|Номер в каталоге||ADC0831|
National ->Texas Instruments
|Компоненты Описание||8-Bit Serial I/O A/D Converters with Multiplexer Options|
|ADC0831 Datasheet PDF : 33 Pages |
The following specifications apply for VCC = 5V, tr = tf = 20 ns and 25˚C unless otherwise specified.
fCLK, Clock Frequency
tC, Conversion Time
Not including MUX Addressing Time
Clock Duty Cycle
tSET-UP, CS Falling Edge or
Data Input Valid to CLK
tHOLD, Data Input Valid
after CLK Rising Edge
tpd1, tpd0 — CLK Falling
Edge to Output Data Valid
Data MSB First
Data LSB First
t1H, t0H, — Rising Edge of
CS to Data Output and
CL=10 pF, RL=10k
(see TRI-STATE® Test Circuits)
CIN, Capacitance of Logic
CL=100 pf, RL=2k
COUT, Capacitance of Logic
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating
the device beyond its specified operating conditions.
Note 2: All voltages are measured with respect to the ground plugs.
Note 3: Internal zener diodes (6.3 to 8.5V) are connected from V+ to GND and VCC to GND. The zener at V+ can operate as a shunt regulator and is connected
to VCC via a conventional diode. Since the zener voltage equals the A/D’s breakdown voltage, the diode insures that VCC will be below breakdown when the device
is powered from V+. Functionality is therefore guaranteed for V+ operation even though the resultant voltage at VCC may exceed the specified Absolute Max of 6.5V.
It is recommended that a resistor be used to limit the max current into V+. (See Figure 3 in Functional Description Section 6.0)
Note 4: When the input voltage (VIN) at any pin exceeds the power supply rails (VIN < V− or VIN > V+) the absolute value of current at that pin should be limited
to 5 mA or less. The 20 mA package input current limits the number of pins that can exceed the power supply boundaries with a 5 mA current limit to four.
Note 5: Human body model, 100 pF discharged through a 1.5 kΩ resistor.
Note 6: Total unadjusted error includes offset, full-scale, linearity, and multiplexer errors.
Note 7: Cannot be tested for ADC0832.
Note 8: For VIN(−)≥VIN(+) the digital output code will be 0000 0000. Two on-chip diodes are tied to each analog input (see Block Diagram) which will forward conduct
for analog input voltages one diode drop below ground or one diode drop greater than the VCC supply. Be careful, during testing at low VCC levels (4.5V), as high
level analog inputs (5V) can cause this input diode to conduct — especially at elevated temperatures, and cause errors for analog inputs near full-scale. The spec
allows 50 mV forward bias of either diode. This means that as long as the analog VIN or VREF does not exceed the supply voltage by more than 50 mV, the output
code will be correct. To achieve an absolute 0 VDC to 5 VDC input voltage range will therefore require a minimum supply voltage of 4.950 VDC over temperature
variations, initial tolerance and loading.
Note 9: Leakage current is measured with the clock not switching.
Note 10: A 40% to 60% clock duty cycle range insures proper operation at all clock frequencies. In the case that an available clock has a duty cycle outside of these
limits, the minimum, time the clock is high or the minimum time the clock is low must be at least 1 µs. The maximum time the clock can be high is 60 µs. The clock
can be stopped when low so long as the analog input voltage remains stable.
Note 11: Since data, MSB first, is the output of the comparator used in the successive approximation loop, an additional delay is built in (see Block Diagram) to allow
for comparator response time.
Note 12: Typicals are at 25˚C and represent most likely parametric norm.
Note 13: Tested limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 14: Guaranteed but not 100% production tested. These limits are not used to calculate outgoing quality levels.
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