XE8000EV120 Semtech, XE8000EV120 Datasheet - Page 48

• Manufacturer Part Number: XE8000EV120
• Description: BOARD EVAL FOR SX8722I070TRLF
• Manufacturer: Semtech
• Series: ZoomingADC™r

Specifications of XE8000EV120

• Number Of Adc's: 1
• Number Of Bits: 16
• Data Interface: I²C
• Inputs Per Adc: 7 Single or 4 Differential
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 125°C
• Utilized Ic / Part: SX8722
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: XM8000EV120; XM8000EV120

11.8. Frequency calibration process
11.8.1. Overview
The SX8722 has an internal RC Oscillator working at 1.2 MHz +/- 600kHz. The calibration is optional. The main reason to
calibrate the RC frequency is to fix the input impedance of the acquisition chain, function of the RC frequency.
This frequency can be calibrated using 2 methods.
11.8.2. Using an 32.768 kHz XTAL
When the SX8722 is connected to a 32.768 XTAL between XIN & XOUT, the CAL pin must be grounded. This indicates to
SX8722 that an XTAL is present and allows frequency auto-calibration at power on.
ACS - Revision 4.2
©2008 Semtech Corp.
ADVANCED COMMUNICATIONS & SENSING
32.768 kHz Xtal
Input of a 32.768 kHz signal on the CAL pin.
Differential
AR1P
AR1N
AR2P
AR2N
BIAS
AC7
AC6
AC5
AC4
AC3
AC2
AC1
AC0
SX8722
October 2008
Figure 28. Calibration : using a 32’768 Hz XTAL
PGA
POST-PROCESS
ZoomingADC
ADC
Page 48
TM
High gain acquisition for sensor interface
CONTROL
POWER
OSC
I
2
C
VMULT
ALRM1
ALRM2
RESET
READY
CKOUT
VBATT
SLEEP
VREG
XOUT
SHUT
GND
SDA
CAL
SCL
XIN
32’768 Hz
5V
DATASHEET
www.semtech.com
SX8722
VBATT
SCL
SDA
GPIO
MCU