ADS7924IRTER

Product Folder Order Now Technical Documents Support & Community Tools & Software ADS7924 SBAS482C – JANUARY 2010 – REVISED SEPTEMBER 2017 ADS7924 2.2 V, 12-Bit, 4-Channel, MicroPOWER Analog-to-Digital Converter With I2C Interface 1 Features 3 Description • The ADS7924 is a four-channel, 12-bit, analog-todigital converter (ADC) with an I2C™ interface. With its low-power ADC core, support for low-supply operation, and a flexible measurement sequencer that essentially eliminates power consumption between conversions, the ADS7924 forms a complete monitoring system for power-critical applications such as battery-powered equipment and energy harvesting systems. 1 • • • Intelligent Monitoring: – Auto-Sequencing of 4-Channel Multiplexer – Individual Alarm Thresholds for Each Channel – Programmable Scan Rate MicroPOWER™ Monitoring: – Four-Channel Scanning: – Every 1 ms → 25 μW – Every 10 ms → 5 μW – < 1 µA of Power-Down Current – Programmable Interrupt Pin Controls Shutdown/Wakeup of the Microcontroller – Auto Power-Down Control – PWRCON Pin Allows Shutdown of External Operational Amplifiers Wide Supply Range: – Analog Supply: 2.2 V to 5.5 V – Digital Supply: 1.65 V to 5.5 V Small Footprint: 3-mm × 3-mm WQFN 2 Applications • • The ADS7924 features dedicated data registers and onboard programmable digital threshold comparators for each input. Alarm conditions can be programmed that generate an interrupt. The combination of data buffering, programmable threshold comparisons, and alarm interrupts minimize the host microcontroller time needed to supervise the ADS7924. The four-channel input multiplexer (MUX) is routed through external pins to allow a common signal conditioning circuit to be used between the MUX and ADC, thereby reducing overall component count. The low-power ADC uses the analog supply as its reference and can acquire and convert signals in only 10 μs. An onboard oscillator eliminates the need to supply a master clock. The ADS7924 is offered in a small 3-mm × 3-mm WQFN and is fully specified for operation over the industrial temperature range of –40°C to 85°C. Portable and Battery-Powered Systems: – Medical, Communications, Remote Sensor Signal Monitoring, Power-Supply Monitoring Energy Harvesting Device Information(1) PART NUMBER ADS7924 PACKAGE WQFN (16) BODY SIZE (NOM) 3.00 mm × 3.00 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. Simplified Schematic MUX OUT ADCIN AVDD DVDD SDA 2 IC Interface CH0 CH1 CH2 4-Channel MUX SAR ADC Data Buffers, Sequencer, and Alarms SCL A0 INT CH3 PWRCON RESET Oscillator AGND DGND 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. ADS7924 SBAS482C – JANUARY 2010 – REVISED SEPTEMBER 2017 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Applications ........................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 6.7 4 4 4 4 5 6 7 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... I2C Timing Requirements.......................................... Typical Characteristics .............................................. Detailed Description ............................................ 10 7.1 Overview ................................................................. 10 7.2 Functional Block Diagram ....................................... 10 7.3 Feature Description................................................. 10 7.4 Device Functional Modes........................................ 13 7.5 Programming........................................................... 20 7.6 Register Map........................................................... 26 8 Application and Implementation ........................ 33 8.1 Application Information............................................ 33 8.2 Typical Application ................................................. 39 9 Power Supply Recommendations...................... 41 10 Layout................................................................... 41 10.1 Layout Guidelines ................................................. 41 10.2 Layout Example .................................................... 41 11 Device and Documentation Support ................. 42 11.1 11.2 11.3 11.4 11.5 Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 42 42 42 42 42 12 Mechanical, Packaging, and Orderable Information ........................................................... 42 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision B (September 2015) to Revision C Page • Changed QFN to WQFN throughout document .................................................................................................................... 1 • Changed direction of RESET arrow in Simplified Schematic figure....................................................................................... 1 • Changed maximum operating temperature range in Absolute Maximum Ratings table ........................................................ 4 • Changed direction of RESET arrow in Functional Block Diagram figure ............................................................................ 10 • Changed description of bits 7:5 in INTCONFIG: Interrupt Configuration Register .............................................................. 30 Changes from Revision A (May 2010) to Revision B • 2 Page Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section ................................................................................................. 1 Submit Documentation Feedback Copyright © 2010–2017, Texas Instruments Incorporated Product Folder Links: ADS7924 ADS7924 www.ti.com SBAS482C – JANUARY 2010 – REVISED SEPTEMBER 2017 5 Pin Configuration and Functions (1) DVDD AVDD ADCIN MUXOUT 15 14 13 8 4 AGND SDA (1) 7 3 Pad PWRCON SCLK Thermal 6 2 DGND INT 5 1 A0 RESET 16 RTE Package 16-Pin WQFN Top View 12 CH0 11 CH1 10 CH2 9 CH3 Connect to AGND. Pin Functions PIN I/O DESCRIPTION NO. NAME 1 RESET Digital input 2 INT Digital output 3 SCLK Digital input Serial clock input 4 SDA Digital input/output Serial data 5 A0 Digital input I2C address selection External reset, active low Interrupt pin, active low; generated when input voltage is beyond programmed threshold 6 DGND Digital 7 PWRCON Digital output Digital ground 8 AGND Analog Analog ground 9 CH3 Analog input Input channel 3 10 CH2 Analog input Input channel 2 11 CH1 Analog input Input channel 1 12 CH0 Analog input Input channel 0 13 MUXOUT Analog output 14 ADCIN Analog input 15 AVDD Analog Analog supply 16 DVDD Digital Digital supply Power control pin to control shutdown/power-up of external operational amplifier Multiplexer output ADC input Submit Documentation Feedback Copyright © 2010–2017, Texas Instruments Incorporated Product Folder Links: ADS7924 3 ADS7924 SBAS482C – JANUARY 2010 – REVISED SEPTEMBER 2017 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings Over operating free-air temperature range, unless otherwise noted. (1) MIN MAX UNIT Supply voltage, AVDD to AGND –0.3 6 V Supply voltage, DVDD to DGND –0.3 6 V Supply voltage, DVDD to AVDD AVDD ≥ DVDD AGND to DGND V –0.3 0.3 V Analog input voltage AGND – 0.3 0.3 V Digital input voltage with respect to DGND (SCL and SDA) DGND – 0.3 6 V Digital input voltage with respect to DGND (A0, RESET) DGND – 0.3 DVDD + 0.3 V Input current to all pins except supply pins –10 10 mA Maximum operating temperature –40 85 °C Storage temperature –60 150 °C (1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) ±2000 Charged-device model (CDM), per JEDEC specification JESD22C101 (2) ±750 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN NOM MAX UNIT AVDD Analog Supply Voltage 2.2 5.5 V DVDD Digital Supply Voltage 1.65 AVDD V 6.4 Thermal Information ADS7924 THERMAL METRIC (1) RTE (WQFN) UNIT 16 PINS RθJA Junction-to-ambient thermal resistance 48.1 °C/W RθJC(top) Junction-to-case(top) thermal resistance 47.3 °C/W RθJB Junction-to-board thermal resistance 60.8 °C/W ψJT Junction-to-top characterization parameter 0.3 °C/W ψJB Junction-to-board characterization parameter 14.1 °C/W RθJC(bot) Junction-to-case(bottom) thermal resistance 0.4 °C/W (1) 4 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Documentation Feedback Copyright © 2010–2017, Texas Instruments Incorporated Product Folder Links: ADS7924 ADS7924 www.ti.com SBAS482C – JANUARY 2010 – REVISED SEPTEMBER 2017 6.5 Electrical Characteristics Minimum and maximum specifications are at TA = –40°C to 85°C, 1.65 V < DVDD < 5.5 V, and 2.2 V < AVDD < 5.5 V. Typical specifications are at TA = 25°C, AVDD = 5 V, and DVDD = 5 V, unless otherwise noted. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT ANALOG INPUT Full-scale input span (CHX – AGND) 0 Input capacitance (1) 4 AVDD V 10 pF ADC sampling capacitance 15 MUX resistance 60 pF Ω Input channel crosstalk 85 dB 12 Bits SYSTEM PERFORMANCE Resolution No missing codes 12 Integral linearity Bits –1.5 ±0.5 1.5 LSBs Differential linearity –1 ±0.6 1.5 LSBs Offset error –5 Offset error drift 5 0.01 Gain error –0.2% Gain error drift –0.01% 0.2% 0.6 Noise (rms) LSBs LSB/°C ppm/°C 0.125 LSB SAMPLING DYNAMICS Monitoring time/channel (2) 10 µs CLOCK Internal clock frequency variation ±20% DIGITAL INPUT/OUTPUT Logic family CMOS Logic level: VIH (SDA, SCL, A0, RESET) 0.8 DVDD DVDD + 0.3 VIL (SDA, SCL, A0, RESET) DGND – 0.3 0.4 V VI = DVDD or DGND –10 10 μA IOH = 100 μA, INT pin 0.8 DVDD DVDD V IOH = 100 µA, PWRCON pin 0.8 AVDD AVDD V DGND 0.4 Input current II VOH (PWRCON, INT) VOL (PWRCON, INT, SDA) IOL = 100 μA Low-level output current IOL SDA pin, VOL = 0.6 V Load capacitance CB SDA pin Data format V V 3 mA 400 pF 5.5 V Straight binary POWER-SUPPLY REQUIREMENTS Power-supply voltage: DVDD (3) 1.65 AVDD IAVDD (4) 2.2 tCYCLE = 2.5 ms, AVDD = 2.2 V 5 IPWRD, power-down current 5.5 V 8 μA