SX8722I070LF SEMTECH [Semtech Corporation], SX8722I070LF Datasheet - Page 17

• Manufacturer Part Number: SX8722I070LF
• Description: High gain acquisition for sensor interface
• Manufacturer: SEMTECH [Semtech Corporation]

ACS - Revision 4.2
©2008 Semtech Corp.
ADVANCED COMMUNICATIONS & SENSING
The ZoomingADC™ is made of 1 input multiplexer, 3 programmable gain amplifiers and a 16 bits Sigma-Delta ADC. The
input multiplexer allows measuring 4 differential sensors or 7 single ended sensors or a combination of differential and
single-ended. The total gain of the PGA enables an amplification of 1000 and the offset correction can reach up to 15
times the full scale input signal.
The SX8722 is not only giving access to the very efficient ZoomingADC™ technology, it also gives access to a very low
power acquisition system entirely configurable to reach as low as 0.5uA in shutdown mode. The low power modes can be
reached through pins or specific serial commands.
The whole chip is controlled by a set of registers; these registers have factory default settings and can be modified in 2
ways: the serial interface commands or an optional external EEPROM. At Startup the SX8722 checks for EEPROM
presence and updates its registers with EEPROM contents.
The whole chip is working at 1.2MHz using its internal RC oscillator, this frequency can be calibrated.
The clock calibration can be done using several methods: External 32.768 kHz XTAL, External 32.768 kHz reference
signal, or EEPROM parameter configuration.
Several corrections can be applied on the measured signal such as different digital filters.
The SX8722 offers two alarm pins. "on" and "off" thresholds can be set independently.
A Clock out pin can be enabled to have the exact frequency of RC oscillator.
External EEPROM and sensors can be biased by the dedicated SX8722 pins EE_POW and BIAS allowing the most
efficient power management.
The pin READY is a single signal that can be used to interrupt the host microcontroller.
The RESET pin enables the host system to reset the SX8722 to its startup settings at any time.
The internal voltage multipliers is automatically enabled when working below 3 Volts.
The SX8722 implements 4 configuration register sets. Each of these sets completely defines the behavior of the
ZoomingADC™. This allows the user to preset 4 different measurement configurations that can be activated by setting a
single bit.
October 2008
Page 17
High gain acquisition for sensor interface
DATASHEET
www.semtech.com
SX8722