MAX125/MAX126 19-1319 Rev 3 7/08 2x4-Channel, Simultaneous-Sampling 14-Bit DAS General Description Features The MAX125/MAX126 are high-speed, multichannel, Four Simultaneous-Sampling T/H Amplifiers with 14-bit data-acquisition systems (DAS) with simultaneous Two Multiplexed Inputs (eight single-ended inputs track/holds (T/Hs). These devices contain a 14-bit, 3s, total) successive-approximation analog-to-digital converter 3s Conversion Time per Channel (ADC), a +2.5V reference, a buffered reference input, and a bank of four simultaneous-sampling T/H ampli- Throughput: 250ksps (1 channel) fiers that preserve the relative phase information of the 142ksps (2 channels) sampled inputs. The MAX125/MAX126 have two multi- 100ksps (3 channels) plexed inputs for each T/H, allowing a total of eight 76ksps (4 channels) inputs. In addition, the converter is overvoltage tolerant to 17V a fault condition on any channel will not harm Input Range: 5V (MAX125) the IC. Available input ranges are 5V (MAX125) and 2.5V (MAX126) 2.5V (MAX126). Fault-Protected Input Multiplexer (17V) An on-board sequencer converts one to four channels 5V Supplies per CONVST pulse. In the default mode, one T/H output (CH1A) is converted. An interrupt signal (INT) is provided Internal +2.5V or External Reference Operation after the last conversion is complete. Convert two, Programmable On-Board Sequencer three, or four channels by reprogramming the MAX125/MAX126 through the bidirectional parallel High-Speed Parallel DSP Interface interface. Once programmed, the MAX125/MAX126 continue to convert the specified number of channels per CONVST pulse until they are reprogrammed. The channels are converted sequentially, beginning with CH1. The INT signal always follows the end of the last Ordering Information conversion in a conversion sequence. The ADC con- verts each assigned channel in 3s and stores the INL result in an internal 14x4 RAM. Upon completion of the PART TEMP RANGE PIN-PACKAGE (LSB) conversions, data can be accessed by applying suc- cessive pulses to the RD pin. Four successive reads MAX125CCAX 0C to +70C 36 SSOP 4 access four data words sequentially. MAX125CEAX -40C to +85C 36 SSOP 4 The parallel interfaces data-access and bus-release MAX126CCAX 0C to +70C 36 SSOP 4 timing specifications are compatible with most popular MAX126CEAX -40C to +85C 36 SSOP 4 digital signal processors and 16-bit/32-bit microproces- sors, so the MAX125/MAX126 conversion results can be accessed without resorting to wait states. Applications Multiphase Motor Control Power-Grid Synchronization Power-Factor Monitoring Typical Operating Circuit appears at end of data sheet. Digital Signal Processing Vibration and Waveform Analysis Pin Configuration appears at end of data sheet. 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EVALUATION KIT AVAILABLE2x4-Channel, Simultaneous-Sampling 14-Bit DAS ABSOLUTE MAXIMUM RATINGS AV to AGND ...........................................................-0.3V to 6V Continuous Power Dissipation (T = +70C) DD A AV to AGND ............................................................0.3V to -6V SSOP (derate 11.8mW/C above +70C) ....................941mW SS DV to DGND ...........................................................-0.3V to 6V Operating Temperature Ranges DD AGND to DGND.......................................................-0.3V to 0.3V MAX125CCAX/MAX126CCAX ............................0C to +70C CH to AGND....................................................................17V MAX125CEAX/MAX126CEAX..........................-40C to +85C REFIN, REFOUT to AGND ..........................................-0.3V to 6V Storage Temperature Range .............................-65C to +150C Digital Inputs/Outputs to DGND ..............-0.3V to (DV + 0.3V) Lead Temperature (soldering, 10sec)................................300C DD 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 (AV = +5V 5%, AV = -5V 5%, DV = +5V 5%, V = 2.5V, AGND = DGND = 0V, 4.7F capacitor from REFOUT to DD SS DD REFIN AGND, 0.1F capacitor from REFIN to AGND, f = 16MHz, external clock, 50% duty cycle, T = T to T , unless otherwise CLK A MIN MAX noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC ACCURACY (Note 1) Resolution N All channels 14 Bits Integral Nonlinearity INL (Note 2) 2 4 LSB No Missing Codes 13 Bits T = +25C 5 15 A Bipolar Zero Error mV T T to T 25 A = MIN MAX Bipolar Zero-Error Match Between all channels 1.2 5 mV Zero-Code Tempco 5 ppm/C T = +25C 5 10 A Gain Error mV T T to T 15 A = MIN MAX Gain-Error Match Between all channels 1.2 5 mV Gain-Error Tempco 5 ppm/C DYNAMIC PERFORMANCE (f = 16MHz, f = 10.06kHz (Notes 1, 3) CLK IN Single-channel mode, MAX125 72 75 Signal-to-Noise Plus Distortion SINAD dB channel 1A, 250ksps (Note MAX126 70 72 4) Single-channel mode, channel 1A, Total Harmonic Distortion THD -89 -80 dB 250ksps (Notes 4, 5) Single-channel mode, channel 1A, Spurious-Free Dynamic Range SFDR 80 90 dB 250ksps (Note 4) Single-channel mode, channel 1A, Channel-to-Channel Isolation 80 dB 250ksps (Note 6) 2 MAX125/MAX126