16-Bit

ADC

DS

SPI

Interface

Voltage

Reference

Oscillator

CS

DIN

DOUT/DRDY

SCLK

Gain=2/3, 1,

2,4,8,or16

PGA

Device

AIN1

AIN2

GND

AIN0

AIN3

VDD

MUX

Temperature

Sensor

ADS1118

SBAS457A

– OCTOBER 2010 – REVISED JULY 2011

www.ti.com

OVERVIEW

The ADS1118 is a very small, low-power, 16-bit, delta-sigma (

ΔΣ) analog-to-digital converter (ADC). The

ADS1118 is extremely easy to configure and design into a wide variety of applications, and allows precise

measurements to be obtained with very little effort. Both experienced and novice users of data converters find

designing with the ADS1118 family to be intuitive and problem-free.

The ADS1118 consists of a

ΔΣ analog-to-digital (A/D) core with adjustable gain, an internal voltage reference, a

clock oscillator, and an SPI. This device is also a highly linear and accurate temperature sensor. All of these

features are intended to reduce required external circuitry and improve performance. Figure 32 shows the

ADS1118 functional block diagram.

Figure 32. ADS1118 Functional Block Diagram

core consists of a differential, switched-capacitor

ΔΣ modulator followed by a digital filter. This architecture

results in a very strong attenuation in any common-mode signals. Input signals are compared to the internal

voltage reference. The digital filter receives a high-speed bitstream from the modulator and outputs a code

proportional to the input voltage.

The ADS1118 has two available conversion modes: single-shot mode and continuous conversion mode. In

single-shot mode, the ADC performs one conversion of the input signal upon request and stores the value to an

internal conversion register. The device then enters a low-power shutdown mode. This mode is intended to

provide significant power savings in systems that require only periodic conversions or when there are long idle

periods between conversions. In continuous conversion mode, the ADC automatically begins a conversion of the

input signal as soon as the previous conversion is completed. The rate of continuous conversion is equal to the

programmed data rate. Data can be read at any time and always reflect the most recent completed conversion.

12

Copyright

© 2010–2011, Texas Instruments Incorporated