LPC122X All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 26 August 2011 42 of 61
NXP Semiconductors
LPC122x
32-bit ARM Cortex-M0 microcontroller
10.4 ADC characteristics
[1] Typical ratings are not guaranteed. The values listed are at room temperature (25 C), nominal supply
voltages.
[2] Conditions: V
SS
=0V, V
DD(3V3)
=3.3V.
[3] The ADC is monotonic, there are no missing codes.
[4] The differential linearity error (E
D
) is the difference between the actual step width and the ideal step width.
See Figure 19
.
[5] The integral non-linearity (E
L(adj)
) is the peak difference between the center of the steps of the actual and
the ideal transfer curve after appropriate adjustment of gain and offset errors. See Figure 19
.
[6] The offset error (E
O
) is the absolute difference between the straight line which fits the actual curve and the
straight line which fits the ideal curve. See Figure 19
.
[7] The gain error (E
G
) is the relative difference in percent between the straight line fitting the actual transfer
curve after removing offset error, and the straight line which fits the ideal transfer curve. See Figure 19
.
[8] The absolute error (E
T
) is the maximum difference between the center of the steps of the actual transfer
curve of the non-calibrated ADC and the ideal transfer curve. See Figure 19
.
[9] T
amb
= 25 C; maximum sampling frequency f
s
= 257 kHz and analog input capacitance C
ia
= 1 pF.
[10] Input resistance R
i
depends on the sampling frequency fs: R
i
= 1 / (f
s
C
ia
).
Table 9. ADC static characteristics
T
amb
=
40
C to +85
C unless otherwise specified; ADC frequency 9 MHz, V
DD(3V3)
= 3.0 V to
3.6 V.
Symbol Parameter Conditions Min Typ
[1]
Max Unit
V
IA
analog input voltage 0 - V
DD(3V3)
V
C
ia
analog input capacitance - - 1 pF
E
D
differential linearity error
[2][3][4]
-- 1LSB
E
L(adj)
integral non-linearity
[2][5]
-- 2.5 LSB
E
O
offset error
[2][6]
-- 1LSB
E
G
gain error
[2][7]
-- 3LSB
E
T
absolute error
[2][8]
-- 3LSB
f
c(ADC)
ADC conversion frequency - - 257 kHz
R
i
input resistance
[9][10]
-- 3.9 M
