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How To       How To    Read Datasheet        Electrical Specification       t h l ti        twww.pantechsolutions.net     ...
What     Where     Why              What Where Why                             Electrical SpecificationRead all Informatio...
Maximum RatingM i     R ti  This will always appear in the 1st page of the data sheet                                     ...
DC CharacteristicDC Ch    t i ti                                                            Test Conditions               ...
DC Characteristic   DC Ch    t i ti                               VOL - maximum output low                                ...
DC Characteristic   DC Characteristic                                                                                   Th...
AC Characteristic   AC Ch    t i ti                                                               Timing requirement for S...
Timing requirement for Bus AccessRead CycleWrite Cycle                                      8
Timing Requirement for Bus Access                     Timing Requirement for Bus Access  Write Cycle  The Chip Datasheet p...
Operating Conditions/ Range                 O    ti C diti / R                          Data in the table is limited to th...
Circuitry                                                                                        Very Important           ...
Pin States                                   Pi St t                                                            The states...
Pin ‐ Internal Configuration   Pi I t       l C fi     ti                                                               Pu...
www.pantechsolutions.net5/23/2011 8:23:15                          © Pantech Solutions Pvt Ltd. | All rights reserved   ww...
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How to read datasheet

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How to read datasheet

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How to read datasheet

  1. 1. How To How To Read Datasheet Electrical Specification t h l ti twww.pantechsolutions.net 1
  2. 2. What     Where     Why What Where Why Electrical SpecificationRead all Information? DC value gives the  Not necessary Not necessary. driveability, consumptionTwo main classifications values  DC AC value provides detail in  AC timing requirementWhat Type of Specifications?  Guaranteed‐minimum Min & Max values are use for design consideration, whereas  Guaranteed‐maximum typical value are purely used as  Typical an indication only  Guaranteed‐but‐not‐testedUnder what Conditions? The data provided will be based on certain condition If condition.  Operating Temperature  operation is out of this range,  Voltage the data will not be guarantee.  Load Condition Thus a chart is normallyOtherOth provided f f th id d for further  Recommended circuitry information Design have to abide to the chip specification. This is to ensure a reliable & quality product The following slides extracted some examples. 2
  3. 3. Maximum RatingM i R ti This will always appear in the 1st page of the data sheet Supply < 7V IO signal < V (7V) i l Vcc System operation temperature < 75 ºC The chip will be damage if operating at this range 3
  4. 4. DC CharacteristicDC Ch t i ti Test Conditions Make sure- right comparison is make: Eg.+ Eg + 1 % error at 25 ºC has no meaning in design consideration Values for Vcc ranging 4- 5.5V VIH - minimum input voltage p g Note: Different requirements when q into the chip, so that this is Conditions are different. recognized as a “High” level. Ie Input signal must be more The input shall not exceed this than 0.8Vcc. Maximum value VIL - maximum input voltage p g into the chip, so that this is recognized as a “Low” level. I.e. input signal must be less than 0.2Vcc 4
  5. 5. DC Characteristic DC Ch t i ti VOL - maximum output low voltage out of the chip. I.e. when the chip output a “Low”, the i th signal will not exceed l ill t d 0.6V. Different PortPins may have different drivability d i bilit Note that the Max Value of VOL is different at different load condition (IOL) This will determine what can the port drive, such as LED. Take note of extra comment On Test conditions 5
  6. 6. DC Characteristic DC Characteristic This part show how much current the chip itself will consume at each particular mode Note the allowable current for each & total pins.5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM
  7. 7. AC Characteristic AC Ch t i ti Timing requirement for Serial Port Take note of the units This may in nsec, or relative to some other reference Find the symbol in the timing diagram to understand what does it really mean.5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM
  8. 8. Timing requirement for Bus AccessRead CycleWrite Cycle 8
  9. 9. Timing Requirement for Bus Access Timing Requirement for Bus Access Write Cycle The Chip Datasheet provide how fast the data and control signal are being g g output. Check point  external chip:- Can the external device (RAM, Chip) ( , p) be able to “latch” in this data? Read Cycle y The Chip Datasheet provide the specification on how can the external data be “latched-in” to the chip. Check point  This Chip:- Can the external data remained on the data bus “long” enough to meet the minimum setup timer ( RDS) & p (t hold timer (tRDH) Setup time Hold time5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM
  10. 10. Operating Conditions/ Range O ti C diti / R Data in the table is limited to the Test condition. Thus X-Y axis Graph is also provided to show the relative operating condition5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM
  11. 11. Circuitry Very Important Connection requirement Suggested use for high current port Test Condition5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM
  12. 12. Pin States Pi St t The states of each Pin at each operating mode is important in the system design. Example: If power up state is “High Impedance”, It will be important to have a pull up resistor to pull-up have a clear define state. This will prevent data contention, or even sudden activation of a motor. motor5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM
  13. 13. Pin ‐ Internal Configuration Pi I t l C fi ti Pull Up MOS for extra current drive Output Control5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM
  14. 14. www.pantechsolutions.net5/23/2011 8:23:15  © Pantech Solutions Pvt Ltd. | All rights reserved www.pantechsolutions.netPM

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