NXP Semiconductors PCA8565AU/5BB/1,01

Overview

The PCA8565AU/5BB/1,01 from NXP Semiconductors is a CMOS real-time clock (RTC) and calendar IC with integrated oscillator capacitors, I²C-bus interface (400 kHz), programmable clock output (32.768 kHz/1.024 kHz/32 Hz/1 Hz), alarm/timer functions, and voltage-low detection. It operates from 1.8 V to 5.5 V, supports −40 °C to +125 °C, and delivers typical backup current of 0.65 µA at 3.0 V - enabling long-life battery-backed timekeeping in automotive instrument clusters.

For engineers reviewing the PCA8565AU/5BB/1,01 datasheet, PCA8565AU/5BB/1,01 pinout, PCA8565AU/5BB/1,01 application, or PCA8565AU/5BB/1,01 equivalent, this page provides verified functional specifications, validated pin roles, confirmed AEC-Q100 compliance, exact register-level BCD time/calendar encoding, and documented interrupt behavior for production-grade automotive and industrial timing design.

Technical Context

The PCA8565AU/5BB/1,01 implements a fully autonomous RTC using an on-chip 32.768 kHz oscillator with two integrated load capacitors, eliminating external crystal tuning components. Its 16-register memory map includes BCD-coded time/date registers (02h–08h), alarm registers (09h–0Ch), timer control (0Eh/0Fh), and CLKOUT configuration (0Dh), all accessible via I²C slave address A2h (write) / A3h (read).

It features dual interrupt sources - alarm flag (AF) and timer flag (TF) - both controllable via Control_status_2 (01h), with open-drain INT output supporting active-low pulsed or latched modes selected by TI_TP bit. The STOP bit (00h) halts RTC counting without affecting 32.768 kHz CLKOUT, enabling precise time initialization before system boot.

Key Specifications

Pinout & Package

PCA8565AU/5BB/1,01 is supplied as a wire bond die (9 bonding pads) on unsawn wafer, thickness 280 µm. It is not packaged in a standard surface-mount or through-hole format; bonding pad layout matches the PCA8565A die footprint per Figure 2 of the datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCF2129AT/1,118 and RV-3028-C7, the PCA8565AU/5BB/1,01 uniquely balances AEC-Q100 compliance, integrated capacitors, and 0.65 µA backup current - making it optimal for cost-sensitive, space-constrained automotive modules where ±20 ppm accuracy suffices.

Availability

The PCA8565AU/5BB/1,01 is available at Aetrix Electronics and suitable for automotive instrument clusters, industrial PLC logging, smart energy metering, and medical infusion pump time tracking requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for PCA8565AU/5BB/1,01 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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with headquarters in Eindhoven, Netherlands.

The PCA8565A product line delivers AEC-Q100-qualified, low-power RTCs optimized for automotive infotainment, body electronics, and ADAS systems requiring robust timekeeping under extreme thermal and electrical conditions.

FAQ

What is the I²C slave address of the PCA8565AU/5BB/1,01?

The PCA8565AU/5BB/1,01 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 (100 kbit/s) and fast-mode (400 kbit/s) I²C communication across its full 1.8 V to 5.5 V supply range. No external address pins or jumpers affect this addressing scheme in the PCA8565AU/5BB/1,01.

Does the PCA8565AU/5BB/1,01 require external load capacitors for the 32.768 kHz crystal?

No, the PCA8565AU/5BB/1,01 integrates two 12.5 pF oscillator load capacitors internally, eliminating the need for external capacitors in standard 32.768 kHz crystal configurations. This integration reduces bill-of-materials count and PCB footprint while maintaining stable oscillation across −40 °C to +125 °C. The PCA8565AU/5BB/1,01 datasheet confirms this in Section 2 ("Features and benefits") and Figure 1 block diagram - explicitly listing "Two integrated oscillator capacitors" as a key feature.

How does the voltage-low (VL) detection work in the PCA8565AU/5BB/1,01?

The PCA8565AU/5BB/1,01 monitors VDD and sets the VL bit (bit 7) in register 02h (VL_seconds) when supply voltage drops below the internal threshold (V_LOW). This flag indicates that clock integrity is no longer guaranteed - timekeeping may halt or become unreliable. The VL bit remains set until cleared by firmware writing 0 to it. It is designed specifically for slow VDD decay scenarios, such as battery depletion, and is independent of the oscillator stop condition. This behavior is documented in Section 8.4.1.1 and Table 9 of the PCA8565AU/5BB/1,01 datasheet.

Can the PCA8565AU/5BB/1,01 generate multiple simultaneous alarms?

Yes, the PCA8565AU/5BB/1,01 supports independent minute, hour, day, and weekday alarms via registers 09h–0Ch, each with dedicated enable bits (AE_M, AE_H, AE_D, AE_W). All enabled alarms are logically ANDed - the alarm flag (AF) triggers only when *all* enabled conditions match simultaneously. For example, setting AE_M=0, AE_H=0, and AE_D=1 configures a daily alarm at a specific minute and hour. AF is latched and must be cleared by software; it drives the open-drain INT pin when AIE=1. This behavior is defined in Section 8.6 and Figure 7 of the PCA8565AU/5BB/1,01 datasheet.

What clock frequencies are available on the CLKOUT pin of the PCA8565AU/5BB/1,01?

The PCA8565AU/5BB/1,01 provides four selectable CLKOUT frequencies: 32.768 kHz, 1.024 kHz, 32 Hz, and 1 Hz. Selection is controlled by FD[1:0] bits (bits 1–0) in register 0Dh (CLKOUT_control): 00 = 32.768 kHz, 01 = 1.024 kHz, 10 = 32 Hz, 11 = 1 Hz. CLKOUT is an open-drain output and enters high-impedance state when CLKOE (pin 9) is low. The 32.768 kHz option remains active even when STOP=1, unlike the lower frequencies - a key detail for system clock backup schemes.