RTC Modules for Automotive

Jul 24,2024
80 VIEWS

Are You Struggling with These Problems? 3 Types of Issues for In-vehicle Equipment

Accuracy of clock gets worse under high temperature conditions...
Due to the increasing functionality of ADAS and autonomous driving, high power SOC with self-heating may significantly elevate the temperature inside the module. In addition, ECU are often installed in high temperature environments (e.g. near the battery).
The 32kHz crystal that is typically used for the clock has a frequency characteristic that shift dramatically with temperature. This frequency shift causes significant the deviation of the time information.
Back up current consumption cannot meet specifications...
The number of ECUs installed in cars is increasing and have become multifunctional. From this trend, the current consumption during standby mode is also increasing, and to reduce the current consumption of each ECUs is becoming more important year by year.
Requirement of reducing current consumption is strong especially for the ECUs that continue to operate when the vehicle is turned off (e.g. BMS, Battery Management System).
Redundancy of the system is mandatory to improve safety of equipment...
Redundancy of systems and parts is required are increasing to meet ISO 26262 requirements.
Material costs and mounting space have become issues to accommodate high ASIL levels.

Epson RTC Module Solves 3 Types of Issues

Automotive and high accuracy RTC module RA4000CE and RA8000CE

It is a RTC module with enhanced features which AEC-Q100 qualified and can operate under a high temperature condition (up to 125°C). RA4000CE supports SPI-Bus interface and RA8000CE supports I²C-Bus interface.

Main features of RA4000CE and RA8000CE

High accuracy time information under a high temperature condition up to 125°C.
This product ensure the high accuracy clock during the temperature range from -40°C to 125°C due to the D-TCXO function.
Automotive grade quality AEC-Q100.
High automotive quality standard in all processes. (e.g. Design, Manufacturing, Process Control)
Reduced current consumption during system standby mode.
Low current consumption (300nA Typ.)
Contribute to system redundancies and BoM reduction
This product has many optional functions (e.g. reset function, time stamp function etc.)
Available to choose the best one from many options and interfaced (I²C-Bus/SPI-Bus).
This product support I²C-Bus interface and each SPI-Bus interfaces. Also supports various configuration of multiple event pins, time stamps, and other functions.

* Applications

- BMS (Battery Management System)
- Vehicle computer
- Central gateway
- Industrial machine

3 Reasons for Using RTC Module

Provide High precision time information when the temperature changes
DTCXO (Digital Temperature Compensated Xtal Oscillator) is installed in the RTC module. The RTC module provides highly accurate time information up to 125°C when the temperature on the customer's board changes.

2.Lowers overall system powe

RTC module can keep the time information with one order of magnitude lower current consumption than the sleep mode of the MCU.　RTC module can significantly reduce the power of the customer's system.

3.A reset function contributes to system redundancy

RTC module detects a drop of the main power supply, and outputs a reset signal to the MCU. This eliminates the need for an external reset IC, which reduces the customer's board space, number of mounted parts, and cost. In addition, Customers who use only the reset function in the MCU can add redundancy to their system by using RTC module reset function.

Recommend Product Lineup

Automotive	Model	Size [mm]	Voltage Range [V	Frequency tolerance [x10-6]	OperatingTemperature [C	Backup Current [μA]	Power Switching	Time stamp	Memory
	RX8901CE	3.2×2.5x1.0	1.1 to 5.5	XS:±3.0	-40 to+85	0.24	√	√	√
				XS:±5.0	+85 to+105
				XB:±5.0	-40 to+85
				XB:±8.0	+85 to+105
	RX4901CE	3.2x2.5x1.0	1.1 to 5.5	XS:±3.0	-40 to+85	0.24	√	√	√
				XS:±5.0	+85 to+105
				XB:±5.0	-40 to+85
				XB:±8.0	+85 to+105
AEC-Q100	RA8000CE	3.2×2.5x1.0	1.3 to 5.5	YB:±5.0	-40 to+85	0.24		√
				YB:±8.0	+85 to+105
				YB:±50.0	+105 to+125
AEC-Q100	RA4000CE	3.2×2.5x1.0	1.3 to 5.5	YB:±5.0	-40 to +85	0.24		√
				YB:±8.0	+85 to+105
				YB:±50.0	+105 to+125
	RX8111CE	3.2×2.5x1.0	1.1 to 5.5	A:±11.5/+25℃	+25	0.1	√	√	√
				B:±23.0/+25℃	+25
	RX4111CE	3.2×2.5x1.0	1.1 to 5.5	A:±11.5/+25℃	+25	0.1	√	√	√
				B:±23.0/+25℃	+25
	RX8804CE	3.2×2.5x1.0	1.1 to 5.5	XA:±3.4	-40 to+85	0.35		√
				XA:±8.0	+85 to+105
				XB:±5.0	-40 to+85
				XB:±8.0	+85 to+105
AEC-Q100	RA8804CE	3.2×2.5x1.0	1.5 to 5.5	XA:±3.4	-40 to+85	0.35		√
				XA:±8.0	+85 to+105
				XB:±5.0	-40 to+85
				XB:±8.0	+85 to+105
	RX8130CE	3.2×2.5x1.0	1.1 to 5.5	B:5±23/+25℃	+25	0.3	√		√
	RX8900CE	3.2x2.5x1.0	1.6 to 5.5	UA:±3.4	-40 to+85	0.7	√
				UB:±5.0	-40 to+85
				UC:±5.0	-30 to+70
AEC-Q200	RA8900CE	3.2x2.5x1.0	1.6 to 5.5	UA:±3.4	-40 to +85	0.7	√
				UB:±5.0	-40 to+85
				UC:±5.0	30 to+70