MAX1402 Datasheet, PDF (1/40 Pages) Maxim Integrated Products – +5V, 18-Bit, Low-Power, Multichannel, Oversampling Sigma-Delta ADC

19-1423; Rev 0; 3/99
EVAALVUAAILTAIOBNLEKIT _{+5V, 18-Bit, Low-Power, Multichannel,}
Oversampling (Sigma-Delta) ADC
General Description
The MAX1402 low-power, multichannel, serial-output
analog-to-digital converter (ADC) features matched
200µA current sources for sensor excitation. This ADC
uses a sigma-delta modulator with a digital decimation
filter to achieve 16-bit accuracy. The digital filter’s user-
selectable decimation factor allows the conversion res-
olution to be reduced in exchange for a higher output
data rate. True 16-bit performance is achieved at an
output data rate of up to 480sps. In addition, the modu-
lator sampling frequency may be optimized for either
lowest power dissipation or highest throughput rate.
The MAX1402 operates from a +5V supply.
This device offers three fully differential input channels
that may be independently programmed with a gain
between +1V/V and +128V/V. Furthermore, it can com-
pensate an input-referred DC offset up to 117% of the
selected full-scale range. These three differential chan-
nels 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.
The MAX1402 may be configured to sequentially scan all
signal inputs and provide the results via the serial inter-
face 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 rejection
without the need for further post-filtering.
The MAX1402 is available in a 28-pin SSOP package.
Applications
Portable Industrial Instruments
Portable Weigh Scales
Loop-Powered Systems
Pressure Transducers
PART
MAX1402CAI
MAX1402EAI
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 Low Quiescent Current
250µA (operating mode)
2µA (power-down mode)
o Matched On-Board Current Sources (200µA) for
Sensor Excitation
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 +5V Analog Supply and +3V or +5V
Digital Supply
o 3-Wire Serial Interface—SPI™/QSPI™ Compatible
o 28-Pin SSOP Package
Pin Configuration
TOP VIEW
CLKIN 1
CLKOUT 2
CS 3
RESET 4
DS1 5
DS0 6
OUT2 7
OUT1 8
AGND 9
V+ 10
AIN1 11
AIN2 12
AIN3 13
AIN4 14
MAX1402
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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