MAX1248/MAX1249 19-1072 Rev 2 5/98 +2.7V to +5.25V, Low-Power, 4-Channel, Serial 10-Bit ADCs in QSOP-16 General Description Features The MAX1248/MAX1249 10-bit data-acquisition sys- 4-Channel Single-Ended or 2-Channel tems combine a 4-channel multiplexer, high-bandwidth Differential Inputs track/hold, and serial interface with high conversion Single +2.7V to +5.25V Operation speed and low power consumption. They operate from Internal 2.5V Reference (MAX1248) a single +2.7V to +5.25V supply, and their analog inputs are software configurable for unipolar/bipolar Low Power: 1.2mA (133ksps, +3V supply) and single-ended/differential operation. 54A (1ksps, +3V supply) The 4-wire serial interface connects directly to SPI/ 1A (power-down mode) QSPI and MICROWIRE devices without external SPI/QSPI/MICROWIRE/TMS320-Compatible logic. A serial strobe output allows direct connection 4-Wire Serial Interface to TMS320-family digital signal processors. The MAX1248/MAX1249 use either the internal clock or an Software-Configurable Unipolar or Bipolar Inputs external serial-interface clock to perform successive- 16-Pin QSOP Package (same area as 8-pin SO) approximation analog-to-digital conversions. The MAX1248 has an internal 2.5V reference, while the MAX1249 requires an external reference. Both parts have a reference-buffer amplifier with a 1.5% voltage adjustment range. Ordering Information These devices provide a hard-wired SHDN pin and a software-selectable power-down, and can be pro- INL grammed to automatically shut down at the end of a PART TEMP. RANGE PIN-PACKAGE (LSB) conversion. Accessing the serial interface automatically powers up the MAX1248/MAX1249, and the quick MAX1248ACPE 0C to +70C 16 Plastic DIP 1/2 turn-on time allows them to be shut down between all MAX1248BCPE 0C to +70C 16 Plastic DIP 1 conversions. This technique can cut supply current to MAX1248ACEE 0C to +70C 16 QSOP 1/2 under 60A at reduced sampling rates. MAX1248BCEE 0C to +70C 16 QSOP 1 The MAX1248/MAX1249 are available in a 16-pin DIP Ordering Information continued at end of data sheet. and a very small QSOP that occupies the same board Contact factory for availability of alternate surface-mount area as an 8-pin SO. packages. For 8-channel versions of these devices, see the MAX148/MAX149 data sheet. Applications Typical Operating Circuit Portable Data Logging Data Acquisition +3V Medical Instruments Battery-Powered Instruments V CH0 V DD DD Pen Digitizers System Supervision C3 0.1F 0V TO DGND +2.5V ANALOG MAX1248 INPUTS AGND CPU CH3 COM I/O CS Pin Configuration appears at end of data sheet. SCLK SCK (SK) VREF DIN MOSI (SO) C1 4.7F DOUT MISO (SI) SSTRB REFADJ V SS SHDN C2 0.01F SPI and QSPI are trademarks of Motorola, Inc. MICROWIRE is a trademark of National Semiconductor Corp. Maxim Integrated Products 1 For free samples & the latest literature: +2.7V to +5.25V, Low-Power, 4-Channel, Serial 10-Bit ADCs in QSOP-16 ABSOLUTE MAXIMUM RATINGS V to AGND, DGND .............................................. -0.3V to +6V QSOP (derate 8.30mW/C above +70C)................... 667mW DD AGND to DGND.................................................... -0.3V to +0.3V CERDIP (derate 10.00mW/C above +70C).............. 800mW CH0CH3, COM to AGND, DGND ............ -0.3V to (V + 0.3V) Operating Temperature Ranges DD VREF to AGND........................................... -0.3V to (V + 0.3V) MAX1248 C E/MAX1249 C E .......................... 0C to +70C DD Digital Inputs to DGND............................................ -0.3V to +6V MAX1248 E E/MAX1249 E E........................ -40C to +85C Digital Outputs to DGND ........................... -0.3V to (V + 0.3V) MAX1248 MJE/MAX1249 MJE .................... -55C to +125C DD Digital Output Sink Current .................................................25mA Storage Temperature Range ............................ -60C to +150C Continuous Power Dissipation (T = +70C) Lead Temperature (soldering, 10sec) ............................ +300C A Plastic DIP (derate 10.53mW/C above +70C) ......... 842mW 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 +5.25V COM = 0V f = 2.0MHz external clock (50% duty cycle) 15 clocks/conversion cycle (133ksps) DD SCLK MAX12484.7F capacitor at VREF pin MAX1249external reference, VREF = 2.500V applied to VREF pin T = T to T , A MIN MAX unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC ACCURACY (Note 1) Resolution 10 Bits MAX124 A 0.5 Relative Accuracy (Note 2) INL LSB MAX124 B 1.0 Differential Nonlinearity DNL No missing codes over temperature 1 LSB MAX124 A 1 Offset Error LSB MAX124 B 2 MAX124 A 1 Gain Error (Note 3) LSB MAX124 B 2 Gain Temperature Coefficient 0.25 ppm/C Channel-to-Channel Offset 0.05 LSB Matching DYNAMIC SPECIFICATIONS (10kHz sine-wave input, 0V to 2.500Vp-p, 133ksps, 2.0MHz external clock, bipolar input mode) Signal-to-Noise + Distortion Ratio SINAD 66 dB Total Harmonic Distortion THD Up to the 5th harmonic -70 dB Spurious-Free Dynamic Range SFDR 70 dB Channel-to-Channel Crosstalk 65kHz, 2.500Vp-p (Note 4) -75 dB 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 Internal clock, SHDN = V 35 65 s CONV DD External clock = 2MHz, 12 clocks/conversion 6 Track/Hold Acquisition Time t 1.5 s ACQ Aperture Delay 30 ns Aperture Jitter <50 ps SHDN = FLOAT 1.8 Internal Clock Frequency MHz SHDN = V 0.225 DD 0.1 2.0 External Clock Frequency MHz Data transfer only 0 2.0 2 MAX1248/MAX1249