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MULTI-BUFFERED A-TO-D CONVERTER (MibADC)
SPNS110E – AUGUST 2005 – REVISED MAY 2008 ......................................................................................................................................................... www.ti.com
The multi-buffered A-to-D converter (MibADC) has a separate power bus for its analog circuitry that enhances
the A-to-D performance by preventing digital switching noise on the logic circuitry, which could be present on VSS
and VCC, from coupling into the A-to-D analog stage. All A-to-D specifications are given with respect to ADREFLO
unless otherwise noted.
Resolution
10 bits (1024 values)
Monotonic
Assured
Output conversion code
00h to 3FFh [00 for VAI ≤ ADREFLO; 3FFh for VAI ≥ ADREFHI]
Table 12. MibADC Recommended Operating Conditions(1)
MIN
MAX
UNIT
ADREFHI
A-to-D high-voltage reference source
VSSAD
VCCAD
V
ADREFLO
A-to-D low-voltage reference source
VSSAD
VCCAD
V
VAI
Analog input voltage
VSSAD– 0.3
VCCAD + 0.3
V
Analog input clamp current(2)
IAIC
–2
2
mA
(VAI < VSSAD – 0.3 or VAI > VCCAD + 0.3)
(1)
For VCCAD and VSSAD recommended operating conditions, see the "Device Recommended Operating Conditions" table.
(2)
Input currents into any ADC input channel outside the specified limits could affect conversion results of other channels.
Table 13. Operating Characteristics Over Full Ranges of Recommended Operating Conditions(1)(2)
PARAMETER
DESCRIPTION/CONDITIONS
MIN
TYP
MAX UNIT
Ri
Analog input resistance
250
500
Conversion
10
pF
Ci
Analog input capacitance
Sampling
30
pF
IAIL
Analog input leakage current
-1
1
A
IADREFHI
ADREFHI input current
ADREFHI = 3.6 V, ADREFLO = VSSAD
5
mA
Conversion range over which specified
CR
ADREFHI - ADREFLO
3
3.6
V
accuracy is maintained
Difference between the actual step width
EDNL
Differential nonlinearity error
±2
LSB
Maximum deviation from the best straight
line through the MibADC. MibADC
EINL
Integral nonlinearity error
±2
LSB
transfer characteristics, excluding the
Maximum value of the difference
E TOT
Total error/absolute accuracy
between an analog value and the ideal
±2
LSB
(1)
VCCAD = ADREFHI
(2)
1 LSB = (ADREFHI - ADREFLO)/2
10 for the MibADC
54
Copyright 2005–2008, Texas Instruments Incorporated