AS1521

AS1520, AS1521 1 0 - B i t , S i n g l e - S u p p l y, L o w - P o w e r, 4 0 0 / 3 0 0 k s ps , 8-Channel A/D Converters D a ta S he e t 1 General Description The AS1520/AS1521 are low-power, 8/4-channel, 400/ 300ksps, 10-bit analog-to-digital (A/D) converters specifically designed to operate with single-supply devices. Superior AC characteristics, very low power consumption, and highly-reliable packaging make these ultrasmall devices perfect for battery-powered remote-sensor and data-acquisition devices. The successive-approximation register (SAR), highspeed sampling, high-bandwidth track/hold circuitry, and multi-mode operation combine to make these devices highly-flexible and configurable. Both devices require low supply current (2.8mA @ 400ksps, AS1520; 2.2mA @ 300ksps, AS1521) and feature a reduced-power mode and a power-down mode to lower power consumption at slower throughput rates. The devices operate from a single supply (+4.5 to +5.5V, AS1520; +2.7 to +3.6V, AS1521). Both devices contain an internal 2.5V reference, an integrated reference buffer, and feature support for an external reference (1V to VDD). Data accesses are made via the high-speed, 4-wire, SPI, QSPI-, and Microwire-compatible serial interface. The devices are available in a 20-pin TSSOP package. 2 Key Features ! Single-Supply Operation: - +4.5 to +5.5V (AS1520) - +2.7 to +3.6V (AS1521) Sampling Rate: - 400ksps (AS1520) - 300ksps (AS1521) Software-Configurable Analog Input Types: - 8-Channel Single-Ended - 8-Channel Pseudo Differential Referenced to COM - 4-Channel Pseudo Differential - 4-Channel Fully Differential Software-Configurable Input Range Internal +2.5V Reference Low-Current Operation: - 2.8mA @ 400ksps (AS1520) - 2.2mA @ 300ksps (AS1521) - 0.4mA in Reduced-Power Mode - 0.5µA in Full Power-Down Mode SPI/QSPI/Microwire/TMS320-Compatible 20-pin TSSOP Package ! ! ! ! ! ! ! 3 Applications The devices are ideal for remote sensors, data-acquisition and data-logging devices, pen-digitizers, process control, or any other space-limited A/D application with low power-consumption requirements. 14 Figure 1. Block Diagram and Pin Assignments 17 CSN 18 SCLK 16 DIN Input Shift Register Output Shift Register DOUT 15 SSTRB CH0 1 CH1 2 20 VDD1 19 VDD2 18 SCLK 17 CSN AS1520/ AS1521 10-Bit SAR 10 VDD3 19 VDD2 CH2 3 CH3 4 CH4 5 CH5 6 CH6 7 Control Logic 1:8 CH0:CH7 9 COM +1.2V REF Analog Input Track/ Hold 17kΩ Av ≈ 2.05 +2.50V IN AS1520/ AS1521 16 DIN 15 SSTRB 14 DOUT 13 GND 12 REFADJ 11 REF OUT REF 20 VDD1 CH7 8 COM 9 VDD3 10 12 REFADJ 11 REF 13 GND www.austriamicrosystems.com Revision 1.00 1 - 29 AS1520/AS1521 Data Sheet Contents 1 General Description ................................................................................................................................ 1 2 Key Features .......................................................................................................................................... 1 3 Applications ............................................................................................................................................ 1 4 Pinout ..................................................................................................................................................... 3 Pin Assignments ..................................................................................................................................................... 3 Pin Descriptions ..................................................................................................................................................... 3 5 Absolute Maximum Ratings .................................................................................................................... 4 6 Electrical Characteristics ........................................................................................................................ 5 AS1520 Electrical Characteristics .......................................................................................................................... 5 AS1521 Electrical Characteristics .......................................................................................................................... 7 Timing Characteristics ............................................................................................................................................ 9 7 Typical Operating Characteristics ......................................................................................................... 11 8 Detailed Description ............................................................................................................................. 14 Analog Input ......................................................................................................................................................... 14 Input Protection ............................................................................................................................................. 14 Track/Hold ............................................................................................................................................................ 14 Control Register ................................................................................................................................................... 15 Analog Input Configuration ................................................................................................................................... 15 Channel Selection ................................................................................................................................................ 16 Single-Ended Input ........................................................................................................................................ 16 Differential Input ............................................................................................................................................ 16 Starting a Conversion ........................................................................................................................................... 17 Transfer Functions ................................................................................................................................................ 18 Power Modes ....................................................................................................................................................... 19 Reduced Power Mode ................................................................................................................................... 20 Full Power-Down Mode ................................................................................................................................. 20 Reference ............................................................................................................................................................. 21 Internal Reference ......................................................................................................................................... 21 External Reference ....................................................................................................................................... 22 9 Application Information ......................................................................................................................... 23 Initialization ........................................................................................................................................................... 23 Serial Interface ..................................................................................................................................................... 23 Serial Interface Configuration ........................................................................................................................ 23 QSPI Interface ............................................................................................................................................... 24 Quick Evaluation Circuit ....................................................................................................................................... 25 Layout Considerations .......................................................................................................................................... 26 10 Package Drawings and Markings ....................................................................................................... 27 11 Ordering Information ........................................................................................................................... 28 www.austriamicrosystems.com Revision 1.00 2 - 29 AS1520/AS1521 Data Sheet - P i n o u t 4 Pinout Pin Assignments Figure 2. Pin Assignments (Top View) CH0 1 CH1 2 CH2 3 CH3 4 CH4 5 CH5 6 CH6 7 CH7 8 COM 9 VDD3 10 20 VDD1 19 VDD2 18 SCLK 17 CSN AS1520/ AS1521 16 DIN 15 SSTRB 14 DOUT 13 GND 12 REFADJ 11 REF Pin Descriptions Table 1. Pin Descriptions Pin Number 1:8 9 10 Pin Name CH0:CH7 COM VDD3 Description Analog Sampling Inputs. These eight pins serve as analog sampling inputs. Common Analog Inputs. Tie this pin to ground in single-ended mode. Positive Supply Voltage Reference-Buffer Output/A/DC Reference Input. This pin serves as the reference voltage for analog-to-digital conversions. In internal reference mode, the reference buffer provides a +2.50V nominal output, externally adjustable at pin REFADJ. In external reference mode, disable the internal buffer by pulling pin REFADJ to VDD1. Reference-Buffer Amplifier Input. To disable the reference-buffer amplifier, tie this pin to VDD1. Analog and Digital Ground Serial Data Output. Data is clocked out at the rising edge of pin SCLK. DOUT is high impedance when CSN is high. Serial Strobe Output. SSTRB pulses high for one clock period before the MSB is clocked out. SSTRB is high impedance when CSN is high. Serial Data Input. Data is clocked in at the rising edge of SCLK. Active-Low Chip Select. Data will not be clocked into pin DIN unless CSN is low. When CSN is high, pins DOUT and SSTRB are high impedance. Serial Clock Input. This pin clocks data into and out of the serial interface, and is used to set the conversion speed. Note: The duty cycle must be between 40 and 60%. Positive Supply Voltage Positive Supply Voltage 11 REF 12 13 14 15 16 17 REFADJ GND DOUT SSTRB DIN CSN 18 19 20 SCLK VDD2 VDD1 www.austriamicrosystems.com Revision 1.00 3 - 29 AS1520/AS1521 Data Sheet - A b s o l u t e Maximum Ratings 5 Absolute Maximum Ratings Stresses beyond those listed in Table 2 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 indicated in Electrical Characteristics on page 5 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Parameter VDD1, VDD2, VDD3 to GND VDD1 to VDD2 to VDD3 CH0:CH7, COM to GND REF, REFADJ to GND DIN, SCLK, CSN, to GND DOUT, SSTRB to GND DOUT, SSTRB Sink Current Continuous Power Dissipation (TAMB = +70ºC) Operating Temperature Range Storage Temperature Range -40 -60 Min -0.3 -0.3 -0.3 -0.3 -0.3 -0.3 Max +7 +0.3 VDD1 + +0.3 VDD1 + +0.3 VDD2 + +0.3 VDD2 + +0.3 25 559 +85 +150 Units V V V V V V mA mW ºC ºC The reflow peak soldering temperature (body temperature) specified is in accordance with IPC/JEDEC J-STD-020C “Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices”. The lead finish for Pb-free leaded packages is matte tin (100% Sn). Derate 7.0mW/ºC above +70ºC Comments Package Body Temperature +260 ºC www.austriamicrosystems.com Revision 1.00 4 - 29 AS1520/AS1521 Data Sheet - E l e c t r i c a l Characteristics 6 Electrical Characteristics AS1520 Electrical Characteristics VDD1 = VDD2 = VDD3 = +4.5 to +5.5V, COM = GND, fSCLK= 6.4MHz, 50% duty cycle, 16 clocks/conversion cycle (400ksps), external +2.5V at REF, REFADJ = VDD1, TAMB = TMIN to TMAX (unless otherwise specified). Typ values at TAMB = +25ºC. Table 3. AS1520 Electrical Characteristics Symbol DC Accuracy INL DNL 1 Parameter Resolution Relative Accuracy Differential Nonlinearity Offset Error 2 Conditions Min 10 -0.5 Typ Max Units Bits +0.5 +1 +3 LSB LSB LSB No missing codes over temperature -1 -3 3 -3 +3 LSB Gain Error Gain-Error Temperature ppm/ ±1.6 Coefficient °C Channel-to-Channel ±0.2 LSB Offset Error Matching Dynamic Specifications: 100kHz sinewave input, 2.5Vp-p, 400ksps, 6.4MHz clock, bit RANGE (page 15) = 0, pseudo-differential input mode Signal-to-Noise plus SINAD 60 dB Distortion Ratio THD Total Harmonic Distortion Up to the 5th harmonic 70 dB Spurious-Free SFDR 70 dB Dynamic Range IMD Intermodulation Distortion fIN1 = 99kHz, fIN2 = 102kHz 76 dB Channel-to-Channel fIN = 200kHz, VIN = 2.5Vp-p -85 dB 4 Crosstalk Full-Power Bandwidth -3dB point 6 MHz Full-Linear Bandwidth SINAD > 68dB 450 kHz Conversion Rate Conversion Time tACQ Track/Hold Acquisition Time tAD Aperture Delay tAJ Aperture Jitter fSCLK Serial Clock Frequency Duty Cycle Analog Inputs: CH0:CH7, COM VCHx - Input Voltage Range: SingleEnded, Pseudo-Differential, VCHy 6 (COM) and Differential Multiplexer Leakage Current Input Capacitance Internal Reference VREF REF Output Voltage REF Short-Circuit Current REF Output Temperature TCVREF Coefficient Load Regulation CBYPREF 7 tCONV 5 2.5 390 7 68dB 350 Conversion Rate dB dB dB dB dB MHz kHz µs Conversion Time tACQ Track/Hold Acquisition Time tAD Aperture Delay tAJ Aperture Jitter Serial Clock Frequency fSCLK Duty Cycle Analog Inputs: CH0:CH7, COM VCHx - Input Voltage Range: SingleEnded, Pseudo-Differential, VCHy 6 (COM) and Differential Multiplexer Leakage Current Input Capacitance Internal Reference REF Output Voltage VREF REF Short-Circuit Current tCONV 5 Normal operation Normal operation 3.3 520 7