Datasheet

NFR =
¸
¸
¹
·
¨
¨
©
§
Peak-to-Peak Noise
2 x VREF/Gain
log
2
ENOB =
¸
¸
¹
·
¨
¨
©
§
RMS Noise
2 x VREF/Gain
log
2
SCLK
SDO
8 9
0.3V
IO
0.7V
IO
t
DOE
DB7
0.3V
IO
SDO
0.9V
IO
0.1V
IO
t
DOF
t
DOR
0.1V
IO
0.9V
IO
LMP90100
www.ti.com SNAS510P –JANUARY 2011–REVISED MARCH 2013
Symbol Parameter Conditions Min Typical Max Units
SDO Enable time from the falling
t
DOE
35 ns
edge of the 8th SCLK
t
DOR
SDO Rise time
(1)
7 ns
t
DOF
SDO Fall time
(1)
7 ns
ODR ≤ 13.42 SPS 64 µs
Data Ready Bar pulse at every
t
DRDYB
1/ODR second, see Figure 53
13.42 < ODR ≤ 214.65 SPS 4 µs
Specific Definitions
COMMON MODE REJECTION RATIO is a measure of how well in-phase signals common to both input pins are
rejected. To calculate CMRR, the change in output offset is measured while the common mode input voltage is
changed.
CMRR = 20 LOG(ΔCommon Input / ΔOutput Offset)
EFFECTIVE NUMBER OF BITS (ENOB, or EFFECTIVE BITS) – says that the converter is equivalent to a
perfect ADC of this (ENOB) number of bits. LMP90100’s ENOB is a DC ENOB spec, not the dynamic ENOB that
is measured using FFT and SINAD. Its equation is as follows:
(1)
GAIN ERROR is the deviation from the ideal slope of the transfer function.
INTEGRAL NON-LINEARITY (INL) is a measure of the deviation of each individual code from a straight line
through the input to output transfer function. The deviation of any given code from this straight line is measured
from the center of that code value. The end point fit method is used. INL for this product is specified over a
limited range, per the Electrical Tables.
NEGATIVE FULL-SCALE ERROR is the difference between the differential input voltage at which the output
code transitions to negative full scale and (-VREF + 1LSB).
NEGATIVE GAIN ERROR is the difference between the negative full-scale error and the offset error divided by
(VREF / Gain).
NOISE FREE RESOLUTION is a method of specifying the number of bits for a converter with noise.
(2)
ODR Output Data Rate.
OFFSET ERROR is the difference between the differential input voltage at which the output code transitions from
code 0000h to 0001h and 1 LSB.
POSITIVE FULL-SCALE ERROR is the difference between the differential input voltage at which the output
code transitions to positive full scale and (VREF – 1LSB).
POSITIVE GAIN ERROR is the difference between the positive full-scale error and the offset error divided by
(VREF / Gain).
POWER SUPPLY REJECTION RATIO (PSRR) is a measure of how well a change in the analog supply voltage
is rejected. PSRR is calculated from the ratio of the change in offset error for a given change in supply voltage,
expressed in dB.
(1) This parameter is specified by design and/or characterization and is not tested in production.
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