怎样阅读IC的数据手册
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Specifications – Definitions
Many datasheets have a ‘Definitions’ or ‘Terminology’ section Most often found in specialized products
Otherwise, search the website glossary
Specifications
Details of the product performance All important, measureable parameters
Accuracy and speed Timing Power requirements
What the company guarantees
Power supplies Operating temperature -- usually 25C Input signal range Reference level, loading, gain setting, etc
Simple for op amps Complex for data converters and other products
Absolute Maximum Ratings Recommendations
What to do if it is certain part has exceeded Absolute Max – but still seems to work
Performance has been compromised in hidden ways Replace the part if you are making critical performance measurements Don’t send evaluation equipment with such parts to customers
Testing and specifications are driven by statistics
Typical Performance Curves (TPCs)
Typical performance curves show performance over the full operating range
All specifications have a distribution of values If it says typical, it’s not tested often
It was tested at release characterization Some units will be above, some below the spec Some distributions are loose, some tight Typical specs are screened by QA
Specifications -- Models
Models in a product family
Different specifications Different temperature ranges Different packages Different shipping packages (reel, tray, tube, etc)
If it says minimum or maximum, it may not be tested 100%
Specifications over temperature are guaranteed by characterization and guardbanding All tests have noise with Gaussian distribution Guardbands are set to keep failure in low ppm range
Spec differences will have separate columns
Test conditions – general and specific
General conditions at the top of specification page Apply to all specifications unless overridden in specific conditions of each spec
Product Selection
Owner’s manual
Choosing a product – the progression
General descriptions of product types Selection tables
Product features on product page Product features on product page
ILIM
50 74 114
100 92
150 100 150 300 500 900 1500 450 5
425
470
VINx Current Consumption Battery Current ConsumptionIQVIN IQVIN_DI源自 IQBATT2 280 20
mA µA µA µA mA
More likely to cover your operating range of interest Characterization of a large number of parts Often difficult to test by users Application may be non-standard, not at the center of specifications Datasheet authors attempt to anticipate most common use cases and operating conditions
Often an important part of product selection
Typical Performance Curves (TPCs)
Absolute Maximum Ratings
Section normally appears after Specifications Describes limits that will result in device damage Maximum voltages between pins Maximum currents into/out of pins Maximum temperatures for usage and storage Soldering and assembly conditions
0.5
0.9
Test conditions – Notes
Notes cited at bottom of page provide definitions, clarifications, and additional conditions The fine print
Minimum/maximum/typical
Test conditions – general and specific
Power supplies get very specific
Parameter Undervoltage lockout Hysteresis Total Input Current Symbol Min Typ Max Unit V mV mA Test Conditions/Comments Falling threshold, higher of VVIN and VBAT_SNS Hysteresis, higher of VVIN and VBAT_SNS rising1 Nominal USB initialized current level USB superspeed USB enumerated current level (specification for China) USB enumerated current level Dedicated charger input Dedicated wall charger Charging or LDO mode DIS_IC1 = high, VISO_B < VINx < 5.5 V LDO mode, VISO_S > VBAT_SNS Standby, includes ISO_Sx pin leakage, VVIN = 0 V, TJ = −40°C to +85°C Standby, battery monitor active
Purposes of a datasheet
Product description
Will this product fit my application Functions and specifications How do I get the functions to work How do I plug it in Complex products, such as DSP, often have separate manual on programming What else can the product do What new applications can I build What performance is guaranteed What voids the warranty
The World Leader in High Performance Signal Processing Solutions
WHAT’S IN A DATASHEET?
Presented by David Kress
Outline
Purposes of a datasheet What info do you need today? Product selection Specifications and conditions Absolute maximum ratings Thermal analysis Theory of operation and applications Packages and pinouts Ways to find what you are looking for What’s not in a datasheet
Test conditions – general and specific
Specific conditions shown at each spec line Describe conditions of testing and guarantees Typical performance charts show wider range of performance
Owner’s manual
Idea generator
Warranty document
What do I need today?
Idea generator
What else can the product do What new applications can I build Will this product fit my application Functions and specifications How do I get the functions to work How do I plug it in What else do I need Software Connecting products Documentation
Choosing a product – the progression
General specs and features look good Go to the datasheet Complete specs Detailed description Applications