MAX1401 Datasheet, PDF (1/36 Pages) Maxim Integrated Products – +3V, 18-Bit, Low-Power, Multichannel, Oversampling Sigma-Delta ADC

19-1480; Rev 0; 5/99
EVAALVUAAILTAIOBNLEKIT _{+3V, 18-Bit, Low-Power, Multichannel,}
Oversampling (Sigma-Delta) ADC
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
PART
MAX1401CAI
MAX1401EAI
Ordering Information
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
28 SSOP
28 SSOP
SPI and QSPI are trademarks of Motorola, Inc.
Features
o 18-Bit Resolution, Sigma-Delta ADC
o 16-Bit Accuracy with No Missing Codes to 480sps
o Access to the Mux Output/ADC Input
o Low Quiescent Current
250µA (operating mode)
2µA (power-down mode)
o 3 Fully Differential or 5 Pseudo-Differential Signal
Input Channels
o 2 Additional Fully Differential Calibration
Channels/Auxiliary Input Channels
o Programmable Gain and Offset
o Fully Differential Reference Inputs
o Converts Continuously or On Command
o Automatic Channel Scanning and Continuous
Data Output Mode
o Operates with Analog and Digital Supplies
from +2.7V to +3.6V
o SPI™/QSPI™-Compatible 3-Wire Serial Interface
o 28-Pin SSOP Package
TOP VIEW
CLKIN 1
CLKOUT 2
CS 3
RESET 4
MUXOUT+ 5
MUXOUT- 6
ADCIN+ 7
ADCIN- 8
AGND 9
V+ 10
AIN1 11
AIN2 12
AIN3 13
AIN4 14
Pin Configuration
MAX1401
SSOP
28 SCLK
27 DIN
26 DOUT
25 INT
24 V_DD
23 DGND
22 CALOFF+
21 CALOFF-
20 REFIN+
19 REFIN-
18 CALGAIN+
17 CALGAIN-
16 AIN6
15 AIN5
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