Specifications

www.digikey.com/maxim-industrial 13
Programmable logic controllers (PLCs)
Analog input function
Benefits
• Simplifies digital interface to a
microcontroller
– Eight MAX11040 ADCs can be daisy-
chained through the SPI interface
• Easily measures a wide dynamic range
– 106dB SNR allows users to measure both
very small and large input voltages
• Easily measures the phase relationship
between multiple input channels
– Simultaneous sampling preserves phase
integrity on multiple channels
MAX11040
The MAX11040 sigma-delta ADC offers 117dB SNR, four differential
channels, and simultaneous sampling that is expandable to 32
channels (eight MAX11040 ADCs in parallel). With programmable
phase and sampling rate, the MAX11040 is ideal for high-precision,
phase-critical measurements within a noisy PLC environment. With
a single command, the MAX11040’s SPI-compatible serial interface
allows data to be read from all the cascaded devices. Four modulators
simultaneously convert each fully differential analog input with
a 0.25ksps to 64ksps programmable data-output-rate range. The
device achieves 106dB SNR at 16ksps and 117dB SNR at 1ksps.
ADC eases firmware complexity by capturing accurate phase and magnitude
information on up to 32 channels
The MAX11040 can be cascaded up to 32 channels.
REF3
SAMPLING
PHASE/FREQ
ADJUSTMENT
XTAL
OSCILLATOR
2.5V
AGND
XIN
ADC
ADC
ADC
ADC
DIGITAL FILTER
AV
DD
DV
DD
XOUT
DIGITAL FILTER
DIGITAL FILTER
DIGITAL FILTER
SYNC
AIN0+
AIN0-
REF0
REF1
REF2
AIN1+
AIN1-
AIN2+
AIN2-
AIN3+
AIN3-
REF
CASCIN
CASCOUT
SPI/DSP
CS
SCLK
DIN
DOUT
INT
DGND
MAX11040
4-channel,
fully differential
bipolar inputs
Fine/coarse sample-
rate and phase adjustment
µC
N = 1
N = 2
N = 8
SPI/DSP
SERIAL
INTERFACE
Single SPI CS