ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Dual, 1MSPS, 16-/14-/12-Bit, 4×2 or 2×2 Channel, Simultaneous Sampling Analog-to-Digital Converter Check for Samples: ADS8363, ADS7263, ADS7223 FEATURES DESCRIPTION • • • The ADS8363 is a dual, 16-bit, 1MSPS analog-to-digital converter (ADC) with eight pseudoor four fully-differential input channels grouped into two pairs for simultaneous signal acquisition. The analog inputs are maintained differentially to the input of the ADC. The input multiplexer can be used in either pseudo-differential mode, supporting up to four channels per ADC (4x2), or in fully-differential mode that allows to convert up to two inputs per ADC (2x2). The ADS7263 is a 14-bit version while the ADS7223 is a 12-bit version of the ADS8363. 1 2 • • • • • Eight Pseudo- or Four Fully-Differential Inputs Simultaneous Sampling of Two Channels Excellent AC Performance: – SNR: 93dB (ADS8363) 85dB (ADS7263) 73dB (ADS7223) – THD: –98dB (ADS8363) –92dB (ADS7263) –86dB (ADS7223) Dual Programmable and Buffered 2.5V Reference Allows: – Two Different Input Voltage Range Settings – Two-Level PGA Implementation Programmable Auto-Sequencer Integrated Data Storage (up to 4 per channel) for Oversampling Applications 2-Bit Counter for Safety Applications Fully Specified over the Extended Industrial Temperature Range APPLICATIONS • • • • • • Motor Control: Current and Position Measurement including Safety Applications Power Quality Measurement Three-Phase Power Control Programmable Logic Controllers Industrial Automation Protection Relays The ADS8363/7263/7223 offer two programmable reference outputs, flexible supply voltage ranges, a programmable auto-sequencer, data storage of up to four conversion results per channel, and several power-down features. All devices are offered in a 5x5mm QFN-32 package. Functional Block Diagram AVDD CHA1P/CHA3 CHA1N/CHA2 CHA0P/CHA1 CHA0N/CHA0 CMA Input Mux DVDD CLOCK Serial Interface and FIFO REF1 REF2 CHB1P/CHB3 CHB1N/CHB2 CHB0P/CHB1 CHB0N/CHB0 CMB CS SAR ADC BUSY SDI RD SDOA Input Mux SAR ADC SDOB REF1 String DAC REFIO1 2.5V REF Control Logic M1 CONVST REF2 REFIO2 M0 String DAC RGND AGND DGND 1 2 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 2010–2011, Texas Instruments Incorporated ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. ORDERING INFORMATION For the most current package and ordering information, see the Package Option Addendum at the end of this document, or visit the device product folder at www.ti.com. FAMILY OVERVIEW (1) PRODUCT RESOLUTION NMC INL SNR THD ADS8363 16 bits 16 or 15 bits (1) ±3 or ±4 LSB (1) 93dB (typ) –98dB (typ) ADS7263 14 bits 14 bits ±1 LSB 85dB (typ) –92dB (typ) ADS7223 12 bits 12 bits ±0.5 LSB 73dB (typ) –86dB (typ) See Electrical Characteristics. ABSOLUTE MAXIMUM RATINGS (1) Over operating free-air temperature range, unless otherwise noted. ADS8363, ADS7263, ADS7223 UNIT –0.3 to +6 V 1.2 × AVDD (2) V Analog and reference input voltage with respect to AGND AGND – 0.3 to AVDD + 0.3 V Digital input voltage with respect to DGND DGND – 0.3 to DVDD + 0.3 V Ground voltage difference |AGND-DGND| 0.3 V Input current to any pin except supply pins –10 to +10 mA Supply voltage, AVDD to AGND or DVDD to DGND Supply voltage, DVDD to AVDD Maximum virtual junction temperature, TJ Electrostatic discharge (ESD) ratings, all pins (1) (2) +150 °C Human body model (HBM), JEDEC standard 22, test method A114-C.01 ±2000 V Charged device model (CDM), JEDEC standard 22, test method C101 ±500 V Stresses above these ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those specified is not implied. Exposure to absolute maximum conditions for extended periods may affect device reliability. Exceeding the specified limit causes an increase of the DVDD leakage current and leads to malfunction of the device. THERMAL INFORMATION ADS8363, ADS7263, ADS7223 THERMAL METRIC (1) UNITS RHB 32 PINS qJA Junction-to-ambient thermal resistance 33.3 qJCtop Junction-to-case (top) thermal resistance 29.5 qJB Junction-to-board thermal resistance 7.3 yJT Junction-to-top characterization parameter 0.2 yJB Junction-to-board characterization parameter 7.4 qJCbot Junction-to-case (bottom) thermal resistance 0.9 (1) 2 °C/W For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953. Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 ELECTRICAL CHARACTERISTICS: ADS8363 All minimum/maximum specifications at TA = –40°C to +125°C, specified supply voltage range, VREF = 2.5V (int), and tDATA = 1MSPS, unless otherwise noted. Typical values are at TA = +25°C, AVDD = 5V, and DVDD = 3.3V. ADS8363 PARAMETER TEST CONDITIONS MIN RESOLUTION TYP MAX UNIT 16 Bits DC ACCURACY INL Integral nonlinearity DNL Differential nonlinearity VOS Input offset error VOS match dVOS/dT Half-clock mode –3 ±1.2 +3 LSB Full-clock mode –4 ±1.5 +4 LSB Half-clock mode –0.99 ±0.6 +2 LSB Full-clock mode –1.5 ±0.8 +3 LSB –2 ±0.2 +2 mV –1 ±0.1 +1 mV ADC to ADC Input offset thermal drift 1 mV/°C Gain error Referenced to the voltage at REFIOx –0.1 ±0.01 +0.1 % GERR match ADC to ADC –0.1 ±0.005 +0.1 % GERR/dT Gain error thermal drift Referenced to the voltage at REFIOx CMRR Common-mode rejection ratio Both ADCs, dc to 100kHz GERR 1 ppm/°C 92 dB AC ACCURACY SINAD Signal-to-noise + distortion VIN = 5VPP at 10kHz 89 92 dB SNR Signal-to-noise ratio VIN = 5VPP at 10kHz 90 93 dB THD Total harmonic distortion VIN = 5VPP at 10kHz SFDR Spurious-free dynamic range VIN = 5VPP at 10kHz –98 90 –90 dB 100 dB ELECTRICAL CHARACTERISTICS: ADS7263 All minimum/maximum specifications at TA = –40°C to +125°C, specified supply voltage range, VREF = 2.5V (int), and tDATA = 1MSPS, unless otherwise noted. Typical values are at TA = +25°C, AVDD = 5V, and DVDD = 3.3V. ADS7263 PARAMETER TEST CONDITIONS MIN RESOLUTION TYP MAX UNIT 14 Bits DC ACCURACY INL Integral nonlinearity DNL Differential nonlinearity VOS Input offset error VOS match –1 ±0.4 +1 LSB –0.5 ±0.2 +1 LSB –2 ±0.2 +2 mV –1 ±0.1 +1 ADC to ADC 1 mV dVOS/dT Input offset thermal drift GERR Gain error Referenced to the voltage at REFIOx –0.1 ±0.01 +0.1 % GERR match ADC to ADC –0.1 ±0.005 +0.1 % GERR/dT Gain error thermal drift Referenced to the voltage at REFIOx CMRR Common-mode rejection ratio Both ADCs, dc to 100kHz mV/°C 1 ppm/°C 92 dB dB AC ACCURACY SINAD Signal-to-noise + distortion VIN = 5VPP at 10kHz 82 84 SNR Signal-to-noise ratio VIN = 5VPP at 10kHz 84 85 THD Total harmonic distortion VIN = 5VPP at 10kHz SFDR Spurious-free dynamic range VIN = 5VPP at 10kHz Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 –92 88 dB –88 92 Submit Documentation Feedback dB dB 3 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com ELECTRICAL CHARACTERISTICS: ADS7223 All minimum/maximum specifications at TA = –40°C to +125°C, specified supply voltage range, VREF = 2.5V (int), and tDATA = 1MSPS, unless otherwise noted. Typical values are at TA = +25°C, AVDD = 5V, and DVDD = 3.3V. ADS7223 PARAMETER TEST CONDITIONS MIN RESOLUTION TYP MAX 12 UNIT Bits DC ACCURACY INL Integral nonlinearity –0.5 ±0.2 +0.5 LSB DNL Differential nonlinearity –0.5 ±0.1 +0.5 LSB VOS Input offset error –2 ±0.2 +2 mV –1 ±0.1 +1 VOS match ADC to ADC 1 mV dVOS/dT Input offset thermal drift GERR Gain error Referenced to the voltage at REFIOx –0.1 ±0.01 +0.1 % GERR match ADC to ADC –0.1 ±0.005 +0.1 % GERR/dT Gain error thermal drift Referenced to the voltage at REFIOx CMRR Common-mode rejection ratio Both ADCs, dc to 100kHz mV/°C 1 ppm/°C 92 dB 72 dB AC ACCURACY SINAD Signal-to-noise + distortion VIN = 5VPP at 10kHz 71 SNR Signal-to-noise ratio VIN = 5VPP at 10kHz 72 THD Total harmonic distortion VIN = 5VPP at 10kHz SFDR Spurious-free dynamic range VIN = 5VPP at 10kHz 73 –86 84 dB –84 86 dB dB ELECTRICAL CHARACTERISTICS: GENERAL All minimum/maximum specifications at TA = –40°C to +125°C, specified supply voltage range, VREF = 2.5V (int), and tDATA = 1MSPS, unless otherwise noted. Typical values are at TA = +25°C, AVDD = 5V, and DVDD = 3.3V. ADS8363, ADS7263, ADS7223 PARAMETER TEST CONDITIONS MIN TYP MAX UNIT +VREF V ANALOG INPUT FSR Full-scale input range (CHxxP – CHxxN) or CHxx to CMx VIN Absolute input voltage CHxxx to AGND CIN Input capacitance CHxxx to AGND CID Differential input capacitance IIL Input leakage current PSRR Power-supply rejection ratio –VREF –0.1 AVDD + 0.1 pF 22.5 pF –16 AVDD = 5.5V V 45 16 75 nA dB SAMPLING DYNAMICS tCONV Conversion time per ADC tACQ Acquisition time fDATA Data rate tA Aperture delay tA match tAJIT 17.5 tCLK Full-clock mode 35 tCLK Half-clock mode 2 tCLK Full-clock Mode 4 tCLK 25 Clock frequency tCLK Clock period Submit Documentation Feedback 1000 6 ADC to ADC 50 Aperture jitter fCLK 4 Half-clock mode kSPS ns ps 50 ps Half-clock mode 0.5 20 MHz Full-clock mode 1 40 MHz Half-clock mode 50 2000 ns Full-clock mode 25 1000 ns Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 ELECTRICAL CHARACTERISTICS: GENERAL (continued) All minimum/maximum specifications at TA = –40°C to +125°C, specified supply voltage range, VREF = 2.5V (int), and tDATA = 1MSPS, unless otherwise noted. Typical values are at TA = +25°C, AVDD = 5V, and DVDD = 3.3V. ADS8363, ADS7263, ADS7223 PARAMETER TEST CONDITIONS MIN TYP MAX UNIT INTERNAL VOLTAGE REFERENCE Resolution Reference output DAC resolution 10 Over 20% to 100% DAC range VREFOUT Reference output voltage Bits 0.2VREFOUT VREFOUT V REFIO1, DAC = 3FFh, 2.485 2.500 2.515 V REFIO2, DAC = 3FFh 2.480 2.500 2.520 V dVREFOUT/dT Reference voltage drift DNLDAC DAC differential linearity error –4 ±10 ±1 4 LSB INLDAC DAC integral linearity error –4 ±0.5 4 LSB VOSDAC DAC offset error –4 ±1 4 LSB PSRR Power-supply rejection ratio IREFOUT Reference output dc current +2 mA IREFSC Reference output short-circuit current (1) tREFON Reference output settling time VREFOUT = 0.5V ppm/°C 73 dB –2 50 mA 8 ms CREF= 22mF VOLTAGE REFERENCE INPUT VREF Reference input voltage range IREF Reference input current 0.5 2.5 50 2.525 mA V CREF External ceramic reference capacitance 22 mF DIGITAL INPUTS (2) IIN Input current CIN Input capacitance VIN = DVDD to DGND –50 +50 5 Logic family nA pF CMOS with Schmitt-Trigger VIH High-level input voltage DVDD = 4.5V to 5.5V 0.7DVDD DVDD + 0.3 V VIL Low-level input voltage DVDD = 4.5V to 5.5V –0.3 0.3DVDD V Logic family LVCMOS VIH High-level input voltage DVDD = 2.3V to 3.6V 2 DVDD + 0.3 V VIL Low-level input voltage DVDD = 2.3V to 3.6V –0.3 0.8 V DIGITAL OUTPUTS (2) V COUT Output capacitance CLOAD Load capacitance 5 Logic family pF CMOS VOH High-level output voltage DVDD = 4.5V, IOH = –100µA VOL Low-level output voltage DVDD = 4.5V, IOH = +100µA 4.44 V 0.5 Logic family V LVCMOS VOH High-level output voltage DVDD = 2.3V, IOH = –100µA VOL Low-level output voltage DVDD = 2.3V, IOH = +100µA (1) (2) pF 30 DVDD – 0.2 V 0.2 V Reference output current is not internally limited. Specified by design; not production tested. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 5 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com ELECTRICAL CHARACTERISTICS: GENERAL (continued) All minimum/maximum specifications at TA = –40°C to +125°C, specified supply voltage range, VREF = 2.5V (int), and tDATA = 1MSPS, unless otherwise noted. Typical values are at TA = +25°C, AVDD = 5V, and DVDD = 3.3V. ADS8363, ADS7263, ADS7223 PARAMETER TEST CONDITIONS MIN TYP MAX UNIT AVDD to AGND, half-clock mode 2.7 5.0 5.5 V AVDD to AGND, full-clock mode 4.5 5.0 5.5 V 3V and 3.3V levels 2.3 2.5 3.6 V 5V levels, half-clock mode only 4.5 5.0 5.5 V AVDD = 3.6V 12.0 16.0 mA AVDD = 5.5V 15.0 20.0 mA AVDD = 3.6V, sleep/auto-sleep modes 0.8 1.2 mA AVDD = 5.5V, sleep/auto-sleep modes 0.9 1.4 mA 0.005 mA mA POWER SUPPLY AVDD DVDD AIDD Analog supply voltage Digital supply voltage Analog supply current Power-down mode DIDD PD 6 Digital supply current Power dissipation (normal operation) Submit Documentation Feedback DVDD = 3.6V, CLOAD = 10pF 1.1 2.5 DVDD = 5.5V, CLOAD = 10pF 3 6 mA AVDD = DVDD = 3.6V 47.2 66.6 mW AVDD = 5.5V, DVDD = 3.6V 86.5 117.0 mW Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 PIN CONFIGURATION CMB CMA AGND AVDD DGND DVDD NC SDOA RHB PACKAGE QFN-32 (TOP VIEW) 32 31 30 29 28 27 26 25 CHB1P/CHB3 1 24 SDOB CHB1N/CHB2 2 23 BUSY CHB0P/CHB1 3 22 CLOCK 21 CS 20 RD 19 CONVST 18 SDI 17 M0 CHB0N/CHB0 4 CHA1P/CHA3 5 CHA1N/CHA2 6 CHA0P/CHA1 7 ADS8363 ADS7263 ADS7223 (Thermal Pad) 12 13 14 AVDD NC 15 16 M1 11 NC 10 AGND REFIO1 9 RGND 8 REFIO2 CHA0N/CHA0 Pin Descriptions PIN NAME NO. TYPE (1) CHB1P/CHB3 1 AI Fully-differential noninverting analog input channel B1 or pseudo-differential input B3 CHB1N/CHB2 2 AI Fully-differential inverting analog input channel B1 or pseudo-differential input B2 DESCRIPTION CHB0P/CHB1 3 AI Fully-differential noninverting analog input channel B0 or pseudo-differential input B1 CHB0N/CHB0 4 AI Fully-differential inverting analog input channel B0 or pseudo-differential input B0 CHA1P/CHA3 5 AI Fully-differential noninverting analog input channel A1 or pseudo-differential input A3 CHA1N/CHA2 6 AI Fully-differential inverting analog input channel A1 or pseudo-differential input A2 CHA0P/CHA1 7 AI Fully-differential nonInverting analog input channel A1 or pseudo-differential input A1 CHA0N/CHA0 8 AI Fully-differential inverting analog input channel A1 or pseudo-differential input A0 REFIO1 9 AIO Reference voltage input/output 1. A ceramic capacitor of 22µF connected to RGND is required. REFIO2 10 AIO Reference voltage input/output 2. A ceramic capacitor of 22µF connected to RGND is required. RGND 11 P Reference ground. Connect to analog ground plane with a dedicated via. AGND 12, 30 P Analog ground. Connect to analog ground plane. AVDD 13, 29 P Analog power supply, 2.7V to 5.5V. Decouple to AGND with a 1mF ceramic capacitor. NC 14, 15, 26 NC This pin is not internally connected. M1 16 DI Mode pin 1. Selects the digital output mode (see Table 4). M0 17 DI Mode pin 0. Selects analog input channel mode (see Table 4). SDI 18 DI Serial data input. This pin is used to set up of the internal registers, and can also be used in ADS8361-compatible manner. The data on SDI are ignored when CS is high. CONVST 19 DI Conversion start. The ADC switches from sample into hold mode on the rising edge of CONVST. Thereafter, the conversion starts with the next rising edge of the CLOCK pin. RD 20 DI Read data. Synchronization pulse for the SDOx outputs and SDI input. RD only triggers when CS is low. (1) AI = analog input, AIO = analog input/output, DI = digital input, DO = digital output, DIO = digital input/output, P = power supply, NC = not connected. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 7 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com Pin Descriptions (continued) PIN 8 NAME NO. TYPE (1) CS 21 DI Chip select. When this pin is low, the SDOx, SDI, and RD pins are active; when this pin is high, the SDOx outputs are 3-stated, while the SDI and RD inputs are ignored. CLOCK 22 DI External clock input. The range is 0.5MHz to 20MHz in half-clock mode, or 1MHz to 40MHz in full-clock mode. BUSY 23 DO Converter busy indicator. BUSY goes high when the inputs are in hold mode and returns to low after the conversion is complete. SDOB 24 DO Serial data output for converter B. Active only if M1 is low. 3-state when CS is high. SDOA 25 DO Serial data output for converter A. 3-state when CS is high. DVDD 27 P Digital supply, 2.3V to 5.5V. Decouple to DGND with a 1mF ceramic capacitor. DGND 28 P Digital ground. Connect to digital ground plane. CMA 31 AI Common-mode voltage input for channels Ax (in pseudo-differential mode only). CMB 32 AI Common-mode voltage input for channels Bx (in pseudo-differential mode only). DESCRIPTION Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 TIMING DIAGRAMS tCLK tCLKL 1 tCLKH 18 21 CLOCK tCONV tACQ CS t1 t2 CONVST tDATA tD2 tD1 BUSY conversion n tH1 tS1 t3 RD tD5 SDOx(1) (CID = ‘0’) tH3 data n-1 CH AD 0/1 A/B MSB D14 D13 D12 D11 D10 D9 tD6 tD3 D8 D7 D6 D5 D4 D3 D2 D6 D5 D4 D3 D2 D1 D0 D1 D0 CH 0/1 data n-1 SDOx(1) (CID = ‘1’) MSB D14 D13 D12 D11 tS2 SDI (1) D15 D14 D13 D10 D9 D8 D7 MSB tH2 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 D15 The ADS7263/7223 output data with the MSB located as ADS8363 and last 2/4 bits being '0'. Figure 1. Detailed Timing Diagram: Half-Clock Mode (ADS8361-Compatible) Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 9 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com TIMING DIAGRAMS (continued) tCLK 1 tCLKL tCLKH 23 25 36 41 CLOCK tCONV tACQ CS tDATA t1 t2 CONVST tD2 tD1 BUSY conversion n tH1 tS1 RD tD5 (CID = ‘0’) SDOx (1) tH4 data n CH AD 0/1 A/B M S B D 14 D 13 D 12 D 15 D 13 D 12 D 11 D 10 D 11 D 10 tD4 D9 D8 D7 D6 D5 D4 D3 D0 D1 D0 tS2 SDI D 14 tD6 tH2 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 RD tD5 (CID = ‘1’) data n tH4 SDOx(1) M S B D 14 D 13 D 12 SDI D 15 D 14 D 13 D 12 D 11 D 10 D 11 D 10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 tS2 (2) tD4 tH2 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 The ADS7263/7223 output data with the MSB located as ADS8363 and last 2/4 bits being '0'. Figure 2. Detailed Timing Diagram: Full-Clock Mode 10 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 TIMING CHARACTERISTICS (1) Over the recommended operating free-air temperature range of –40°C to +125°C, and DVDD = 2.3V to 5.5V, unless otherwise noted. ADS8363, 7263, 7223 PARAMETER tDATA Data throughput tCONV Conversion time tACQ Acquisition time fCLK TEST CONDITIONS fCLK = max MIN MAX 1 ms Half-clock mode 17.5 tCLK Full-clock mode 35 tCLK 100 Half-clock mode CLOCK frequency UNIT 0.5 ns 20 MHz MHz Full-clock mode 1 40 Half-clock mode 50 2000 ns Full-clock mode 25 1000 ns tCLK CLOCK period tCLKL CLOCK low time 11.25 ns tCLKH CLOCK high time 11.25 ns t1 CONVST rising edge to first CLOCK rising edge 12 ns 10 ns t2 CONVST high time t3 RD high time tS1 RD high to CLOCK falling edge setup time 5 ns tH1 RD high to CLOCK falling edge hold time 5 ns tS2 Input data to CLOCK falling edge setup time 5 ns tH2 Input data to CLOCK falling edge hold time 4 tD1 CONVST rising edge to BUSY high delay (2) tD2 CLOCK 18th falling edge (half-clock mode) or 24th rising edge (full-clock mode) to BUSY low delay tD3 CLOCK rising edge to next data valid delay Half-clock mode: timing modes II and IV only 1 tCLK Half-clock mode: timing modes II, IV, SII, and SIV only 1 tCLK 19 ns 4.5V < DVDD < 5.5V 16 ns 2.3V < DVDD < 3.6V 25 ns 4.5V < DVDD < 5.5V 20 ns Half-clock mode, 2.3V < DVDD < 3.6V 14 ns Half-clock mode, 4.5V < DVDD < 5.5V 12 ns tH3 Output data to CLOCK rising edge hold time Half-clock mode tD4 CLOCK falling edge to next data valid delay Full-clock mode tH4 Output data to CLOCK falling edge hold time Full-clock mode tD5 RD falling edge to first data valid tD6 CS rising edge to SDOx 3-state (1) (2) ns 2.3V < DVDD < 3.6V 3 ns 19 7 ns ns 2.3V < DVDD < 3.6V 16 ns 4.5V < DVDD < 5.5V 12 ns 6 ns All input signals are specified with tR = tF = 1.5ns (10% to 90% of DVDD) and timed from a voltage level of (VIL + VIH)/2. Not applicable in auto-sleep power-down mode. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 11 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com TYPICAL CHARACTERISTICS At TA = +25°C, AVDD = 5V, DVDD = 3.3V, VREF = 2.5V (internal), and fDATA = 1MSPS, unless otherwise noted. INTEGRAL NONLINEARITY vs DATA RATE DIFFERENTIAL NONLINEARITY vs DATA RATE 3.0 3.0 ADS8363 Positive ADS7263 Positive ADS7223 Positive 2.5 2.0 1.5 1.5 1.0 1.0 0.5 0 -0.5 -1.0 -1.5 200 300 400 500 600 700 Data Rate (kSPS) 800 900 0 -0.5 -1.0 ADS8363 Negative ADS7263 Negative ADS7223 Negative -2.5 -3.0 -3.0 100 0.5 -1.5 -2.0 ADS8363 Negative ADS7263 Negative ADS7223 Negative -2.0 -2.5 ADS8363 Positive ADS7263 Positive ADS7223 Positive 2.5 DNL (LSB) INL (LSB) 2.0 1000 100 200 300 400 500 600 700 Data Rate (kSPS) Figure 3. INTEGRAL NONLINEARITY vs CODE 1.5 1.5 1.0 1.0 DNL (LSB) INL (LSB) 2.0 0.5 0 -0.5 -1.0 0 -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 -2.5 -3.0 8192 16384 24576 32768 40960 49152 57344 65536 Code 0 Figure 6. INTEGRAL NONLINEARITY vs TEMPERATURE DIFFERENTIAL NONLINEARITY vs TEMPERATURE 3.0 ADS8363 AVDD = 5V, Positive AVDD = 3V, Positive 2.5 2.0 1.5 1.0 1.0 DNL (LSB) 1.5 0.5 0 -0.5 -1.0 -2.5 -3.0 8192 16384 24576 32768 40960 49152 57344 65536 Code Figure 5. 3.0 INL (LSB) 0.5 -1.5 -2.0 -1.5 -2.0 ADS8363 2.5 2.0 2.0 5 -0.5 -1.0 -2.5 -3.0 20 35 50 65 Temperature (°C) 80 95 110 125 AVDD = 5V, Negative AVDD = 3V, Negative -40 -25 -10 5 Figure 7. 12 Submit Documentation Feedback ADS8363 AVDD = 5V, Positive AVDD = 3V, Positive 0.5 0 -1.5 -2.0 AVDD = 5V, Negative AVDD = 3V, Negative -40 -25 -10 1000 DIFFERENTIAL NONLINEARITY vs CODE 3.0 ADS8363 2.5 2.5 900 Figure 4. 3.0 0 800 20 35 50 65 Temperature (°C) 80 95 110 125 Figure 8. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, AVDD = 5V, DVDD = 3.3V, VREF = 2.5V (internal), and fDATA = 1MSPS, unless otherwise noted. OFFSET ERROR AND OFFSET MATCH vs ANALOG SUPPLY VOLTAGE OFFSET ERROR AND OFFSET MATCH vs TEMPERATURE 2.0 2.0 All Devices Offset Error Offset Match 1.5 Offset Error and Match (mV) Offset Error and Match (mV) All Devices 1.0 0.5 0 -0.5 -1.0 0.5 0 -0.5 -1.0 -2.0 -2.0 2.7 3.1 3.5 3.9 4.3 AVDD (V) 4.7 5.1 5.5 -40 -25 -10 5 20 35 50 65 Temperature (°C) 80 95 Figure 9. Figure 10. GAIN ERROR AND GAIN MATCH vs ANALOG SUPPLY VOLTAGE GAIN ERROR AND GAIN MATCH vs TEMPERATURE 0.10 110 125 0.10 All Devices 0.08 Gain Error Gain Match 0.06 0.08 Gain Error and Match (%) Gain Error and Match (%) 1.0 -1.5 -1.5 0.04 0.02 0 -0.02 -0.04 -0.06 All Devices Gain Error Gain Match 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 -0.08 -0.08 -0.10 -0.10 2.7 3.1 3.5 3.9 4.3 AVDD (V) 4.7 5.1 5.5 5 -40 -25 -10 20 35 50 65 Temperature (°C) 80 95 110 125 Figure 11. Figure 12. COMMON-MODE REJECTION RATIO vs ANALOG SUPPLY VOLTAGE COMMON-MODE REJECTION RATIO vs TEMPERATURE 100 100 95 95 90 90 CMRR (dB) CMRR (dB) Offset Error Offset Match 1.5 85 80 85 80 75 75 All devices f = 100kHz 70 2.7 3.1 3.5 3.9 4.3 AVDD (V) 4.7 5.1 5.5 All devices f = 100kHz 70 -40 -25 -10 5 Figure 13. 20 35 50 65 Temperature (°C) 80 95 110 125 Figure 14. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 13 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = +25°C, AVDD = 5V, DVDD = 3.3V, VREF = 2.5V (internal), and fDATA = 1MSPS, unless otherwise noted. FREQUENCY SPECTRUM (4096 Point FFT; fIN = 10kHz) FREQUENCY SPECTRUM (4096 Point FFT; fIN = 10kHz, fSAMPLE = 0.5MSPS) 0 0 All Devices -20 -20 -40 -40 -60 -60 Amplitude (dB) Amplitude (dB) All Devices -80 -100 -120 -80 -100 -120 -140 -140 -160 -160 -180 -180 50 100 150 200 250 300 350 400 450 500 Frequency (kHz) 0 100 150 Frequency (kHz) 250 SIGNAL-TO-NOISE RATIO AND SIGNAL-TO-NOISE + DISTORTION vs INPUT SIGNAL FREQUENCY SIGNAL-TO-NOISE RATIO AND SIGNAL-TO-NOISE + DISTORTION vs TEMPERATURE 100 100 95 95 90 90 85 80 75 70 65 85 80 75 70 65 60 ADS8363 SINAD ADS7263 SINAD ADS7223 SINAD ADS8363 SNR ADS7263 SNR ADS7223 SNR 55 ADS8363 SNR ADS7263 SNR ADS7223 SNR 55 ADS8363 SINAD ADS7263 SINAD ADS7223 SINAD 50 50 10 20 30 fIN (kHz) 40 -40 -25 -10 50 5 20 35 50 65 Temperature (°C) 80 95 Figure 17. Figure 18. TOTAL HARMONIC DISTORTION vs INPUT SIGNAL FREQUENCY TOTAL HARMONIC DISTORTION vs TEMPERATURE -80 110 125 -80 ADS8363 ADS7263 ADS7223 -84 ADS8363 ADS7263 ADS7223 -84 -88 THD (dB) -88 -92 -92 -96 -96 -100 -100 -104 -104 10 20 30 fIN (kHz) 40 50 fIN = 10kHz -40 -25 -10 5 Figure 19. 14 200 Figure 16. 60 THD (dB) 50 Figure 15. SNR and SINAD (dB) SNR and SINAD (dB) 0 Submit Documentation Feedback 20 35 50 65 Temperature (°C) 80 95 110 125 Figure 20. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 TYPICAL CHARACTERISTICS (continued) At TA = +25°C, AVDD = 5V, DVDD = 3.3V, VREF = 2.5V (internal), and fDATA = 1MSPS, unless otherwise noted. SPURIOUS-FREE DYNAMIC RANGE vs INPUT SIGNAL FREQUENCY SPURIOUS-FREE DYNAMIC RANGE vs TEMPERATURE 105 104 ADS8363 ADS7263 ADS7223 100 ADS8363 ADS7263 ADS7223 101 99 SFDR (dB) 96 SFDR (dB) fIN = 10kHz 103 92 88 97 95 93 91 89 84 87 85 80 10 20 20 30 fIN (kHz) 40 20 35 50 65 Temperature (°C) 80 95 Figure 22. ANALOG SUPPLY CURRENT vs TEMPERATURE DIGITAL SUPPLY CURRENT vs TEMPERATURE 20 All Devices AVDD = 5.5V AVDD = 3.6V 16 14 14 IDVDD (mA) 16 12 10 8 All Devices 110 125 DVDD = 5.5V DVDD = 3.6V 18 12 10 8 6 6 4 4 2 2 0 0 -40 -25 -10 5 20 35 50 65 Temperature (°C) 80 95 110 125 -40 -25 -10 5 20 35 50 65 Temperature (°C) 80 95 110 125 Figure 23. Figure 24. ANALOG SUPPLY CURRENT vs DATA RATE ANALOG SUPPLY CURRENT vs DATA RATE (Auto-Sleep Mode) 20 20 All Devices 18 External Reference Internal Reference 16 16 14 14 12 10 8 All Devices in Auto-Sleep Mode 18 IAVDD (mA) IAVDD (mA) 5 Figure 21. 18 IAVDD (mA) -40 -25 -10 50 External Reference Internal Reference 12 10 8 6 6 4 4 2 2 0 0 0 100 200 300 400 500 600 700 800 900 1000 fSAMPLE (kSPS) 0 100 200 Figure 25. 300 400 500 fSAMPLE (kSPS) 600 700 800 Figure 26. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 15 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com THEORY OF OPERATION GENERAL DESCRIPTION The ADS8363/7263/7223 contain two 16-/14-/12-bit analog-to-digital converters (ADCs), respectively, that operate based on the successive approximation register (SAR) principle. These ADCs sample and convert simultaneously. Conversion time can be as low as 875ns. Adding an acquisition time of 100ns, and a margin of 25ns for propagation delay and CONVST pulse generation, results in a maximum conversion rate of 1MSPS. Each ADC has a fully-differential 2:1 multiplexer front-end. In many common applications, all negative input signals remain at the same constant voltage (for example, 2.5V). For these applications, the multiplexer can be used in a pseudo-differential 4:1 mode, where the CMx pins function as common-mode pins and all four analog inputs are referred to the corresponding CMx pin. The ADS8363/7263/7223 also include a 2.5V internal reference. This reference drives two independently-programmable, 10-bit digital-to-analog converters (DACs), allowing the voltage at each of the REFIOx pins to be adjusted through the internal REFDACx registers in 2.44mV steps. A low-noise, unity-gain operational amplifier buffers each of the DAC outputs and drives the REFIOx pin. The ADS8363/7263/7223 provide a serial interface that is compatible with the ADS8361. However, instead of the ADS8361 A0 pin that controls the channel selection, the ADS8363/7263/7223 offers a serial data input (SDI) pin that supports additional functions described in the Digital section of this data sheet (also see the ADS8361 Compatibility section). ANALOG This section discusses the analog input circuit, the ADCs, and the reference design of the device. Analog Inputs Each ADC is fed by an input multiplexer, as shown in Figure 27. Each multiplexer is used in either a fully-differential 2:1 configuration (as shown in Table 1) or a pseudo-differential 4:1 configuration (as shown in Table 2). Channel selection is performed using either the external M0 pin or the C[1:0] bits in the Configuration (CONFIG) register in fully-differential mode, or using the SEQFIFO register in pseudo-differential mode. In either case, changing the multiplexer settings impacts the conversion started with the next CONVST pulse. Table 1. Fully-Differential 2:1 Multiplexer Configuration C1 C0 ADC+ ADC– 0 x CHx0P CHx0N 1 x CHx1P CHx1N Table 2. Pseudo-Differential 4:1 Multiplexer Configuration C1 C0 ADC+ ADC– 0 0 CHx0 CMx/REFIOx 0 1 CHx1 CMx/REFIOx 1 0 CHx2 CMx/REFIOx 1 1 CHx3 CMx/REFIOx The input path for the converter is fully differential and provides a good common-mode rejection of 92dB at 100kHz (for the ADS8363). The high CMRR also helps suppress noise in harsh industrial environments. Each of the 40pF sample-and-hold capacitors (shown as CS in Figure 28) is connected through switches to the multiplexer output. Opening the switches holds the sampled data during the conversion process. After the conversion completes, both capacitors are precharged for the duration of one clock cycle to the voltage present at the REFIOx pin. After precharging, the multiplexer outputs are connected to the sampling capacitors again. The voltage at the analog input pin is usually different from the reference voltage; therefore, the sample capacitors must be charged to within one-half LSB for 16-, 14-, or 12-bit accuracy during the acquisition time tACQ (see the Timing Diagrams). AVDD RSER 100W CHxx+ CHx1N/CHx2 CHx0P/CHx1 CPAR 5pF AVDD CS 40pF RSER AGND 100W CPAR 5pF CHx1P/CHx3 RSW 100W RSW 100W CS 40pF CHxx- Input Mux To ADC AGND CHx0N/CHx0 Figure 28. Equivalent Analog Input Circuit Figure 27. Input Multiplexer Configuration 16 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Acquisition is indicated with the BUSY signal being low. It starts by closing the input switches (after finishing the previous conversion and precharging) and finishes with the rising edge of the CONVST signal. If the device operates at full speed, the acquisition time is typically 100ns. The minimum –3dB bandwidth of the driving operational amplifier can be calculated as shown in Equation 1, with n = 16 for the resolution of the ADS8363, n = 14 for the ADS7263, or n = 12 for the ADS7223: ln(2)(n + 1) f-3dB = 2ptACQ (1) With tACQ = 100ns, the minimum bandwidth of the driving amplifier is 19MHz for the ADS8363, 17MHz for the ADS7263, and 15MHz for the ADS7223. The required bandwidth can be lower if the application allows a longer acquisition time. A gain error occurs if a given application does not fulfill the settling requirement shown in Equation 1. However, linearity and THD are not directly affected as a result of precharging the capacitors. The OPA365 from Texas Instruments is recommended as a driver; in addition to offering the required bandwidth, it also provides a low offset and excellent THD performance (see also Application Information section). It is important to keep the voltage to all inputs within the 0.3V limit below AGND and above AVDD, while not allowing dc current to flow through the inputs (exceeding these limits causes the internal ESD diodes to conduct, leading to increased leakage current that may damage the device). Current is only necessary to recharge the sample-and-hold capacitors. Unused inputs should be directly tied to AGND or RGND without the need of a pull-down resistor. Analog-to-Digital Converters (ADCs) The ADS8363/7263/7223 include two SAR-type, 1MSPS, 16-/14-/12-bit ADCs that include sample-and-hold (S&H), respectively, as shown in the Functional Block Diagram on the front page of this data sheet. CONVST The analog inputs are held with the rising edge of the CONVST (conversion start) signal. The setup time of CONVST referred to the next rising edge of CLOCK (system clock) is 12ns (minimum). The conversion automatically starts with the rising CLOCK edge. A rising edge of CONVST should not be issued during a conversion (that is, when BUSY is high). The phase margin of the driving operational amplifier is usually reduced by the ADC sampling capacitor. A resistor placed between the capacitor and the amplifier limits this effect; therefore, an internal 100Ω resistor (RSER) is placed in series with the switch. The switch resistance (RSW) is typically 100Ω, as shown in Figure 28). RD (read data) and CONVST can be shorted to minimize necessary software and wiring. The RD signal is triggered by the device on the falling edge of CLOCK. Therefore, the combined signals must be activated with the rising CLOCK edge. The conversion then starts with the subsequent rising CLOCK edge. In modes with only SDOA active (that is, in modes II, IV, SII, and SIV), the maximum length of the combined RD and CONVST signal is one clock cycle if the half-clock timing is used. An input driver may not be required, if the impedance of the signal source (RSOURCE) fulfills the requirement of Equation 2: tACQ RSOURCE < - (RSER + RSW) CSln(2)(n + 1) If CONVST and RD are combined, CS must be low whenever a new conversion starts; however, this condition is not required if RD and CONVST are controlled separately. Note that if FIFO is used, CONVST must be controlled separately from RD. Where: n = 16/14/12 for the resolution of the ADS8363/7263/7223, respectively. CS = 40pF sample capacitance. RSER = 100Ω input resistor value. RSW = 100Ω switch resistance value. (2) After completing a conversion, the sample capacitors are automatically precharged to the value of the reference voltage used to significantly reduce the crosstalk among the multiplexed input channels. With tACQ = 100ns, the maximum source impedance should be less than 12Ω for the ADS8363, less than 40Ω for the ADS7263, and less than 77Ω for the ADS7223. The source impedance can be higher if the ADC is used at a lower data rate. The differential input voltage range of the ADC is ±VREF, the voltage at the selected REFIOx pin. CLOCK The ADS8363/7263/7223 use an external clock with an allowable frequency range that depends on the mode being used. By default (after power-up), the ADC operates in half-clock mode, which supports a clock in the range of 0.5MHz to 20MHz. In full-clock mode, the ADC requires a clock in the range of 1MHz to 40MHz. For maximum data throughput, the clock Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 17 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com signal should be continuously running. However, in applications that use the device in burst mode, the clock may be held static low or high upon completion of the read access and before starting a new conversion. capacitor connected. Smaller reference capacitance values reduce the DNL, INL, and ac performance of the device. By default, both reference outputs are disabled and the respective values are set to 2.5V after power-up. The CLOCK duty cycle should be 50%. However, the device functions properly with a duty cycle between 30% and 70%. For applications that use an external reference source, the internal reference can be disabled (default) using the RPD bit in the CONFIG register (see the Digital section). The REFIOx pins are directly connected to the ADC; therefore, the internal switching generates spikes that can be observed at this pin. Therefore, also in this case, an external 22µF capacitor to the analog ground (AGND) should be used to stabilize the reference input voltage. RESET The ADS8363/7263/7223 feature an internal power-on reset (POR) function. A user-controlled reset can also be issued using SDI register bits A[3:0] (see the Digital section). Disabled REFIOx pins can be left floating or can be directly tied to AGND or RGND. REFIOx The ADS8363/7263/7223 include a low-drift, 2.5V internal reference source. This source feeds two, 10-bit string DACs that are controlled through registers. As a result of this architecture, the reference voltages at REFIOx are programmable in 2.44mV steps and can be adjusted to the application requirements without the use of additional external components. The actual output voltage can be calculated using Equation 3, with code being the decimal value of the REFDACx register content: 2.5V(code +1) VREF = 1024 (3) Each of the reference DAC outputs can be individually selected as a source for each channel input using the Rxx bits in the REFCM register. Figure 29 illustrates a simplified block diagram of the internal circuit. ADC A REFCM Bits[3:0] REFCM Bits[7:4] The reference DAC has a fixed transition at the code 508 (0x1FC). At this code, the DAC may show a jump of up to 10mV in its transfer function. Table 3 lists some examples of internal reference DAC settings. However, to ensure proper performance, the REFDACx output voltage should not be programmed below 0.5V. Table 3. REFDACx Setting Examples VREFOUT (NOM) DECIMAL CODE BINARY CODE HEXADECIMAL CODE 0.5000V 205 00 1100 1101 0CD 1.2429V 507 01 1111 1100 1FB 1.2427V 508 01 1111 1101 1FC 2.5000V 1023 11 1111 1111 3FF A minimum of 22mF capacitance is required on each REFIOx output to keep the references stable. The settling time is 8ms (maximum) with the reference 18 Submit Documentation Feedback ADC B REFDAC1 Bit 10 REFIO1 DAC 1 REFIO2 DAC 2 2.5V Reference REFDAC2 Bit 10 Figure 29. Reference Selection Circuit Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 DIGITAL This section reviews the timing and control of the serial interface. The ADS8363/7263/7223 offer a set of internal registers (see the Register Map section for details), which allows the control of several features and modes of the device, as Table 5 shows. Mode Selection Pin M0 and M1 The ADS8363/7263/7223 can be configured to four different operating modes by using mode pins M0 and M1, as shown in Table 4. Table 4. M0/M1 Truth Table M0 M1 CHANNEL SELECTION 0 0 Manual (through SDI) SDOA and SDOB 0 1 Manual (through SDI) SDOA only 1 0 Automatic SDOA and SDOB 1 1 Automatic SDOA only SDOx USED The M0 pin sets either manual or automatic channel selection. In Manual mode, CONFIG register bits C[1:0] are used to select between channels CHx0 and CHx1. In Automatic mode, CONFIG register bits C[1:0] are ignored and channel selection is controlled by the device after each conversion. The automatic channel selection is only performed on fully-differential inputs in this case; for pseudo-differential inputs, the internal sequencer controls the input multiplexer. The M1 pin selects between serial data being transmitted simultaneously on both SDOA and SDOB outputs for each channel, respectively, or using only the SDOA output for transmitting data from both channels (see Figure 34 through Figure 39 and the associated text for more information). Additionally, the SDI pin is used for controlling device functionality through the internal register; see the Register Map section for details. Half-Clock Mode (default mode after power-up and reset) The ADS8363/7263/7223 power up in half-clock mode, in which the ADC requires at least 20 CLOCKs for a complete conversion cycle, including the acquisition phase. The conversion result can only be read during the next conversion cycle. The first output bit is available with the falling RD edge, while the following output data bits are refreshed with the rising edge of CLOCK. Full-Clock Mode (allowing conversion and data readout within 1µs, supported in dual output modes) The full-clock mode allows converting data and reading the result within 1µs. The entire cycle requires 40 CLOCKs. The first output bit is available with the falling RD edge while the following output data bits are refreshed with the falling edge of the CLOCK in this mode. The full-clock mode can only be used with analog power supply AVDD in the range of 4.5V to 5.5V and digital supply DVDD in the range of 2.3V to 3.6V. The internal FIFO is disabled in full-clock mode. 2-Bit Counter These devices offers a selectable 2-bit counter (activated using the CE bit in the CONFIG register) that is a useful feature in safety applications. The counter value automatically increments whenever a new conversion result is stored in the output register, indicating a new value. The counter default value after power-up is '01' (followed by '10', '11', '00', '01', and so on), as shown in Figure 31. Because the counter value increments only when a new conversion results are transferred to the output register, this counter is used to verify that the ADC has performed a conversion and the data read is the result of this new conversion (not a old result read multiple times). Table 5. Supported Operating Modes INPUT SIGNAL TYPE MANUAL CHANNEL SELECTION AUTOMATIC CHANNEL SELECTION Fully-differential (PDE bit = '0') Operating modes: I, II, and special mode II Channel information selectable through CID bit FIFO: not available Operating modes: III, IV and special mode IV Channel information selectable through CID bit FIFO: available in mode III and special mode IV; when used, a single read pulse allows reading of all data Pseudo-differential (PDE bit = '1') Operating modes: I, II and special mode II Channel information selectable through CID bit FIFO: not available Operating modes: III and special mode IV Channel information not available (CID bit forced to '1') FIFO: available in mode III and special mode IV; when used, a single read pulse allows reading of all data Pseudo-differential sequencer is enabled Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 19 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com REGISTERS Register Map ADS8363/7263/7223 operation is controlled through a set of registers described in the following sections. Table 6 shows the register map. The contents of these 16-bit registers can be set using the serial data input (SDI) pin, which is coupled to RD and clocked into the device on each falling edge of CLOCK. All data must be transferred MSB first. All register updates become active with the rising edge of CLOCK after completing the 16-clock-cycle write access operation. Table 6. Register Map REGISTER CONFIG REFDAC1 BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 C1 C0 R1 R0 0 0 0 0 BIT 3 BIT 2 BIT 1 BIT 0 PD1 PD0 FE SR FC PDE CID CE A3 A2 A1 A0 0 RPD D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 REFDAC2 0 0 0 0 0 RPD D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 SEQFIFO S1 S0 SL1 SL0 C11 C10 C21 C20 C31 C30 C41 C40 SP1 SP0 FD1 FD0 CMB3 CMB2 CMB1 CMB0 CMA3 CMA2 CMA1 CMA0 RB3 RB2 RB1 RB0 RA3 RA2 RA1 RA0 REFCM To update the CONFIG register, a single write access is required. To update the contents of all the other registers, a write access to the control register with the appropriate register address (bits A[3:0]), followed by a write access to the actual register is required (refer to Figure 30). It is possible to update the CONFIG register contents while issuing a register read out access with a single register write access. For example, it is possible to change the mode of the device to full-clock mode while activating the REFDAC1 register read access; because full-clock mode is active upon the 16th clock cycle of the CONFIG register update, the REFDAC1 data are then presented according to the full-clock mode timing. To verify the register contents, a read access may be issued using CONFIG register bits A[3:0]. Such access is described in the Programming the Reference DAC section, based on an example of verifying the reference DAC register settings. The register contents are always available on SDOA with the next read command. For example, if the FIFO is used, the register contents are presented after completion of the FIFO read access (see Table 10 for more details). In both cases, a complete read or write access requires a total of 40 clock cycles, during which a new access to the CONFIG register is not allowed. CID = ‘1’ 20 1 20 1 1 20 1 20 1 20 1 CLOCK Half-Clock Mode SEQFIFO register setting value SDI R[1:0]=’01’ → update enabled A[3:0]=’1001’ → SEQFIFO update CONVST and RD SDOx(1) conversion n conversion n + 1 conversion result n-1 conversion result n R[1:0]=’01’ → update enabled A[3:0]=’1011’ → read SEQFIFO SDI ignored because a register read access is ongoing conversion n + 2 conversion n + 3 conversion result n+1 SEQFIFO register value conversion n + 4 conversion result n+3 Full-Clock Mode SEQFIFO register setting value SDI R[1:0]=’01’ → update enabled A[3:0]=’1001’ → SEQFIFO update CONVST and RD conversion n conversion result n SDOx(1) (1) conversion n + 1 conversion result n+1 ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 30. Updating Internal Register Settings (Example: Half-Clock Mode, CID = '1') 20 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Configuration (CONFIG) Register The configuration register selects the input channel, the activation of power-down modes, and the access to the sequencer/FIFO, reference selection, and reference DAC registers. Table 7. CONFIG: Configuration Register (default = 0000h) MSB BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 C1 C0 Bits[15:14] R1 R0 PD1 PD0 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 FE SR FC PDE CID CE A3 A2 A1 A0 C[1:0]—Input Channel Selection (ADS8361-compatible). These bits control the multiplexer input selection depending on the status of the PDE bit. If PDE = '0' (default), the multiplexer is in fully-differential mode and bits C[1:0] control the input multiplexer in the following manner: 0x = conversion of analog signals at inputs CHx0P/CHx0N (default). 1x = conversion of analog signals at inputs CHx1P/CHx1N. If PDE = '1', the multiplexer is in pseudo-differential mode and bits C[1:0] control the input multiplexer in the following manner: 00 = conversion of analog signal at input CHx0 versus the selected CMx or REFIOx (default). 01 = conversion of analog signal at input CHx1 versus the selected CMx or REFIOx. 10 = conversion of analog signal at input CHx2 versus the selected CMx or REFIOx. 11 = conversion of analog signal at input CHx3 versus the selected CMx or REFIOx. Bits[13:12] R[1:0]—Configuration register update control. These bits control the access to the CONFIG register. 00 01 10 11 Bits[11:10] PD[1:0]—Power-down control. These bits control the different power-down modes of the device. 00 01 10 11 Bit 9 = If M0 = '0', update of input selection bits C[1:0] only (ADS8361-compatible behavior); if M0 = '1', no action (default). = Update of the entire CONFIG register content enabled. = Reserved for factory test; do not use. Changes may result in false behavior of the device. = If M0 = '0', update of input selection bits C[1:0] only (ADS8361-compatible behavior); if M0 = '1', no action. = Normal operation (default). = Device is in power-down mode (see the Power-Down Modes and Reset section for details). = Device is in sleep power-down mode (see the Power-Down Modes and Reset section for details). = Device is in Auto-sleep power-down mode (see the Power-Down Modes and Reset section for details). FE—FIFO enable control. 0 = The internal FIFO is disabled (default). 1 = The internal FIFO is enabled. The depth of the FIFO is controlled by SEQFIFO register bits FD[1:0]. Bit 8 SR—Special read mode control. 0 = Special read mode is disabled (default). 1 = Special read mode is enabled; see Figure 36 and Figure 39 for details. Bit 7 FC—Full clock mode operation control. 0 = Full-clock mode operation is disabled (default); see Figure 1 for details. 1 = Full-clock mode operation is enabled; see Figure 2 for details. Bit 6 PDE—Pseudo-differential mode operation enable. 0 = 2 x 2 fully-differential operation (default). 1 = 4 x 2 pseudo-differential operation. Bit 5 CID—Channel information disable. 0 = The channel information followed by conversion results or register contents are present on SDOx (default). 1 = Conversion data or register content is present on SDOx immediately after the falling edge of RD. Bit 4 CE—2-bit counter enable (see Figure 31). 0: The internal counter is disabled (default). 1: The counter value is available prior to the conversion result on SDOx (active only if CID = '0'). Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 21 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Bits[3:0] www.ti.com A[3:0]—Register access control. These bits allow reading of the CONFIG register contents and control the access to the remaining registers of the device. x000 = Update CONFIG register contents only (default) 0001 = Read CONFIG register content on SDOA with next access (see Figure 30). x010 = Write to REFDAC1 register with next access (see Figure 30). 0011 = Read REFDAC1 register content on SDOA with next access (see Figure 30). 0100 = Generate software reset of the device. x101 = Write to REFDAC2 register with next access (see Figure 30). 0110 = Read REFDAC2 register content on SDOA with next access (see Figure 30). x111 = Update CONFIG register contents only. 1001 = Write to SEQFIFO register with next access (see Figure 30). 1011 = Read SEQFIFO register content on SDOA with next access (see Figure 30). 1100 = Write to REFCM register with next access (see Figure 30). 1110 = Read REFCM register content on SDOA with next access (see Figure 30). CS 20 1 1 20 1 20 1 20 1 20 1 CLOCK CONVST RD SDI R[1:0]=’01’ → register update CE = ‘1’ conversion n of both CHx0 BUSY C H x SDOx(1) (1) R[1:0]=’11’ → no update conversion n+1 of both CHx1 16bit data n-1 CHxx 16bit data n CHx0 R[1:0]=’00’ → no update conversion n+2 of both CHx1 16bit data n+1 data CHx1 R[1:0]=’00’ → no update conversion n+3 of both CHx0 16bit data n+2 CHx1 R[1:0]=’00’ → no update conversion n+4 both CHx0 16bit data n+3 CHx0 ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 31. 2-Bit Counter Feature (Half-Clock Mode, Manual Channel Control, CID = '0') 22 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 REFDAC1 and REFDAC2 Registers Two reference DAC registers allow for enabling and setting up the appropriate value for each of the output string DACs that are connected to the REFIO1 and REFIO2 pins. Table 8. REFDAC1 Control Register (default = 07FFh) MSB BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 0 0 0 0 0 RPD Bits[15:11] Not used; always set to '0'. Bit 10 RPD—DAC1 power down. BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 0 = Internal reference path 1 is enabled and the reference voltage is available at the REFIO1 pin. 1 = The internal reference path is disabled (default). Bits[9:0] D[9:0]—DAC1 setting bits. These bits correspond to the settings of the internal reference DACs (compare REFIO section). The D9 bit is the MSB value of the DAC. Default value is 1FFh (2.5V nom) Table 9. REFDAC2 Control Register (default = 07FFh) MSB BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 0 0 0 0 0 RPD Bits[15:11] Not used; always set to '0'. Bit 10 RPD—DAC2 power down. BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB BIT 0 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 0 = Internal reference path 2 is enabled and the reference voltage is available at the REFIO2 pin. 1 = The internal reference path is disabled (default). Bits[9:0] D[9:0]—DAC2 setting bits. These bits correspond to the settings of the internal reference DACs (compare REFIO section). The D9 bit is the MSB value of the DAC. Default value is 1FFh (2.5V nom) Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 23 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com Sequencer/FIFO (SEQFIFO) Register The ADS8363/7363/7223 feature a programmable sequencer that controls the switching of the ADC input multiplexer in pseudo-differential, automatic channel-selection mode only. When used, a single read pulse allows reading of all stored conversion data. A single CONVST is required to control the conversion of the entire sequence. If the sequencer is used, CONVST and RD must be controlled independently (see Figure 32 and Figure 33). Additionally, a programmable FIFO is available on each channel that allows for storing up to four conversion results. Both features are controlled using this register. If FIFO is used, CONVST and RD must be controlled independently. Note that after activation of this feature, the FIFO should be full before being read for the first time. If the FIFO is full and a new conversion starts, the contents are shifted by one while the oldest result is lost. Only when the sequencer is used are the entire FIFO contents lost (that is, all bits are automatically set to '0'). The FIFO can be used independently from the sequencer. When both are used, the complete sequence must be finished before reading the data out of the FIFO; otherwise, the data may be corrupted. Table 10 contains details of the data readout requirements depending on the FIFO settings in automatic channel selection mode. Table 10. Conversion Result Read Out in FIFO Mode AUTOMATIC CHANNEL SELECTION INPUT SIGNAL TYPE FE = '0' FE = '1' Fully-differential input mode Read cycle length = 1 word One RD pulse required after each conversion Read cycle length = 2 · FIFO length One RD pulse required for the entire FIFO content Pseudo-differential input mode Read cycle length = 1 word One RD pulse required after each conversion or after completing the sequence if S1 = '1' and S0 = '1' Read cycle length = 2 · sequencer length · FIFO length One RD pulse required for the entire FIFO content Table 11. SEQFIFO: Sequencer and FIFO Register (default = 0000h) (1) MSB BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 S1 (1) S0 SL1 SL0 C11 C10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB BIT 0 C21 C20 C31 C30 C41 C40 SP1 SP0 FD1 FD0 The sequencer is used in pseudo-differential mode only; this register should be set before setting the REFCM register. Bits[15:14] S[1:0]—Sequencer mode selection (see Figure 32) in pseudo-differential mode only. These bits allow for the control of the number of CONVSTs required, and the behavior of the BUSY pin in Sequencer mode. 0x = An individual CONVST is required with BUSY indicating each conversion (default). 10 = A single CONVST is required for the entire sequence with BUSY indicating each conversion (half-clock mode only). 11 = A single CONVST is required for the entire sequence with BUSY remaining high throughout the sequence (half-clock mode only) Bits[13:12] SL[1:0] Sequencer length control. These bits control the length of a sequence. Bits [11:6] are only active if SL > '00'. 00 = Do not use; use Mode I or II instead, where M0 = '0' (default). 01 = Sequencer length = 2; C1x (bits[11:10]) and C2x (bits[9:8]) define the actual channel selection. 10 = Sequencer length = 3; C1x (bits[11:10]), C2x (bits[9:8]) and C3x (bits[7:6]) define the actual channel selection. 11 = Sequencer length = 4; C1x (bits[11:10]), C2x (bits[9:8]), C3x (bits[7:6]), and C4x (bits[5:4]) define the actual channel selection. Bits[11:10] C1[1:0]—First channel in sequence selection bits. Bits[9:8] C2[1:0]—Second channel in sequence selection bits. Bits[7:6] C3[1:0]—Third channel in sequence selection bits. Bits[5:4] C4[1:0]—Fourth channel in sequence selection bits. Bits [11:4] control the pseudo-differential input multiplexer channel selection in sequencer mode. 00 01 10 11 24 = CHA0 = CHA1 = CHA2 = CHA3 and CHB0 and CHB1 and CHB2 and CHB3 Submit Documentation Feedback are are are are selected for selected for selected for selected for the the the the next next next next conversion (default). conversion. conversion. conversion. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Bits[3:2] SP[1:0]—Sequence position bits (read only). These bits indicate the setting of the pseudo-differential input multiplexer in sequencer mode. 00 01 10 11 Bits [1:0] = Inputs selected using bits = Inputs selected using bits = Inputs selected using bits = Inputs selected using bits C1[1:0] are C2[1:0] are C3[1:0] are C4[1:0] are converted converted converted converted with next with next with next with next rising edge of CONVST (default). rising edge of CONVST. rising edge of CONVST. rising edge of CONVST. FD[1:0]—FIFO depth control (see Figure 33). These bits control the depth of the internal FIFO if CONFIG register bit FE = '1'. 00 01 10 11 = One conversion result per channel is stored in the FIFO for burst read access (default). = Two conversion results per channel are stored in the FIFO for burst read access. = Three conversion results per channel are stored in the FIFO for burst read access. = Four conversion results per channel are stored in the FIFO for burst read access . S1 = ‘0’ CONVST BUSY CONVERSION 1 CONVERSION 2 CONVERSION 3 CONVERSION 2 CONVERSION 3 CONVERSION 2 CONVERSION 3 S1 = ‘1’, S0 = ‘0’ (half-clock mode only) CONVST BUSY CONVERSION 1 S1 = ‘1’, S0 = ‘1’ (half-clock mode only) CONVST BUSY CONVERSION 1 Figure 32. Sequencer Modes Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 25 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com FD[1:0] = ‘01’, SL[1:0] = ‘00’ … CONVST BUSY Conversion 1 … Conversion 2 … RD … CONV1 CONV2 SDOx (2x16 clock cycles) FD[1:0] = ‘01’, SL[1:0] = ‘10’ … CONVST BUSY 1.CHx2 1.CHx1 1.CHx0 2.CHx2 2.CHx1 2.CHx0 CHx1+ … … RD 1.CHx2 1.CHx1 1.CHx0 2.CHx2 2.CHx1 2.CHx0 SDOx … (6x16 clock cycles) Figure 33. FIFO and Sequencer Operation Example 26 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Reference and Common-Mode Selection (REFCM) Register To allow flexible adjustment of the common-mode voltage in pseudo-differential mode while simplifying the circuit layout, the ADS8363/7263/7223 provide this register to assign one of the CMx inputs as a reference for each of the input signals. According to the register settings, the CMx signals are internally connected to the appropriate negative input of each ADC. Additionally, this register also allows for the flexible assignment of one of the internal reference DAC outputs as a reference for each channel in both fully- and pseudo-differential modes. Table 12. REFCM: Reference and Common-Mode Selection Register (default = 0000h) (1) MSB BIT 15 BIT 14 BIT 13 BIT 12 BIT 11 BIT 10 BIT 9 BIT 8 BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 LSB BIT 0 CMB3 CMA1 CMA0 RB3 RB2 RB1 RB0 RA3 RA2 RA1 RA0 (1) CMB2 CMB1 CMB0 CMA3 CMA2 This register should be set after setting the SEQFIFO register. Bits[15:8] CMxx—Common-mode source selection bits (per input channel). These bits allow selection of the CMx input pins or the internal reference source as common-mode for pseudo-differential inputs B[3:0] and A[3:0]. The selected signal is connected to the negative input of the corresponding ADC. 0 = external common-mode source through CMx (default). 1 = internal common-mode source = REFIOx, depending on settings of bits Rx[3 :0]. Bit 7 RB3—Internal reference DAC output selection for CHB3 in pseudo-differential mode, or channel CHB1P/N in fully-differential mode. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Bit 6 RB2—Internal reference DAC output selection for CHB2 in pseudo-differential mode only. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Bit 5 RB1—Internal reference DAC output selection for CHB1 in pseudo-differential mode only. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Bit 4 RB0—Internal reference DAC output selection for CHB0 in pseudo-differential mode, or channel CHB0P/N in fully-differential mode. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Bit 3 RA3—Internal reference DAC output selection for CHA3 in pseudo-differential mode, or channel CHA1P/N in fully-differential mode. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Bit 2 RA2—Internal reference DAC output selection for CHA2 in pseudo-differential mode only. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Bit 1 RA1—Internal reference DAC output selection for CHA1 in pseudo-differential mode only. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Bit 0 RA0—Internal reference DAC output selection for CHA0 in pseudo-differential mode, or channel CHA0P/N in fully-differential mode. 0 = internal reference source REFIO1 selected (default). 1 = internal reference source REFIO2 selected. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 27 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com READ DATA INPUT (RD) The RD input is used to control serial data outputs SDOx. The falling edge of the RD pulse triggers the output of the first bit of the output data. When CID = '0' this is the analog input channel indicator; when CID = '1', this is the MSB of the conversion result, or the 15th bit of the selected register, followed by output bits that are updated with the rising edge of the CLOCK in half-clock mode, or falling edge of the CLOCK in full-clock mode. The RD input can be controlled separately or in combination with the CONVST input (see Figure 43 for a detailed timing diagram of this case). If RD is controlled separately, it can be issued whenever a conversion process has been finished (that is, after the falling edge of BUSY). However, in order to achieve the maximum data rate, the conversion results must be read during an ongoing conversion. In this case, the RD pulse should not be issued between the 16th and 19th clock cycle in half-clock mode, or between the 34th and 36th clock cycle in full-clock mode, after starting the conversion. Note that in full-clock mode, only the first read access delivers the correct channel information (if CID = '0' in the CONFIG register), while the following readouts contain invalid channel details. The channel information is corrected with the next conversion. Read access to verify the content of the internal registers is described in the Register Map section. SERIAL DATA OUTPUTS (SDOx) The following sections explain the different modes of operation in detail. The digital output code format of the ADS8363/7263/7223 is binary twos complement, as shown in Table 13. Consider both detailed timing diagrams (Figure 1 and Figure 2) shown in the Timing Diagrams section. For maximum data throughput, the description and diagrams given in this data sheet assume that the CONVST and RD pins are tied together; see Figure 43 for timing details in this case. Note that these pins can also be controlled independently. If a read access is repeated without issuing a new conversion, the result of the last conversion is presented on the output(s) again. A repeated readout should only be performed when BUSY is low. Table 13. Output Data Format DESCRIPTION Positive full-scale DIFFERENTIAL INPUT VOLTAGE VREF Midscale 0V Midscale – 1LSB –VREF/resolution Negative full-scale 28 –VREF Submit Documentation Feedback INPUT VOLTAGE AT CHxxP (CHxxN = VREF = 2.5V) BINARY CODE HEXADECIMAL CODE ADS8363: 0111 1111 1111 1111 7FFF ADS7263: 0111 1111 1111 1100 7FFC ADS7223: 0111 1111 1111 0000 7FF0 2.5V 0000 0000 0000 0000 0000 ADS8363: 2.499924V ADS8363: 1111 1111 1111 1111 FFFF ADS7263: 2.499847V ADS7263: 1111 1111 1111 1100 FFFC ADS7223: 2.499390V ADS7223: 1111 1111 1111 0000 FFF0 0V 1000 0000 0000 0000 8000 5V Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Mode I With the M0 and M1 pins both set to '0', the device enters manual channel-control operation and outputs data on both SDOA and SDOB, accordingly. The SDI pin can be used to switch between the channels, as explicitly shown in the corresponding timing diagrams. A conversion is initiated by bringing CONVST high. With the rising edge of CONVST, the device switches asynchronously to the external CLOCK from sample to hold mode, and the BUSY output pin goes high and remains high for the duration of the conversion cycle. On the falling edge of the second CLOCK cycle, the device latches in the channel for the next conversion cycle, depending on the status of This mode can be used for fullyor pseudo-differential inputs; in both cases, channel information bits are '00' if CID = '0'. Note that FIFO is not available in this mode. 20 1 20 1 1 CONFIG register bits C[1:0]. CS must be brought low to enable both serial outputs. Data are valid on the falling edge of every 20 clock cycles per conversion. The first two bits are set to '0'. The subsequent data contain the 16-, 14-, or 12-bit conversion result (the most significant bit is transferred first), with trailing zeroes, as shown in Figure 34. 20 1 20 1 20 1 CLOCK Half-Clock Mode SDI C[1:0]=’00’ → CHx0 next R[1:0]=’00’ → no update C[1:0]=’11’ → CHx1 next R[1:0]=’11’ → no update C[1:0]=’11’ → CHx1 next R[1:0]=’11’ → no update conversion n - 1 of both CHxx conversion n of both CHx0 conversion n + 1 of both CHx1 C[1:0]=’00’ → CHx0 next R[1:0]=’00’ → no update C[1:0]=’00’ → CHx0 next R[1:0]=’00’ → no update CONVST and RD BUSY SDOx(1) 16-bit data n - 1 CHxx 16-bit data n - 2 CHxx 16-bit data n CHx0 conversion n + 2 of both CHx1 16-bit data n + 1 CHx1 conversion n + 3 of both CHx0 16-bit data n + 2 CHx1 Full-Clock Mode SDI C[1:0]=’00’ → CHx0 next R[1:0]=’00’ → no update C[1:0]=’11’ → CHx1 next R[1:0]=’11’ → no update CONVST and RD BUSY conversion n - 1 of both CHxx 16-bit data n - 1 CHxx SDOx(1) (1) conversion n of both CHx0 conversion n + 1 of both CHx1 16-bit data n CHx0 ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 34. Mode I Timing (M0 = '0', M1 = '0', PDE = '0', CID = '1', Fully-Differential Example) Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 29 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com Mode II (Half-Clock Mode Only) With M0 = '0' and M1 = '1', the ADS8363/7263/7223 also operate in manual channel-control mode and output data on the SDOA pin only while SDOB is set to high impedance. All other pins function in the same manner as they do in Mode I. In half-clock mode, because it takes 40 clock cycles to output the results from both ADCs (instead of 20 cycles if M1 = '0'), the device requires 2.0ms to perform a complete read cycle. If the CONVST signal is issued every 1.0ms (required for the RD signal) as in Mode I, every second pulse is ignored, as shown in Figure 35. CONVST and RD signals must not be longer than one clock cycle to ensure proper functionality and avoid corruption of output data. Full-clock mode is not supported in this operational mode. 20 1 1 The output data consist of a '0', followed by an ADC indicator ('0' for CHAx or '1' for CHBx), and then 16, 14, or 12 bits of conversion result along with any trailing zeroes. This mode can be used for fullyor pseudo-differential inputs. Channel information is valid in fully-differential mode only if CID = '0' (it contains correct ADC information while the channel bit is invalid in pseudo-differential mode). Note that FIFO is not available in this mode. Changes to register bits FE, SR, PDE, and CID are active with the start of the next conversion; this is with a delay of one read access. The register settings should be updated using every other RD pulse, aligned either with the one starting the conversion or the one to read the conversion results of channel B, as shown in Figure 35. 20 1 20 1 20 1 20 1 CLOCK SDI C[1:0] = ‘00’ → CHx0/CMx R[1:0] = ‘00’ → no update C[1:0] are ignored R[1:0] = ‘00’ → no update CONVST and RD SDOA(1) (1) C[1:0] are ignored R[1:0] = ‘11’ → no update every 2nd CONVST is ignored M[1:0] = ‘00’ BUSY C[1:0] = ‘01’ → CHx1/CMx R[1:0] = ‘11’ → no update C[1:0]=’10’ → CHx2/CMx R[1:0]=’00’ → no update every 2nd CONVST is ignored M[1:0] = ‘10’ conversion n - 1 of both CHx0 16-bit data n - 2 CHA0 no conversion read access only conversion n of both CHx0/CMx A D B 16-bit data n - 1 CHB0 A D A 16-bit data n CHA0/CMA conversion n + 1 of both CHx1 A D B 16-bit data n CHB0/CMB no conversion read access only A D A 16-bit data n + 1 CHA1/CMA ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 35. Mode II Timing (M0 = '0', M1 = '1', PDE = '0', CID = '0', Pseudo-Differential Example) 30 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Special Read Mode II (Half-Clock Mode Only) For Mode II, a special read mode is available in the ADS8363/7263/7223 where both data results can be read out triggered by a single RD pulse (refer to Figure 36). To activate this mode, The SR bit in the CONFIG register must be set to '1' (see Table 6). The CONVST and RD pins can still be tied together but are issued every 40 CLOCK cycles instead of 20. Output data are presented on SDOA only while SDOB is held in 3-state. This special mode can be used for fully- or pseudo-differential inputs. Channel information is valid in fully-differential mode only if CID = '0' (it contains correct ADC information while the channel bit is invalid in pseudo-differential mode). Note that FIFO is not available in this mode. 20 1 20 1 1 The RD signal in this mode must not be longer than one clock cycle to avoid corruption of output data. 20 1 20 1 20 1 CLOCK SDI C[1:0] = ‘11’ → CHx1 next C[1:0] = ‘00’ → CHx0 next R[1:0] = ‘01’ → register update R[1:0] = ‘11’ → no update → SR = ‘1’ C[1:0] = ‘00’ → CHx0 next R[1:0] = ‘00’ → no update CONVST and RD SDOA(1) A D x 16-bit data n - 2 CHAx SDOB(1) A D x 16-bit data n - 2 CHBx (1) no conversion, read access only conversion n of both CHx0 conversion n-1 of both CHxx BUSY A D x 16-bit data n - 1 CHBx A D A 16-bit data n CHA0 no conversion, read access only conversion n + 1 of both CHx1 A D B 16-bit data n CHB0 A D A 16-bit data n + 1 CHA1 High-Z ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 36. Special Read Mode II Timing Diagram (M0 = '0', M1 = '1', PDE = '0', SR = '1', CID = '0', Fully-Differential Example) Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 31 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com Mode III This mode can be used for fullyor pseudo-differential inputs (in pseudo-differential mode the sequencer is used to control the input multiplexer). Channel information is available in fully-differential mode only if CID = '0' (CID is forced to '1' in pseudo-differential mode). With M0 = '1' and M1 = '0', the device automatically cycles between the differential inputs (CONFIG register bits C[1:0] are ignored) while offering the conversion result of CHAx on SDOA and the conversion result of CHBx on SDOB, as shown in Figure 37. The internal FIFO is available in this mode; when used, a single read pulse allows for reading of all stored conversion data. The FIFO should be completely filled when used for the first time in order to ensure proper functionality. Output data consist of a channel indicator ('0' for CHx0, or '1' for CHx1), followed by a '0', and then 16, 14, or 12 bits of conversion result along with any trailing zeroes. 20 1 20 1 1 20 1 20 1 20 1 CLOCK M1 M0 Half-Clock Mode CONVST and RD conversion n - 1 of both CHxx BUSY SDOx (1) C H x conversion n of both CHx0 16-bit data n - 2 CHxx C H x 16-bit data n - 1 CHxx conversion n + 1 of both CHx1 C H 0 16-bit data n CHx0 conversion n + 2 of both CHx0 C H 1 16-bit data n + 1 CHx1 conversion n + 3 of both CHx1 C H 0 16-bit data n + 2 CHx0 Full-Clock Mode CONVST and RD BUSY SDOx (1) conversion n - 1 of both CHxx C H x (1) conversion n + 1 of both CHx1 conversion n of both CHx0 16-bit data n - 1 CHxx C H 0 16-bit data n CHx0 C H 1 ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 37. Mode III Timing (M0 = '1', M1 = '0', PDE = '0', CID = '0', Fully-Differential Example) 32 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Fully-Differential Mode IV (Half-Clock Mode Only) In the same way as Mode II, Mode IV uses the SDOA output line exclusively to transmit data while the differential channels are switched automatically. Following the first conversion after M1 goes high, the SDOB output 3-states, as shown in Figure 38. Output data consist of a channel indicator ('0' for CHx0, or '1' for CHx1), followed by the ADC indicator ('0' for CHAx or '1' for CHBx), and then 16 or 14 bits of conversion result, ending with '00' for the ADS8363, '0000' for the ADS7263, or '000000' for the ADS7223. CONVST and RD signals must not be longer than one clock cycle to ensure proper functionality and avoid corruption of output data. 20 1 1 Full-clock mode is not supported in this operational mode. Channel information is available in fully-differential mode if CID = '0'. In pseudo-differential mode, the sequencer controls the channel selection in this mode and must be set appropriately using the SEQFIFO register. The internal FIFO is not available in this mode. Changes to CONFIG register bits FE, SR, PDE, and CID are active with the start of the next conversion with a delay of one read access. The register settings should be updated using every other RD pulse (aligned either with the one starting the conversion or the one to read the conversion results of channel B; compare with Figure 35). 20 1 20 1 20 1 20 1 CLOCK M0 M1 CONVST and RD every 2nd CONVST is ignored SDOA(1) (1) CA HD xA 16-bit data n - 2 CHAx no conversion read access only Conversion n of both CHx0 no conversion read access only BUSY every 2nd CONVST is ignored CA HD xB 16-bit data n - 1 CHBx CA HD 0A 16-bit data n CHA0 Conversion n + 1 of both CHx1 CA HD 0B 16-bit data n CHB0 no conversion read access only CA HD 1A 16-bit data n + 1 CHA1 ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 38. Fully-Differential Mode IV Timing (M0 = '1', M1 = '1', PDE = '0', and CID = '0' Example) Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 33 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com Special Mode IV (Half-Clock Mode Only) If auto-sleep power-down mode is enabled, the conversion results are presented during the next conversion, as shown in Figure 39. As with Special Mode II, these devices also offer a special read mode for Mode IV, where both data results of a conversion can be read by triggering a single RD pulse (refer to Figure 39). Additionally, in this case, the SR bit in the CONFIG register must be set to '1' while the CONVST and RD pins can still be tied together, but are issued every 40 CLOCK cycles instead of 20. The RD signal in this mode must not be longer than one clock cycle to avoid corruption of output data. This mode can be used for fullyor pseudo-differential inputs (note that in pseudo-differential mode, the sequencer is used to control the input multiplexer); channel information is available if CID = '0' in fully-differential mode only (CID forced to '1' in pseudo-differential mode). The internal FIFO is available in this mode; when used, a single read pulse allows for reading of all stored conversion data. The FIFO should be completely filled when used for the first time in order to ensure proper functionality. Data are available on the SDOA pin, accordingly. 20 1 20 1 1 20 1 20 1 20 1 CLOCK SDI C[1:0] are ignored R[1:0] = ‘00’ → no update C[1:0] are ignored C[1:0] are ignored R[1:0] = ‘01’ → register update R[1:0] = ‘11’ → no update → SR = ‘1’ CONVST and RD conversion n - 1 of both CHxx BUSY SDOA(1) CA HD xx 16-bit data n - 2 CHAx SDOB(1) CA HD xx n - 2 16-bit data CHBx SDOA(1) CA HD xx 16-bit data n - 2 CHAx SDOB(1) CA HD xx 16-bit data n - 2 CHBx no conversion, read access only conversion n of both CHx0 CA HD xx 16-bit data n - 1 CHBx CA HD 0A 16-bit data n CHA0 no conversion, read access only conversion n + 1 of both CHx1 CA HD 0B 16-bit data n CHB0 CA HD 1A 16-bit data n + 1 CHA1 CA HD 0A 16-bit data n CHA0 High-Z Auto-Sleep Mode (1) CA HD xx 16-bit data n - 1 CHBx CA HD 0B 16-bit data n CHB0 High-Z ADS7263/7223 output data with the MSB located as ADS8363 and the last 2/4 bits being '0'. Figure 39. Special Read Mode IV Timing (M0 = '1', M1 = '1', PDE = '0', SR = '1', CID = '0', Fully-Differential Example) 34 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 PROGRAMMING THE REFERENCE DAC When channel information is enabled (CID = '0'), the first two bits of the data output contain the currently selected analog input channel indicator ('0' for CHx0 or '1' for CHx1), followed by the 16-bit DAC register contents and an additional '00'. While the register contents are valid on SDOA, the conversion result of channel Ax is lost (if a conversion was performed in parallel), the conversion result of channel Bx is valid on SDOB (if enabled), and data on SDI are ignored, as shown in Figure 40). The internal reference DACs can be set by issuing an RD pulse while providing an control word with R[1:0] = '01' and A[3:0] = 'X010' or 'X101', depending on which DAC is going to be updated. Thereafter, a second RD pulse must be generated with a control word that starts with the first five bits being ignored followed by the reference power control and the corresponding 10-bit DAC value (refer to Figure 40). To verify the DACs settings, an RD pulse must be generated while providing a control word containing R[1:0] = '01' and A[3:0] = '0011' or '0110' to initialize the read access of the appropriate DAC register. Triggering the RD line again causes the SDOA output to provide the 16-bit DAC register value followed by '0000', if channel information is disabled (CID = '1'). CID = ‘0’ 20 1 1 The default value of the DAC registers after power-up is 7FFh, corresponding to a disabled reference voltage of 2.5V on both REFIOx pins. 20 1 20 1 20 20 1 CLOCK Half-Clock Mode CONVST and RD conversion n BUSY SDI CC 1 0 conversion n + 1 SFPCC RCD I E ED R[1:0] = ‘01’ → CR update A[3:0] = ‘x010’ → REFDAC1 update SDOA(1) C H x 16-bit data n - 1 CHAx 12-bit data DAC settings RPD = ‘1’ → REFDAC1 enabled C H x 16-bit data n CHAx conversion n + 2 CC 1 0 conversion n + 3 SFPCC RCD I E ED conversion n + 4 new settings ignored R[1:0] = ‘01’ → CR update A[3:0] = ‘0011’ → read REFDAC1 C H x 16-bit data n + 1 CHAx C H x 16-bit REFDAC1 register content C H x 16-bit data n + 3 CHAx Full-Clock Mode CONVST and RD BUSY SDI (Write) conversion n conversion n + 1 CC 1 0 SFPCC RCD I E ED R[1:0] = ‘01’ → CR update A[3:0] = x010’ → REFDAC1 update SDI (Read) CC 1 0 conversion n + 2 12-bit REFDAC1 register contents RPD = ‘1’ → REFDAC1 enabled SFPCC RCD I E ED ignored R[1:0] = ‘01’ → CR update A[3:0] = ‘0011’ → read REFDAC1 SDOA(1) C H x 16-bit data n CHAx C H x 16-bit REFDAC1 register content C H x Figure 40. DAC Register Write and Read Access Timing (Both SDOx Active and CID = '0') Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 35 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com POWER-DOWN MODES AND RESET These devices have a comprehensive built-in power-down feature. There are three power-down modes: Power-Down, Sleep, and Auto-Sleep Power-Down. All three power-down modes are activated with the completion of the write access, during which the related bit(s) are asserted (PD[1:0]). All modes are deactivated by deasserting the respective bit(s) in the CONFIG register. The content of the CONFIG register is not affected by any of the power-down modes. Any ongoing conversion is finished before entering any of the power-down modes. Table 14 summarizes the differences among the three power-down modes. Power-Down Mode In Power-Down mode (PD[1:0] = '01'), all functional blocks except the digital interface are disabled. In this mode, the current demand is reduced to 5µA within 20µs. The wakeup time from Power-Down mode is 8ms when using a reference capacitor of 22µF. The device goes into Power-Down mode after completing any ongoing conversions. Sleep Mode In Sleep mode (PD[1:0] = '10'), the device reduces its current demand to approximately 0.9mA within 10µs. The device goes into Sleep mode after completing any ongoing conversions. Auto-Sleep Mode Auto-Sleep mode is almost identical to Sleep mode. The only differences are the method of activating the mode and waking up the device. CONFIG register bits PD[1:0] = '11' are only used to enable/disable this feature. If the Auto-Sleep mode is enabled, the device automatically turns off the biasing after finishing a conversion; thus, the end of conversion actually activates Auto-Sleep mode. If Sequencer mode is used and individual conversion start pulses are chosen (S1 = '0'), the device automatically powers-down after each conversion; in case of a single CONVST pulse starting the sequence (S1 = '1'), power-down is activated upon completion of the entire sequence. The device wakes up with the next CONVST pulse but the analog input is held in sample mode for another seven clock cycles in half-clock mode, or 14 clock cycles in full-clock mode, before starting the actual conversion (BUSY goes high thereafter), as shown in Figure 41. This time is required to settle the internal circuitry to the required voltage levels. The conversion result is delayed in Auto-Sleep mode as shown in Figure 39. In this mode, the current demand is reduced to approximately 1.2mA within 10µs. Reset To issue a device reset, an RD pulse must be generated along with a control word containing A[3:0] = '0100'. With the completion of this write access, the entire device including the serial interface is forced into reset, interrupting any ongoing conversions, setting the input into acquisition mode, and returning the register contents to their default values. After ~20ns, the serial interface becomes active again. The device also supports an automatic power-up reset (POR) that ensures proper (default) settings of the device. Table 14. Power-Down Modes DELAY TIME TO POWERDOWN NORMAL OPERATION BY WAKEUP TIME POWERDOWN DISABLED BY Write access completed 20µs PD[1:0] = '00' 8ms PD[1:0] = '00' PD[1:0] = '10' Write access completed 10µs PD[1:0] = '00' 7 or 14 CLOCK cycles PD[1:0] = '00' PD[1:0] = '11' Each end of conversion 10µs CONVST pulse 7 or 14 CLOCK cycles PD[1:0] = '00' POWERDOWN MODE POWERDOWN CURRENT POWERDOWN ENABLED BY POWERDOWN START BY Power-Down 5µA PD[1:0] = '01' Sleep 1.2mA (3.6V) Auto-Sleep 1.2mA (3.6V) 36 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 Half-Clock Mode CLOCK CONVST tACQ BUSY Auto-Sleep Power-Down conversion n 7 CLOCKs conversion n + 1 Full-Clock Mode CLOCK CONVST tACQ BUSY Auto-Sleep Power-Down conversion n 14 CLOCKs conversion n + 1 Figure 41. Actual Conversion Start in Auto-Sleep Mode ADS8361 COMPATIBILITY Pinout This section describes the differences between the ADS8361 and the ADS8363/7263/7223 family of devices in default mode without changing the internal register settings (that are not available on the ADS8361). The ADS8363/7263/7223 family is pin-compatible to ADS8361IRHB. However, there are some differences that must be considered when migrating from an ADS8361-based design, as summarized in Table 15. Table 15. Pinout Differences Between the ADS8363/7263/7223 and ADS8361 PIN NAME PIN NO. ADS8361 ADS8363/7263/7223 IMPACT 9 REFIN REFIO1 If external reference is used, see the Internal Reference section for details. If internal reference is used, REFIO1 must be enabled using the RPD bit in the DAC1 register. 10 REFOUT REFIO2 Because REFIO2 is disabled by default, no adjustment is required. 11 NC RGND 18 A0 SDI 29 NC AVDD This pin should be connected to the analog supply and decoupled with a 1µF capacitor to ensure proper functionality of the ADS8363/7263/7223 family. 30 NC AGND This pin should be connected to the analog ground plane to ensure proper functionality of the ADS8363/7263/7223 family. 31 NC CMA In default mode of the ADS8363 family; no changes required. 32 NC CMB In default mode of the ADS8363 family; no changes required. If external reference is used, no changes required. If REFIO1 is enabled, this pin should be tied to the analog ground plane with a dedicated via. Furthermore, a 22µF ceramic capacitor should be used between this pin and pin 9. See the SDI vs. A0 section for details. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 37 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com SDI versus A0 • Pin 18 (SDI) of the ADS8363/7263/7223 is used to update the internal registers, whereas on the ADS8361, pin 18 (A0) is used in conjunction with M0 to select the input channel. • If, in an existing design, the ADS8361 is used in two-channel mode (M0 = '0') and the status of the A0 pin is unchanged within the first four clock cycles after issuing a conversion start (rising edge of CONVST), the ADS8363/7263/7223 act similarly to the ADS8361 and convert either channels CHx0 (if SDI is held low during the entire period) or channels CHx1 (if SDI is held high during the entire period). Figure 37 shows the behavior of the ADS8363/7263/7223 in such a situation. In the latter case, while the capacitor stabilizes the reference voltage during the entire conversion, the buffer must recharge it by providing an average current only; thus, the required minimum bandwidth of the buffer can be calculated using Equation 4: ln(2) × 2 f-3dB = 2p × 20tCLK (4) The ADS8363/7263/7223 can be also be used to replace the ADS8361 when run in four-channel mode (M0 = '1'). In this case, the A0 pin is held static (high or low), which is also required in for the SDI pin to prevent accidental update of the SDI register. Timing In both cases described above, the additional features of the ADS8363/7263/7223 (pseudo-differential input mode, programmable reference voltage output, and the various power-down modes) cannot be accessed, but the hardware and software would remain backward-compatible to the ADS8361. Internal Reference The internal reference of the ADS8361 delivers 2.5V (typ) after power up, while the reference output of the ADS8363/7263/7223 is powered down by default. In this case, the unbuffered reference input has a code-dependent input impedance, while the ADS8361 offers a high-impedance (buffered) reference input. If an existing ADS8361-based design uses the internal reference of the device and relies on an external resistor divider to adjust the input voltage range of the ADC, migration to the ADS8363 family requires one of the following conditions: 38 Submit Documentation Feedback A software change to setup internal reference DAC1 properly through SDI while removing the external resistors; or An additional external buffer between the resistor divider and the required 22µF (min) capacitor on the REFIO1 input. The buffer must also be capable of driving the 22µF load while maintaining its stability. In half-clock mode (default), the ADS8363/7263/7223 family of devices provides the conversion delay after completion of the conversion (see Figure 1), while the ADS8361 offers the conversion result during the conversion process. RD The ADS8363/7263/7223 output the first bit with the falling edge of the RD input. The ADS8361 starts the data transfer with the first falling edge of the clock if RD is high. If the ADS8363/7263/7223 operate with half-clock timing in modes II and IV, the RD input should not be held high longer than one clock cycle to ensure proper function of the data output SDOA. CONVST If the ADS8363/7263/7223 operate with half-clock timing in modes II and IV, the CONVST input must not be held high longer than one clock cycle to ensure proper function of the device. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 APPLICATION INFORMATION MINIMUM CONFIGURATION EXAMPLE Those values can be calculated using Equation 5: ln(2)(n + 1) fFILTER = 2p2RC An example of a minimum configuration for the ADS8363/7263/7223 is shown in Figure 42. In this case, the device is used in dual-channel, fully-differential input mode with a four-wire digital interface connected to the controller device and with default settings of the device after power up. Because the internal reference is disabled upon power up (to prevent driving against an external reference if used), an external reference source is shown in this example. To allow the use of the internal reference, the SDI input must be connected to the controller, allowing access to the REFDAC registers. The corresponding timing diagram including the timing requirements are shown in Figure 43 and the Timing Characteristics table. Where n = 16 as the resolution of the ADS8363 (n = 14 for ADS7263, n = 12 for ADS7223). (5) As a good trade-off between required minimum driver bandwidth and the capacitor value, it is recommended to use a capacitor value of at least 1nF. Keeping the acquisition time in mind, the resistor value can be calculated as shown in Equation 6 for each of the series resistors: tACQ R= ln(2)(n + 1)2C The input signal for the amplifiers must fulfill the common-mode voltage requirements of the device in this configuration. The actual values of the resistors and capacitors depend on the bandwidth and performance requirements of the application. Where n = the device resolution. (6) DGND AGND AVDD DVDD 1mF 1mF 32 31 30 29 28 27 26 25 CMA AGND AVDD DGND DVDD NC SDOA R CMB AVDD 1 CHB1P SDOB 24 2 CHB1N BUSY 23 3 CHB0P 4 CHB0N 5 CHA1P 6 CHA1N CONVST 19 7 CHA0P SDI 18 8 CHA0N M0 17 OPA2365 R CLOCK 22 C AGND AVDD ADS8363 ADS7263 ADS7223 CS 21 RD 20 DGND Controller Device R R REFIO2 RGND AGND AVDD NC NC M1 OPA2365 REFIO1 C 9 10 11 12 13 14 15 16 AVDD 22mF AGND DGND 1mF DVDD REF5025 AGND AGND AVDD Figure 42. Four-Wire Application Configuration Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 39 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com 18 1 21 CLOCK tCONV tACQ tDATA CS t1 tH1 t3 CONVST and RD conversion n tD5 tD3 data n - 1 SDOA/B (ADS8363) CH 0/1 CH MSB D14 D13 D12 D11 D10 A/B SDOA/B (ADS7263) CH 0/1 CH MSB D12 D11 D10 A/B D9 D8 SDOA/B (ADS7223) CH 0/1 CH MSB D10 A/B D7 D6 D9 D8 tH3 D7 D6 D5 D4 D3 D2 D5 D4 D3 D2 D1 LSB D3 D2 D1 LSB D1 LSB CH 0/1 CH A/B CH 0/1 CH A/B CH 0/1 CH A/B data n - 1 D7 D6 data n - 1 D9 D8 D5 D4 Figure 43. Four-Wire Application Timing (Half-Clock Mode) 40 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 LAYOUT For optimum performance, care should be taken with the physical layout of the ADS8363/7263/7223 circuitry, particularly if the device is used at the maximum throughput rate. In this case, it is recommended to have a fixed phase relationship between CLOCK and CONVST. Additionally, the high-performance SAR architecture is sensitive to glitches or sudden changes on the power supply, reference, ground connections, and digital inputs that occur just before latching the output of the internal analog comparator. Therefore, during an operation of an n-bit SAR converter, there are n windows in which large external transient voltages (glitches) can affect the conversion result. Such glitches might originate from switching power supplies, nearby digital logic, or high-power devices. The degree of impact depends on the reference voltage, layout, and the actual timing of the external event. With this possibility in mind, power to the device should be clean and well-bypassed. A 1µF ceramic bypass capacitor should be placed at each supply pin (connected to the corresponding ground pin) as close to the device as possible. If the reference voltage is external, the operational amplifier should be able to drive the 22µF capacitor without oscillation. A series resistor between the driver output and the capacitor may be required. To minimize any code-dependent voltage drop on this path, a small value should be used for this resistor (10Ω max). TI's REF50xx family is able to directly drive such a capacitive load. GROUNDING The AGND, RGND, and DGND pins should be connected to a clean ground reference. All connections should be kept as short as possible to minimize the inductance of these paths. It is recommended to use vias connecting the pads directly to the ground plane. In designs without ground planes, the ground trace should be kept as wide as possible. Avoid connections that are close to the grounding point of a microcontroller or digital signal processor. Depending on the circuit density of the board, placement of the analog and digital components, and the related current loops, a single solid ground plane for the entire printed circuit board (PCB) or a dedicated analog ground area may be used. In case of a separated analog ground area, ensure a low-impedance connection between the analog and digital ground of the ADC by placing a bridge underneath (or next) to the ADC (see Figure 44). Otherwise, even short undershoots on the digital interface with a value of less than –300mV can lead to conduction of ESD diodes, causing current flow through the substrate and degrading the analog performance. During the layout of the PCB, care should be taken to avoid any return currents crossing any sensitive analog areas or signals. No signal must exceed the limit of –300mV with respect to the corresponding (AGND or DGND) ground plane. SUPPLY The ADS8363/7263 has two separate supplies: the DVDD pin for the buffers of the digital interface and the AVDD pin for all the remaining circuits. DVDD can range from 2.3V to 5.5V, allowing the ADC to easily interface with processors and controllers. To limit the injection of noise energy from external digital circuitry, DVDD should be properly filtered. A bypass capacitor of 1µF should be placed between the DVDD pin and the digital ground plane. AVDD supplies the internal analog circuitry. For optimum performance, a linear regulator (for example, the UA7805 family) is recommended to generate the analog supply voltage in the range of 2.7V to 5.5V for the ADC and the necessary analog front-end. Bypass capacitors of 1µF should be connected to the analog ground plane such that the current is allowed to flow through the pad of these capacitors (that is, the vias should be placed on the opposite side of the connection between the capacitor and the power-supply pin of the ADC). DIGITAL INTERFACE To further optimize performance of the device, a series resistor of between 10Ω to 100Ω can be used on each digital pin of the device. In this way, the slew rate of the input and output signals is reduced, limiting the noise injection from the digital interface. Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 41 ADS8363 ADS7263 ADS7223 SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 www.ti.com to AVDD to DVDD 25 26 DGND 1 mF AVDD 31 AGND 32 1 mF DVDD (Top View) 19 7 18 8 17 22mF 16 6 15 20 14 21 5 AVDD 22 4 AGND 23 3 RGND 2 REFIO2 24 REFIO1 1 1mF LEGEND 22mF Top layer: copper pour and traces Lower layer: AGND area to AVDD Lower layer: DGND area via Figure 44. Optimized Layout Recommendation 42 Submit Documentation Feedback Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 ADS8363 ADS7263 ADS7223 www.ti.com SBAS523B – OCTOBER 2010 – REVISED JANUARY 2011 REVISION HISTORY NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision A (December, 2010) to Revision B Page • Revised test conditions for gain error parameter .................................................................................................................. 3 • Revised test conditions for gain error parameter .................................................................................................................. 3 • Revised test conditions for gain error parameter .................................................................................................................. 4 • Updated CONVST high time specification .......................................................................................................................... 11 • Revised CONVST section .................................................................................................................................................. 17 • Revised Mode II section ..................................................................................................................................................... 30 • Revised Special Read Mode II section ............................................................................................................................... 31 • Revised Fully-Differential Mode IV section ......................................................................................................................... 33 • Revised Special Mode IV section ....................................................................................................................................... 34 • Added CONVST section in ADS8361 Compatibility ........................................................................................................... 38 Changes from Original (October, 2010) to Revision A Page • Updated Figure 1 .................................................................................................................................................................. 9 • Added RD high time (t3) parameter to Timing Characteristics table ................................................................................... 11 • Revised RD section in ADS8361 Compatibility .................................................................................................................. 38 • Added t3 timing trace to Figure 43 ...................................................................................................................................... 40 • Deleted Four-Wire Application Timing Requirements table ................................................................................................ 40 Copyright © 2010–2011, Texas Instruments Incorporated Product Folder Link(s): ADS8363 ADS7263 ADS7223 Submit Documentation Feedback 43 PACKAGE OPTION ADDENDUM www.ti.com 27-Jul-2013 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish (2) MSL Peak Temp Op Temp (°C) Device Marking (3) (4/5) ADS7223SRHBR ACTIVE VQFN RHB 32 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 125 ADS 7223 ADS7223SRHBT ACTIVE VQFN RHB 32 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 125 ADS 7223 ADS7263SRHBR ACTIVE VQFN RHB 32 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 125 ADS 7263 ADS7263SRHBT ACTIVE VQFN RHB 32 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 125 ADS 7263 ADS8363SRHBR ACTIVE VQFN RHB 32 3000 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 125 ADS8363 ADS8363SRHBT ACTIVE VQFN RHB 32 250 Green (RoHS & no Sb/Br) CU NIPDAU Level-3-260C-168 HR -40 to 125 ADS8363 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. 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