ADC12181EVAL datasheet(7/17 Pages) NSC

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AC Electrical Characteristics (Continued)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is

functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed

specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test

conditions.

Note 2: All voltages are measured with respect to GND = AGND = DGND = 0V, unless otherwise specified.

Note 3: When the input voltage at any pin exceeds the power supplies (that is, VIN < AGND, or VIN > VA,VD or VD I/O), the current at that pin should be limited

to 25 mA. The 50 mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 25 mA to

two.

Note 4: The absolute maximum junction temperatures (TJmax) for this device is 150˚C. The maximum allowable power consumption is dictated by TJmax, the

junction-to-ambient thermal resistance (

θJA), and the ambient temperature, (TA), and can be calculated using the formula PDMAX=(TJmax - TA )/θJA. In the 32-pin

TQFP,

θJA is 74˚C/W, so PDMAX = 1,689 mW at 25˚C and 1,013 mW at the maximum operating ambient temperature of 75˚C. Note that the power consumption

of this device under normal operation will typically be about 255 mW (typical power consumption + 20 mW TTL output loading). The values for maximum power

consumption listed above will be reached only when the ADC12181 is operated in a severe fault condition (e.g. when input or output pins are driven beyond the

power supply voltages, or the power supply polarity is reversed). Obviously, such conditions should always be avoided.

Note 5: Human body model is 100 pF capacitor discharged through a 1.5k

Ω resistor. Machine model is 220 pf discharged through ZERO Ohms.

Note 6: See AN450, "Surface Mounting Methods and Their Effect on Product Reliability", or the section entitled "Surface Mount" found in any post 1986 National

Semiconductor Linear Data Book, for other methods of soldering surface mount devices.

Note 7: The inputs are protected as shown below. Input voltage magnitudes up to 5V above VA or to 5V below GND will not damage this device, provided current

is limited per Note 3. However, errors in the A/D conversion can occur if the input goes above VA or below GND by more than 100 mV. As an example, if VA is 4.75V,

the full-scale input voltage must be

≤4.85V to ensure accurate conversions.

10103908

Note 8: To guarantee accuracy, it is required that |VA -VD| ≤ 100mV and separate bypassed capacitors are used at each power supply pin.

Note 9: With the test condition for VREF = +2.0V, the 12-bit LSB is 488µV.

Note 10: Typical figures are at TA =TJ = 25˚C, and represent most likely parametric norms.

Note 11: Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

Note 12: Integral Non Linearity is defined as the deviation of the analog value, expressed in LSBs, from the straight line that passes through positive full-scall and

zero.

Note 13: Timing specifications are tested at the TTL logic levels, VIL = 0.4V for a falling edge and VIH = 2.4V for a rising edge. TRI-STATE output voltage is forced

to 1.4V.

Note 14: Optimum SNR performance will be obtained by keeping the reference input in the 1.8V to 2.2V range. The LM4041CIM3-ADJ (SOT-23 package), the

LM4041CIZ-ADJ (TO-92 package), or the LM4041CIM-ADJ (SOT-8 package) bandgap voltage reference is recommended for this application.

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