MAX146/MAX147 19-0465 Rev 2 10/01 +2.7V, Low-Power, 8-Channel, Serial 12-Bit ADCs General Description Features The MAX146/MAX147 12-bit data-acquisition systems 8-Channel Single-Ended or 4-Channel combine an 8-channel multiplexer, high-bandwidth Differential Inputs track/hold, and serial interface with high conversion Single-Supply Operation speed and low power consumption. The MAX146 oper- +2.7V to +3.6V (MAX146) ates from a single +2.7V to +3.6V supply the MAX147 +2.7V to +5.25V (MAX147) operates from a single +2.7V to +5.25V supply. Both devices analog inputs are software configurable for Internal 2.5V Reference (MAX146) unipolar/bipolar and single-ended/differential operation. Low Power The 4-wire serial interface connects directly to SPI/ 1.2mA (133ksps, 3V supply) QSPI and MICROWIRE devices without external 54A (1ksps, 3V supply) logic. A serial strobe output allows direct connection to 1A (power-down mode) TMS320-family digital signal processors. The SPI/QSPI/MICROWIRE/TMS320-Compatible MAX146/MAX147 use either the internal clock or an exter- 4-Wire Serial Interface nal serial-interface clock to perform successive-approxi- mation analog-to-digital conversions. Software-Configurable Unipolar or Bipolar Inputs The MAX146 has an internal 2.5V reference, while the 20-Pin DIP/SSOP Packages MAX147 requires an external reference. Both parts have a reference-buffer amplifier with a 1.5% voltage- Ordering Information adjustment range. INL These devices provide a hard-wired SHDN pin and a PART TEMP RANGE PIN-PACKAGE (LSB) software-selectable power-down, and can be pro- MAX146ACPP 0C to +70C 20 Plastic DIP 1/2 grammed to automatically shut down at the end of a con- version. Accessing the serial interface automatically MAX146BCPP 0C to +70C 20 Plastic DIP 1 powers up the MAX146/MAX147, and the quick turn-on MAX146ACAP 0C to +70C 20 SSOP 1/2 time allows them to be shut down between all conver- MAX146BCAP 0C to +70C 20 SSOP 1 sions. This technique can cut supply current to under MAX146BC/D 0C to +70C Dice* 1 60A at reduced sampling rates. Ordering Information continued at end of data sheet. The MAX146/MAX147 are available in 20-pin DIP and *Dice are specified at T = +25C, DC parameters only. A SSOP packages. For 4-channel versions of these devices, see the MAX1246/MAX1247 data sheet. Typical Operating Circuit Applications +3V Portable Data Logging Data Acquisition V CH0 V DD DD 0.1 F Medical Instruments Battery-Powered Instruments 0V TO DGND +2.5V ANALOG Pen Digitizers Process Control MAX146 INPUTS AGND CPU CH7 COM I/O VREF CS 4.7 F SCLK SCK (SK) DIN MOSI (SO) Pin Configuration appears at end of data sheet. DOUT MISO (SI) REFADJ 0.047 F SSTRB V SS SHDN SPI and QSPI are registered trademarks of Motorola, Inc. MICROWIRE is a registered trademark of National Semiconductor Corp. Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE+2.7V, Low-Power, 8-Channel, Serial 12-Bit ADCs ABSOLUTE MAXIMUM RATINGS V to AGND, DGND................................................. -0.3V to 6V Continuous Power Dissipation (T = +70C) DD A AGND to DGND...................................................... -0.3V to 0.3V Plastic DIP (derate 11.11mW/C above +70C) ......... 889mW CH0CH7, COM to AGND, DGND ............ -0.3V to (V + 0.3V) SSOP (derate 8.00mW/C above +70C) ................... 640mW DD VREF, REFADJ to AGND ........................... -0.3V to (V + 0.3V) CERDIP (derate 11.11mW/C above +70C).............. 889mW DD Digital Inputs to DGND .............................................. -0.3V to 6V Operating Temperature Ranges Digital Outputs to DGND ........................... -0.3V to (V + 0.3V) MAX146 C P/MAX147 C P .............................. 0C to +70C DD Digital Output Sink Current .................................................25mA MAX146 E P/MAX147 E P............................ -40C to +85C MAX146 MJP/MAX147 MJP ........................ -55C to +125C Storage Temperature Range ............................ -60C to +150C Lead Temperature (soldering, 10s) ................................ +300C Stresses beyond those listed under Absolute Maximum 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 indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V = +2.7V to +3.6V (MAX146) V = +2.7V to +5.25V (MAX147) COM = 0 f = 2.0MHz external clock (50% duty cycle) 15 DD DD SCLK clocks/conversion cycle (133ksps) MAX1464.7F capacitor at VREF pin MAX147external reference, VREF = 2.500V applied to VREF pin T = T to T unless otherwise noted.) A MIN MAX PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS ) DC ACCURACY (Note 1 Resolution 12 Bits MAX14 A 0.5 MAX14 B 1.0 Relative Accuracy (Note 2) INL LSB MAX147C 2.0 No Missing Codes NMC 12 Bits MAX14 A/MAX14 B 1.0 Differential Nonlinearity DNL LSB MAX147C 0.8 MAX14 A 0.5 3 Offset Error LSB MAX14 B/MAX147C 0.5 4 Gain Error (Note 3) 0.5 4 LSB Gain Temperature Coefficient 0.25 ppm/C Channel-to-Channel Offset 0.25 LSB Matching DYNAMIC SPECIFICATIONS (10kHz sine-wave input, 0V to 2.500Vp-p, 133ksps, 2.0MHz external clock, bipolar input mode) MAX14 A/MAX14 B 70 73 Signal-to-Noise + Distortion Ratio SINAD dB MAX147C 73 MAX14 A/MAX14 B -88 -80 Up to the 5th Total Harmonic Distortion THD dB harmonic MAX147C -88 MAX14 A/MAX14 B 80 90 Spurious-Free Dynamic Range SFDR dB MAX147C 90 Channel-to-Channel Crosstalk 65kHz, 2.500V (Note 4) -85 dB p-p Small-Signal Bandwidth -3dB rolloff 2.25 MHz Full-Power Bandwidth 1.0 MHz CONVERSION RATE Internal clock, SHDN = FLOAT 5.5 7.5 Conversion Time (Note 5) t s Internal clock, SHDN = V 35 65 CONV DD External clock = 2MHz, 12 clocks/conversion 6 2 MAX146/MAX147