12-Bit, 1MSPS SAR ADCs ISL267450 Features The ISL267450 is a 12-bit, 1MSPS sampling SAR-type ADC with a differential input span of 2*VREF volts. The ISL267450 features excellent linearity over supply and temperature variations and is drop-in compatible with the AD7450. The device can operate from a supply voltage of either 5V or 3V and maintain measurement accuracy with input signals up to the supply rails. • Drop-in Compatible with AD7450 The serial digital interface is SPI compatible and is easily interfaced to popular FPGAs and microcontrollers. Power dissipation is 9.0mW at a sampling rate of 1MSPS, and just 5µW between conversions utilizing Auto Power-Down mode (with a 3V supply). • 3V or 5V Operation The ISL267450 is available in 8 Ld SOIC or MSOP packages, and are specified for operation over the Industrial temperature range (–40°C to +85°C). • Power-down Current between Conversions: 1µA • Differential Input • Simple SPI-compatible Serial Digital Interface • Guaranteed No Missing Codes • 1MHz Sampling Rate • Low Operating Current - 1.25mA at 833kSPS with 3V Supplies - 1.7mA at 1MSPS with 5V Supplies • Excellent Differential Non-Linearity • Low THD: -83dB (typ) • Pb-Free (RoHS Compliant) • Available in SOIC and MSOP Packages Applications • Remote Data Acquisition • Battery Operated Systems • Industrial Process Control • Energy Measurement • Data Acquisition Systems • Pressure Sensors • Flow Controllers Block Diagram +VDD VIN+ VIN- VREF ADC SERIAL INTERFACE SCLK SDATA CS GND August 10, 2012 FN8341.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2012. All Rights Reserved Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. ISL267450 Typical Connection Diagram VREF 0.1µF 0.1µF VREF VDD VREF(P-P) VIN+ SCLK VREF(P-P) VIN– SDATA + 10µF +3V/5V SUPPLY µP/µC CS GND SERIAL INTERFACE Pin Configuration ISL267450 (8 LD SOIC, MSOP) TOP VIEW VREF 1 8 VDD VIN+ 2 7 SCLK VIN- 3 6 SDATA GND 4 5 CS Pin Description ISL267450 PIN NAME PIN NUMBER VDD 8 Supply voltage, +2.7V to 5.25V. SCLK 7 Serial clock input. Controls digital I/O timing and clocks the conversion. SDATA 6 Digital conversion output. CS 5 Chip select input. Controls the start of a conversion when going low. GND 4 Ground VIN– 3 Negative analog input. VIN+ 2 Positive analog input. VREF 1 Reference voltage. 2 DESCRIPTION FN8341.0 August 10, 2012 ISL267450 Ordering Information PART NUMBER (Notes 1, 2, 3) PART MARKING VDD RANGE (V) TEMP RANGE (°C) PACKAGE (PB-free) PKG. DWG. # ISL267450IBZ 267450 IBZ 2.7 to 5.25 -40 to +85 8 Ld SOIC M8.15 ISL267450IUZ 67450 2.7 to 5.25 -40 to +85 8 Ld MSOP M8.118 NOTES: 1. Add “-T*” suffix for tape and reel. Please refer to TB347 for details on reel specifications. 2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 3. For Moisture Sensitivity Level (MSL), please see device information page for ISL267450. For more information on MSL please see techbrief TB363. 3 FN8341.0 August 10, 2012 ISL267450 Table of Contents Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Thermal Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Typical Performance Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ADC Transfer Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Analog Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Voltage Reference Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Converter Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power-On Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acquisition Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Short Cycling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Power vs Throughput Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 14 14 14 14 Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Application Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Grounding and Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Signal-to-(Noise + Distortion) Ratio (SINAD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Total Harmonic Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Peak Harmonic or Spurious Noise (SFDR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Intermodulation Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Aperture Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Aperture Jitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Full Power Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Common-Mode Rejection Ratio (CMRR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Integral Nonlinearity (INL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Differential Nonlinearity (DNL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Zero-Code Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Positive Gain Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Negative Gain Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Track and Hold Acquisition Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Power Supply Rejection Ratio (PSRR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Package Outline Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4 FN8341.0 August 10, 2012 ISL267450 Absolute Maximum Ratings Thermal Information Any Pin to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6.0V Analog Input to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VDD+0.3V Digital I/O to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VDD+0.3V Digital Input Voltage to GND . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VDD+0.3V Maximum Current In to Any Pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10mA ESD Rating Human Body Model (Tested per JESD22-A114F) . . . . . . . . . . . . . . . . 8kV Machine Model (Tested per JESD22-A115B) . . . . . . . . . . . . . . . . . 400V Charged Device Model (Tested per JESD22-C101E). . . . . . . . . . . . 1.5kV Latch Up (Tested per JESD78C; Class 2, Level A) . . . . . . . . . . . . . . . 100mA Thermal Resistance (Typical) θJA (°C/W) θJC (°C/W) 8 Ld SOIC Package (Notes 4, 5). . . . . . . . . . 120 64 8 Ld MSOP Package (Notes 4, 5). . . . . . . . . 165 64 Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to +85°C Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+150°C Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below http://www.intersil.com/pbfree/Pb-FreeReflow.asp CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and result in failures not covered by warranty. NOTES: 4. θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details. 5. For θJC, the “case temp” location is taken at the package top center. Electrical Specifications VDD = +3.0V to +3.3V, FSCLK = 15MHz, FS = 833kSPS, VREF = 1.25V, FIN = 200kHz; VDD = +4.75V to +5.25V, FSCLK = 18MHz, FS = 1MSPS, VREF = 2.5V, FIN = 300kHz; VCM = VREF, TA = TMIN to TMAX unless otherwise noted. Typical values are at TA = +25°C. Boldface limits apply over the operating temperature range, -40°C to +85°C. SYMBOL PARAMETER TEST CONDITIONS MIN (Note 6) TYP MAX (Note 6) UNITS DYNAMIC PERFORMANCE SINAD THD SFDR IMD Signal-to (Noise + Distortion) Ratio VDD = 5V 70 dB VDD = 3V 67 dB Total Harmonic Distortion VDD = 5V -80 -75 dB VDD = 3V -78 -73 dB Spurious Free Dynamic Range VDD = 5V -82 -75 dB VDD = 3V -80 -73 dB 2nd Order Terms –89 dB 3rd Order Terms -85 dB Intermodulation Distortion tpd Aperture Delay 10 ns Δtpd Aperture Jitter 50 ps β3dB Full Power Bandwidth @ –3dB 20 MHz @ –0.1dB 2.5 MHz -87 dB PSRR Power Supply Rejection Ratio DC ACCURACY N Resolution 12 INL Integral Nonlinearity -1 1 LSB DNL Differential Nonlinearity Guaranteed no missed codes to 12 bits -0.95 0.95 LSB Zero-Code Error VDD = 5V -3 3 LSB VDD = 3V -6 6 LSB VDD = 5V -3 3 LSB VDD = 3V -6 6 LSB VDD = 5V -3 3 LSB VDD = 3V -6 6 LSB OFFSET GAIN Positive Gain Error Negative Gain Error 5 Bits FN8341.0 August 10, 2012 ISL267450 Electrical Specifications VDD = +3.0V to +3.3V, FSCLK = 15MHz, FS = 833kSPS, VREF = 1.25V, FIN = 200kHz; VDD = +4.75V to +5.25V, FSCLK = 18MHz, FS = 1MSPS, VREF = 2.5V, FIN = 300kHz; VCM = VREF, TA = TMIN to TMAX unless otherwise noted. Typical values are at TA = +25°C. Boldface limits apply over the operating temperature range, -40°C to +85°C. (Continued) SYMBOL PARAMETER TEST CONDITIONS MIN (Note 6) TYP MAX (Note 6) UNITS ANALOG INPUT (Note 7) |AIN| VIN+, VIN– Full-Scale Input Span 2 x VREF Absolute Input Voltage Range VCM = VREF VIN+ - VIN– V V VIN+ VCM ± VREF/2 V VIN– VCM ± VREF/2 V ILEAK Input Leakage Current CVIN Input Capacitance -1 1 µA Track Mode 12 pF Hold Mode 6 pF VDD = 5V (±1% tolerance for specified performance) 2.5 V VDD = 3V (±1% tolerance for specified performance) 1.25 V REFERENCE INPUT VREF VREF Input Voltage Range ILEAK DC Leakage Current CVREF VREF Input Capacitance -1 1 19 μA pF LOGIC INPUTS VIH Input High Voltage VIL Input Low Voltage ILEAK CIN 2.4 Input Leakage Current V -1 Input Capacitance 0.8 V 1 µA 10 pF LOGIC OUTPUTS VOH Output High Voltage ISOURCE = 200µA VOL Output Low Voltage ISINK = 200µA ILEAK Floating-State Leakage Current COUT Floating-State Output Capacitance VDD - 0.3 V -1 Output Coding 0.4 V 1 µA 10 pF Two’s Complement CONVERSION RATE tCONV Conversion Time 888ns with FSCLK = 18MHz 16 SCLK Cycles 1.07µs with FSCLK = 15MHz 16 SCLK Cycles tACQ Acquisition Time (Note 8) Sine Wave Input 200 ns Fmax Throughput Rate VDD = 5V 1 MSPS VDD = 3V 833 kSPS POWER REQUIREMENTS VDD Positive Supply Voltage Range 6 3.3V ± 10% 3.0 3.6 V 5V ± 5% 4.75 5.25 V FN8341.0 August 10, 2012 ISL267450 Electrical Specifications VDD = +3.0V to +3.3V, FSCLK = 15MHz, FS = 833kSPS, VREF = 1.25V, FIN = 200kHz; VDD = +4.75V to +5.25V, FSCLK = 18MHz, FS = 1MSPS, VREF = 2.5V, FIN = 300kHz; VCM = VREF, TA = TMIN to TMAX unless otherwise noted. Typical values are at TA = +25°C. Boldface limits apply over the operating temperature range, -40°C to +85°C. (Continued) SYMBOL IDD PD PARAMETER TEST CONDITIONS MIN (Note 6) TYP MAX (Note 6) UNITS 1 µA Positive Supply Input Current Static VDD = 3V/5V; SCLK ON or OFF Dynamic VDD = 5V; fS = 1MSPS 1.7 mA VDD = 3V; fS = 833kSPS 1.25 mA 5 µW Power Dissipation Static Mode VDD = 3V/5V; SCLK ON or OFF Dynamic VDD = 5V; fS = 1MSPS 8.5 mW VDD = 3V; fS = 833kSPS 3.75 mW NOTES: 6. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design. 7. The absolute voltage applied to each analog input must not exceed VDD. 8. Read about “Acquisition Time” on page 14 for a discussion of this parameter. Electrical Specifications Limits established by characterization and are not production tested. VDD = +4.75V to +5.25V, FSCLK = 18MHz, FS = 1MSPS, VREF = 2.5V, FIN = 300kHz; VCM = VREF, TA = TMIN to TMAX unless otherwise noted. Typical values are at TA = +25°C. Boldface limits apply over the operating temperature range, -40°C to +85°C. SYMBOL PARAMETER fSCLK Clock Frequency tSCLK Clock Period tCONVERT tQUIET tCSS tDISABLE TEST CONDITIONS MIN (Note 6) TYP 0.05 MAX (Note 6) UNITS 18 MHz 55 Conversion Time ns 16 x tSCLK 888 ns Quiet Time Before Sample 25 ns CS Falling Edge to SCLK Falling Edge Setup Time 10 ns CS Falling Edge to SDATA Disable Time (Note 9) Extrapolated back to true bus relinquish 10 35 ns Data Access Time after SCLK Falling Edge tSWH SCLK High Pulsewidth 0.4 x tSCLK 0.6 x tSCLK ns tSWL SCLK Low Pulsewidth 0.4 x tSCLK 0.6 x tSCLK ns 40 ns tCLKDV SCLK Falling Edge to SDATA Valid tSDH SCLK Falling Edge to SDATA Hold tACQ Acquisition Time (Note 8) tCSW CS Pulse Width tCDV CS Falling Edge to SDATA Valid 10 ns ns 10 ns 20 ns Electrical Specifications Limits established by characterization and are not production tested. VDD = +3.0V to +3.3V, FSCLK = 15MHz, FS = 833kSPS, VREF = 1.25V, FIN = 200kHz; VREF = 2.5V; VCM = VREF, TA = TMIN to TMAX unless otherwise noted. Typical values are at TA = +25°C. Boldface limits apply over the operating temperature range, -40°C to +85°C. SYMBOL PARAMETER fSCLK Clock Frequency tSCLK Clock Period tCONVERT TEST CONDITIONS MIN (Note 6) 0.05 TYP MAX (Note 6) UNITS 15 MHz 55 Conversion Time 16 x tSCLK 7 ns 1.07 µs FN8341.0 August 10, 2012 ISL267450 Electrical Specifications Limits established by characterization and are not production tested. VDD = +3.0V to +3.3V, FSCLK = 15MHz, FS = 833kSPS, VREF = 1.25V, FIN = 200kHz; VREF = 2.5V; VCM = VREF, TA = TMIN to TMAX unless otherwise noted. Typical values are at TA = +25°C. Boldface limits apply over the operating temperature range, -40°C to +85°C. (Continued) SYMBOL tQUIET tCSS tDISABLE PARAMETER TEST CONDITIONS MIN (Note 6) TYP MAX (Note 6) UNITS Quiet Time Before Sample 25 ns CS Falling Edge to SCLK Falling Edge Setup Time 10 ns CS Falling Edge to SDATA Disable Time (Note 9) Extrapolated back to true bus relinquish 10 35 µs tSWH SCLK High Pulsewidth 0.4 x tSCLK 0.6 x tSCLK ns tSWL SCLK Low Pulsewidth 0.4 x tSCLK 0.6 x tSCLK ns 40 ns tCLKDV SCLK Falling Edge to SDATA Valid tSDH SCLK Falling Edge to SDATA Hold tACQ Acquisition Time (Note 8) tCSW CS Pulse Width tCDV CS Falling Edge to SDATA Valid 10 ns ns 10 ns 20 ns NOTE: 9. During characterization, tDISABLE is measured from the release point with a 10pF load (see Figure 2 on page 8) and the equivalent timing using the AD7450 loading (50pF) is calculated. FIGURE 1. SERIAL INTERFACE TIMING DIAGRAM VDD RL 2.85k OUTPUT PIN CL 10 pF FIGURE 2. EQUIVALENT LOAD CIRCUIT 8 FN8341.0 August 10, 2012 ISL267450 Typical Performance Characteristics 0 0 8192-POINT FFT fSAMPLE = 1MSPS fIN = 300kHz SINAD = 71.55dB THD = -80.88dB SFDR = 84.08dB -40 -60 -80 -100 -120 -140 -160 8192-POINT FFT fSAMPLE = 833kSPS fIN = 300kHz SINAD = 69.83dB THD = -82.02dB SFDR = 82.93dB -20 AMPLITUDE (dBFS) AMPLITUDE (dBFS) -20 -40 -60 -80 -100 -120 -140 0 100 200 300 400 -160 500 0 100 FREQUENCY (kHz) 200 300 400 FREQUENCY (kHz) FIGURE 3. DYNAMIC PERFORMANCE AT 1MSPS WITH VDD = 5V FIGURE 4. DYNAMIC PERFORMANCE AT 833KSPS WITH VDD = 3V 1.0 74 0.8 72 0.6 0.4 DNL (LSB) SINAD (dBc) 70 68 2.7V 3.3V 66 4.75V 0.0 -0.2 -0.4 5.25V 64 0.2 -0.6 62 -0.8 60 10 100 -1.0 1k 0 1024 TEST FREQUENCY (Hz) 1.0 1.0 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.0 -0.2 0.0 -0.2 -0.4 -0.6 -0.6 -0.8 -0.8 1024 2048 CODE 3072 FIGURE 7. TYPICAL DNL FOR VDD = 3V 9 4096 0.2 -0.4 0 3072 FIGURE 6. TYPICAL DNL FOR VDD = 5V INL (LSB) DNL (LSB) FIGURE 5. SINAD vs ANALOG FREQUENCY FROM VARIOUS SUPPLY VOLTAGES -1.0 2048 CODE 4096 -1.0 0 1024 2048 3072 4096 CODE FIGURE 8. TYPICAL INL FOR VDD = 5V FN8341.0 August 10, 2012 ISL267450 Typical Performance Characteristics (Continued) 1.0 3.0 0.8 2.5 0.6 2.0 1.5 DNL (LSB) INL (LSB) 0.4 0.2 0.0 -0.2 1.0 0.0 -0.4 -0.6 -0.5 -0.8 -1.0 -1.0 0 POS DNL 0.5 1024 2048 3072 NEG DNL -1.5 0.0 4096 0.5 1.0 CODE 3.0 1.5 2.0 1.0 POS DNL INL (LSB) DNL (LSB) 1.0 0.5 0.0 3.5 0.0 NEG INL NEG DNL -2.0 -1.0 0.5 1.0 1.5 2.0 -3.0 2.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 VREF (V) VREF (V) FIGURE 11. CHANGE IN DNL vs VREF FOR VDD = 3.3V FIGURE 12. CHANGE IN INL vs VREF FOR VDD = 5V 2.5 1.0 2.0 0.0 3.3V VDD -1.0 1.5 -2.0 1.0 POS INL ZCE (LSB) INL (LSB) 3.0 POS INL -1.0 0.5 0.0 -0.5 -3.0 -5.0 -6.0 NEG INL -7.0 -1.5 -8.0 0.0 0.5 1.0 1.5 VREF (V) 2.0 FIGURE 13. CHANGE IN INL vs VREF FOR VDD = 3.3V 10 5V VDD -4.0 -1.0 -2.0 2.5 FIGURE 10. CHANGE IN DNL vs VREF FOR VDD = 5V 2.0 -1.5 0.0 2.0 VREF (V) FIGURE 9. TYPICAL INL FOR VDD = 3V -0.5 1.5 2.5 -9.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 VREF (V) FIGURE 14. CHANGE IN OFFSET ERROR vs VREF FOR VDD = 5V AND 3.3V FN8341.0 August 10, 2012 ISL267450 (Continued) 70000 70000 60000 60000 COUNT FREQUENCY COUNT FREQUENCY Typical Performance Characteristics 50000 40000 30000 20000 10000 0 50000 40000 30000 20000 10000 2044 2045 2046 2047 2048 2049 0 2050 2044 2045 2046 OUTPUT CODE 2047 2048 2049 2050 OUTPUT CODE FIGURE 15. HISTOGRAM OF THE OUTPUT CODES WITH A DC INPUT FOR VDD = 5V FIGURE 16. HISTOGRAM OF THE OUTPUT CODES WITH A DC INPUT FOR VDD = 3V -40 12.0 11.5 -50 11.0 -60 5V VDD 10.0 PSRR (dB) ENOB (BITS) 10.5 3.3V VDD 9.5 9.0 8.5 -70 -80 -90 8.0 -100 7.5 7.0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 -110 10 100 FIGURE 17. CHANGE IN ENOB vs VREF FOR VDD = 5V AND 3.3V 1k 10k FREQUENCY (kHz) VREF (V) FIGURE 18. CMRR vs INPUT FREQUENCY FOR VDD = 5V AND 3V 11 CONV VIN+ VIN- ACQ ACQ CONV VREF CS ACQ CONV SAR LOGIC CS DAC The ISL267450 is based on a successive approximation register (SAR) architecture utilizing capacitive charge redistribution digital-to-analog converters (DACs). Figure 19 shows a simplified representation of the converter. During the acquisition phase (ACQ), the differential input is stored on the sampling capacitors (CS). The comparator is in a balanced state since the switch across its inputs is closed. The signal is fully acquired after tACQ has elapsed, and the switches then transition to the conversion phase (CONV) so the stored voltage may be converted to digital format. The comparator will become unbalanced when the differential switch opens and the input switches transition (assuming that the stored voltage is not exactly at mid-scale). The comparator output reflects whether the stored voltage is above or below mid-scale, which sets the value of the MSB. The SAR logic then forces the capacitive DACs to adjust up or down by one quarter of full-scale by switching in binarily weighted capacitors. Again the comparator output reflects whether the stored voltage is above or below the new value, setting the value of the next lowest bit. This process repeats until all 12 bits have been resolved. DAC Functional Description FIGURE 19. SAR ADC ARCHITECTURAL BLOCK DIAGRAM FN8341.0 August 10, 2012 ISL267450 An external clock must be applied to the SCLK pin to generate a conversion result. The allowable frequency range for SCLK is 50kHz to 18MHz. Serial output data is transmitted on the falling edge of SCLK. The receiving device (FPGA, DSP or Microcontroller) may latch the data on the rising edge of SCLK to maximize set-up and hold times. A stable, low-noise reference voltage must be applied to the VREF pin to set the full-scale input range and common-mode voltage. See “Voltage Reference Input” on page 13 for more details. ADC Transfer Function The output coding for the ISL267450 is two’s complement. The first code transition occurs at successive LSB values (i.e., 1 LSB, 2 LSB, and so on). The LSB size of the ISL267450 is 2*VREF/4096. The ideal transfer characteristic of the ISL267450 is shown in Figure 20. 011...111 V 5.0 VIN- 4.0 VIN+ 2.0VP-P 3.0 VCM 2.0 1.0 t VREF = 2V 1LSB = 2•V REF/4096 V 011...110 ADC CODE 5.0 VIN- 000...001 000...000 4.0 111...111 2.5VP-P VIN+ VCM 3.0 100...010 100...001 2.0 100...000 –VREF + ½LSB 0V +VREF +VREF – 1½LSB – 1LSB ANALOG INPUT VIN+ – (VIN–) t FIGURE 20. IDEAL TRANSFER CHARACTERISTICS Analog Input The ISL267450 features a fully differential input with a nominal full-scale range equal to twice the applied VREF voltage. Each input swings VREF VP-P, 180° out-of-phase from one another for a total differential input of 2*VREF (see Figure 21). VREF(P-P) VIN+ ISL267450 VCM VREF(P-P) 1.0 VIN- FIGURE 21. DIFFERENTIAL INPUT SIGNALING Differential signaling offers several benefits over a single-ended input, such as: VREF = 2.5V FIGURE 22. RELATIONSHIP BETWEEN VREF AND FULL-SCALE RANGE Figure 22 shows the relationship between the reference voltage and the full-scale input range for two different values of VREF. Note that there is a trade-off between VREF and the allowable common mode input voltage (VCM). The full-scale input range is proportional to VREF; therefore the VCM range must be limited for larger values of VREF in order to keep the absolute maximum and minimum voltages on the VIN+ and VIN– pins within specification. Figures 23 and 24 illustrate this relationship for 5V and 3V operation, respectively. The dashed lines show the theoretical VCM range based solely on keeping the VIN+ and VIN– pins within the supply rails. Additional restrictions are imposed due to the required headroom of the input circuitry, resulting in practical limits shown by the shaded area. • Doubling of the full-scale input range (and therefore the dynamic range) • Improved even order harmonic distortion • Better noise immunity due to common mode rejection 12 FN8341.0 August 10, 2012 ISL267450 Voltage Reference Input VCM The voltage magnitude applied to the VREF pin defines the full scale span of the ADC as 2* VREF. The device is specified with a voltage reference of 2.5V for 5V operation and with a voltage reference of 2.0V for 3V operation. But, VREF input accepts voltages ranging from 0.1V to 3.5V for operation from 5 V VDD and voltages ranging from 0.1V to 2.2V for operation from a 3V VDD. 5.0 4.0 3.0 2.0 1.0 Figures 25 and 26 illustrate possible voltage reference options for the ISL267450. Figure 25 uses the ISL21090 precision voltage reference, which exhibits exceptionally low drift and low noise. The ISL21090 must use a power supply greater than 4.7V. The VREF input pin on the ISL267450 uses very low current, so the decoupling capacitor can be small (0.1µF). VREF 0.5 1.0 1.5 2.0 2.5 3.0 3.5 FIGURE 23. RELATIONSHIP BETWEEN VREF AND VCM FOR VDD = 5V VCM Figure 26 illustrates the ISL21010 voltage reference. The ISL21010 is available in various output voltages. It has higher noise and drift than the ISL26090, but consumes very low operating current, which makes it an excellent choice for battery-powered applications. 3.0 2.5 2.0 1.5 1.0 0.5 V R EF 0.5 1.0 1.5 2.0 2.5 FIGURE 24. RELATIONSHIP BETWEEN VREF AND VCM FOR VDD = 3V 5V + BULK 0.1µF 0.1µF 1 DNC DNC 8 2 VIN DNC 7 3 COMP VOUT 6 4 GND 5 VDD ISL267450 VREF 2.5V 0.1µF TRIM ISL21090 FIGURE 25. PRECISION VOLTAGE REFERENCE FOR +5V SUPPLY +3.0V TO +3.3V OR +5V VIN VOUT + BULK 1 GND 3 0.1µF 0.1µF ISL267450 VDD VREF 2 1.25, 2.048 OR 2.5V ISL21010 0.1µF FIGURE 26. VOLTAGE REFERENCE FOR +3.0V TO +3.3V, OR FOR +5V SUPPLY 13 FN8341.0 August 10, 2012 ISL267450 FIGURE 27. NORMAL MODE OPERATION CONVERTER OPERATION The ISL267450 is designed to minimize power consumption by only powering up the SAR comparator during conversion time. When the converter is in track mode (its sample capacitors are tracking the input signal), the SAR comparator is powered down. The state of the converter is dictated by the logic state of CS. When CS is high, the SAR comparator is powered down while the sampling capacitor array is tracking the input. When CS transitions low, the capacitor array immediately captures the analog signal that is being tracked. After CS is taken low, the SCLK pin is toggled 16 times. For the first 3 clocks, the comparator is powered up and auto-zeroed, then the SAR decision process is begun. This process uses 12 SCLK cycles. Each SAR decision is presented to the SDATA output on the next clock cycle after the SAR decision is performed. The SAR process (12 bits) is completed on SCLK cycle 15. At this point in time, the SAR comparator is powered down and the capacitor array is placed back into Track mode. The last SAR comparator decision is output from SDATA on the 16th SCLK cycle. When the last data bit is output from SDATA, the output switches to a logic 0 until CS is taken high, at which time, the SDATA output enters a High-Z state. SCLK value than 18MHz, the minimum acquisition time is 200ns. This minimum acquisition time also applies to the device when operated at 3V supply or if short cycling is utilized. SHORT CYCLING In cases where a lower resolution conversion is acceptable, CS can be pulled high before all 12 bits are clocked out. This is referred to as short cycling, and it can be used to further optimize power dissipation. In this mode, a lower resolution result will be output, but the ADC will enter static mode sooner and exhibit a lower average power consumption than if the complete conversion cycle were carried out. The minimum acquisition time (tACQ) requirement of 200ns must be met for the next conversion to be valid. POWER vs THROUGHPUT RATE The ISL267450 provides reduced power consumption at lower conversion rates by automatically switching into a low-power mode after completing a conversion. The average power consumption of the ADC decreases at lower throughput rates. Figure 28 shows the typical power consumption over a wide range of throughput rates. Figure 27 illustrates the serial port system timing for the ISL267450. 100 POWER-ON RESET ACQUISITION TIME POWER (mW) 10 When power is first applied, the ISL267450 performs a power-on reset that requires approximately 2.5ms to execute. After this is complete, a single dummy conversion must be executed (by taking CS low) in order to initialize the switched capacitor track and hold. The dummy conversion cycle will take 889ns with an 18MHz SCLK. Once the dummy cycle is complete, the ADC mode will be determined by the state of CS. Regular conversions can be started immediately after this dummy cycle is completed and time has been allowed for proper acquisition. VDD = 5V 1 VDD = 3V 0.1 0.01 0 50 100 150 200 250 300 350 THROUGHPUT (kSPS) To achieve the maximum sample rate (1MSps) in the ISL267450 device, the maximum acquisition time is 200ns. For slower conversion rates, or for conversions performed using a slower 14 FIGURE 28. POWER CONSUMPTION vs THROUGHPUT RATE FN8341.0 August 10, 2012 ISL267450 Serial Interface Conversion data is accessed with an SPI-compatible serial interface. The interface consists of the serial clock (SCLK), serial data output (SDATA), and chip select (CS). A falling edge on the CS signal initiates a conversion by placing the part into the acquisition (ACQ) phase. After tACQ has elapsed, the part enters the conversion (CONV) phase and begins outputting the conversion result starting with a null bit followed by the most significant bit (MSB) and ending with the least significant bit (LSB). The CS pin can be pulled high at this point to put the device into Standby mode and reduce the power consumption. If CS is held low after the LSB bit has been output, the conversion result will be repeated in reverse order until the MSB is transmitted, after which the serial output enters a high impedance state. The ISL267450 will remain in this state, dissipating typical dynamic power levels, until CS transitions high then low to initiate the next conversion. Data Format Output data is encoded in two’s complement format as shown in Table 1. The voltage levels in the table are idealized and don’t account for any gain/offset errors or noise. TABLE 1. TWO’S COMPLEMENT DATA FORMATTING microstrip technique is by far the best but is not always possible with a double-sided board. In this technique, the component side of the board is dedicated to ground planes, while signals are placed on the solder side. Good decoupling is also important. All analog supplies should be decoupled with μF tantalum capacitors in parallel with 0.1μF capacitors to GND. To achieve the best from these decoupling components, they must be placed as close as possible to the device. Terminology Signal-to-(Noise + Distortion) Ratio (SINAD) This is the measured ratio of signal-to-(noise + distortion) at the output of the ADC. The signal is the rms amplitude of the fundamental. Noise is the sum of all nonfundamental signals up to half the sampling frequency (fs/2), excluding DC. The ratio is dependent on the number of quantization levels in the digitization process; the more levels, the smaller the quantization noise. The theoretical signal-to-(noise + distortion) ratio for an ideal N-bit converter with a sine wave input is given by Equation 1: Signal-to-(Noise + Distortion) = ( 6.02 N + 1.76 )dB (EQ. 1) Thus, for a 12-bit converter this is 74dB, and for a 10-bit it is 62dB. INPUT VOLTAGE DIGITAL OUTPUT –Full Scale –VREF 1000 0000 0000 –Full Scale + 1LSB –VREF + 1LSB 1000 0000 0001 Total Harmonic Distortion Midscale 0 0000 0000 0000 +Full Scale – 1LSB +VREF – 1LSB 0111 1111 1110 Total harmonic distortion (THD) is the ratio of the rms sum of harmonics to the fundamental. For the ISL267450, it is defined as Equation 2: +Full Scale +VREF 0111 1111 1111 Application Hints Grounding and Layout The printed circuit board that houses the ISL267450 should be designed so that the analog and digital sections are separated and confined to certain areas of the board. This facilitates the use of ground planes that can be easily separated. A minimum etch technique is generally best for ground planes since it gives the best shielding. Digital and analog ground planes should be joined in only one place, and the connection should be a star ground point established as close to the GND pin on the ISL267450 as possible. Avoid running digital lines under the device, as this will couple noise onto the die. The analog ground plane should be allowed to run under the ISL267450 to avoid noise coupling. The power supply lines to the device should use as large a trace as possible to provide low impedance paths and reduce the effects of glitches on the power supply line. Fast switching signals, such as clocks, should be shielded with digital ground to avoid radiating noise to other sections of the board, and clock signals should never run near the analog inputs. Avoid crossover of digital and analog signals. Traces on opposite sides of the board should run at right angles to each other. This reduces the effects of feed-through through the board. A 15 V 22 + V 32 + V 42 + V 52 + V 62 THD ( dB ) = 20 log ----------------------------------------------------------------------V 12 (EQ. 2) where V1 is the rms amplitude of the fundamental and V2, V3, V4, V5, and V6 are the rms amplitudes of the second to the sixth harmonics. Peak Harmonic or Spurious Noise (SFDR) Peak harmonic or spurious noise is defined as the ratio of the rms value of the next largest component in the ADC output spectrum (up to fS/2 and excluding DC) to the rms value of the fundamental. It is also referred to as Spurious Free Dynamic Range (SFDR). Normally, the value of this specification is determined by the largest harmonic in the spectrum, but for ADCs where the harmonics are buried in the noise floor, it will be a noise peak. Intermodulation Distortion With inputs consisting of sine waves at two frequencies, fa and fb, any active device with nonlinearities will create distortion products at sum and difference frequencies of mfa ± nfb where m and n = 0, 1, 2 or 3. Intermodulation distortion terms are those for which neither m nor n are equal to zero. For example, the second order terms include (fa + fb) and (fa – fb), while the third order terms include (2fa + fb), (2fa – fb), (fa + 2fb), and (fa –2fb). FN8341.0 August 10, 2012 ISL267450 The ISL267450 is tested using the CCIF standard, where two input frequencies near the top end of the input bandwidth are used. In this case, the second order terms are usually distanced in frequency from the original sine waves, while the third order terms are usually at a frequency close to the input frequencies. As a result, the second and third order terms are specified separately. The calculation of the intermodulation distortion is as per the THD specification, where it is the ratio of the rms sum of the individual distortion products to the rms amplitude of the sum of the fundamentals expressed in dBs. Aperture Delay This is the amount of time from the leading edge of the sampling clock until the ADC actually takes the sample. Aperture Jitter Differential Nonlinearity (DNL) This is the difference between the measured and the ideal 1 LSB change between any two adjacent codes in the ADC. Zero-Code Error This is the deviation of the midscale code transition (111...111 to 000...000) from the ideal VIN+ – VIN– (i.e., 0 LSB). Positive Gain Error This is the deviation of the last code transition (011...110 to 011...111) from the ideal VIN+ – VIN– (i.e., +VREF – 1 LSB), after the zero code error has been adjusted out. Negative Gain Error This is the sample-to-sample variation in the effective point in time at which the actual sample is taken. This is the deviation of the first code transition (100...000 to 100...001) from the ideal VIN+ – VIN– (i.e., -VREF + 1 LSB), after the zero code error has been adjusted out. Full Power Bandwidth Track and Hold Acquisition Time The full power bandwidth of an ADC is that input frequency at which the amplitude of the reconstructed fundamental is reduced by 0.1dB or 3dB for a full-scale input. The track and hold acquisition time is the minimum time required for the track and hold amplifier to remain in track mode for its output to reach and settle to within 0.5 LSB of the applied input signal. Common-Mode Rejection Ratio (CMRR) The common-mode rejection ratio is defined as the ratio of the power in the ADC output at full-scale frequency, f, to the power of a 200mVP-P sine wave applied to the common-mode voltage of VIN+ and VIN– of frequency fs as shown by Equation 3.: CMRR ( dB ) = 10 log ( Pfl ⁄ Pfs ) (EQ. 3) Pf is the power at the frequency f in the ADC output; Pfs is the power at frequency fs in the ADC output. Integral Nonlinearity (INL) Power Supply Rejection Ratio (PSRR) The power supply rejection ratio is defined as the ratio of the power in the ADC output at full-scale frequency, f, to ADC VDD supply of frequency fS. The frequency of this input varies from 1kHz to 1MHz. PSRR ( dB ) = 10 log ( Pf ⁄ Pfs ) (EQ. 4) Pf is the power at frequency f in the ADC output; Pfs is the power at frequency fs in the ADC output. This is the maximum deviation from a straight line passing through the endpoints of the ADC transfer function. For additional products, see www.intersil.com/product_tree Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted in the quality certifications found at www.intersil.com/design/quality Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see www.intersil.com 16 FN8341.0 August 10, 2012 ISL267450 Revision History The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make sure you have the latest revision. DATE REVISION August 10, 2012 FN8341.0 CHANGE Initial Release. Products Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products address some of the industry's fastest growing markets, such as, flat panel displays, cell phones, handheld products, and notebooks. Intersil's product families address power management and analog signal processing functions. Go to www.intersil.com/products for a complete list of Intersil product families. For a complete listing of Applications, Related Documentation and Related Parts, please see the respective device information page on intersil.com: ISL267450 To report errors or suggestions for this datasheet, please go to: www.intersil.com/askourstaff FITs are available from our website at: http://rel.intersil.com/reports/search.php 17 FN8341.0 August 10, 2012 ISL267450 Package Outline Drawing M8.15 8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE Rev 4, 1/12 DETAIL "A" 1.27 (0.050) 0.40 (0.016) INDEX 6.20 (0.244) 5.80 (0.228) AREA 0.50 (0.20) x 45° 0.25 (0.01) 4.00 (0.157) 3.80 (0.150) 1 2 8° 0° 3 0.25 (0.010) 0.19 (0.008) SIDE VIEW “B” TOP VIEW 2.20 (0.087) SEATING PLANE 5.00 (0.197) 4.80 (0.189) 1.75 (0.069) 1.35 (0.053) 1 8 2 7 0.60 (0.023) 1.27 (0.050) 3 6 4 5 -C- 1.27 (0.050) 0.51(0.020) 0.33(0.013) SIDE VIEW “A 0.25(0.010) 0.10(0.004) 5.20(0.205) TYPICAL RECOMMENDED LAND PATTERN NOTES: 1. Dimensioning and tolerancing per ANSI Y14.5M-1994. 2. Package length does not include mold flash, protrusions or gate burrs. Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 3. Package width does not include interlead flash or protrusions. Interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 4. The chamfer on the body is optional. If it is not present, a visual index feature must be located within the crosshatched area. 5. Terminal numbers are shown for reference only. 6. The lead width as measured 0.36mm (0.014 inch) or greater above the seating plane, shall not exceed a maximum value of 0.61mm (0.024 inch). 7. Controlling dimension: MILLIMETER. Converted inch dimensions are not necessarily exact. 8. This outline conforms to JEDEC publication MS-012-AA ISSUE C. 18 FN8341.0 August 10, 2012 ISL267450 Package Outline Drawing M8.118 8 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE Rev 4, 7/11 5 3.0±0.05 A DETAIL "X" D 8 1.10 MAX SIDE VIEW 2 0.09 - 0.20 4.9±0.15 3.0±0.05 5 0.95 REF PIN# 1 ID 1 2 B 0.65 BSC GAUGE PLANE TOP VIEW 0.55 ± 0.15 0.25 3°±3° 0.85±010 H DETAIL "X" C SEATING PLANE 0.25 - 0.36 0.08 M C A-B D 0.10 ± 0.05 0.10 C SIDE VIEW 1 (5.80) NOTES: (4.40) (3.00) 1. Dimensions are in millimeters. (0.65) (0.40) (1.40) TYPICAL RECOMMENDED LAND PATTERN 19 2. Dimensioning and tolerancing conform to JEDEC MO-187-AA and AMSEY14.5m-1994. 3. Plastic or metal protrusions of 0.15mm max per side are not included. 4. Plastic interlead protrusions of 0.15mm max per side are not included. 5. Dimensions are measured at Datum Plane "H". 6. Dimensions in ( ) are for reference only. FN8341.0 August 10, 2012