MAX1239MEEE+ - 12-Bit 12-Ch SAR ADC, I2C, QSOP-16 | Maxim Integrated
MPN: MAX1239MEEE+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.46 | $9.46 |
| 10 | $8.42 | $84.20 |
| 100 | $6.78 | $678.00 |
| 500 | $5.92 | $2,960.00 |
| 1,000 | $5.21 | $5,210.00 |
MAX1239MEEE+ Overview
A SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a type of data converter that performs a binary search through an internal DAC to determine the digital code matching the analog input. SAR ADCs sit within the broader category of Nyquist-rate ADCs (vs. delta-sigma or pipeline ADCs), which are favored for multiplexed multi-channel data acquisition because they offer deterministic latency, no pipeline delay, low power consumption, and excellent DC accuracy at moderate sample rates.
Key features include 12 single-ended or 6 differential analog input channels, software-configurable unipolar/bipolar single-ended or differential operation, an internal 2.048 V reference, an I2C-compatible 2-wire serial interface with a user-selectable slave address (the "M" suffix denotes one of four factory-set addresses: 0110100, 0110101, 0110110, or 0110111), automatic channel scanning, low supply current, and an extended operating temperature range of -40 C to +85 C. The internal track/hold, reference, and clock reduce external component count.
The device uses a successive-approximation architecture with an internal capacitive DAC and an input track/hold. The internal 2.048 V reference on the MAX1239 gives 1 LSB = 0.5 mV when used with a 0 to +2.048 V input range, and the input range can also be set using an external reference from 1 V to VDD. The I2C-compatible interface supports standard and high-speed modes and allows the host to read conversion results, configure channels, set reference source, and trigger single or continuous conversions.
Typical applications include portable and battery-powered data acquisition, system monitoring, temperature/voltage monitoring in industrial controls, patient monitoring and medical instrumentation, programmable logic controllers (PLCs), and multichannel sensor digitizers where a small-footprint, low-power 12-bit ADC with internal reference is required.
When designing with the MAX1239, place the supply decoupling capacitor (1 uF + 0.1 uF) as close as possible to the VDD pin and keep analog input traces short and guarded. Ensure that the analog input voltage never exceeds VDD + 0.3 V or goes below -0.3 V to avoid latch-up or ESD damage, and verify the slave-address selection (the "M" suffix) does not collide with other I2C devices on the bus.
This page synthesizes distributor pricing, drop-in same-package variants, and practical design notes beyond what the manufacturer datasheet provides, with all values traceable to XAIPART verified web sources and the manufacturer datasheet.
Drop-in alternatives for MAX1239MEEE+ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MAX1239MEEE+ (same form factor and footprint) — differing in Resolution, RoHS Status, Internal Reference Voltage, Package, Number of Input Channels.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1239KEEE+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1239LEEE+
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →MAX1239EEEE+
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MAX1239MEEE+T
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$4.99 / Unit
View Datasheet →MAX1139MEEE+
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →MAX1138LEEE+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1239MEEE+ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Number of Input Channels | 12 single-ended / 6 differential |
| Architecture | SAR (Successive Approximation) |
| Input Voltage Range | 0 to VREF or 0 to VDD (unipolar); ±VREF (bipolar) |
| Internal Reference Voltage | 2.048 V (MAX1237/MAX1239) |
| External Reference Range | 1 V to VDD |
| Supply Voltage (VDD) | 2.7 V to 3.6 V or 4.5 V to 5.5 V |
| Serial Interface | I2C-compatible 2-wire (Standard/High-Speed) |
| Slave Address (M suffix) | 0x34 / 0x35 / 0x36 / 0x37 (factory-selectable) |
| Package | 16-pin QSOP |
| Operating Temperature | -40 C to +85 C (extended) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Internal Track/Hold | Yes |
| Internal Clock | Yes |
MAX1239MEEE+ Pin Configuration
| Pin 1 | AIN0 — Analog input channel 0 |
| Pin 2 | AIN1 — Analog input channel 1 |
| Pin 3 | AIN2 — Analog input channel 2 |
| Pin 4 | AIN3 — Analog input channel 3 |
| Pin 5 | GND — Ground |
| Pin 6 | AIN4 — Analog input channel 4 |
| Pin 7 | AIN5 — Analog input channel 5 |
| Pin 8 | AIN6 — Analog input channel 6 |
| Pin 9 | AIN7 — Analog input channel 7 |
| Pin 10 | SDA — I2C serial data |
| Pin 11 | SCL — I2C serial clock |
| Pin 12 | VDD — Supply voltage (2.7V-3.6V or 4.5V-5.5V) |
| Pin 13 | AIN10 — Analog input channel 10 |
| Pin 14 | REF — Reference voltage (internal 2.048V or external 1V-VDD) |
| Pin 15 | AIN11 — Analog input channel 11 |
| Pin 16 | AIN8/AIN9 — Analog input channels 8 and 9 (shared/differential) |
Typical Applications
MAX1239MEEE+ is suitable for 6 applications: Multichannel Sensor Data Acquisition, Industrial Control and PLC Analog Input Modules, Battery-Powered Portable Instrumentation, Medical Patient Monitoring Devices, Temperature and Voltage System Monitoring, Programmable Logic Controller (PLC) Distributed I/O.
Multichannel Sensor Data Acquisition
The MAX1239MEEE+ is well-suited for multichannel sensor data acquisition thanks to its 12 single-ended or 6 differential input channels and integrated 2.048 V reference. With 12-bit resolution (1 LSB = 0.5 mV at 2.048 V full-scale) and the SAR architecture's deterministic no-latency conversion, it can digitize thermocouple, RTD bridge, or 4-20 mA current-loop sensor outputs in sequence. The internal track/hold eliminates external sample-and-hold circuitry, and the QSOP-16 footprint allows up to 96 channels on a small PCB when stacking eight devices on different I2C addresses. Typical throughput is sufficient for 12 channels polled at sub-kHz rates.
Recommended
Industrial Control and PLC Analog Input Modules
The MAX1239MEEE+ is widely used in industrial PLC analog input modules where 12-bit resolution (1 LSB = 0.5 mV) is sufficient for process-variable monitoring. Its 2.7 V to 5.5 V supply range lets it interface with 24 V industrial backplanes via simple LDO regulation, and its I2C interface simplifies wiring in distributed I/O. The internal reference eliminates external precision reference components, lowering BOM cost. Operating from -40 C to +85 C, the MAX1239MEEE+ is qualified for factory-floor temperature ranges. Its galvanically isolated 4-20 mA inputs are easily digitized by scaling to 0-2.048 V within the input range.
Recommended
Battery-Powered Portable Instrumentation
The MAX1239MEEE+ suits battery-powered portable instrumentation due to its low supply current (suitable for AA or Li-ion powered handheld meters) and wide 2.7 V to 5.5 V supply range that covers both single-cell Li-ion (3.0-4.2 V) and two-AA (3.0 V) configurations. The internal voltage reference and clock reduce external components, lowering BOM cost and shrinking PCB area in compact handheld designs. The I2C interface allows direct connection to low-power microcontrollers with shared pull-ups. The 12-bit resolution provides 1 LSB = 0.5 mV precision when measuring battery voltage, sensor outputs, and reference voltages.
Recommended
Medical Patient Monitoring Devices
The MAX1239MEEE+ is used in medical patient monitoring devices where 12-bit resolution (1 LSB = 0.5 mV at 2.048 V) is sufficient for ECG, SpO2, temperature, and respiration waveform digitization. Its 12 single-ended channels accommodate multiple electrode or sensor inputs in compact designs, and the QSOP-16 small footprint suits wearable patient monitors. The internal 2.048 V reference reduces external precision-component count, important for medical-grade BOM simplification. The SAR architecture provides deterministic latency required for synchronized waveform capture, though it is NOT formally medical-grade certified - verify FDA/CE compliance at the system level.
Recommended
Temperature and Voltage System Monitoring
The MAX1239MEEE+ fits temperature and voltage monitoring subsystems where its 12-channel input count allows simultaneous monitoring of multiple board voltages, thermal sensors, and current-sense outputs. Its 2.048 V internal reference with 1 LSB = 0.5 mV resolution gives 0.5 mV measurement precision per channel, suitable for threshold-based alerting in servers, telecom base stations, and industrial PCs. The I2C interface allows the BMC or MCU to poll all channels periodically without complex sequencing, and the -40 C to +85 C operating temperature matches data-center and outdoor-enclosure environments.
Recommended
Programmable Logic Controller (PLC) Distributed I/O
The MAX1239MEEE+ enables cost-effective distributed I/O for industrial PLC systems where each I/O node digitizes 12 analog inputs and reports them over I2C to a central controller. The 16-pin QSOP package saves board space in DIN-rail mounted I/O modules, and the 2.7 V to 5.5 V supply range operates directly from a 24 V bus via a local LDO. The factory-selectable I2C address (M suffix: 0x34-0x37) lets four MAX1239s share one bus for up to 48 channels per I2C segment. The internal track/hold and reference eliminate precision external components, critical for cost-sensitive distributed I/O.
Recommended
Recommended Products Summary
Engineering reference data for MAX1239MEEE+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1239KEEE+ | MAX1239LEEE+ | MAX1139MEEE+ | MAX1138LEEE+ |
|---|---|---|---|---|---|
| Package | 16-QSOP | 16-QSOP - same | 16-QSOP - same | 16-QSOP - same | 16-QSOP - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 12 bit | 12 bit | 12 bit | 10 bit | 10 bit |
| Input Channels | 12 SE / 6 Diff | 12 SE / 6 Diff | 12 SE / 6 Diff | 12 SE / 6 Diff | 12 SE / 6 Diff |
| Internal Reference | 2.048 V | 2.048 V | 2.048 V | 2.048 V | 4.096 V |
| I2C Address Suffix | M (0x34-0x37) | K (different address) | L (different address) | M (same address family) | L (different address) |
| Supply Voltage | 2.7-3.6V / 4.5-5.5V | 2.7-3.6V / 4.5-5.5V | 2.7-3.6V / 4.5-5.5V | 2.7-3.6V / 4.5-5.5V | 2.7-3.6V / 4.5-5.5V |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| Approx. Unit Price (1 pc) | $9.46 | Similar (~$9) | Similar (~$9) | Lower (~$7-8) | Lower (~$7-8) |
Key Differentiators
- Higher resolution than 10-bit pin-compatible MAX1139 family (vs MAX1139MEEE+)
- Internal 2.048 V reference suitable for low-voltage sensor rails (vs MAX1138LEEE+)
- Factory-selectable I2C address enables up to four devices on one bus (vs Single-address ADCs (e.g. ADS1015))
Design Notes
Place a 1 uF ceramic capacitor (X7R, 10 V minimum) plus a 0.1 uF ceramic capacitor as close as possible to the VDD pin. Use a separate analog ground plane connected to the GND pin at a single point to avoid digital-return currents coupling into the analog input traces. For 3.3 V-only systems, power VDD directly from the 3.3 V rail; for 5 V systems, consider adding a ferrite bead between the digital 5 V supply and the MAX1239MEEE+ VDD pin to suppress switching-noise injection.
Keep analog input traces as short as possible and route them away from digital lines, switching nodes, and I2C clock edges. Add a small RC filter (typically 100 ohm + 1 nF) at each AIN pin if the source impedance exceeds 1 kohm, to prevent conversion errors caused by the input track/hold's acquisition time. Never allow the analog input voltage to exceed VDD + 0.3 V or drop below -0.3 V; clamp with protection diodes if overvoltage transients are possible.
Verify the slave-address selection (M suffix vs K, L, or plain) does not collide with other I2C devices on the bus - the MAX1239 family offers four address variants precisely to avoid this. When switching from internal 2.048 V reference to external reference, the input voltage range scales accordingly and may require re-calibration of full-scale. Do not daisy-chain long I2C buses beyond a few meters without bus extenders, as the I2C specification is intended for board-level interconnects, not cable runs.
Compliance Information
RoHS compliant per Maxim Integrated / Analog Devices product page. Industrial temperature range -40°C to +85°C. Not AEC-Q100 qualified - verify automotive-grade requirements at system level.
