SX8724E082TRT Semtech, SX8724E082TRT Datasheet

IC DAS PRESSURE/TEMP SENS 16MLPQ

SX8724E082TRT

Manufacturer Part Number
SX8724E082TRT
Description
IC DAS PRESSURE/TEMP SENS 16MLPQ
Manufacturer
Semtech
Series
ZoomingADC™r
Type
Pressure/Temperature Sensorr
Datasheet

Specifications of SX8724E082TRT

Input Type
Differential
Output Type
Digital
Interface
2-Wire
Mounting Type
Surface Mount
Package / Case
16-MLPQ
For Use With
XE8000EV121 - BOARD EVAL FOR SX8723/24
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Current - Supply
-
Other names
SX8724E082TR
ADVANCED COMMUNICATIONS & SENSING
Description
The SX8724 is a data acquisition system based on
Semtech’s low power ZoomingADC™ technology. It
directly connects most types of miniature sensors
with a general purpose microcontroller.
With 3 differential inputs, it can adapt to multiple
sensor systems. Its digital outputs are used to bias
or reset the sensing elements.
Applications
V1.23 © 2009 Semtech Corp.
Functional Block Diagram
Industrial pressure sensing
Industrial temperature sensing
Barometer
Compass
ZoomingADC™ for Pressure and Temperature Sensing
1
Features
Ordering Information
1) Available in tape and reel only
2) Lead free, WEEE and RoHS compliant.
SX8724E082TRT
SX8724E082TDT
Device
Up to 16-bit differential data acquisition
Programmable gain: (1/12 to 1000)
Sensor offset compensation up to 15 times
full scale of input signal
3 differential or 6 single-ended signal inputs
Programmable Resolution versus Speed
versus Supply current
4 digital outputs to bias Sensors
Internal or external voltage reference
Internal time base
Low-power (250 uA for 16b @ 500 S/s)
2-wire interface
MLPQ-16 4x4
MLPQ-16 4x4
Package
www.semtech.com
Reel quantity
SX8724
3000
1000

Related parts for SX8724E082TRT

SX8724E082TRT Summary of contents

Page 1

... Supply current 4 digital outputs to bias Sensors Internal or external voltage reference Internal time base Low-power (250 uA for 16b @ 500 S/s) 2-wire interface Ordering Information Device SX8724E082TRT SX8724E082TDT 1) Available in tape and reel only 2) Lead free, WEEE and RoHS compliant. 1 SX8724 Package Reel quantity ...

Page 2

... Registers Descriptions .......................................................................................................................................... 28 RC Register........................................................................................................................................................... 28 GPIO Registers ..................................................................................................................................................... 29 ZADC Registers .................................................................................................................................................... 30 Mode Register ....................................................................................................................................................... 31 Optional Operating Modes: External Voltage Reference Option .......................................................................... 32 Application Hints..................................................................................................................................................33 Recommended Operation Mode and Registers Settings...................................................................................... 33 Operation Mode..................................................................................................................................................... 33 V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Table of Contents 2 SX8724 www.semtech.com ...

Page 3

... Noise ..................................................................................................................................................................... 44 Gain Error and Offset Error ................................................................................................................................... 46 Power Consumption .............................................................................................................................................. 47 PCB Layout Considerations................................................................................................................................49 How to Evaluate....................................................................................................................................................49 Package Outline Drawing: MLPQ-16 4x4 ...........................................................................................................50 Land Pattern Drawing: MLPQ-16 4x4 .................................................................................................................51 Tape and Reel Specification ...............................................................................................................................52 V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 3 SX8724 www.semtech.com ...

Page 4

... Storage temperature Temperature under bias Max sensor common mode Input voltage Peak reflow temperature Notes: This device is ESD sensitive. Use of standard ESD handling precautions is required. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Symbol Comments / Conditions V BATT ...

Page 5

... Input logic high Input logic low Output logic high Output logic low VREF: Internal Bandgap Reference Absolute output voltage Variation over Temperature Total Output Noise V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Symbol Comments / Conditions V BATT T OP ...

Page 6

... Integral Non-Linearity, INL Differential Non-Linearity, DNL Common Mode input range Power Supply Rejection Ratio ADC Dynamic Performance Conversion Time Throughput Rate (Continuous Mode) Nbr of Initialization Cycles V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing = +25° +5V, GND = 0V GDOff ...

Page 7

... Bias currents in PGAs and ADC set to 3/4 of nominal values, i.e. IB_AMP_PGA[1:0] = '10', IB_AMP_ADC[1:0] = '10'. (18) Bias currents in PGAs and ADC set to 1/2 of nominal values, i.e. IB_AMP_PGA[1:0] = '01', IB_AMP_ADC[1:0] = '01'. (19) Bias currents in PGAs and ADC set to 1/4 of nominal values, i.e. IB_AMP_PGA[1:0] = '00', IB_AMP_ADC[1:0] = '00'. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Symbol ...

Page 8

... The READY pulse indicates End of Conversion. This is a Low going pulse of duration equal to one cycle of the ADC sampling rate. 2-WIRE Timing Waveforms SDA SCL SDA SCL V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Symbol Comments / Conditions t IRQ ...

Page 9

... V Power Input SS Notes: (1) This pin is internally connected V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Marking Information Differential sensor input in conjunction with AC Differential sensor input in conjunction with AC Differential sensor input in conjunction with AC Differential sensor input in conjunction with AC Differential sensor input in conjunction with AC 2 ...

Page 10

... The bandgap has relatively weak output drive recommended that if the bandgap is required as a signal input then PGA1 must be enabled with Gain = 1. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Figure 3 - SX8724 Block Diagram voltages of 3V and above ...

Page 11

... When the bits VREF_D0_OUT and VREF_D1_IN in the RegMode register are set to 1 the D0 and D1 pins digital behavior are automatically bypassed in order to either input or output the voltage reference signals. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing RegOut[4] ...

Page 12

... The block will also indicate when the pumped output voltage is sufficiently high to allow ADC conversions to be started. This will be a simple comparison which will give a ready signal when the V V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing ...

Page 13

... Once this has been done, the oscillator will be shut down and the chip will enter a sleep state while waiting for a 2-WIRE communication. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing ...

Page 14

... Address The default 2-WIRE slave address is 1001000 in binary. This is the standard part 2-WIRE slave address. Other addresses between 1001001 and 1001111 are available by special request. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Memory Address ACK ...

Page 15

... The core of the zooming section is made of three differential programmable amplifiers (PGA). After selection of an input and reference signals V and V IN V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing PGA1 PGA2 V D1 ...

Page 16

... The sampling frequency to throughput ratio is large (typically 10-500). These converters include digital decimation filtering. They are mainly used for high resolution, and/or low-to-medium speed applications. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing ...

Page 17

... AMUX(4:0): (rw) AMUX(4) sets the mode (0 sets the sign (0 straight, 1 VMUX: (rw) sets the differential reference channel ( read write read & write) V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Bit Position ...

Page 18

... In the "on-request" mode, the internal behavior of the converter is the same as in the "continuous-time" mode, but the conversion is initiated on user request (with the START bit). As shown in Figure 10, the conversion time is also T . CONV V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing T CONV BUSY Figure 10 - ADC " ...

Page 19

... Table 3. The selection bit is VMUX. The reference inputs V REF,ADC (common-mode) can the power supply range. REFN (RegACCfg5[0]) V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing to AC and four reference inputs AC_R 0 7 and reference voltage V IN ...

Page 20

... Table 7 - PGA2 Offset Settings V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing PGA3_GAIN[6:0] Block (RegACCfg3[6:0]) ADC disabled ADC enabled PGA1 disabled PGA1 enabled PGA2 disabled PGA2 enabled ...

Page 21

... PGA3_GAIN[6:0] and PGA3_OFFSET[6:0]. To remain within the signal compliance of the PGA stages, the condition: must be verified. Finally, combining equations for the three PGA stages, the input voltage where the total PGA gain is defined as: and the total PGA offset is: V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Equation 5 ...

Page 22

... Elementary Conversion. This may be useful to help eliminate bandgap related internal offset voltage and 1/f Over-Sampling Frequency The word FIN[1:0] (see Table 10) is used to select the over-sampling frequency f is derived from the 4MHz oscillator clock. (RegACCfg2[7:6]) Table 10 - Over-Sampling Frequency Settings V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing s ELCONV OSR 1 ...

Page 23

... This number is set with the word SET_NELC[1:0] in power of 2 steps (see Table 12) given by: Table 12 - Number of Elementary Conversion Settings As already mentioned, N must be equal or greater than 2 to reduce internal amplifier offsets. ELCONV V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 3 SET _ ...

Page 24

... PGA and of ELCONV external noises (see section “PGA Gain & Offset, Linearity and Noise” in page 37). Table 13 - Resolution vs. SET_OSR[2:0] and SET_NELC[1:0] Settings V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing n 2 ...

Page 25

... Table 14 - Normalized Conversion Time (T Note Some high sample rate configurations can not be used due to 2-WIRE speed limitation. Figure 13 - Resolution vs. Normalized Conversion Time for Different SET_NELC[1:0] V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing N OSR 1 ...

Page 26

... Table 16 - Last Forced LSBs in Conversion Output Registers for Resolution Settings Smaller than 16 bits (n < 16) (RegACOutMsb[7:0] & RegACOutLsb[7:0]) V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing V OSR IN , ADC 16 OUT 2 ADC ...

Page 27

... ADC can even be disabled, thus, reducing power consumption to its minimum. This can considerably improve battery life. IB_AMP_ADC[1:0] IB_AMP_PGA[1:0] (RegACCfg1[7:6]) (RegACCfg1[5:4 Table 17 - ADC & PGA Power Saving Modes and Maximum Sampling Frequency V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing V 1 OSR REF , ADC LSB n 2 ...

Page 28

... After power on reset the registers will have the values indicated in the tables “Reset” column. RC Register Bit Name Mode 7 RC_EN rw V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Bits 1 RC oscillator control pads data output and direction control pads input data 8 LSB of the ADC result ...

Page 29

... Mode 7 D3_IN r 2 D2_IN r 1 D1_IN r 0 D0_IN r V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Reset 1 D3 pad direction Output 1 D2 pad direction Output 1 D1 pad direction Output 1 D0 pad direction Output 0 D3 pad output value. Only valid when D3_DIR = pad output value ...

Page 30

... Mode 7 BUSY r 6 DEF rw 5:1 AMUX[4: VMUX rw V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Reset 00000000 LSB of the ADC result Table 21 - RegACOutLsb (0x50) Reset 00000000 MSB of the ADC result Table 22 - RegACOutMsb (0x51) Reset 0 Starts an ADC conversion ...

Page 31

... ADC. If the ADC is not being run at full rate or full accuracy then it may operate sufficiently well when V is less than 3V. BATT V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Reset 1 1: Indicates that the charge pump has settled and the output voltage is ...

Page 32

... ADC, or the option to filter the internal V The internally generated trimmed bandgap reference with a nominal value of 1.22V. REF When using an external V REF,ADC the external value for 1. the ADC conversion calculations. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing GPIO D0/REF OUT 0 ZoomingADC ...

Page 33

... RegACCfg0 0 IB_AMP_ADC[1:0] RegACCfg1 01 FIN[1:0] RegACCfg2 10 PGA1_G RegACCfg3 0 - RegACCfg4 0 BUSY DEF RegACCfg5 0 0 V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Value Analog multiplexers VBATT VINP = AC3 & VINN = AC2 PGA OFF OFF 1 0 OFF ADC 250 16 512 ...

Page 34

... ADVANCED COMMUNICATIONS & SENSING Schematic Figure 18 - Recommended Operation Mode Schematic V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 34 SX8724 www.semtech.com ...

Page 35

... Therefore, with a gain of 1 and a sampling frequency of 125 kHz, Z The input impedance on channels that are not selected is very high (>100MΩ). V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 9 ...

Page 36

... One can increase the mean input impedance of the ZoomingADC by decreasing the gain of the first enabled amplifier. One can increase the effective input impedance of the ZoomingADC by having a source with a high electrical bandwidth (sensor electrical bandwidth much higher than V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing ...

Page 37

... For lowest output offset error at the output of the ADC, bypass PGA2 and PGA3. Indeed, PGA2 and PGA3 typically introduce an offset of about LSB (16 bit) at their output. Note, however, that the ADC output offset is easily calibrated out by software. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 37 SX8724 www ...

Page 38

... Normalized Frequency - f *(OSR/f 1.2 1 0.8 0.6 0.4 0 Normalized Frequency - f *(OSR/f Figure 21 - Frequency Response: Normalized Magnitude vs. Frequency for Different N V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing OSR N ELCONV (Hz) for Equation 24 [Hz] f [kHz 125 61 250 ...

Page 39

... SX8724 does not support multiple devices on the same 2-WIRE bus. A separate 2-WIRE bus should be used to address other devices as seen on the following schematic. Figure 22 - Recommended connections with other devices V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 39 SX8724 ...

Page 40

... PGA is important and the first stage of the PGA should be used. The following figures show the Integral non linearity for different gain settings over the chip temperature range. -40 ° ° C V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Gain 1 40 SX8724 25 ° ...

Page 41

... ADVANCED COMMUNICATIONS & SENSING -40 ° ° C -40 ° ° C V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Gain 10 Gain 100 41 SX8724 25 ° C 125 ° ° C 125 ° C www.semtech.com ...

Page 42

... ADVANCED COMMUNICATIONS & SENSING -40 ° ° C V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Gain 1000 42 SX8724 25 ° C 125 ° C www.semtech.com ...

Page 43

... ADVANCED COMMUNICATIONS & SENSING Differential Non-Linearity The differential non-linearity is generated by the ADC. The PGA does not add differential non-linearity. Figure 23 shows the differential non-linearity. Figure 23 - Differential Non-Linearity of the ADC Converter V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 43 SX8724 www.semtech.com ...

Page 44

... ADC averaging effect, but reduces noise). Parameter Standard deviation at ADC output (LSB) Output rms noise (µV) Table 33 - PGA Noise Measurements ( bits, OSR = 512, N V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 2 2     V  ...

Page 45

... ADC. Considering 0.2 V (rms) maximum signal amplitude, the signal-to-noise ratio is 90dB. Noise can also be reduced by implementing a software filter. By making an average on a number of subsequent measurements, the apparent noise is reduced the square root of the number of measurement used to make the average. V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 80 60 ...

Page 46

... LSB for 16-bit setting, is normalized to 25° C. Notice that if the ADC alone, the output offset error is below 1 LSB and has no drift. Figure 27 - Gain Error vs. Temperature for Different PGA Gains Figure 28 - Offset Error vs. Temperature for Different PGA Gains V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing NORMALIZED TO 25° C 0.2 ...

Page 47

... Quiescent current consumption vs. temperature is depicted in Figure 31, showing a relative increase of nearly 40% between -45 and +85°C. Figure 29 - Quiescent Current Consumption vs. Supply Voltage Figure 30 - Quiescent Current Consumption vs. Supply Voltage for Different Sampling Frequencies V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 47 SX8724 ...

Page 48

... Figure 32 - Relative Change in Quiescent Current Consumption vs. Temperature Supply Back Bone 142 3 2 Table 34 - Typical Quiescent Current Distributions in Acquisition Chain ( bits, f V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing ADC PGA1 PGA2 127 96 86 105 87 73 105 SX8724 ...

Page 49

... The “SX87xx Evaluation Tools” software gives the user the ability to control the SX8724 registers as well as getting the raw data from the ZoomingADC and displaying it on the “Graphical User interface”. For more information please look at SEMTECH web site (http://www.semtech.com). V1.23 © 2009 Semtech Corp. ...

Page 50

... ADVANCED COMMUNICATIONS & SENSING Package Outline Drawing: MLPQ-16 4x4 V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 50 SX8724 www.semtech.com ...

Page 51

... ADVANCED COMMUNICATIONS & SENSING Land Pattern Drawing: MLPQ-16 4x4 V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing 51 SX8724 www.semtech.com ...

Page 52

... V1.23 © 2009 Semtech Corp. ZoomingADC™ for Pressure and Temperature Sensing Reel Size (in) 2.25 2.25 1.00 7 2.60 2.60 1.00 13 3.30 3.30 1.10 13 4.35 4.35 1.10 7/13 3 ...

Page 53

... CUSTOMER’S OWN RISK. Should a customer purchase or use Semtech products for any such unauthorized application, the customer shall indemnify and hold Semtech and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs damages and attorney fees which could arise. ...

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