MAX125_08 Datasheet, PDF (1/15 Pages) Maxim Integrated Products – 2x4-Channel, Simultaneous-Sampling 14-Bit DAS

19-1319; Rev 3; 7/08
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2x4-Channel, Simultaneous-Sampling
14-Bit DAS
General Description
The MAX125/MAX126 are high-speed, multichannel,
14-bit data-acquisition systems (DAS) with simultaneous
track/holds (T/Hs). These devices contain a 14-bit, 3µs,
successive-approximation analog-to-digital converter
(ADC), a +2.5V reference, a buffered reference input,
and a bank of four simultaneous-sampling T/H ampli-
fiers that preserve the relative phase information of the
sampled inputs. The MAX125/MAX126 have two multi-
plexed inputs for each T/H, allowing a total of eight
inputs. In addition, the converter is overvoltage tolerant
to ±17V; a fault condition on any channel will not harm
the IC. Available input ranges are ±5V (MAX125) and
±2.5V (MAX126).
An on-board sequencer converts one to four channels
per CONVST pulse. In the default mode, one T/H output
(CH1A) is converted. An interrupt signal (INT) is provided
after the last conversion is complete. Convert two,
three, or four channels by reprogramming the
MAX125/MAX126 through the bidirectional parallel
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
conversion in a conversion sequence. The ADC con-
verts each assigned channel in 3µs and stores the
result in an internal 14x4 RAM. Upon completion of the
conversions, data can be accessed by applying suc-
cessive pulses to the RD pin. Four successive reads
access four data words sequentially.
The parallel interface’s data-access and bus-release
timing specifications are compatible with most popular
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
Digital Signal Processing
Vibration and Waveform Analysis
Features
♦ Four Simultaneous-Sampling T/H Amplifiers with
Two Multiplexed Inputs (eight single-ended inputs
total)
♦ 3µs Conversion Time per Channel
♦ Throughput: 250ksps (1 channel)
142ksps (2 channels)
100ksps (3 channels)
76ksps (4 channels)
♦ Input Range: ±5V (MAX125)
±2.5V (MAX126)
♦ Fault-Protected Input Multiplexer (±17V)
♦ ±5V Supplies
♦ Internal +2.5V or External Reference Operation
♦ Programmable On-Board Sequencer
♦ High-Speed Parallel DSP Interface
Ordering Information
PART
TEMP RANGE
MAX125CCAX
MAX125CEAX
MAX126CCAX
MAX126CEAX
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
36 SSOP
36 SSOP
36 SSOP
36 SSOP
INL
(LSB)
±4
±4
±4
±4
Typical Operating Circuit appears at end of data sheet.
Pin Configuration appears at end of data sheet.
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