DS1603

DS1603 MAXIM | Alldatasheet

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Technical content

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata.

FEATURES

§ Two 32-bit counters keep track of real-time and elapsed time § Counters keep track of seconds for over 125 years § Battery powered counter counts seconds from the time battery is attached until VBAT is less than 2.5V § VCC powered counter counts seconds while VCC is above VTP and retains the count in the absence of VCC under battery backup power § Clear function resets selected counter to 0 § Read/write serial port affords low pin count § Powered internally by a lithium energy cell that provides over 10 years of operation § One-byte protocol defines read/write, counter address and software clear function § Self-contained crystal provides an accuracy of ±2 min per month § Operating temperature range of 0°C to +70°C § Low-profile SIP module § Underwriters Laboratory (UL) recognized PIN ASSIGNMENT PIN DESCRIPTION RST - Reset CLK - Clock DQ - Data Input/Output GND - Ground VCC - +5V OSC - 1Hz Oscillator Output NC - No Connect

DESCRIPTION

The DS1603 is a real -time clo ck/elapsed time counter designed to count seconds when V CC power is applied and continually count seconds under battery backup power with an additional counter regardless of the condition of VCC. The continuous counter can be used to derive time of day, we ek, month, and year by using a software algorithm. The V CC powered counter will automatically record the amount of time that VCC power is applied. This function is particularly useful in determining the operational time of equipment in which the DS1603 is used. Alternatively, this counter can also be used under software control to record real-time events. Communication to and from the DS1603 takes place via a 3 -wire serial port. A 1 -byte protocol selects read/ write functions, counter clear functions and os cillator trim. The device contains a 32.768kHz crystal that will keep track of time to within ±2 min/mo. An internal lithium energy source contains enough energy to power the continuous seconds counter for over 10 years. OPERATION The main elements of the DS1603 are shown in Figure 1. As shown, communications to and from the elapsed time counter occur over a 3-wire serial port. The port is activated by driving RST to a high state. VCC RST DQ NC CLK OSC GND DS1603 Elapsed Time Counter Module www.maxim -ic.com www.maxim-ic.com

power was lost. The 32-bit VCC counter is gated by VCC and the internal 1Hz signal. Table 1. Each data transfer to the protocol register designates what action is to occur. As defined, the 32 clock cycles should always follow the protocol. RST turns on the serial port logic, which allows access to the protocol register for the pro tocol data entry. 8 + 32 bits when reading or writing either counter. Data transfer is illustrated in Figure 3.

Following the 8-bit protocol that inputs write mode, 32 bits of data are written to the selected counter on the rising edge of the next 32 CLK cycles. After 32 bits have been entered any additional CLK cycles will be ignored until RST is transitioned low to end data transfer and then high again to begin new data transfer. DATA OUTPUT Following the eight CLK cycles that input read mode protocol, 32 bits of data will be output from the selected counter on the next 32 CLK cycles. The first data bit to be transmitted from the selected 32 -bit counter occurs on the falling edge after the last bit of protocol is written. When transmitting data from the selected 32-bit counter, RST must remain at high level as a transition to low level will terminate data transfer. Data is driven out the DQ pin as long as CLK is low. When CLK is high the DQ pin is tristated. OSCILLATOR OUTPUT Pin 6 of the DS1603 module is a 1Hz output signal. This signal is present only when V CC is applied and greater than the internal power supply. However, the output is guaranteed to meet TTL requirement only while VCC is within normal limits. This output can be used as a 1 -second interrupt or time tick needed in some applications. INTERNAL POWER The internal battery of the DS1603 module provides 35mAh and will run the elapsed time counter for over 10 years in the absence of power. PIN DESCRIPTIONS VCC, GND – DC power is provided to the device on these pins. VCC is the +5V input. When 5V is applied within normal limits, the device is fully accessible and data can be written and read. When a 3V battery is connected to the device and VCC is below 1.25 x VBAT, reads and writes are inhibited. As V CC falls below VBAT the continuous counter is switched over to the internal battery. CLK (Serial Clock Input) – CLK is used to synchronize data movement on the serial interface. DQ (Data Input/Output) – The DQ pin is the bi-directional data pin for the 3-wire interface. RST (Reset) – The reset signal must be asserted high during a read or a write. OSC (One Hertz Output Signal) – This signal is only present when Vcc is at a valid level and the oscillator is enabled.

Table 1. VALID PROTOCOLS

Figure 3. DATA TRANSFER Note: tCL, tCH, tR, and tF apply to both read and write data transfer.

Voltage Range on Any Pin Relative to Ground -0.3V to +7.0V Operating Temperature Range 0°C to +70°C Storage Temperature Range -40°C to +70°C Soldering Temperature Range See IPC/JEDEC J-STD-020A (See Note 11) This is a stress rating only and functional operation of the device at these or any other conditions beyond t hose indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time can affect reliability. RECOMMENDED DC OPERATING CONDITIONS (0°C to +70°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Supply Voltage VCC 4.5 5.0 5.5 V 1 Logic 1 Input VIH 2.0 VCC + 0.3 V 1 Logic 0 Input VIL -0.3 0.8 V 1 DC ELECTRICAL CHARACTERISTICS (0°C to +70°C; VCC = 5V ±10%) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Input Leakage ILI -1 +1 µA I/O Leakage ILO -1 +1 µA Logic 1 Output VOH 2.4 V 2 Logic 0 Output VOL 0.4 V 3 Active Supply Current ICC 1 mA 4 Timekeeping Current ICC1 50 µA 5 Battery Trip Point VTP 3.0 4.5 V 9 CAPACITANCE (TA = +25°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Input Capacitance CI 5 pF I/O Capacitance CI/O 10 pF

AC ELECTRICAL CHARACTERISTICS (VCC = +5V ±10%; 0°C to +70°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Data to CLK Setup tDC 50 ns 6 CLK to Data Hold tCDH 60 ns 6 CLK to Data Delay tCDD 200 ns 6, 7, 8 CLK Low Time tCL 250 ns 6 CLK High Time tCH 250 ns 6 CLK Frequency fCLK DC 2.0 MHz 6 CLK Rise and Fall tF, tR 500 ns RST to CLK Setup tCC 100 ns 6 CLK to RST Hold tCCH 60 ns 6 RST Inactive Time tCWH 1 µs 6 RST Low to I/O High-Z tRDZ 70 ns 6 CLK High to I/O High-Z tCDZ 20 ns 6 (TA = +25°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Expected Data Retention Time tDR 10 years 10 NOTES: 1) All voltages are referenced to ground. 2) Logic 1 voltages are specified at a source current of 1mA. 3) Logic 0 voltages are specified at a sink current of 4mA. 4) ICC is specified with the DQ pin open. 5) ICC1 is specified with VCC at 5.0V and RST = GND. 6) Measured at VIH = 2.0V or VIL = 0.8V. 7) Measured at VOH = 2.4V or VOL - 0.4V. 8) Load capacitance = 50pF. 9) Battery trip point is the point at which the V CC powered counter and the serial port stops operation. The battery trip point drops below the minimum once the internal lithium energy cell is exhausted. 10) The expected t DR is defined as accumulative time in the absence of V CC wit h the clock oscillator running. 11) Real-time clock modules can be successfully processed through conventional wave -soldering techniques as long as temperature exposure to the lithium energy source contained within does not exceed +85 °C. Post -solder cleaning with water -washing techniques is acceptable, provided that ultrasonic vibration is not used.

A IN. MM 0.830 21.08 0.850 21.59 B IN. MM 0.650 16.51 0.670 17.02 C IN. MM 0.310 7.87 0.330 8.38 D IN. MM 0.015 0.38 0.030 0.76 E IN. MM 0.110 2.79 0.140 3.56 F IN. MM 0.015 0.38 0.021 0.53 G IN. MM 0.090 2.29 0.110 2.79 H IN. MM 0.105 2.67 0.135 3.43 J IN. MM 0.360 9.14 0.390 9.91