AS1537

AS1536/AS1537 1 2 - B i t , S i n g l e S u p p l y, L o w - P o w e r, 7 3 k s ps A / D C o n verters D a ta s h e e t 1 General Description The AS1536/AS1537 are low-power, 12-bit, 73ksps analog-to-digital (A/D) converters specifically designed for single-supply A/D applications. Superior AC characteristics, very low power consumption, and robust packaging make these ultra-small devices perfect for battery-powered analog-data collection devices. The integrated successive-approximation register (SAR) and a fast (1.5µs) sampling track/hold time provide an economic and highly-reliable A/D conversion solution. The AS1536/AS1537 operate from a single 2.7V to 5.25V supply. The AS1537 requires an external reference, using less power than the AS1536, however, the AS1536 features an internal 2.5V reference. As with the AS1537, the AS1536 can also be used with an external reference, which uses the input range 0V to VREF, including the positive supply range. The AS1537 consumes only 3mW (VDD = 3V) at the 73ksps maximum sampling speed. Both devices feature a low-current (0.3µA) shutdown mode, which reduces power consumption at slower throughput rates. Data accesses are made via the standard, high-speed 3-wire serial interface, which is SPI-, QSPI-, and Microwire-compatible. Both devices contain an internal clock, however, both devices also support an external clock for increased flexibility. The AS1536/AS1537 are available in an 8-pin SOIC-150 package. 2 Key Features ! ! ! ! ! ! 12-Bit Resolution with 7.5µs Conversion Time Sampling Rate: 73ksps Straight Binary (Unipolar) Data Format Single-Supply Operation:+2.7V to +5.25V Internal 2.5V Reference (AS1536) Low Power-Consumption: - 4mW (73ksps, AS1536) - 3mW (73ksps, AS1537) - 66µW (1ksps, AS1537) - 1µW (Shutdown Mode) Integrated Track/Hold Amplifier Internal Clock SPI/QSPI/Microwire 3-Wire Serial Interface Operating Temperature Range: -40 to +85ºC 8-pin SOIC-150 Package ! ! ! ! ! 3 Applications The devices are ideal for remote sensors, data-acquisition, data logging devices, lab instruments, or for any other space-limited A/D devices with low power consumption and single-supply requirements. Figure 1. Block Diagram 1 VDD 7 CSN 8 SCLK 3 SHDNN Control Logic Internal Clock Output Shift Register 6 DOUT AS1536/AS1537 2 AIN 4 REF Track/ Hold 12-Bit SAR 2.5V Ref 5 GND AS1536 only www.austriamicrosystems.com Revision 1.01 2 - 22 AS1536/AS1537 Datasheet - Table of C o n t e n t Contents 1 General Description 2 Key Features 3 Applications 4 Pinout ............................................................................................................................. 2 ........................................................................................................................................ 2 .......................................................................................................................................... 2 ..................................................................................................................................................... 4 ................................................................................................................................................... 4 ................................................................................................................. 5 Pin Description 5 Absolute Maximum Ratings 6 Electrical Characteristics Timing Characteristics ...................................................................................................................... 6 ........................................................................................................ 9 ......................................................................................................................................... 8 7 Typical Operating Characteristics 8 Detailed Description Analog Input Track/Hold External Clock ........................................................................................................................... 12 ....................................................................................................................................................... 12 .......................................................................................................................................................... 13 .................................................................................................................................................... 13 ............................................................................................................................................. 13 ............................................................................................................................................... 15 ................................................................................................................................... 15 ..................................................................................................................... 16 Timing and Control Transfer Function Reducing Supply Current External Reference Initialization Internal 2.5V Reference (AS1536) ............................................................................................................................................ 16 9 Application Information Serial Interface ...................................................................................................................... 17 ........................................................................................................................................................ 17 ................................................................................................................................................... 17 ....................................................................................................................................... 19 Layout Considerations 10 Package Drawings and Markings 11 Ordering Information .................................................................................................... 20 ....................................................................................................................... 21 www.austriamicrosystems.com Revision 1.01 3 - 22 AS1536/AS1537 Datasheet - P i n o u t 4 Pinout Figure 2. Pin Assignments (Top View) VDD 1 8 SCLK AIN 2 7 CSN AS1536/ AS1537 SHDNN 3 6 DOUT REF 4 5 GND Pin Description Table 1. Pin Descriptions Pin Number 1 2 Pin Name VDD AIN Description Positive Supply Voltage. +2.7V to +5.25V Sampling Analog Input. 0V to VREF range. Three-Level Shutdown Input. Pulling this pin low puts the AS1536/AS1537 in shutdown mode, down to 4µA (max) supply current. The devices are fully operational with this pin high or floating. Note: For the AS1536, pulling this pin high enables the internal reference; letting this pin float disables the internal reference allowing for the use of an external reference. See also pin 4. A/D Conversion Reference Voltage. This pin serves as the internal 2.5V reference output for the AS1536; bypass this pin with a 4.7µF capacitor. This pin also serves as the external reference voltage input for the AS1537, or for AS1536 if the internal reference is disabled. Bypass this pin with a minimum of 0.1µF when using an external reference. See also pin 3. Analog and Digital Ground Serial Data Output. Data changes state at SCLK’s falling edge. Note: This pin is high-impedance when pin CSN is high. Active-Low Chip Select. The falling edge of this pin initiates a conversion. Note: When this pin is high, DOUT is high-impedance. Serial Clock Input. This pin clocks data out at rates up to 2.1MHz. 3 SHDNN 4 REF 5 6 7 8 GND DOUT CSN SCLK www.austriamicrosystems.com Revision 1.01 4 - 22 AS1536/AS1537 Datasheet - A b s o l u t e M a x i m u m R a t i n g s 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 Section 6 Electrical Characteristics on page 6 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Parameter VDD to GND AIN to GND REF to GND Digital Inputs to GND DOUT to GND DOUT 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 -25 Max +7 VDD + 0.3V VDD + 0.3V VDD + 0.3V VDD + 0.3V +25 471 +85 +150 Units 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-020D “Moisture/Reflow Sensitivity Classification for non-hermetic Solid State Surface Mount Devices”. Derate 5.88mW/ºC above +70ºC Comments Package-Body Peak Temperature 260 °C www.austriamicrosystems.com Revision 1.01 5 - 22 AS1536/AS1537 Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s 6 Electrical Characteristics VDD = +2.7V to +5.25V, 73ksps, fSCLK = 2.1MHz (50% duty cycle); AS1536:4.7µF capacitor at REF, AS1537: external reference; VREF = 2.5V applied to REF; TAMB = TMIN to TMAX (unless otherwise specified). Table 3. Electrical Characteristics Symbol DC Accuracy 1 Parameter Conditions Min Typ Max Units Resolution Relative Accuracy DNL 2 12 ±1 No missing codes over temperature ±1 ±6 ±6 ±1 Bits LSB LSB LSB LSB ppm/°C Differential Non-Linearity Offset Error Gain Error 3 Gain Temperature Coefficient Dynamic Specifications (10kHz sine-wave input, 0V to 2.5Vp-p, 73ksps, fSCLK =2.1MHz) SINAD THD SFDR Signal-to-Noise + Distortion Ratio Total Harmonic Distortion Spurious-Free Dynamic Range Small-Signal Bandwidth Full-Power Bandwidth Conversion Rate tCONV tACQ Conversion Time Track/Hold Acquisition Time Throughput Rate tAP Aperture Delay Aperture Jitter Analog Input Input Voltage Range Input Capacitance Internal Reference (AS1536 only) REF Output Voltage REF Short-Circuit Current REF Temperature Coefficient Load Regulation CREFBYP 6 4 67 Up to the 5th harmonic 80 -3dB rolloff 70.5 -83 88 2.5 2.5 -80 dB dB dB MHz MHz 5.5 7.5 1.5 µs µs ksps ns ps fSCLK = 2.1MHz Figure 27 on page 14 7