MAX1270ACNG - 12-Bit 8-Ch 110kSPS SPI ADC | Maxim Integrated
MPN: MAX1270ACNG ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $21.75 | $21.75 |
| 10 | $19.58 | $195.80 |
| 100 | $17.4 | $1,740.00 |
| 500 | $15.66 | $7,830.00 |
| 1,000 | $13.92 | $13,920.00 |
MAX1270ACNG Overview
What is a multirange SAR ADC? A successive-approximation register (SAR) ADC converts analog inputs to digital codes one bit per clock cycle using an internal comparator and a binary-weighted capacitor network. The "multirange" designation means the MAX1270's input range is software-configurable per channel between 0 to VREF, 0 to VREF/2, ±VREF, and ±VREF/2, allowing the same part to digitize single-ended unipolar, single-ended bipolar, and differential signals without external signal conditioning. SAR ADCs sit at the lowest latency tier of precision ADCs and are ubiquitous in industrial data-acquisition systems (DAS), instrumentation, and process control.
Key features include ±17 V fault-protected analog inputs (analog signals can exceed the supply without damaging the part), four software-selectable input ranges, internal 4.096 V reference (VREF) with optional external reference override, software-selectable unipolar/bipolar conversion modes, and an internal/external serial-clock option. The 1/2LSB linearity specification provides accurate 12-bit conversion without missing codes, while the single +5 V supply simplifies analog and digital power-rail design.
The MAX1270 architecture combines an on-chip input protection network, an 8-to-1 analog multiplexer, a 5 MHz track/hold, and a charge-redistribution SAR core with a serial output register. Internal scaling for the bipolar ranges is performed with a matched resistor network referenced to the internal 4.096 V reference, eliminating external precision resistors. The serial interface operates from SCLK up to the throughput limit and provides three-wire compatibility with common microcontroller and DSP serial peripherals.
Typical applications include industrial process control and data acquisition, multi-loop programmable logic controllers (PLCs), battery-powered instrumentation, signal conditioning for sensors and transducers, multichannel data loggers, and embedded industrial control. The wide ±17 V fault-tolerant input range makes it especially useful when signals come from external transducers that may be mis-wired or transient-overloaded.
When designing with the MAX1270, observe the supply decoupling recommendations in the Typical Operating Circuit: a 0.1 µF ceramic bypass capacitor close to VDD, a bulk tantalum or ceramic on AVDD, and a low-impedance ground return. Ensure SCLK noise does not couple into the analog input path through ground inductance. Bipolar input signals must observe the 17 V fault tolerance limit, not the absolute maximum, to avoid damage to the input protection network over time.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found in the manufacturer datasheet alone, helping procurement and design engineers evaluate the MAX1270ACNG against its MAX1270 family variants and modern 24-pin PDIP pin-compatible replacements.
Drop-in alternatives for MAX1270ACNG — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1270BCNG+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1270AENG+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1271BENG+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1270ACNG Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits |
| Number of Channels | 8 |
| Architecture | SAR (Successive Approximation) |
| Throughput / Sample Rate | 110 kSPS |
| Input Type | Single-Ended, software-selectable unipolar/bipolar |
| Supply Voltage | +5 V single supply |
| Analog Input Range (per channel, software-selectable) | 0 to VREF, 0 to VREF/2, ±VREF, ±VREF/2 |
| Internal Reference Voltage | 4.096 V |
| External Reference Option | Yes |
| Fault-Protected Analog Input Voltage | ±17 V (signals may exceed supply without damage) |
| Linearity (DNL) | ±1/2 LSB (max, no missing codes) |
| Track/Hold Bandwidth | 5 MHz |
| Serial Interface | SPI / QSPI / MICROWIRE-compatible 3-wire |
| Internal / External Clock | Software-selectable |
| Package | 24-pin PDIP (N) |
| Mounting Type | Through-Hole |
| Operating Temperature Range | 0°C to +70°C (commercial) |
| RoHS Status | Compliant (with + suffix) |
MAX1270ACNG Pin Configuration
| Pin 1 | CH0 — Analog input channel 0 |
| Pin 2 | CH1 — Analog input channel 1 |
| Pin 3 | CH2 — Analog input channel 2 |
| Pin 4 | CH3 — Analog input channel 3 |
| Pin 5 | CH4 — Analog input channel 4 |
| Pin 6 | CH5 — Analog input channel 5 |
| Pin 7 | CH6 — Analog input channel 6 |
| Pin 8 | CH7 — Analog input channel 7 |
| Pin 9 | AGND — Analog ground |
| Pin 10 | REF — Reference voltage (internal 4.096 V or external override) |
| Pin 11 | REFADJ — Reference adjust / bypass |
| Pin 12 | AVDD — Analog +5 V supply |
| Pin 13 | DGND — Digital ground |
| Pin 14 | DVD — Digital +5 V supply |
| Pin 15 | DOUT — Serial data output |
| Pin 16 | SSTRB — Serial status strobe (conversion complete) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | SCLK — Serial clock input |
| Pin 19 | DIN — Serial data input |
| Pin 20 | CS — Chip select (active low) |
| Pin 21 | SHDN — Shutdown input (active low) |
| Pin 22 | NC — Not connected (per datasheet) |
| Pin 23 | NC — Not connected (per datasheet) |
| Pin 24 | NC — Not connected (per datasheet) |
Typical Applications
MAX1270ACNG is suitable for 6 applications: Industrial Process Control & Data Acquisition, Multi-Loop PLC Backplane Digitizer, Battery-Powered Field Instrumentation, Sensor Signal Conditioning & Multiplexing, Multichannel Data Loggers, Embedded Industrial Control.
Industrial Process Control & Data Acquisition
The MAX1270ACNG is widely used in industrial process-control front ends where multi-channel analog signals from transducers must be digitized for PLC backplane processing. Its 8 single-ended input channels and software-selectable input ranges (0 to VREF, 0 to VREF/2, ±VREF, ±VREF/2) eliminate the external signal-conditioning resistor networks typically required to scale 4-20 mA loops, thermocouple millivolts, and bridge sensors. The ±17 V fault-protected analog inputs tolerate mis-wired field wiring and ESD events common in factory-floor installations, while 110 kSPS throughput is more than sufficient for the typical 10-100 Hz loop scan rates found in PID controllers and SCADA remote terminal units (RTUs).
Recommended
Multi-Loop PLC Backplane Digitizer
In PLC analog-input modules, the MAX1270ACNG digitizes 4-20 mA current loops from field sensors by interfacing directly to shunt resistors across each channel. The 110 kSPS throughput supports simultaneous scanning of up to 8 loops at typical 1 kHz loop update rates with substantial oversampling margin for digital filtering. The SPI-compatible 3-wire serial port is optimized for direct connection to PLC backplane microcontrollers such as the Maxim MAXQ2000 or industrial DSPs, eliminating external logic. The +5 V single-supply operation matches the PLC backplane rail and the 24-pin PDIP package supports standard IC sockets for field-replaceable serviceability in industrial automation panels.
Recommended
Battery-Powered Field Instrumentation
Portable field instruments benefit from the MAX1270ACNG's single +5 V supply and software-configurable input scaling, allowing a single part to handle both unipolar (0 to 10 V) and bipolar (±5 V) transducer outputs without a boost converter or negative rail. The 110 kSPS throughput is appropriate for sensor sampling rates in portable vibration, strain-gage, and environmental monitoring instruments. Combined with the MAX1270's automatic power-down between conversions (achieving microampere-level standby), the part is a good fit for handheld multimeters and remote data loggers where total system current draw directly determines battery life.
Recommended
Sensor Signal Conditioning & Multiplexing
The MAX1270ACNG integrates an 8-channel analog input multiplexer directly into the ADC, eliminating external MUX chips for typical multi-sensor measurement applications. For thermocouple, RTD, and bridge-sensor conditioning, the on-chip input range switching allows the same part to handle both millivolt-level (VREF/2 range) and 0-10 V (VREF range) inputs sequentially. The internal 4.096 V reference with external override allows users to ratiometric-reference against a bridge excitation voltage for improved stability, while the ±17 V fault protection tolerates common-mode overvoltage events from sensor wiring errors in instrumentation systems.
Recommended
Multichannel Data Loggers
Data loggers requiring eight or fewer analog input channels are well served by the MAX1270ACNG, which provides 110 kSPS burst-mode conversion with on-chip FIFO buffering through the SPI/QSPI-compatible 3-wire serial interface. The internal track/hold with 5 MHz bandwidth preserves signal fidelity for transient capture, while the 12-bit resolution is appropriate for general-purpose logging of temperature, pressure, flow, and level signals. The 24-pin PDIP package simplifies breadboard and through-hole prototype construction, and the +5 V single-supply operation matches typical logger power architectures using USB or battery inputs.
Recommended
Embedded Industrial Control
Embedded industrial controllers that digitize analog setpoints, sensor feedback, and actuator outputs use the MAX1270ACNG as a compact 8-channel ADC front end. The SPI-compatible interface connects directly to popular industrial embedded microcontrollers and DSPs (such as the TI C2000 or Maxim MAXQ families) for real-time control loops. The +5 V single-supply operation, software-selectable bipolar input ranges, and ±17 V fault protection allow direct connection to industrial sensors with minimal external protection circuitry, reducing total BOM and board area in space-constrained embedded designs.
Recommended
Recommended Products Summary
Engineering reference data for MAX1270ACNG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1270BCNG+ | MAX1270AENG+ | MAX1271BENG+ |
|---|---|---|---|---|
| Brand | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) | Analog Devices (Maxim) |
| Package | 24-pin PDIP (N) | 24-pin PDIP (N) - same | 24-pin PDIP (N) - same | 24-pin PDIP (N) - same |
| Resolution | 12-bit | 12-bit | 12-bit | 12-bit |
| Number of Channels | 8 single-ended | 8 single-ended | 8 single-ended | 8 single-ended |
| Sample Rate | 110 kSPS | 110 kSPS | 110 kSPS | 110 kSPS |
| Supply Voltage | +5 V single | +5 V single | +5 V single | +5 V single |
| Operating Temperature | 0C to +70C (commercial) | 0C to +70C (commercial) | -40C to +85C (industrial) | -40C to +85C (industrial) |
| Serial Interface | SPI/QSPI/MICROWIRE 3-wire | SPI/QSPI/MICROWIRE 3-wire | SPI/QSPI/MICROWIRE 3-wire | SPI/QSPI/MICROWIRE 3-wire |
Key Differentiators
- Eight channels integrated in one power device with software-selectable input ranges per channel (vs MAX1270BCNG+ (B-grade))
- Commercial temperature range at lower cost vs industrial-temperature variants (vs MAX1270AENG+ (industrial))
- Through-hole 24-pin PDIP simplifies prototype and field-replaceable designs (vs MAX1068AEEG+ (24-pin SSOP))
Design Notes
Place a 0.1 µF ceramic bypass capacitor as close as possible to the AVDD and DVDD pins (pins 12 and 14 respectively in 24-pin PDIP). Add a 10 µF bulk tantalum or ceramic capacitor on AVDD for low-frequency noise suppression. The MAX1270 draws only a few milliamps from AVDD during conversion and ~1 µA in shutdown mode, so power-rail noise from nearby digital logic can couple into the analog conversion if decoupling is inadequate. Estimated: total AVDD current at 110 kSPS is approximately 1.5 mA typical.
Route analog input traces away from digital clock traces (especially SCLK on pin 18) and keep the analog and digital ground returns separated, joining them at a single point at the AGND/DGND pins (9 and 13). The 24-pin PDIP footprint allows generous trace spacing for through-hole designs; for multilayer SMT conversions use a ground plane under the analog input traces. The ±17 V fault-protected inputs tolerate wiring overvoltage, but capacitor bypass to ground is still recommended on each analog input for high-impedance sensor connections.
Do not exceed ±17 V on any analog input pin even with fault protection - the protection network relies on clamping diodes and prolonged exposure at the fault limit can degrade the part over time. Always observe the datasheet absolute maximum ratings section. When using an external reference on the REF pin (pin 10), add a 0.1 µF ceramic bypass capacitor to AGND to prevent reference instability. The MAX1270 requires a minimum SCLK pulse width for reliable serial communication at the 110 kSPS throughput limit.
Use a star-ground topology with the MAX1270's AGND/DGND as the central ground reference, with analog and digital returns rejoined at the IC. Keep digital SCLK and DOUT traces short and series-terminated at the MAX1270 end if trace length exceeds 50 mm. The internal 4.096 V reference is shared with the input scaling for all eight channels, so reference noise appears as common-mode error - bypass the REF pin heavily and consider external reference for precision applications.
Compliance Information
RoHS and REACH compliant per the + suffix designation standard Maxim Integrated marking; lead-free reflow-compatible per the + suffix. Not AEC-Q100 qualified - the MAX1270ACNG is intended for industrial/commercial use, not automotive. Halogen-free status not stated in the verified web data - confirm with manufacturer if required.
