Data Sheet

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SD2405ALPI IIC 串行接口的实时时钟IC

High Precision RTC module－SD2405AL (V1.00)

Integrated

RTC/Crystal

1.General Description

The SD2405AL is an extremely accurate I

c real-time clock(RTC) with crystal

compensation, inner chargeable battery. The SD2405AL is available in industrial

temperature ranges.

The SD2405AL is dual power supply system. When the primary power supply

goes down to an assigned value or resumes from low power, the system can switch

between the primary power supply and battery automatically.

The SD2405AL can generates various periodic interrupt clock pulses lasting for

long period (one year), and three alarm interrupts can be made by year,month,date,days

of the week, hours, and minutes, seconds. It also provides a selectable 32.768KHz~1Hz

clock output for an external MCU. The product incorporates a time trimming circuit that

adjusts the clock with higher precision by adjusting any errors in crystal oscillator

frequencies based on signals from the CPU. A 12-bytes general SRAM is implemented in

the SD2405AL.

2.Features：

! Operation voltage range:3.3V~5.5V.

Low-power:typical 1uA (inner battery, Ta=25°C)

Accuracy ±5ppm from -40°C to +85°C.

Fast (400kHz) I

C Interface(4.5~5.5V).

! Real-Time Clock Counts Seconds, Minutes,Hours, Day, Date, Month, and

Year with Leap Year Compensation Valid Up to 2100.

Time-of-Year,Month,Day,Week,Hour,Minute,Second

Alarms.

Programmable Square-Wave Output:32768hz,4096hz...1hz..1/16hz.

Countdown timer interrupt.

High precision time trimming circuit.

12-hour/24-hour time display selectable.

CMOS logic

ROHS Recognized.

Package: 16-pin, 300-mil DIP.

Summary of content (16 pages)

PAGE 1
SD2405ALPI IIC 串行接口的实时时钟IC High Precision RTC module－SD2405AL (V1.00) Integrated RTC/Crystal 1.General Description The SD2405AL is an extremely accurate I2c real-time clock(RTC) with crystal compensation, inner chargeable battery. The SD2405AL is available in industrial temperature ranges. The SD2405AL is dual power supply system. When the primary power supply goes down to an assigned value or resumes from low power, the system can switch between the primary power supply and battery automatically.
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SD2405ALPI IIC 串行接口的实时时钟IC 3. block diagram 4.Pin Configuration DIP-16（300mil） Pin Number 1、5、6、7、16 Nam e NC Function No connection Typical No connection or GND connection Testing pin for Voltage of Inner battery, output via No connection(only use 100k resistor for testing) 2 TEST 8 GND Ground 9 SDA Serial Data Input/Output. This pin is the data input/output for the I2C serial interface. This open-drain pin requires an external pull-up resistor. Open-N-channel output, cmos input.
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SD2405ALPI IIC 串行接口的实时时钟IC Active-Low Interrupt or Square-Wave Output. This Open-N-channel output open-drain pin requires an external pullup resistor connected to a supply at 5.5V or less. If not used, this pin can be left float 11 INT 12 VDD DC Power Pin for Primary Power Supply. This pin 3.3V～5.5V should be decoupled using a 0.1µF 15 VOUT 3.0V Output Power Pin I≤30mA ，V=3.0V±2% 5.Registers 5.
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SD2405ALPI IIC 串行接口的实时时钟IC Day of the Week: from 0 to 6. 24 HOUR TIME If 12_/24 bit of the Hour register is “1”, the RTC uses a 24-hour format. If the 12_/24 bit is “0”, the RTC uses a 12-hour format Note: 1. You must clear the hour's highest bit 12_/24 after you have gotten the data from the hour register, otherwise it will be incorrect when the time is P.M. 2. After power on reset, the real time clock data registers aren't cleaned or set to be "1". 3.
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SD2405ALPI IIC 串行接口的实时时钟IC When one or more of the alarm registers are loaded with a valid second,minute, hour, day ,week,month,year and its corresponding alarm enable bit is a logic 1, then that information will be compared with the current second,minute, hour, day ,week,month,year, When all enabled comparisons first match, the bit INTAF (Alarm flag) is set. Note: 1. When the week alarm and the date alarm are both enable at the same time, only the date alarm is valid and the week alarm is invalid.
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SD2405ALPI IIC 串行接口的实时时钟IC frequency(HZ) FS3 FS2 FS1 FS0 0 0 0 0 0 32768 0 0 0 1 4096 0 0 1 0 1024 0 0 1 1 64 0 1 0 0 32 0 1 0 1 16 0 1 1 0 8 0 1 1 1 4 1 0 0 0 2 1 0 0 1 1 1 0 1 0 1/2 1 0 1 1 1/4 1 1 0 0 1/8 1 1 0 1 1/16 1 1 1 0 1S 1 1 1 1 (3) Countdown timer interrupt The countdown timer interrupt is enabled and disabled via the timer control register bit INTDE.
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IIC 串行接口的实时时钟IC SD2405ALPI 3) Here, the clock accuracy at room temperature varies along with the variation of the characteristic of crystal oscillator. 4) The influence of stray capacitance on circuit board These factors will cause large errors Using the time trimming circuit gain or lose of clock may be adjusted with high precision by changing clock pulses for one second every 20 seconds.
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SD2405ALPI IIC 串行接口的实时时钟IC *1) Oscillation frequency: Clock frequency output from the INT pin *2) Target frequency: TYP. 32.768KHz to 32.000KHz *3) Adjustment amount: A value to be set finally to F6 to F0 bits. This value is expressed in 7 bit binary digits with sign bit (two’s compliment). 2. When oscillation frequency = target frequency (no clock gain or loss) Set the adjustment value to 0 or +1, or –64, or –63 to disable adjustment. 3.
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IIC 串行接口的实时时钟IC SD2405ALPI (1) WRITE RTC ENABLE BIT (WRTC1 ,WRTC2,WRTC3): Registers (00H ~ 1FH) RTC write enable bits. When the three bits are set to “1”, RTC is enable to be written. Write enable: Setting the three bits must follow the sequencing: Set the WRTC1 bit to “1” first, then set the WRTC2 and WRTC3 to “1”. Write disable: Setting the three bits must follow the sequencing: Set the WRTC2 and WRTC3 bits to “0” first, then set the WRTC1 to “0”.
PAGE 10
SD2405ALPI IIC 串行接口的实时时钟IC The state of the data line represents valid data when, after a START condition, the data line is stable for the duration of the HIGH period of the clock signal. The data on the line must be changed during the LOW period of the clock signal. There is one clock pulse per bit of data. Each data transfer is initiated with a START condition and terminated with a STOP condition.
PAGE 11
SD2405ALPI Data is written into the slave from the master IIC 串行接口的实时时钟IC When data is read from the slave immediately after 7bit addressing from the master When the transmission direction is to be changed during transmission (3)Data Transmission Write Format in the SD2405AL 1）First send 7 address bit(0110010), the eighth bit is write command “0”. when the ninth bit is ACK signal, SD2405AL is under writing condition.
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SD2405ALPI IIC 串行接口的实时时钟IC data reading condition. 3) After another bit’s ACK signal, it starts reading data normally. 4) When a byte data is read and CPU sends 1 bit ACK signal, a next byte data can be read. Only when the 1 bit ACK signal which is sent by CPU is high voltage, can the reading operation be stopped and then CPU sends stop signal.
PAGE 13
SD2405ALPI IIC 串行接口的实时时钟IC regarded as the “repeated start condition”. Therefore, when 0.5 seconds passed after the first start condition, access to the SD2405AL is automatically released. The user shall always be able to access the real-time clock as long as the following two conditions are met. 1）No stop condition shall be generated until clock read/write is started and completed. 2) One cycle read/write operation shall be completed within 0.5 second. 7.
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SD2405ALPI General RAM IIC 串行接口的实时时钟IC 10. instructions 1. To prevent the noise of the circus, two capacities should be laid near the chip. Typically 0.1uF and 22uF 11. Application reference circuit 12. Absolute Maximum Rating Voltage on VDD,SCL,SDA,and INT pins(Respect to Ground)……....…………………-0.5V to 7.0V Lead Temperature(Soldering,10s)………........…………………....………..…………….260℃/10s 13. DC CHARACTERISTICS SYMBOL VDD IDD1 PARAMETER CONDITIONS Main Power Supply Supply Current VDD =5.
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SD2405ALPI IIC 串行接口的实时时钟IC 15.
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SD2405ALPI IIC 串行接口的实时时钟IC 16. The relationship between frequency error and temperature 17. Ordering Information product model work order serial numbers 00—99 four alphabets work order lot number 18.