WM0831, WM0832
Electrical Characteristics
(continued)
Notes:
1. Absolute Maximum Ratings are stress ratings only.
Permanent damage to the device may be caused by
continuously operating at or beyond these limits. De-
vice functional operating range limits are given under
Recommended Operating Conditions.
Guaran-
teed performance specifications are given under Elec-
trical Characteristics at the test conditions specified.
2.
All voltage values, except differential voltages are with
respect to the ground.
When the input voltage V
IN
at any pin exceeds the
power supply rails (GND > V
IN
> V
CC
) 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 supply current to four.
A clock duty cycle range of 40% to 60% ensures
correct operation at all clock frequencies. For a clock
with a duty cycle outside these limits, the minimum time
the clock is high or low must be at least 666 ns, with
the maximum time for clock high or low being 60 ms.
All typical values are at V
CC
= 5 V, T
A
= 25
o
C for 5V
devices and V
CC
= 3.3V, T
A
= 25
o
C.
All parameters are measured under open-loop
conditions with zero common mode input voltage
(unless otherwise stated).
7. Total Unadjusted Error (TUE) is the sum of integral
linearity error, zero code error and full scale error over
the output code range.
8. A Differential linearity of "n" bits ensures a code width
exists to "n" bits. Hence a Differential Linearity of 8
bits for an 8 bit ADC guarantees no missing codes.
9. For V
IN
(-) greater than or equal to V
IN
(+) the digital out-
put code will be 00 Hex. Connected to each analogue
input are two diodes which will forward conduct for a
diode drop outside the supply rails, V
CC
and GND. If an
analogue input voltage does not exceed the supply volt-
age by more than 50 mV, the output code will be cor-
rect. To use an absolute input voltage range of 0 to V
CC
a minimum V
CC
- 0.05 V is required for all variations of
temperature. Care should be exercised when testing at
low V
CC
levels with a maximum analogue voltage as
this can cause the input diode to conduct, especially at
high temperature, and cause errors for analogue inputs
near full scale.
10. Standby input leakage currents, are currents going in
or out of the on or off channels when the ADC is not
performing conversion and the clock input is in a high
or low steady-state condition.
11. For WM0832 the reference current is included in the
supply current as V
REF
is internally connected to V
CC
.
3.
4.
5.
6.
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6
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
