MAX1238EEE/V+ - 12-Bit 12-Ch 94.4ksps SAR ADC | Maxim Integrated
MPN: MAX1238EEE/V+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.5 | $9.50 |
| 10 | $8.55 | $85.50 |
| 100 | $7.41 | $741.00 |
| 500 | $6.2 | $3,100.00 |
| 1,000 | $5.1 | $5,100.00 |
MAX1238EEE/V+ Overview
A SAR ADC is a converter architecture that uses a binary-weighted capacitor network and a comparator to resolve each input sample in N clock cycles, where N is the resolution in bits. It belongs to the data-acquisition IC family, sitting between precision analog front ends and digital microcontrollers; the taxonomy runs SAR ADC -> ADC -> data converter -> data acquisition IC -> mixed-signal IC. This category matters because SAR ADCs offer deterministic latency, no-pipeline-delay sampling, and very low power, making them the workhorse for multiplexed sensor reading in industrial and instrumentation systems.
Key specifications include 12 input channels (configurable as 6 or 12 single-ended or pseudo-differential pairs), ±1 LSB INL and DNL, an internal 4.096 V reference (±1% accuracy per Maxim datasheet), and 2-wire serial compatibility at clock rates up to 400 kHz (Fast-Mode). The 16-QSOP exposed-pad version provides a low thermal-resistance path to PCB copper, allowing the part to dissipate internally generated heat during continuous 94.4 ksps bursts.
Internally, the device combines a high-impedance input mux, the SAR logic core, an auto-shutdown mode that drops supply current to 1.5 µA between conversions, and a configurable scan mode that sequentially cycles through selected channels and stores results in the I²C-accessible register map. The /V suffix denotes the automotive-grade operating range (-40 °C to +125 °C), distinguishing it from the commercial MAX1238EEE+.
Typical applications include industrial process-control sensor multiplexing, portable data loggers, patient-monitoring front ends, factory-automation PLC analog input modules, and HVAC environmental sensor hubs. The wide analog input range (0 to VREF when internal reference is used, or up to VDD with external reference) supports direct connection to 4-20 mA loop shunts, thermistor dividers, and bridge sensors. When designing with this part, place the 0.1 µF and 10 µF decoupling capacitors within 5 mm of AVDD/DVDD pins, and follow Maxim's QSOP thermal-pad layout to keep junction temperature within the /V grade's 125 °C ceiling under worst-case 5.5 V × 670 µA continuous sampling.
This page synthesizes distributor pricing for the /V automotive-grade variant, drop-in cross-reference parts from the same MAX1236-MAX1239 family, and practical design notes not bundled in the manufacturer datasheet.
Drop-in alternatives for MAX1238EEE/V+ — 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 MAX1238EEE/V+ (same form factor and footprint) — differing in Package.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX1238EEE+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1236EEE+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1236CEE+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1237KEUA+
✅ Drop-In✓ In Stock
$4.49 / Unit
View Datasheet →MAX1238EEE/V+ Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit |
| Number of Input Channels | 6 or 12 (single-ended / pseudo-differential) |
| Architecture | Successive Approximation (SAR) |
| Sampling Rate (max) | 94.4 ksps |
| Supply Voltage (analog) | 4.5 V to 5.5 V |
| Supply Current (max sampling) | 670 µA |
| Shutdown Supply Current | 1.5 µA |
| Internal Reference Voltage | 4.096 V |
| Integral Nonlinearity (INL) | ±1 LSB (max) |
| Differential Nonlinearity (DNL) | ±1 LSB (max) |
| Digital Interface | I²C-compatible 2-wire serial, up to 400 kHz Fast-Mode |
| Package | 16-pin QSOP |
| Operating Temperature Range | -40 °C to +125 °C (automotive /V grade) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
MAX1238EEE/V+ 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 | AVDD — Analog supply voltage (4.5 V to 5.5 V) |
| Pin 6 | REF — Internal 4.096 V reference / external reference input |
| Pin 7 | GND — Ground reference |
| Pin 8 | SHDN — Shutdown input (active low - per datasheet) |
| Pin 9 | ADD0 — I²C slave address select |
| Pin 10 | SDA — I²C serial data (bidirectional) |
| Pin 11 | SCL — I²C serial clock |
| Pin 12 | DVDD — Digital supply voltage |
| Pin 13 | DGND — Digital ground |
| Pin 14 | AIN4 — Analog input channel 4 |
| Pin 15 | AIN5 — Analog input channel 5 |
| Pin 16 | EP — Exposed thermal pad (connect to GND) |
Typical Applications
MAX1238EEE/V+ is suitable for 6 applications: Industrial Process Control Sensor Multiplexing, Portable Data Logger / Field Instrumentation, Patient Monitoring Front End, Factory Automation PLC Analog Input Module, HVAC Environmental Sensor Hub, Battery-Operated Multi-Sensor IoT Edge Node.
Industrial Process Control Sensor Multiplexing
The MAX1238EEE/V+ scans 12 thermocouple, RTD, or pressure-sensor channels at 94.4 ksps while drawing only 670 µA. Its 4.5V to 5.5V analog supply interfaces directly to 4-20 mA loop shunts terminated at 250 Ω for 1-5V input, while the I²C 2-wire serial interface streams results to a host MCU. Compared with discrete ADCs per channel, the integrated mux eliminates eight external components and the 1.5 µA shutdown current between scan cycles cuts idle power to negligible levels - critical in PLC modules that loop-cycle through field-sensor arrays every 100 ms.
Recommended
Portable Data Logger / Field Instrumentation
Battery-powered data loggers benefit from the MAX1238EEE/V+ because the auto-scan mode and 1.5 µA shutdown current let a 9 V or Li-ion source run for weeks while continuously digitizing temperature, humidity, and strain-gauge channels. The 12-bit result and 4.096 V internal reference provide enough dynamic range for environmental monitoring without an external precision reference, and the QSOP-16 footprint keeps the analog section under 30 mm² on a 2-layer PCB. This makes it ideal for handheld multi-sensor instruments where power, board area, and channel count all compete for budget.
Recommended
Patient Monitoring Front End
Patient monitors require simultaneous digitization of ECG, SpO2, respiration, and temperature signals with medical-grade accuracy. The MAX1238EEE/V+ pairs its 12-bit resolution and 94.4 ksps burst rate with the /V-grade -40 °C to +125 °C temperature range needed for clinical environments. The internal 4.096 V reference simplifies medical-isolation barriers by removing the high-precision analog reference wire, and the I²C interface keeps the patient-connected digital side optically isolated to a single SDA/SCL pair, reducing creepage-distance challenges on the medical-isolation transformer.
Recommended
Factory Automation PLC Analog Input Module
PLC analog-input modules typically accept 8 to 16 channels of 4-20 mA loops or ±10 V field signals, exactly the input range the MAX1238EEE/V+ covers when paired with a front-end resistor divider. The automotive-grade /V temperature rating lets a single design serve cabinet-internal and cabinet-external installations, and the QSOP-16 exposed-pad package drops onto a heat-spreader copper pour to handle the 670 µA continuous current at 5 V. The I²C bus further reduces pin count at the CPU interface, freeing MCU GPIO for digital I/O.
Recommended
HVAC Environmental Sensor Hub
Building-automation HVAC controllers scan CO2, temperature, humidity, and occupancy sensors across each zone of a commercial building, and the MAX1238EEE/V+ consolidates 12 sensor inputs into a single I²C device. Auto-scan mode cycles through zones while the host MCU sleeps, drawing an average supply current dominated by the 670 µA burst-conversion spikes - ideal for grid-tied controllers where standby power is regulated under EuP Lot 6. The 5 V analog supply is also the natural rail for HVAC damper-driver circuits, eliminating an extra DC-DC converter.
Recommended
Battery-Operated Multi-Sensor IoT Edge Node
Wireless IoT edge nodes need to read as many sensors as possible on a single coin cell, and the MAX1238EEE/V+ delivers 12 channels at 670 µA active with 1.5 µA shutdown. The I²C interface stacks natively with most low-power wireless SoCs from Nordic, TI, and Silicon Labs, and the QSOP-16 footprint is small enough to live on a 20×25 mm sensor board. With auto-scan mode the host MCU stays in deep sleep while the ADC collects one full frame of 12 readings, then wakes once per scan period - extending battery life by 5-10× compared to keeping the host MCU active during conversion.
Recommended
Recommended Products Summary
Engineering reference data for MAX1238EEE/V+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX1238EEE+ | MAX1236EEE+ | MAX1236CEE+ | MAX1237KEUA+ |
|---|---|---|---|---|---|
| Brand | Analog Devices (Maxim Integrated) | 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 | µMAX-8 - different 8-pin package |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Input Channels | 12 (6 single-ended / 6 pseudo-differential pairs) | 12 | 4 | 4 | 4 |
| Sampling Rate | 94.4 ksps | 94.4 ksps | 94.4 ksps | 94.4 ksps | 94.4 ksps |
| Supply Voltage | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 4.5 V to 5.5 V | 2.7 V to 3.6 V |
| Internal Reference | 4.096 V | 4.096 V | 4.096 V | 4.096 V | 2.048 V |
Key Differentiators
- Automotive -40 °C to +125 °C operating grade with same drop-in QSOP-16 footprint (vs MAX1238EEE+ (commercial grade))
- 12-channel input mux reduces external component count for multi-sensor designs (vs MAX1236 (4-channel))
- Integrated 4.096 V reference eliminates need for external precision reference (vs MAX1237 (2.048 V reference))
Design Notes
Decouple AVDD with a 0.1 µF X7R ceramic within 5 mm of the pin and a 10 µF tantalum or ceramic within 10 mm. DVDD requires the same 0.1 µF + 10 µF stack on the digital supply pin to prevent I²C-bus switching noise from corrupting the SAR comparator. Do not skip the AVDD bulk capacitor - the SAR core draws bursts up to several mA during bit-trial comparison, and inadequate bulk capacitance directly degrades INL on the lower channels.
Solder the QSOP-16 exposed thermal pad to a continuous copper pour tied to the analog ground plane; this keeps junction-to-ambient thermal resistance low enough for continuous 94.4 ksps sampling at 5.5 V across the full -40 °C to +125 °C automotive /V grade. Estimated: at 670 µA continuous active current and 5.5 V AVDD, internal dissipation is ~3.7 mW, well within the QSOP limit when the exposed pad is properly soldered. Skipping the exposed-pad land connection can push junction temperature several degrees above ambient and trigger thermal shutdown during high-channel-count scanning.
Route AVDD and DGND separately and join them at a single ground-star point near the package to avoid digital return-current contamination of the analog reference. Keep the I²C SDA/SCL traces short and away from AIN0-AIN5 lines; adding 100 Ω series resistors near the MCU can suppress ringing on the bus without impacting SAR conversion timing. Place the REF bypass capacitor (typically 0.1 µF + 4.7 µF) directly at the REF pin to keep reference noise out of the SAR comparator decision.
Drive long analog input cables (sensor leads) with shielded twisted pair and an RC low-pass filter (typically 1 kΩ + 1 nF) to clamp RF injection before it enters the mux. The MAX1238 input mux is not buffered, so source-impedance mismatch between channels appears as gain error - if channels come from different sensor impedances, recalibrate each in software rather than expecting default accuracy.
Compliance Information
RoHS and REACH compliant per Maxim Integrated datasheet; the /V suffix denotes the extended operating temperature grade which is not equivalent to full AEC-Q100 qualification - confirm with the manufacturer for mission-critical automotive safety applications.
