MAX1401
+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
________________________________________________________________ Maxim Integrated Products 1
19-1480; Rev 1; 7/02
EVALUATION KIT
AVAILABLE
General Description
The MAX1401 18-bit, low-power, multichannel, serial-
output ADC uses a sigma-delta modulator with a digital
decimation filter to achieve true 16-bit accuracy. The
user-selectable decimation factor of the digital filter
allows the conversion resolution to be reduced in
exchange for a higher output data rate. The device
achieves true 16-bit performance at an output data rate of
up to 480sps. In addition, the modulator sampling
frequency may be optimized for either lowest power
dissipation or highest throughput rate. The MAX1401
operates from +3V.
This device offers three fully differential input channels
that can be independently programmed with a gain
between +1V/V and +128V/V. Furthermore, it can com-
pensate an input-referred DC offset (such as system off-
set) up to 117% of the selected full-scale range. These
three differential channels may also be configured to
operate as five pseudo-differential input channels. Two
additional, fully differential system-calibration channels
are provided for gain and offset error correction. External
access is provided to the multiplexer (mux) output to
facilitate additional signal processing.
The MAX1401 can be configured to sequentially scan all
signal inputs and provide the results through the serial
interface with minimum communications overhead. When
used with a 2.4576MHz or 1.024MHz master clock, the
digital decimation filter can be programmed to produce
zeros in its frequency response at the line frequency
and associated harmonics, ensuring excellent line rejec-
tion without the need for further postfiltering.
The MAX1401 is available in a 28-pin SSOP package.
Applications
Portable Industrial Instruments
Portable Weigh Scales
Loop-Powered Systems
Pressure Transducers
Features
18-Bit Resolution, Sigma-Delta ADC
16-Bit Accuracy with No Missing Codes to 480sps
Access to the Mux Output/ADC Input
Low Quiescent Current
250µA (operating mode)
A (power-down mode)
3 Fully Differential or 5 Pseudo-Differential Signal
Input Channels
2 Additional Fully Differential Calibration
Channels/Auxiliary Input Channels
Programmable Gain and Offset
Fully Differential Reference Inputs
Converts Continuously or On Command
Automatic Channel Scanning and Continuous
Data Output Mode
Operates with Analog and Digital Supplies
from +2.7V to +3.6V
SPI™/QSPI™-Compatible 3-Wire Serial Interface
28-Pin SSOP Package
28
27
26
25
24
23
22
21
20
19
18
17
16
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
SCLK
DIN
DOUT
INT
V
DD
DGND
AIN5
CALOFF+
CALOFF-
REFIN+
REFIN-
CALGAIN+
CALGAIN-
AIN6
AIN4
AIN3
AIN2
AIN1
V+
AGND
ADCIN-
ADCIN+
MUXOUT-
MUXOUT+
RESET
CS
CLKOUT
CLKIN
SSOP
TOP VIEW
MAX1401
SPI and QSPI are trademarks of Motorola, Inc.
Pin Configuration
Ordering Information
28 SSOP
28 SSOP
PIN-PACKAGETEMP RANGE
0°C to +70°C
-40°C to +85°CMAX1401EAI
MAX1401CAI
PART
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAX1401
+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = +2.7V to +3.6V, V
DD
= +2.7V to +3.6V, V
REFIN+
= +1.25V, REFIN- = AGND, f
CLKIN
= 2.4576MHz, T
A
= T
MIN
to T
MAX
, unless
otherwise noted. Typical values are at T
A
= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
V+ to AGND, DGND .................................................-0.3V to +6V
V
DD
to AGND, DGND...............................................-0.3V to +6V
AGND to DGND.....................................................-0.3V to +0.3V
Analog Inputs to AGND................................-0.3V to (V+ + 0.3V)
Analog Outputs to AGND .............................-0.3V to (V+ + 0.3V)
Reference Inputs to AGND...........................-0.3V to (V+ + 0.3V)
CLKIN and CLKOUT to DGND...................-0.3V to (V
DD
+ 0.3V)
All Other Digital Inputs to DGND..............................-0.3V to +6V
All Digital Outputs to DGND.......................-0.3V to (V
DD
+ 0.3V)
Maximum Current Input into Any Pin ..................................50mA
Continuous Power Dissipation (T
A
= +70°C)
28-Pin SSOP (derate 9.52mW/°C above +70°C) ........524mW
Operating Temperature Ranges
MAX1401CAI .....................................................0°C to +70°C
MAX1401EAI...................................................-40°C to +85°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Bipolar Negative Full-Scale Drift
0.3
µV/°C
For gains of 8, 16, 32, 64, 128
PARAMETER SYMBOL MIN TYP MAX UNITS
Unipolar Offset Error -1 2 %FSR
Nominal Gain (Note 3) 0.98
-0.0015 0.0015
Output Noise (Table 16)
0.5
Unipolar Offset Drift
0.3
µV/°C
Bipolar Zero Error -2.0 2.0 %FSR
0.8
Noise-Free Resolution 16 Bits
Bipolar Zero Drift
0.3
Positive Full-Scale Error
(Note 4)
-2.5 2.5
%FSR
Full-Scale Drift (Note 5)
0.8
0.3
µV/°C
-2 2
Gain Error (Note 6)
-3 3
%FSR
1
Gain-Error Drift (Note 7)
5
ppm/°C
-2.5 2.5
%FSR
0.8
CONDITIONS
For gains of 8, 16, 32, 64, 128
Relative to nominal offset of 1% FSR
For gains of 1, 2, 4, 8, 16, 32, 64
Bipolar mode; FS1 = 0; MF1, MF0 = 0
Depends on filter setting and selected gain
For gains of 1, 2, 4
For gains of 8, 16, 32, 64, 128
For gains of 1, 2, 4
For gains of 1, 2, 4
For gains of 8, 16, 32, 64, 128
For gains of 1, 2, 4, 8, 16, 32, 64
For gain of 128
For gains of 1, 2, 4, 8, 16, 32, 64
For gain of 128
For gains of 1, 2, 4, 8, 16, 32, 64
No missing codes guaranteed by design;
for filter settings with FS1 = 0
For gains of 1, 2, 4
µV/°C
For gain of 128 -3.5 3.5
Bipolar Negative Full-Scale Error
-3.5 3.5For gain of 128
Integral Nonlinearity
(Notes 1, 2)
INL
±0.001
%FSR
FS1 = 0; MF1, MF0 = 1, 2, 3
STATIC PERFORMANCE
Inp
MAX1401
+3V, 18-Bit, Low-Power, Multichannel,
Oversampling (Sigma-Delta) ADC
________________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = +2.7V to +3.6V, V
DD
= +2.7V to +3.6V, V
REFIN+
= +1.25V, REFIN- = AGND, f
CLKIN
= 2.4576MHz, T
A
= T
MIN
to T
MAX
, unless
otherwise noted. Typical values are at T
A
= +25°C.)
Unipolar mode
CONDITIONS
-116.7 116.7
Bipolar mode
UNITSMIN TYP MAXSYMBOLPARAMETER
%FSR
-58.35 58.35
Offset DAC Range (Note 8)
-2.5 2.5
For filter notch 50Hz, ±0.02 · f
NOTCH
,
MF1 = 0, MF0 = 0, f
CLKIN
= 2.4576MHz (Note 10)
DAC code = 0000
For filter notch 50Hz, ±0.02 · f
NOTCH
,
MF1 = 0, MF0 = 0, f
CLKIN
= 2.4576MHz
150
dB100NMR
Normal-Mode 50Hz Rejection
(Note 10)
At DC
µV
RMS
0
Additional Noise from Offset
DAC (Note 9)
90
REFIN and AIN for BUFF = 0 VV
AGND
V+
Common-Mode Voltage Range
(Note 11)
BUFF = 1 V
V
AGND
V+
+ 200mV - 1.5
Absolute and Common-Mode
AIN Voltage Range
pA40
DC Input Leakage Current
(Note 12)
Unipolar mode 16.7
Bipolar mode
%FSR
8.35
Offset DAC Resolution
For filter notch 60Hz, ±0.02 · f
NOTCH
,
MF1 = 0, MF0 = 0, f
CLKIN
= 2.4576MHz (Note 10)
dB
150
CMRCommon-Mode Rejection
For filter notch 60Hz, ±0.02 · f
NOTCH
,
MF1 = 0, MF0 = 0, f
CLKIN
= 2.4576MHz
dB100NMR
Normal-Mode 60Hz Rejection
(Note 10)
REFIN and AIN for BUFF = 0 V
V
AGND
V+
- 30mV + 30mV
Absolute Input Voltage Range
REFIN and AIN for
BUFF = 0
T
A
= +25°C
T
A
= T
MIN
to T
MAX
10 nA
34
38
45
BUFF = 0
60
BUFF = 1, all gains 30
AIN Input Capacitance
(Note 13)
pF
Bipolar input range (U/B bit = 0)
±V
REF
/ gain
AIN Differential Voltage Range
(Note 14)
V
Gain = 1
Gain = 2
Gain = 4
Gain = 8, 16, 32, 64, 128
Unipolar input range (U/B bit = 1)
0 to V
REF
/ gain
%FSR0Offset DAC Zero-Scale Error
BUFF = 1 10AIN Input Current (Note 12) nA
Input referred %FSR
-3.5 3.5
Offset DAC Full-Scale Error
OFFSET DAC
ANALOG INPUTS/REFERENCE INPUTS (Specifications for AIN and REFIN, unless otherwise noted.)
Gain = 1, 2, 4, 8, 16, 32, 64
Gain = 128

MAX1401EAI+

Mfr. #:
Manufacturer:
Maxim Integrated
Description:
Analog to Digital Converters - ADC 18-Bit 5Ch 4.8ksps 1.25V Precision ADC
Lifecycle:
New from this manufacturer.
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