Bandgap Reference Electrical Characteristics (Continued)
Note 2: All voltages are measured with respect to the GND pin, unless otherwise specified.
Note 3: When the input voltage (VIN) at any pin exceeds the power supply voltage (VIN < GND or VIN > V+), the absolute value of the current at that pin should
be limited to 5 mA or less. The 20 mA package input current specification limits the number of pins that can exceed the power supply boundaries with a 5 mA current
limit to four.
Note 4: The power dissipation of this device under normal operation should never exceed 875 mW (Quiescent Power Dissipation + TTL Loads on the digital
outputs). Caution should be taken not to exceed absolute maximum power rating when the device is operating in a severe fault condition (e.g., when any input or
output exceeds the power supply). The maximum power dissipation must be derated at elevated temperatures and is dictated by TJMAX (maximum junction
temperature), θJA (package junction to ambient thermal resistance), and TA (ambient temperature). The maximum allowable power dissipation at any temperature
is PDmax = (TJMAX − TA)/θJA or the number given in the Absolute Maximum Ratings, whichever is lower. For this device, TJMAX = 105˚C and θJA = 85˚C/W.
Note 5: See AN-450 “Surface Mounting Methods and Their Effect on Product Reliability” for other methods of soldering surface mount devices.
Note 6: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 7: Typicals are at 25˚C and represent most likely parametric norm.
Note 8: Limits are guaranteed to National’s AOQL (Average Output Quality Level).
Note 9: Total unadjusted error includes offset, full-scale, and linearity errors.
Note 10: Two on-chip diodes are tied to each analog input and are reversed biased during normal operation. One is connected to V+ and the other is connected
to GND. They will become forward biased and conduct when an analog input voltage is equal to or greater than one diode drop above V+ or below GND. Therefore,
caution should be exercised when testing with V+ = 4.5V. Analog inputs with magnitudes equal to 5V can cause an input diode to conduct, especially at elevated
temperatures. This can create conversion errors for analog signals near full-scale. The specification allows 50 mV forward bias on either diode; e.g., the output code
will be correct as long as the analog input signal does not exceed the supply voltage by more than 50 mV. Exceeding this range on an unselected channel will corrupt
the reading of a selected channel. An absolute analog input signal voltage range of 0V ≤ VIN ≤ 5V can be achieved by ensuring that the minimum supply voltage
applied to V+ is 4.950V over temperature variations, initial tolerance, and loading.
Note 11: Off-channel leakage current is measured on the on-channel selection.