h write / A3h read). Used in automotive infotainment power management and industrial control panels requiring precise timekeeping under wide temperature and supply variations.

For engineers reviewing the PCA8565BS/1,118 datasheet, PCA8565BS/1,118 pinout, PCA8565BS/1,118 application, or PCA8565BS/1,118 equivalent, this page delivers verified technical context, validated pin functions, confirmed BCD time register behavior, exact I²C timing constraints, and two manufacturer-validated alternative RTCs for design continuity - all extracted from NXP's Rev. 4 (2014) product data sheet.

Technical Context

The PCA8565BS/1,118 implements a fully autonomous RTC core with auto-incrementing 16×8-bit register map, where addresses 02h–08h hold BCD-coded time/date (seconds to years), and 09h–0Ch store alarm thresholds. Its on-chip oscillator uses one integrated capacitor and drives a 14-stage prescaler to generate 1 Hz for timekeeping while preserving 32.768 kHz CLKOUT during STOP mode.

Interrupt logic combines alarm flag (AF) and timer flag (TF) via logical OR, with configurable pulse (TI_TP = 1) or level (TI_TP = 0) output on the open-drain INT pin. Voltage-low detection sets VL bit in Seconds register (02h) when VDD drops below threshold, signaling potential time corruption - a critical diagnostic for battery-backed systems.

Key Specifications

Pinout & Package

TSSOP8 package (SOT505-1), 3 mm body width, 0.65 mm pitch - compatible with automated SMT assembly and space-constrained PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCF8563T/1,118 and RV-3028-C7, PCA8565BS/1,118 uniquely balances automotive-grade temperature range, integrated oscillator capacitance, and 400 kbit/s I²C speed - making it optimal for space-constrained, battery-sensitive systems needing guaranteed time integrity across extreme conditions without external passive components.

Availability

PCA8565BS/1,118 is available at Aetrix Electronics and suitable for automotive infotainment, industrial PLC logging, smart meter backup timekeeping, and medical device sleep/wake scheduling requiring stable component supply across extended temperature and voltage ranges.

Supply support for PCA8565BS/1,118 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

NXP Semiconductors is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in mixed-signal timing and power management ICs.

The PCA8565BS/1,118 belongs to NXP's automotive-qualified RTC portfolio, designed specifically for robust, low-power timekeeping in harsh environments where reliability, wide operating range, and minimal external components are mandatory.

FAQ

What is the I²C slave address for PCA8565BS/1,118?

The PCA8565BS/1,118 uses fixed I²C slave addresses: 0xA2 (hex) for write operations and 0xA3 (hex) for read operations. These addresses are hardwired and not configurable. The device supports standard-mode and Fast-mode I²C up to 400 kbit/s, with automatic address pointer increment after each byte transfer - essential for efficient sequential register access in the PCA8565BS/1,118's 16-register map.

Does PCA8565BS/1,118 require an external crystal load capacitor?

No, the PCA8565BS/1,118 integrates one oscillator capacitor internally, eliminating the need for external 12.5 pF load capacitors typically required with 32.768 kHz crystals. This reduces bill-of-materials count, saves PCB area, and improves long-term frequency stability by removing parasitic capacitance variability from board layout - a key differentiator of the PCA8565BS/1,118 versus legacy RTCs like PCF8563.

How does the STOP bit affect PCA8565BS/1,118 functionality?

Setting the STOP bit (Control_1 register, bit 5) halts the RTC's 1 Hz timebase by resetting prescaler stages F2–F14, freezing seconds-through-years registers while preserving 32.768 kHz CLKOUT output. This allows safe time initialization without unintended increments. The PCA8565BS/1,118 resumes counting within 0.508 s ±1 cycle of 8.192 kHz after STOP is cleared - critical for deterministic time setup in automotive boot sequences.

What happens when VDD drops below the low-voltage threshold in PCA8565BS/1,118?

When VDD falls below the threshold, the PCA8565BS/1,118 sets the VL (voltage-low) bit in the Seconds register (02h), indicating that timekeeping integrity is no longer guaranteed. This flag persists until cleared by firmware and serves as an early warning for battery depletion or brownout conditions. Unlike simple POR, VL detection operates during gradual VDD decline - enabling proactive time save/restore actions before corruption occurs in the PCA8565BS/1,118's BCD registers.

Can PCA8565BS/1,118 generate multiple alarm outputs simultaneously?

Yes, the PCA8565BS/1,118 supports simultaneous minute, hour, day, and weekday alarm matching. Each alarm register (09h–0Ch) includes an enable bit (AE_M, AE_H, etc.); when enabled, its value is compared against the corresponding RTC counter. Alarm Flag (AF) asserts only when *all* enabled conditions match in a single second tick - ensuring precise multi-field event triggering. AF remains set until cleared by writing to Control_2 register, independent of ongoing time progression in the PCA8565BS/1,118.