SX8724C View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX8724C' PDF : 67 Pages View PDF
SX8724C
ADVANCED COMMUNICATIONS & SENSING
ZoomingADC for sensing data acquisition
DATASHEET
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:
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
Analog
Inputs
AMUX
VSS
VREF
AC2
AC3
AC4
AC5
AC6
AC7
VIN
VD1
VD2
±Vin
±Vin
±Vin
S
PGA1
±Voff PGA2
±Voff PGA3
VIN,ADC
±Vin
±Vref ADC
Reference
Inputs
VBATT
VSS
VREF
VSS
VREF,ADC
VMUX
ANALOG ZOOM
Figure 10. ZADC General Functional Block Diagram
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 10, page 18 shows the general block diagram of the acquisition chain (AC). A control block (not shown in
Figure 10) manages all communications with the I2C peripheral. The clocking is derived from the internal 4 MHz
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 VREF) are available
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.
Revision 1.01
© Semtech
January 2011
Page 18
www.semtech.com/products/
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