MAX1270BENG
MAX1270BENG - 12-Bit, 8-Ch, +5V Multirange Serial ADC | Maxim
The Analog Devices (formerly Maxim Integrated Products) MAX1270BENG is a multirange, +5V, 8-channel, serial 12-bit successive-approximation analog-to-digital converter (ADC) housed in a 24-pin PDIP (N) package. It integrates an 8-channel analog multiplexer with ±17V fault-protected inputs, a 5MHz bandwidth track/hold, software-selectable internal/external clock, 110 ksps throughput, and an internal 4.096V reference (with external reference support). The SPI/QSPI/MICROWIRE-compatible serial interface connects directly to host microcontrollers without external glue logic, simplifying layout in data-acquisition front ends.
A successive-approximation register (SAR) ADC is a type of data converter that performs a binary search against the analog input using an internal DAC and comparator, producing one code per N conversion cycles. SAR ADCs offer deterministic throughput, low latency (no pipeline delay), and excellent DC accuracy. Within the broader converter hierarchy, the MAX1270BENG sits as a 12-bit precision SAR ADC \u2192 general-purpose data-acquisition ADC \u2192 mixed-signal IC \u2192 semiconductor. It is engineered for embedded systems requiring simultaneous multi-channel, high-impedance signal digitization.
Key features include bipolar input ranges (0\u201310V, 0\u20135V, \u00b15V, \u00b110V) software-configurable per channel, ±17V over-voltage protection without external clamping, internal 4.096V reference with external-reference option, single +5V supply operation, low +5V supply current of typically 1mA in operating mode, and a hardware-/software-shutdown mode that drops current below 10\u03bcA. The internal MUX-and-track/hold front end supports true-differential signal acquisition across the eight channels while keeping channel-to-channel crosstalk low.
The MAX1270BENG operates from a single +5V supply and accepts analog inputs that span above the power-supply rail, enabling direct connection to industrial sensors and process signals. The bipolar +5V/-5V bipolar analog inputs allow interfacing with legacy \u00b110V industrial transducers, PLC analog modules, and instrumentation amplifiers. An on-chip 4.096V reference (50 ppm/\u00b0C typical drift) eliminates the need for an external reference in cost-sensitive designs while still allowing an external reference for high-accuracy systems. The internal/external clock mode lets designers trade conversion determinism for software simplicity. Industry-compliant design alternatives span RoHS-compliant and lead-free variants of the same die, ensuring long-term supply continuity.
Typical applications include industrial process control and PLC analog input modules, multichannel data-acquisition systems, data loggers, embedded sensor front ends, instrumentation and test equipment, and medical/patient-monitoring equipment. The ±17V fault protection is particularly valuable in harsh industrial environments where transients and miswiring are common, since it lets designers omit external protection diodes and TVS clamps on every analog input line.
When designing with the MAX1270BENG, place the +5V supply decoupling capacitors (0.1\u03bcF ceramic in parallel with 10\u03bcF tantalum/ceramic) within 5 mm of the AVDD and AGND pins. Keep analog and digital ground returns separated and join them in one star-point near the ADC. For best noise performance, the analog inputs should be driven by low-impedance buffers (op-amp output impedance < 100\u03a9 at the signal bandwidth) since the internal MUX and track/hold present a switched-capacitor load that draws transient current at each conversion. Allow at least 1\u03bcs settling time after MUX channel changes before initiating a conversion to avoid channel-to-channel crosstalk.
This page synthesizes distributor pricing, parametric drop-in alternatives (MAX1270AENG, MAX1270BCNG, MAX1270BCAI), and practical design notes that are not found in the manufacturer datasheet alone \u2014 useful for engineers evaluating the MAX1270BENG for new designs and for those maintaining existing MAX1270-based hardware.
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