Electrical characteristics of the XBee/XBee-PRO RF Module
XBee / XBee-PRO RF Modules 802.15.4 Product Manual 17
INL
Integral non-linearity
6
- ±0.5 ±1.0 LSB
E
ZS
Zero-scale error
7
- ±0.4 ±1.0 LSB
F
FS
Full-scale error
8
- ±0.4 ±1.0 LSB
E
IL
Input leakage error
9
- ±0.05 ±5.0 LSB
E
TU
Total unadjusted error
10
- ±1.1 ±2.5 LSB
1. All accuracy numbers are based on the processor and system being in WAIT state (very little activity and no
IO switching) and that adequate low-pass filtering is present on analog input pins (filter with 0.01 μF to 0.1 μF
capacitor between analog input and VREFL). Failure to observe these guidelines may result in system or
microcontroller noise causing accuracy errors which will vary based on board layout and the type and
magnitude of the activity. Data transmission and reception during data conversion may cause some
degradation of these specifications, depending on the number and timing of packets. We advise testing the
ADCs in your installation if best accuracy is required.
2. R
AS
is the real portion of the impedance of the network driving the analog input pin. Values greater than this
amount may not fully charge the input circuitry of the ATD resulting in accuracy error.
3. Analog input must be between V
REFL
and V
REFH
for valid conversion. Values greater than V
REFH
will convert to
$3FF.
4. The resolution is the ideal step size or 1LSB = (V
REFH
–V
REFL
)/1024.
5. Differential non-linearity is the difference between the current code width and the ideal code width (1LSB).
The current code width is the difference in the transition voltages to and from the current code.
6. Integral non-linearity is the difference between the transition voltage to the current code and the adjusted
ideal transition voltage for the current code. The adjusted ideal transition voltage is (Current Code–1/2)*(1/
((VREFH+EFS)–(VREFL+EZS))).
7. Zero-scale error is the difference between the transition to the first valid code and the ideal transition to that
code. The Ideal transition voltage to a given code is (Code–1/2)*(1/(VREFH–VREFL)).
8. Full-scale error is the difference between the transition to the last valid code and the ideal transition to that
code. The ideal transition voltage to a given code is (Code–1/2)*(1/(VREFH–VREFL)).
9. Input leakage error is error due to input leakage across the real portion of the impedance of the network
driving the analog pin. Reducing the impedance of the network reduces this error.
10.Total unadjusted error is the difference between the transition voltage to the current code and the ideal
straight-line transfer function. This measure of error includes inherent quantization error (1/2LSB) and
circuit error (differential, integral, zero-scale, and full-scale) error. The specified value of ETU assumes zero
EIL (no leakage or zero real source impedance).
Table 5: ADC timing/performance characteristics
1
Symbol Characteristic Condition Min Typical Max Unit
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