sx8724s Semtech Corporation, sx8724s Datasheet - Page 17

• Manufacturer Part Number: sx8724s
• Description: Zoomingadc For Sensing Data Acquisition
• Manufacturer: Semtech Corporation

Revision 1.0
© Semtech
7 ZoomingADC
7.1 Overview
The ZoomingADC is a complete and versatile low-power analog front-end interface typically intended for sensing
applications. In the following text the ZoomingADC will be referred as ZADC.
The key features of the ZADC are:
The total acquisition chain consists of an input multiplexer, 3 programmable gain amplifier stages and an over sampled
A/D converter. The reference voltage can be selected on two different channels. Two offset compensation amplifiers
allow for a wide offset compensation range. The programmable gain and offset allow the application to zoom in on a
small portion of the reference voltage defined input range.
7.1.1 Acquisition Chain
Figure 11, page 17
Figure
Oscillator.
Analog inputs can be selected through an 8 input multiplexer, while reference input is selected between two
differential channels. It should however be noted that only 7 acquisition channels (including the V
when configured as single ended since the input amplifier is always operating in differential mode with both positive
and negative input selected through the multiplexer.
ADVANCED COMMUNICATIONS & SENSING
Analog
Inputs
Reference
Inputs
Programmable 6 to 16-bit dynamic range over-sampled ADC
Flexible gain programming between 1/12 and 1000
Flexible and large range offset compensation
Differential or single-ended input
2-channel differential reference inputs
Power saving modes
11) manages all communications with the SPI peripheral. The clocking is derived from the internal 4 MHz
V
V
AC
AC
AC
AC
AC
AC
V
V
V
V
SS
REF
BATT
SS
REF
SS
2
3
4
5
6
7
shows the general block diagram of the acquisition chain (AC). A control block (not shown in
AMUX
VMUX
February 2011
V
REF,ADC
Figure 11. ZADC General Functional Block Diagram
S
±
Vin
V
IN
PGA1
Page 17
ANALOG ZOOM
±
±
V
Vin
Voff
ZoomingADC for sensing data acquisition
D1
PGA2
±
±
Vin
Voff
V
D2
PGA3
SX8724S
REF
www.semtech.com
DATASHEET
) are available
±
±
Vin
Vref
V
IN,ADC
ADC