DS1302 RTC: Pinout, Datasheet, Circuit
8 Terminations 3.3V 8 Pin DS1302 Real Time Clocks 0.032MHz
The DS1302 trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM. It communicates with a microprocessor via a simple serial interface. This article covers its pinout, alternatives, circuit and more details about DS1302+.

How to use Arduino Real Time Clock module with DS1302 chip
DS1302 Pinout

DS1302 Pinout
DS1302 CAD Model
Symbol

DS1302 Symbol
Footprint

DS1302 Footprint
3D Model

DS1302 3D Model
DS1302 Description
The DS1302 trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM which communicates with a microprocessor via a simple serial interface. The real-time clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator.
DS1302 Features
Completely Manages All Timekeeping Functions
o Real-Time Clock Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100
o 31 x 8 Battery-Backed General-Purpose RAM
Simple Serial Port Interfaces to Most Microcontrollers
o Simple 3-Wire Interface
o TTL-Compatible (VCC = 5V)
o Single-Byte or Multiple-Byte (Burst Mode) Data Transfer for Reading or Writing of Clock or RAM Data
Low Power Operation Extends Battery Backup Run Time
o 2.0V to 5.5V Full Operation
o Uses Less Than 300nA at 2.0V
8-Pin DIP and 8-Pin SO Minimizes Required Space
Optional Industrial Temperature Range: -40°C to +85°C Supports Operation in a Wide Range of Applications
Underwriters Laboratories® (UL) Recognized
DS1302 Block Diagram
The Block Diagram is given to show the main elements of the serial timekeeper: shift register, control logic, oscillator, real-time clock, and RAM.

Specifications
- TypeParameter
- Factory Lead Time9 Weeks
- Contact Plating
Contact plating (finish) provides corrosion protection for base metals and optimizes the mechanical and electrical properties of the contact interfaces.
Tin - Package / Case
refers to the protective housing that encases an electronic component, providing mechanical support, electrical connections, and thermal management.
8-DIP (0.300, 7.62mm) - Mounting Type
The "Mounting Type" in electronic components refers to the method used to attach or connect a component to a circuit board or other substrate, such as through-hole, surface-mount, or panel mount.
Through Hole - Mount
In electronic components, the term "Mount" typically refers to the method or process of physically attaching or fixing a component onto a circuit board or other electronic device. This can involve soldering, adhesive bonding, or other techniques to secure the component in place. The mounting process is crucial for ensuring proper electrical connections and mechanical stability within the electronic system. Different components may have specific mounting requirements based on their size, shape, and function, and manufacturers provide guidelines for proper mounting procedures to ensure optimal performance and reliability of the electronic device.
Through Hole - Number of Pins8
- Weight930.006106mg
- Published2002
- Packaging
Semiconductor package is a carrier / shell used to contain and cover one or more semiconductor components or integrated circuits. The material of the shell can be metal, plastic, glass or ceramic.
Tube - Operating Temperature
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
0°C~70°C - JESD-609 Code
The "JESD-609 Code" in electronic components refers to a standardized marking code that indicates the lead-free solder composition and finish of electronic components for compliance with environmental regulations.
e3 - Pbfree Code
The "Pbfree Code" parameter in electronic components refers to the code or marking used to indicate that the component is lead-free. Lead (Pb) is a toxic substance that has been widely used in electronic components for many years, but due to environmental concerns, there has been a shift towards lead-free alternatives. The Pbfree Code helps manufacturers and users easily identify components that do not contain lead, ensuring compliance with regulations and promoting environmentally friendly practices. It is important to pay attention to the Pbfree Code when selecting electronic components to ensure they meet the necessary requirements for lead-free applications.
yes - Part Status
Parts can have many statuses as they progress through the configuration, analysis, review, and approval stages.
Active - Moisture Sensitivity Level (MSL)
Moisture Sensitivity Level (MSL) is a standardized rating that indicates the susceptibility of electronic components, particularly semiconductors, to moisture-induced damage during storage and the soldering process, defining the allowable exposure time to ambient conditions before they require special handling or baking to prevent failures
1 (Unlimited) - Number of Terminations8
- ECCN Code
An ECCN (Export Control Classification Number) is an alphanumeric code used by the U.S. Bureau of Industry and Security to identify and categorize electronic components and other dual-use items that may require an export license based on their technical characteristics and potential for military use.
EAR99 - TypeClock/Calendar
- Additional Feature
Any Feature, including a modified Existing Feature, that is not an Existing Feature.
BURST MODE RAM DATA TRANSFER; TIMEKEEPING CURRENT = 0.3UA - Voltage - Supply
Voltage - Supply refers to the range of voltage levels that an electronic component or circuit is designed to operate with. It indicates the minimum and maximum supply voltage that can be applied for the device to function properly. Providing supply voltages outside this range can lead to malfunction, damage, or reduced performance. This parameter is critical for ensuring compatibility between different components in a circuit.
2V~5.5V - Terminal Position
In electronic components, the term "Terminal Position" refers to the physical location of the connection points on the component where external electrical connections can be made. These connection points, known as terminals, are typically used to attach wires, leads, or other components to the main body of the electronic component. The terminal position is important for ensuring proper connectivity and functionality of the component within a circuit. It is often specified in technical datasheets or component specifications to help designers and engineers understand how to properly integrate the component into their circuit designs.
DUAL - Peak Reflow Temperature (Cel)
Peak Reflow Temperature (Cel) is a parameter that specifies the maximum temperature at which an electronic component can be exposed during the reflow soldering process. Reflow soldering is a common method used to attach electronic components to a circuit board. The Peak Reflow Temperature is crucial because it ensures that the component is not damaged or degraded during the soldering process. Exceeding the specified Peak Reflow Temperature can lead to issues such as component failure, reduced performance, or even permanent damage to the component. It is important for manufacturers and assemblers to adhere to the recommended Peak Reflow Temperature to ensure the reliability and functionality of the electronic components.
260 - Supply Voltage
Supply voltage refers to the electrical potential difference provided to an electronic component or circuit. It is crucial for the proper operation of devices, as it powers their functions and determines performance characteristics. The supply voltage must be within specified limits to ensure reliability and prevent damage to components. Different electronic devices have specific supply voltage requirements, which can vary widely depending on their design and intended application.
3.3V - Terminal Pitch
The center distance from one pole to the next.
2.54mm - Time@Peak Reflow Temperature-Max (s)
Time@Peak Reflow Temperature-Max (s) refers to the maximum duration that an electronic component can be exposed to the peak reflow temperature during the soldering process, which is crucial for ensuring reliable solder joint formation without damaging the component.
30 - Base Part Number
The "Base Part Number" (BPN) in electronic components serves a similar purpose to the "Base Product Number." It refers to the primary identifier for a component that captures the essential characteristics shared by a group of similar components. The BPN provides a fundamental way to reference a family or series of components without specifying all the variations and specific details.
DS1302 - Pin Count
a count of all of the component leads (or pins)
8 - Number of Outputs1
- Operating Supply Voltage
The voltage level by which an electrical system is designated and to which certain operating characteristics of the system are related.
3.3V - Power Supplies
an electronic circuit that converts the voltage of an alternating current (AC) into a direct current (DC) voltage.?
3/5V - Interface
In electronic components, the term "Interface" refers to the point at which two different systems, devices, or components connect and interact with each other. It can involve physical connections such as ports, connectors, or cables, as well as communication protocols and standards that facilitate the exchange of data or signals between the connected entities. The interface serves as a bridge that enables seamless communication and interoperability between different parts of a system or between different systems altogether. Designing a reliable and efficient interface is crucial in ensuring proper functionality and performance of electronic components and systems.
3-Wire Serial - Memory Size
The memory capacity is the amount of data a device can store at any given time in its memory.
31B - Operating Supply Current
Operating Supply Current, also known as supply current or quiescent current, is a crucial parameter in electronic components that indicates the amount of current required for the device to operate under normal conditions. It represents the current drawn by the component from the power supply while it is functioning. This parameter is important for determining the power consumption of the component and is typically specified in datasheets to help designers calculate the overall power requirements of their circuits. Understanding the operating supply current is essential for ensuring proper functionality and efficiency of electronic systems.
1.2mA - Clock Frequency
Clock frequency, also known as clock speed, refers to the rate at which a processor or electronic component can execute instructions. It is measured in hertz (Hz) and represents the number of cycles per second that the component can perform. A higher clock frequency typically indicates a faster processing speed and better performance. However, it is important to note that other factors such as architecture, efficiency, and workload also play a significant role in determining the overall performance of a component. In summary, clock frequency is a crucial parameter that influences the speed and efficiency of electronic components in processing data and executing tasks.
0.032MHz - Logic Function
In electronic components, the term "Logic Function" refers to the specific operation or behavior of a component based on its input signals. It describes how the component processes the input signals to produce the desired output. Logic functions are fundamental to digital circuits and are used to perform logical operations such as AND, OR, NOT, and XOR.Each electronic component, such as logic gates or flip-flops, is designed to perform a specific logic function based on its internal circuitry. By understanding the logic function of a component, engineers can design and analyze complex digital systems to ensure proper functionality and performance. Different logic functions can be combined to create more complex operations, allowing for the creation of sophisticated digital devices and systems.
Clock - Time Format
Time is based on a 24 hour system. This is frequently referred to as "military time". The 24 hour system is the default format.
HH:MM:SS (12/24 hr) - Date Format
The international standard recommends writing the date as year, then month, then the day:?YYYY-MM-DD.
YY-MM-DD-dd - Current - Timekeeping (Max)
The parameter "Current - Timekeeping (Max)" in electronic components refers to the maximum current that a device can draw while performing timekeeping functions. Timekeeping functions typically involve maintaining accurate time and date information within a device, such as in a real-time clock (RTC) or a microcontroller with a built-in clock. The maximum current specified for timekeeping is important for determining the power consumption of the device when it is in standby or low-power modes, as excessive current draw can drain the battery quickly. Designers need to consider this parameter when selecting components for battery-powered devices to ensure efficient power management and longer battery life.
0.3μA~1μA @ 2V~5V - Time-Min
Time-Min is a parameter in electronic components that refers to the minimum amount of time required for a specific operation or function to be completed. This parameter is crucial in determining the speed and efficiency of the component's performance. It is often specified in datasheets and technical documentation to provide users with information on the component's timing characteristics. Understanding the "Time-Min" parameter is essential for designing and integrating electronic components into circuits to ensure proper functionality and timing synchronization.
SECONDS - Interrupt Capability
Returns the number of interrupts available for a specified hardware device and interrupt type.
N - Voltage - Supply, Battery
Voltage - Supply, Battery refers to the nominal voltage level provided by a battery to power electronic components or circuits. It indicates the standard voltage output that a battery can deliver under typical operating conditions. This parameter is crucial for ensuring compatibility between the battery and the electronic device, as it affects performance and functionality. The voltage supply rating helps in selecting the appropriate battery for specific applications, ensuring that the device operates efficiently and safely.
2V~5.5V - Volatile
In the context of electronic components, the term "Volatile" refers to a type of memory or storage that requires power to maintain the stored data. When power is removed or lost, the data stored in volatile memory is also lost. This is in contrast to non-volatile memory, which retains data even when power is turned off.Volatile memory is commonly used in devices like RAM (Random Access Memory) in computers, where data needs to be quickly accessed and modified. However, it is not suitable for long-term storage of important data as it requires continuous power supply to retain information.Overall, the volatile nature of this type of memory makes it fast and efficient for temporary data storage and processing, but it is not ideal for permanent data storage due to its dependency on power supply.
YES - Information Access Method
Information Access Method refers to the techniques and protocols used to retrieve, manage, and manipulate data stored in electronic systems. It encompasses various approaches such as direct memory access, polling, interrupts, and data buses, enabling efficient communication between different components within a system. This method is crucial for optimizing data retrieval speed and ensuring effective interaction between hardware and software in electronic devices.
SERIAL, 3-WIRE - Features
In the context of electronic components, the term "Features" typically refers to the specific characteristics or functionalities that a particular component offers. These features can vary depending on the type of component and its intended use. For example, a microcontroller may have features such as built-in memory, analog-to-digital converters, and communication interfaces like UART or SPI.When evaluating electronic components, understanding their features is crucial in determining whether they meet the requirements of a particular project or application. Engineers and designers often look at features such as operating voltage, speed, power consumption, and communication protocols to ensure compatibility and optimal performance.In summary, the "Features" parameter in electronic components describes the unique attributes and capabilities that differentiate one component from another, helping users make informed decisions when selecting components for their electronic designs.
Leap Year, NVSRAM, Trickle-Charger - Height4.45mm
- Width7.87mm
- Length9.91mm
- RoHS Status
RoHS means “Restriction of Certain Hazardous Substances” in the “Hazardous Substances Directive” in electrical and electronic equipment.
ROHS3 Compliant - Radiation Hardening
Radiation hardening is the process of making electronic components and circuits resistant to damage or malfunction caused by high levels of ionizing radiation, especially for environments in outer space (especially beyond the low Earth orbit), around nuclear reactors and particle accelerators, or during nuclear accidents or nuclear warfare.
No - REACH SVHC
The parameter "REACH SVHC" in electronic components refers to the compliance with the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) regulation regarding Substances of Very High Concern (SVHC). SVHCs are substances that may have serious effects on human health or the environment, and their use is regulated under REACH to ensure their safe handling and minimize their impact.Manufacturers of electronic components need to declare if their products contain any SVHCs above a certain threshold concentration and provide information on the safe use of these substances. This information allows customers to make informed decisions about the potential risks associated with using the components and take appropriate measures to mitigate any hazards.Ensuring compliance with REACH SVHC requirements is essential for electronics manufacturers to meet regulatory standards, protect human health and the environment, and maintain transparency in their supply chain. It also demonstrates a commitment to sustainability and responsible manufacturing practices in the electronics industry.
No SVHC - Lead Free
Lead Free is a term used to describe electronic components that do not contain lead as part of their composition. Lead is a toxic material that can have harmful effects on human health and the environment, so the electronics industry has been moving towards lead-free components to reduce these risks. Lead-free components are typically made using alternative materials such as silver, copper, and tin. Manufacturers must comply with regulations such as the Restriction of Hazardous Substances (RoHS) directive to ensure that their products are lead-free and environmentally friendly.
Lead Free
How to use DS1302
Interfacing the DS1302 with a microprocessor is simplified by using synchronous serial communication. Only three wires are required to communicate with the clock/RAM: CE, I/O (data line), and SCLK (serial clock). Data can be transferred to and from the clock/RAM 1 byte at a time or in a burst of up to 31 bytes. It is designed to operate on very low power and retain data and clock information on less than 1µW. The typical operating circuit is given below.

DS1302 Alternatives

DS1302 Package

DS1302 Manufacturer
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Datasheet PDF
- Datasheets :
- Environmental Information :
- Application Notes :
- Other Related Documents :
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Parts with Similar Specs
- ImagePart NumberManufacturerPackage / CaseNumber of PinsMemory SizeInterfaceLogic FunctionSupply VoltageNumber of TerminationsMountView Compare
DS1302
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Popularity by Region
How does DS1302 work?
The DS1302 trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM. It communicates with a microprocessor via a simple serial interface. The real-time clock/calendar provides seconds, minutes, hours, day, date, month, and year information.
Is I2C a DS1302?
The DS1302 chip is very power efficient and can run on the 3V lithium battery for up to 5 years. The supply voltage is 5V. RTC module uses the serial I2C communication protocol, which makes the interfacing of this module with the microcontroller very easy.
What difference is between DS1302 and DS1307?
DS1307 and DS1302 have different pin layouts and use different codes. So you could use it but there will be a bunch of changes you have to make.
What RTC means?
Real-time clock A real-time clock (RTC) is a battery-powered clock that is included in a microchip in a computer motherboard. The time values are for the year, month, date, hours, minutes, and seconds.
Why RTC is used?
The purpose of an RTC or a real-time clock is to provide precise time and date which can be used for various applications. It plays a very important role in real-time systems like a digital clock, attendance system, digital camera etc. In applications where the timestamp is needed, RTC is a good option.
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