MAX1139KEEE+ - 10-Bit 12-Ch SAR ADC, I2C, 16-QSOP | Maxim Integrated
MPN: MAX1139KEEE+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $8.1 | $8.10 |
| 10 | $7.2 | $72.00 |
| 100 | $6.05 | $605.00 |
| 500 | $5.2 | $2,600.00 |
| 1,000 | $4.45 | $4,450.00 |
MAX1139KEEE+ Overview
An SAR (Successive Approximation Register) ADC is a type of analog-to-digital converter that uses a binary search algorithm through an internal capacitive DAC to convert an analog input to a digital code in N conversion cycles for N bits of resolution. SAR ADCs are prized for low power consumption, deterministic latency, and excellent DC accuracy, making them a cornerstone architecture for multi-channel data-acquisition systems, sensor monitoring, and industrial control loops where a single ADC must sequentially scan many analog signals.
Key features of the MAX1139KEEE+ include 117ksps maximum sampling rate (K-grade), I2C-compatible 2-wire serial interface (Fast Mode 400kHz), six analog input channels configurable as 6 single-ended or 3 differential inputs (12 total input pins), internal 4.096V voltage reference (K/M variants), low 670µA supply current at maximum sampling rate, and 1µA power-down current. The wide supply range lets the same part serve both 3.3V and 5V digital systems without level shifters.
The architecture combines an input track/hold, a 10-bit charge-redistribution DAC, a comparator, and an internal 4.096V bandgap reference. The I2C address is factory-set (with 16 possible addresses) and the device supports both Standard Mode (100kHz) and Fast Mode (400kHz). The QSOP-16 package has a thermal resistance of approximately 150°C/W and is specified for the -40°C to +85°C extended industrial temperature range.
Typical applications include portable data logging, patient monitoring, battery-powered instrumentation, HVAC sensor arrays, and process control. The 12 single-ended / 6 differential input channels make the part especially attractive for scanning multi-sensor arrays (temperature, pressure, flow) with a single ADC. The internal reference eliminates external reference components, reducing BOM and PCB area.
When designing with this ADC, place 0.1µF bypass capacitors close to VDD and VAVDD pins, and ensure the I2C pull-ups (typically 2.2kΩ-10kΩ) are sized for the bus capacitance. The analog input impedance is high (multiplexer-based) so source-impedance effects are minimal, but a low-impedance input driver is still recommended for best AC performance.
This page synthesizes distributor pricing, verified drop-in alternatives, and practical design notes not found in the bare manufacturer datasheet. Pin-compatible 12-bit and 8-bit alternatives (MAX1239 and MAX1039 respectively) are documented in the alternatives section.
Drop-in alternatives for MAX1139KEEE+ — 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 MAX1139KEEE+ (same form factor and footprint) — differing in Package, Interface, Internal Reference, Operating Temperature, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1139LEEE+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1139MEEE+
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →MAX1139KEEE+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1239LEEE+T
✅ Drop-In✓ In Stock
$4.62 / Unit
View Datasheet →MAX1039EKA+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1039EKA+T
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1139KEEE+ Maximum Ratings & Electrical Characteristics
| Resolution | 10 bit |
| Number of Inputs | 6 / 12 (6 single-ended or 3 differential, 12 input pins) |
| Architecture | SAR (Successive Approximation Register) |
| Sampling Rate | 117 ksps (K-grade, external clock) |
| Supply Voltage | 2.7 V to 3.6 V or 4.5 V to 5.5 V |
| Supply Current (max sampling) | 670 µA |
| Power-Down Current | 1 µA |
| Internal Reference | 4.096 V (K/M grade) |
| Analog Input Range | 0 to VAVDD |
| Interface | I2C-compatible 2-wire serial (Standard 100kHz / Fast 400kHz) |
| I2C Addresses | 16 factory-set (K/M grade: 0x33-0x40 / 0x51-0x5E, L/N grade: 0x52-0x57) |
| Package | 16-pin QSOP |
| Operating Temperature | -40°C to +85°C (extended industrial) |
| Track/Hold | Internal |
| RoHS Status | Compliant |
MAX1139KEEE+ Pin Configuration
| Pin 1 | SDA — I2C serial data (open-drain, requires pull-up) |
| Pin 2 | SCL — I2C serial clock (requires pull-up) |
| Pin 3 | AIN0 — Analog input 0 |
| Pin 4 | AIN1 — Analog input 1 |
| Pin 5 | AIN2 — Analog input 2 |
| Pin 6 | AIN3 — Analog input 3 |
| Pin 7 | AIN4 — Analog input 4 |
| Pin 8 | AIN5 — Analog input 5 |
| Pin 9 | AIN6 — Analog input 6 |
| Pin 10 | AIN7 — Analog input 7 |
| Pin 11 | AIN8 — Analog input 8 |
| Pin 12 | AIN9 — Analog input 9 |
| Pin 13 | AIN10 — Analog input 10 |
| Pin 14 | AIN11 — Analog input 11 |
| Pin 15 | GND — Ground |
| Pin 16 | VDD/VAVDD — Analog and digital supply (tie together) |
Typical Applications
MAX1139KEEE+ is suitable for 6 applications: Portable Data Logging, Patient Monitoring Systems, HVAC Sensor Array Scanning, Process Control and Factory Automation, Battery-Powered Instrumentation, IoT Edge Sensor Hubs.
Portable Data Logging
The MAX1139KEEE+ is ideal for portable multi-channel data loggers where 12 analog inputs and 1µA power-down current extend battery life. Its 117 ksps sampling rate captures fast transients, while the 10-bit resolution (1024 codes, ~4mV/LSB at 4.096V reference) provides sufficient precision for temperature, voltage, and current monitoring in field-deployed environmental sensors.
Recommended
Patient Monitoring Systems
Medical monitoring equipment such as patient temperature arrays, multi-lead ECG front ends, and pulse-oximeter signal chains benefit from the MAX1139KEEE+'s 12 single-ended input channels and 1µA standby current. The internal 4.096V reference eliminates external reference components, reducing BOM for compact bedside monitors. The wide 2.7V-5.5V supply lets the same PCB run on 3.3V or 5V rails.
Recommended
HVAC Sensor Array Scanning
HVAC control boards need to scan dozens of thermistor, humidity, pressure, and airflow sensors. The MAX1139KEEE+ handles 12 inputs with internal multiplexer and 670µA supply current at full sampling, reducing per-channel power. The internal 4.096V reference provides adequate accuracy for thermistor linearization, and the QSOP-16 footprint fits compact control-panel PCBs.
Recommended
Process Control and Factory Automation
Industrial PLC analog input modules and process-control I/O use the MAX1139KEEE+ for its 12 input channels, -40°C to +85°C extended industrial temperature range, and 4.5V-5.5V supply compatibility with industrial 5V backplanes. The internal reference and track/hold simplify the analog front end, and the I2C interface minimizes GPIO usage on the host microcontroller.
Recommended
Battery-Powered Instrumentation
Handheld multimeters, portable test equipment, and field instruments use the MAX1139KEEE+ for its 1µA power-down current that allows the ADC to idle between measurement bursts, drawing essentially zero current when the host MCU sleeps. The 2.7V-3.6V supply range (L/M-grade variants) directly accepts a single Li-Ion cell (3.0V-4.2V) without a separate regulator, simplifying the power tree.
Recommended
IoT Edge Sensor Hubs
IoT edge devices aggregating temperature, light, gas, and motion sensors use the MAX1139KEEE+ to convert 12 analog signals to digital codes over I2C, freeing the host MCU's ADC for other tasks. The QSOP-16 package occupies only 30 mm² of PCB area, leaving room for radio modules and batteries. The 1µA shutdown current contributes negligibly to the IoT node's sleep budget.
Recommended
Recommended Products Summary
Engineering reference data for MAX1139KEEE+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1139LEEE+ | MAX1239LEEE+T | MAX1039EKA+ |
|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) | Analog Devices (Maxim Integrated) |
| Package | 16-QSOP | 16-QSOP - same | 16-QSOP - same | 16-QSOP - same |
| Resolution | 10 bit | 10 bit | 12 bit | 8 bit |
| Number of Input Channels | 12 (6 SE / 3 DIFF) | 12 (6 SE / 3 DIFF) | 12 (6 SE / 3 DIFF) | 12 (6 SE / 3 DIFF) |
| Maximum Sampling Rate | 117 ksps | 117 ksps | 94.4 ksps | 117 ksps |
| Supply Voltage Range | 4.5V to 5.5V (K-grade) | 2.7V to 3.6V | 2.7V to 3.6V | 2.7V to 3.6V |
| Internal Reference | 4.096 V | 2.048 V | 2.048 V | 2.048 V |
| Interface | I2C (2-wire, 400 kHz) | I2C (2-wire, 400 kHz) | I2C (2-wire, 400 kHz) | I2C (2-wire, 400 kHz) |
Key Differentiators
- 12 input channels in a small QSOP-16 package (vs MAX1136/MAX1137 8-pin µMAX variants)
- Internal 4.096V reference eliminates external reference IC (vs MAX1239LEEE+T (12-bit upgrade))
- Higher sampling rate than 12-bit upgrade variant (vs MAX1239LEEE+T)
Design Notes
Estimated: at 5.0V supply and 117 ksps continuous sampling, the MAX1139KEEE+ draws 670µA = 3.35mW. In power-down mode (between conversions), draw drops to 1µA = 5µW. For a duty-cycled application sampling once per second with a 10ms active window, average current is approximately (670µA * 0.01) + (1µA * 0.99) = 7.7µA, so a 1000mAh battery lasts over 14 years in theory. Tie VDD and VAVDD together at the IC pin with a 0.1µF bypass capacitor to ground, placed within 5mm of the package.
Place 0.1µF ceramic bypass capacitors as close as possible to both VDD and VAVDD pins (within 5mm). Add a 10µF bulk capacitor on the supply rail. Use a star-ground topology with the analog ground plane isolated from the digital ground beneath the QSOP package, joining at a single point near the IC. Route analog input traces away from the SDA/SCL clock edges to avoid digital switching noise coupling into the analog front end.
Do not leave unused analog inputs floating - tie them to mid-supply or ground through a 100kΩ resistor to prevent charge accumulation that can couple into adjacent active channels. The I2C bus requires external pull-up resistors (2.2kΩ-10kΩ depending on bus capacitance and speed); the MAX1139KEEE+ SDA and SCL are open-drain outputs. Do not exceed the absolute maximum analog input voltage of VAVDD + 0.3V or go below GND - 0.3V, or the input ESD diodes will forward-conduct and damage the device.
Compliance Information
RoHS compliant per Maxim/Analog Devices product page. Pb-free QSOP-16 package. Not AEC-Q100 qualified - intended for industrial, instrumentation, and consumer applications.
