sx8725s Semtech Corporation, sx8725s Datasheet - Page 13

• Manufacturer Part Number: sx8725s
• Description: Zoomingadc For Sensing Data Acquisition
• Manufacturer: Semtech Corporation

Revision 1.0
© Semtech
6 General Description
The SX8725S is a complete low-power acquisition path with programmable gain, acquisition speed and resolution.
6.1 Bloc diagram
6.2 VREF
The internally generated V
voltage reference for the ZoomingADC.
This reference voltage is directly connected to one of the ZoomingADC reference multiplexer inputs.
The bandgap voltage stability is only guaranteed for V
bandgap voltage could reduce by up to 50mV.
The bandgap has relatively weak output drive so it is recommended that if the bandgap is required as a signal input
then PGA1 must be enabled with gain = 1.
6.3 GPIO
The GPIO block is a multipurpose 2 bit input/output port. In addition to digital behavior, D0 and D1 pins can be
programmed as analog pins in order to be used as output (reference voltage monitoring) and input for an external
ADVANCED COMMUNICATIONS & SENSING
D0/VREF
D1/VREF
AC2
AC3
OUT
IN
February 2011
SX8725S
REF
V
REF
is a trimmed bandgap reference with a nominal value of 1.22V that provides a stable
+
-
AC1
AC0
+
+
-
-
GPIO
Figure 4. SX8725S bloc diagram
PGA
CHARGE
PUMP
CONTROL LOGIC
Page 13
BATT
voltages of 3V and above. As V
ZoomingADC
4MHz
OSC
ZoomingADC for sensing data acquisition
ADC
SPI
TM
BATT
drops down to 2.4V, the
MISO/READY
SX8725S
VPUMP
VBATT
READY
SCLK
MOSI
VSS
SS
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