Datasheet

AIN0
AIN1
AIN2
AIN3
AIN4
AIN5
AIN6
AIN7
AIN8
AIN9
AIN10
AIN11
AIN12
AIN13
AIN14
AIN15
AINCOM
Control
Logic
VREFPVREFN
AVSS
PLLCAP XTAL1XTAL2
DRDY
PWDN
RESET
START
SPI
Interface
CS
SCLK
DIN
DOUT
DigitalFilter
ClockControl
16-Channel
MUX
AVDD
Sensor
Bias
MUXOUTP
MUXOUTN
ADCINP
GND
ADCINN
ADCChannelControl
SupplyMonitor
GPIO
GPIO[7:0]
DVDD
Temperature
ExtRefMonitor
InternalRef
ADC
CLKSELCLKIO
ADS1158
www.ti.com SBAS429D –JUNE 2008– REVISED MARCH 2011
OVERVIEW
The ADS1158 is a flexible, 16-bit, low-noise ADC The ADS1158 converter consists of a fourth-order,
optimized for fast multi-channel, high-resolution delta-sigma modulator followed by a programmable
measurement systems. The converter provides a digital filter. The modulator measures the differential
maximum channel scan rate of 23.7kSPS, giving a input signal, V
IN
= (ADCINP – ADCINN), against the
complete 16-channel scan in less than 700μs. differential reference input, V
REF
= (VREFP –
VREFN). The digital filter receives the modulator
Figure 20 shows the block diagram of the ADS1158.
signal and provides a low-noise digital output. The
The input multiplexer selects which analog input pins
ADC channel block controls the multiplexer
connect to the multiplexer output pins
Auto-Scan feature. Channel Auto-Scan occurs at a
(MUXOUTP/MUXOUTN). External signal conditioning
maximum rate of 23.7kSPS. Slower scan rates can
can be used between the multiplexer output pins and
be used with corresponding increases in resolution.
the ADC input pins (ADCINP/ADCINN) or the
multiplexer output can be routed internally to the ADC Communication is handled over an SPI-compatible
inputs without external circuitry. Selectable current serial interface with a set of simple commands to
sources within the input multiplexer can be used to control the ADS1158. Onboard registers store the
bias sensors or detect for a failed sensor. On-chip various settings for the input multiplexer, sensor
system function readings provide readback of detect bias, data rate selection, etc. Either an
temperature, supply voltage, gain, offset, and external external 32.768kHz crystal, connected to pins XTAL1
reference. and XTAL2, or an external clock applied to pin CLKIO
can be used as the clock source. When using the
external crystal oscillator, the system clock is
available as an output for driving other devices or
controllers. General-purpose digital I/Os (GPIO)
provide input and output control of eight pins.
Figure 20. ADS1158 Block Diagram
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Product Folder Link(s): ADS1158