ISL1208 Intersil Corporation, ISL1208 Datasheet

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... Data Sheet Low Power RTC with Battery Backed SRAM The ISL1208 device is a low power real time clock with timing and crystal compensation, clock/calendar, power fail indicator, periodic or polled alarm, intelligent battery backup switching and battery-backed user SRAM. The oscillator uses an external, low-cost 32.768kHz crystal. ...

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... The Serial Clock (SCL) input is used to clock all serial data into and out of the device. 7 IRQ/F Interrupt Output/Frequency Output is a multi-functional pin that can be used as interrupt or frequency output pin. The OUT function is set via the configuration register Power supply ISL1208 RTC INTERFACE CONTROL LOGIC RTC DIVIDER POR ...

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... V SDA and SCL input buffer HIGH IH voltage Hysteresis SDA and SCL input buffer hysteresis V SDA output buffer LOW voltage, OL sinking 3mA 3 ISL1208 Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Lead Temperature (Soldering, 10s 300°C + 0.5 (V Mode 0.5 (V Mode) BAT BAT Temperature = -40°C to +85°C, unless otherwise stated. ...

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... NOTES: 1. IRQ & F Inactive. OUT 2. LPMODE = 0 (default order to ensure proper timekeeping, the V 4. Typical values are for T = 25°C and 3.3V supply voltage. 4 ISL1208 Over the recommended operating conditions unless otherwise specified. (Continued) TEST CONDITIONS T = 25° 1MHz 5V ...

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... SDA (OUTPUT TIMING) Symbol Table WAVEFORM INPUTS Must be steady May change from LOW to HIGH May change from HIGH to LOW Don’t Care: Changes Allowed N/A 5 ISL1208 HIGH LOW t SU:DAT t HD:DAT OUTPUTS Will be steady Will change from LOW to HIGH Will change ...

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... TEMPERATURE (°C) FIGURE TEMPERATURE DD1 2.1E-6 2.0E-6 1.9E-6 1.8E-6 1.7E-6 1.6E-6 1.5E-6 1.4E-6 1.3E-6 1.2E-6 F OUT (Hz) FIGURE DD1 OUT 6 ISL1208 Temperature is 25°C unless otherwise specified 000E+0 4.5 5.0 5.5 BAT 800.0E-9 600.0E-9 400.0E 3.3V DD 1E-6 800E-9 600E-9 400E-9 200E-9 -40 - TEMPERATURE (°C) FIGURE TEMPERATURE AT V BAT 2 ...

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... X1, X2 The X1 and X2 pins are the input and output, respectively inverting amplifier. An external 32.768kHz quartz crystal is used with the ISL1208 to supply a timebase for the real time clock. Internal compensation circuitry provides high accuracy over the operating temperature range from -40°C to +85°C. This oscillator compensation network can ...

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... ISL1208 for years. Another option is to use a Super Cap for applications where month. See the Applications Section for more information. Normal Mode ( Battery Backup Mode BAT To transition from the mode, both of the DD BAT following conditions must be met: ...

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... The frequency output can be enabled/disabled during battery backup mode using the FOBATB bit. General Purpose User SRAM The ISL1208 provides 2 bytes of user SRAM. The SRAM will continue to operate in battery backup mode. However should be noted that the I C bus is disabled in battery backup mode ...

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... USR2 USR27 10 ISL1208 instruction latches all clock registers into a buffer update of the clock does not change the time being read. A sequential read will not result in the output of data from the memory array. At the end of a read, the master supplies a stop condition to end the operation and free the bus ...

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... Years divisible by 100 are not leap years, unless they are also divisible by 400. This means that the year 2000 is a leap year, the year 2100 is not. The ISL1208 does not correct for the leap year in the year 2100. ...

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... This bit enables/disables the alarm function. When the ALME bit is set to “1”, the alarm function is enabled. When the ALME 12 ISL1208 is cleared to “0”, the alarm function is disabled. The alarm function can operate in either a single event alarm or a periodic interrupt alarm (see IM bit). ...

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... Note that these are typical values. BATTERY MODE ATR SELECTION (BMATR <1:0>) Since the accuracy of the crystal oscillator is dependent on the V /V operation, the ISL1208 provides the capability DD BAT to adjust the capacitance between V DD device switches between power sources. ...

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... Data states on the SDA line can change only during SCL LOW periods. SDA state changes during SCL HIGH are reserved for indicating START and STOP conditions (See Figure 12). On power up of the ISL1208, the SDA pin is in the input mode. 2 All I ...

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... SDA line LOW to acknowledge the reception of the eight bits of data (See Figure 13). The ISL1208 responds with an ACK after recognition of a START condition followed by a valid Identification Byte, and once again after successful receipt of an Address Byte. The ISL1208 also responds with an ACK after receiving a Data ...

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... Identification byte with the R/W bit set to “1”. After each of the three bytes, the ISL1208 responds with an ACK. Then the ISL1208 transmits Data Bytes as long as the master responds with an ACK during the SCL cycle following the eighth bit of each byte. The master terminates the read operation (issuing a STOP condition) following the last bit of the last Data Byte (See Figure 16) ...

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... ISL1208 In addition to the analog compensation afforded by the adjustable load capacitance, a digital compensation feature is available for the ISL1208. There are 3 bits known as the Digital Trimming Register (DTR). The range provided is ±60ppm in increments of 20ppm. DTR operates by adding or skipping pulses in the clock counter very useful for ...

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... T A sample curve of the ATR setting vs. Frequency Adjustment for the ISL1208 and a typical RTC crystal is given in Figure 18. This curve may vary with different crystals good practice to evaluate a given crystal in an ISL1208 circuit before establishing the adjustment values ...

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... BAT voltage from fully charged to loss of operation. Note that I is the total of the supply current of the ISL1208 (I TOT plus the leakage current of the capacitor and the diode these calculations assumed to be extremely small LKG and will be ignored ...

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... Packaging Information 8-Lead Miniature Small Outline Gull Wing Package Type M 0.012 + 0.006 / -0.002 (0.30 + 0.15 / -0.05) 0.036 (0.91) 0.032 (0.81) 0.040 ± 0.002 (1.02 ± 0.05) 0.007 (0.18) 0.005 (0.13) 20 ISL1208 0.118 ± 0.002 (3.00 ± 0.05) 0.0256 (0.65) Typ. 0.118 ± 0.002 (3.00 ± 0.05) 0.030 (0.76) 0.0216 (0.55) 7° Typ. 0.008 (0.20) 0.004 (0.10) 0.150 (3.81) Ref. 0.193 (4.90) Ref ...

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... However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 21 ISL1208 8-Lead Plastic, SOIC, Package Code S8 Pin 1 0.014 (0.35) ...