DS1687-5+ Dallas Semiconductor, DS1687-5+ Datasheet
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DS1687-5+
Specifications of DS1687-5+
Related parts for DS1687-5+
DS1687-5+ Summary of contents
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... RAM Clear Input Century Register Date Alarm Register Compatible with Existing BIOS for Original DS1287 Functions Available as Chip (DS1685) or Stand-Alone Encapsulated DIP (EDIP) with Embedded Battery and Crystal (DS1687) Timekeeping Algorithm Includes Leap-Year Compensation Valid Through 2099 Underwriters Laboratory (UL) Recognized PWR ...
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ORDERING INFORMATION PART* TEMP RANGE DS1685-3 0°C to +70°C DS1685-3+ 0°C to +70°C DS1685-5 0°C to +70°C DS1685-5+ 0°C to +70°C DS1685-5IND -40°C to +85°C DS1685-5IND+ -40°C to +85°C DS1685E-3 0°C to +70°C DS1685E-3+ 0°C to +70°C DS1685E-5 0°C to ...
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... DS1685S-5/T&R 0°C to +70°C DS1685S-5+T&R 0°C to +70°C DS1687-3 0°C to +70°C DS1687-3+ 0°C to +70°C DS1687-5 0°C to +70°C DS1687-5+ 0°C to +70°C DS1687-3IND -40°C to +85°C DS1687-3IND+ -40°C to +85°C DS1687-5IND -40°C to +85°C DS1687-5IND+ -40°C to +85°C + Denotes a lead-free/RoHS-compliant device. A “+” anywhere on the top mark indicates a lead-free/RoHS-compliant device. ...
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... EDIP. The entire unit is fully tested at Dallas Semiconductor such that a minimum of 10 years of timekeeping and data retention in the absence of V OPERATION The block diagram in Figure 1 shows the pin connections with the major internal functions of the DS1685/DS1687. The following paragraphs describe the function of each pin. is guaranteed. ...
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... WR register. Read Input, Active Low. RD identifies the time period when the DS1685/DS1687 drives the bus with RTC read data. The RD signal enable signal for the output buffers of the clock FUNCTION ...
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... NAME Kickstart Input, Active Low. When V DS1685/DS1687, the system can be powered on in response to an active- low transition on the KS pin, as might be generated from a key closure. V must be present and the auxiliary-battery enable bit (ABE) and kick- BAUX KS start enable bit (KSE) must be set the kickstart function is used, and the KS pin must be pulled up to the V KS pin can be used as an interrupt input ...
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... Figure 1. Block Diagram X1 OSC X2 DS1687 only V CC GND V Power BAUX V Control BAT DS1687 only BUS W R Interface ALE AD0 - AD7 OSCILLATOR CIRCUIT The DS1685 uses an external 32.768kHz crystal. The oscillator circuit does not require any external resistors or capacitors to operate. Table 1 specifies several crystal parameters for the external crystal, and Figure 2 shows a functional schematic of the oscillator circuit ...
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Table 1. Crystal Specifications* PARAMETER Nominal Frequency Series Resistance Load Capacitance * The crystal, traces, and crystal input pins should be isolated from RF generating signals. Refer to Application Note 58: Crystal Considerations for Dallas Real-Time Clocks for additional specifications. ...
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... A). This time period allows the system to stabilize after power is applied. If the oscillator is not enabled, the oscillator enable bit will be enabled on power up, and the device becomes immediately accessible. The DS1685/DS1687 is available in either device. The 5V device is fully accessible and data can be written and read only when V falls below V , read and writes are inhibited ...
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... Date 0 10 Month DV1 DV0 RS3 RS2 AIE UIE SQWE Century 10 Date DS1685/DS1687 3V/5V Real-Time Clocks BIT 1 BIT 0 FUNCTION Seconds Seconds Alarm Minutes Minutes Alarm Hours Hours Hours Hours Alarm Day Day Date Date Month Month Year Year RS1 RS0 Control ...
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... Date 0 0 Year DV1 DV0 RS3 RS2 AIE UIE SQWE Century 10 Date DS1685/DS1687 3V/5V Real-Time Clocks BIT 1 BIT 0 FUNCTION Seconds Seconds Alarm Minutes Minutes Alarm Hours Hours Hours Hours Alarm Day Day Date Month Month Year RS1 RS0 Control 24/12 ...
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CONTROL REGISTERS The four control registers and D reside in both bank 0 and bank 1. These registers are accessible at all times, even during the update cycle. Register A (0Ah) MSB BIT 7 BIT 6 UIP ...
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... When the AIE bit is set to 0, the AF bit does not initiate the IRQ signal. The internal functions of the DS1685/DS1687 do not affect the AIE bit. UIE – The update-ended interrupt-enable (UIE) bit is a read/write bit that enables the update-end flag (UF) bit in Register C to assert IRQ. The SET bit going high clears the UIE bit. SQWE – ...
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Register C (0Ch) MSB BIT 7 BIT 6 BIT 5 IQRF PF IRQF – The interrupt-request flag (IRQF) bit is set when one or more of the following are true PIE = ...
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... The IRQF bit in Register whenever the IRQ pin is being driven low as a result of one of the six possible active sources. Therefore, determination that the DS1685/DS1687 initiated an interrupt is accomplished by reading Register C and finding IRQF = 1. IRQF remains set until all enabled interrupt flag bits are cleared to 0 ...
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... DS1287. Any other bit combination for DV2 and DV1 keeps the oscillator off. OSCILLATOR CONTROL BITS When the DS1687 is shipped from the factory, the internal oscillator is turned off. This feature prevents the lithium energy cell from being used until it is installed in a system. A pattern of 01X in bits 4 through 6 of Register A turns the oscillator on and enables the countdown chain ...
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Table 3. Periodic Interrupt Rate and Square-Wave Output Frequency EXT. SELECT BITS REGISTER A REG B E32K RS3 RS2 ...
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... PF EXTENDED FUNCTIONS The extended functions provided by the DS1685/DS1687 that are new to the RAMified RTC family are accessed by a software-controlled bank-switching scheme, as illustrated in Figure 5. In bank 0, the clock/calendar registers and 50 bytes of user RAM are in the same locations as for the DS1287 result, existing routines implemented within BIOS, DOS, or application software packages can gain access to the DS1685/DS1687 clock registers with no changes ...
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... Figure 5. DS1685/DS1687 Register Map and Extended Register Bank Definition BANK 0 DV0 MSB = 0 00 TIMEKEEPING AND CONTROL BYTES-USER RAM 3F 64 BYTES-USER RAM 7F When bank 1 is selected, the clock/calendar registers and the original 50 bytes of user RAM still appear as bank 0. However, the registers that provide control and status for the extended functions are accessed in place of the additional 64 bytes of user RAM ...
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... KS pin, without operating voltage applied to the V system power can be applied upon such events as a key closure or modem-ring detect signal. In order to use either the wake-up or the kickstart features, the DS1685/DS1687 must have an auxiliary battery connected to the V pin and the oscillator must be running, and the countdown chain must not be in reset (Register A DV2, DV1, BAUX DV0 = 01X) ...
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... At the beginning of Interval 3, the system processor has begun code execution and clears the interrupt condition of WF and/ writing 0’s to both of these control bits. As long as no other interrupt within the DS1685/DS1687 is pending, the IRQ line is taken inactive once these bits are reset. Execution of the application software can proceed. ...
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... Two extended control registers are provided to supply controls and status information for the extended features offered by the DS1685/DS1687. These are designated as extended control registers 4A and 4B and are located in register bank 1, locations 04AH and 04BH, respectively. The functions of the bits within these registers are described as follows ...
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... CS – Crystal Select Bit. When CS is set the oscillator is configured for operation with a crystal that has a 6pF specified load capacitance. When the oscillator is configured for a 12.5pF crystal disabled in the DS1687 EDIP and should be set RCE – RAM Clear-Enable bit. When set this bit enables a low level on RCLR to clear all 242 bytes of user RAM. When RCE = 0, RCLR and the RAM clear function are disabled. PRS – ...
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The RTC address is latched on the falling edge of the ALE signal. Each time an RTC address is latched, the register address stack is pushed. The stack is only four registers deep, holding the three previous RTC addresses in ...
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ABSOLUTE MAXIMUM RATINGS Voltage Range on Any Pin Relative to Ground………………………………………………………………….0.3V to +6V Operating Temperature Range, Commercial ...……………………………………………………………….0°C to +70°C Operating Temperature Range, Industrial…………………………………………………………………...-40°C to +85°C Storage Temperature Range………………………………………………………………………………….-40°C to +85°C Soldering Temperature, leads, 10 seconds (max).……………………………………………………..260°C (DIP, EDIP) Soldering ...
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DC ELECTRICAL CHARACTERISTICS (V = 5.0V±10 3.0V±10 PARAMETER (-5) Average V Power- CC Supply Current (-3) CMOS Standby (-5) Current (-3) ( 0.2V) CC Input Leakage Current (Any Input) Output Leakage ...
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RTC AC TIMING CHARACTERISTICS (V = 3.0V±10 0°C to +70° PARAMETER Cycle Time Pulse Width, RD/WR Low Pulse Width, RD/WR High Input Rise and Fall Time Chip-Select Setup Time Before Chip-Select Hold ...
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RTC AC TIMING CHARACTERISTICS (V = 5.0V±10 0°C to +70° PARAMETER Cycle Time Pulse Width, RD/WR Low Pulse Width, RD/WR High Input Rise and Fall Time Chip-Select Setup Time Before Chip-Select Hold ...
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... DS1685/DS1667 BUS TIMING FOR READ CYCLE TO RTC AND RTC REGISTERS DS1685/DS1687 BUS TIMING FOR WRITE CYCLE TO RTC AND RTC REGISTERS ...
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POWER-UP/DOWN TIMING— +25°C) A PARAMETER CS High to Power-Fail Recovery at Power-Up V Slew Rate Power-Down CC V Slew Rate Power-Down CC V Slew Rate Power-Up CC Expected Data Retention POWER-UP/DOWN TIMING— +25°C) A PARAMETER CS ...
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POWER-UP CONDITION—3V CS 2.6V 2. POWER FAIL POWER-DOWN CONDITION— POWER FAIL REC 2. 2.7V 2.6V 2. ...
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POWER-UP CONDITION—5V CS 4.5V 4.25V 4. POWER FAIL POWER-DOWN CONDITION— REC 4.5V FB 4.25V ...
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... V SW Note 9: The DS1687 keeps time to an accuracy of ±1 minute per month at 25°C during data retention time for the period of t Note 10 the amount of time that the internal battery can power the internal oscillator and internal registers of the DS1687 DR at 25° ...
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PACKAGE INFORMATION (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo ...
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PACKAGE INFORMATION (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo ...
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PACKAGE INFORMATION (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo ...
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PACKAGE INFORMATION (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo ...
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PACKAGE INFORMATION (continued) (The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information www.maxim-ic.com/DallasPackInfo ...
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... No circuit patent licenses are implied. Maxim/Dallas Semiconductor reserves the right to change the circuitry and specifications without notice at any time The Maxim logo is a registered trademark of Maxim Integrated Products, Inc. The Dallas logo is a registered trademark of Dallas Semiconductor Corporation © 2005 Maxim Integrated Products • Printed USA DS1685/DS1687 3V/5V Real-Time Clocks ...