MAX1238LEEE+T - 12-Ch 12-Bit 94.4ksps I2C SAR ADC | Analog Devices
Référence : MAX1238LEEE+T ✓ Actif| Qté | Prix unitaire | Total |
|---|---|---|
| 1 | $9.2 | $9,20 |
| 10 | $8.3 | $83,00 |
| 100 | $7.05 | $705,00 |
| 500 | $5.95 | $2 975,00 |
| 1 000 | $5.1 | $5 100,00 |
MAX1238LEEE+T Présentation
A SAR ADC (Successive Approximation Register Analog-to-Digital Converter) is a type of analog-to-digital converter that uses a binary-search feedback loop with an internal DAC to digitize an analog input, producing one conversion per N clock cycles for N bits of resolution. SAR ADCs sit in the hierarchy: ADC -> data converter -> mixed-signal IC -> semiconductor. They are favored over delta-sigma and pipeline ADCs when low latency, deterministic sample timing, and a small footprint are needed, which is why they dominate multi-channel sensor-acquisition and embedded instrumentation front-ends.
Key specifications include 12-bit resolution, ±1 LSB INL/DNL (typ.), an internal 4.096 V reference with 50 ppm/°C tempco, an input range of 0 V to VREF (unipolar) or ±VREF (bipolar software-configurable), a software-configurable unipolar/bipolar mode with 4 single-ended or 12 differential inputs, an I2C-compatible 2-wire serial interface running at up to 400 kHz in standard mode, an integrated temperature sensor with ±2 °C accuracy, and operation over the extended industrial temperature range of -40 °C to +85 °C.
The architecture combines an internal charge-redistribution DAC, sample-and-hold, configurable input multiplexer, and internal clock, so external components are limited to bypass capacitors and pull-ups on the I2C bus. Power-down sequencing through software reduces quiescent current to sub-microamp levels between conversions, making it suitable for battery-powered sensor polling.
Typical applications include portable data-acquisition loggers, industrial process-control sensor multiplexing, thermocouple and RTD temperature measurement, medical instrumentation front-ends, battery-powered handheld test equipment, and remote HVAC monitoring. The integrated temperature sensor is useful for cold-junction compensation in thermocouple chains. Designers should keep analog and digital grounds joined at a single point near the IC and place 1 µF + 0.1 µF decoupling caps close to AVDD/DVDD to preserve 12-bit noise performance across heavy digital switching. Pricing is current as of 2026-10-14 and reflects typical distributor inventory.
Alternatives de remplacement direct pour MAX1238LEEE+T — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
Variantes de cette série
Modèles de la même série directement compatibles avec MAX1238LEEE+T (même facteur de forme et même empreinte) — différant par Resolution, Interface, Internal Reference, Operating Temperature, Supply Voltage.
Outil de comparaison rapide — sélectionnez des références alternatives pour une comparaison côte à côte :
MAX1238EEE+T
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX1238EEE+
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX1139MEEE+T
✅ Remplacement direct✓ En stock
$3.9 / unité
Voir la fiche technique →MAX1139KEEE+
✅ Remplacement direct✓ En stock
$4.45 / unité
Voir la fiche technique →MAX1239LEEE+
✅ Remplacement direct✓ En stock
$5.55 / unité
Voir la fiche technique →MAX1039LEEE
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
MAX1238LEEE+T Valeurs maximales et caractéristiques électriques
| Résolution | 12 bit |
| Architecture | SAR (Successive Approximation) |
| Analog Input Channels | 6 or 12 single-ended / 12 differential (software-configurable) |
| Input Type | Differential, Single-Ended |
| Sampling Rate (max) | 94.4 ksps |
| Analog Supply Voltage (AVDD) | 4.5 V to 5.5 V (MAX1236/MAX1238 family) |
| Supply Current (max sample rate) | 670 µA at 94.4 ksps |
| Courant d'arrêt | 0.5 µA |
| Integral Nonlinearity (INL) | ±1 LSB (typical) |
| Differential Nonlinearity (DNL) | ±1 LSB (typical) |
| Internal Reference | 4.096 V |
| Reference Tempco | 50 ppm/°C |
| Serial Interface | I2C-compatible 2-wire, up to 400 kHz |
| Plage de température de fonctionnement | -40 °C to +85 °C |
| Internal Temperature Sensor Accuracy | ±2 °C |
| Boîtier | 16-pin QSOP (SSOP equivalent, 0.154" / 3.90 mm body width) |
| Type de montage | Surface Mount |
| Statut RoHS | Compliant |
Configuration des broches de MAX1238LEEE+T
| Broche 1 | AIN0 / AIN0+ — Analog input channel 0 (single-ended) or differential positive input 0 |
| Broche 2 | AIN1 / AIN0- — Analog input channel 1 (single-ended) or differential negative input 0 |
| Broche 3 | AIN2 / AIN1+ — Analog input channel 2 (single-ended) or differential positive input 1 |
| Broche 4 | AIN3 / AIN1- — Analog input channel 3 (single-ended) or differential negative input 1 |
| Broche 5 | AIN4 / AIN2+ — Analog input channel 4 (single-ended) or differential positive input 2 |
| Broche 6 | AIN5 / AIN2- — Analog input channel 5 (single-ended) or differential negative input 2 |
| Broche 7 | AIN6 / AIN3+ — Analog input channel 6 (single-ended) or differential positive input 3 |
| Broche 8 | AIN7 / AIN3- — Analog input channel 7 (single-ended) or differential negative input 3 |
| Broche 9 | AVDD — Analog supply voltage, 4.5 V to 5.5 V, decouple with 0.1 µF + 10 µF ceramic as close as possible |
| Broche 10 | GND — Ground reference for both analog and digital supplies - use single-point ground |
| Broche 11 | REF — Voltage reference input/output - internal 4.096 V reference; can be overdriven by external reference |
| Broche 12 | DVDD — Digital supply voltage, 2.7 V to 5.5 V, decouple with 0.1 µF + 10 µF ceramic |
| Broche 13 | SDA — I2C-compatible serial data line, open-drain; requires external pull-up resistor |
| Broche 14 | SCL — I2C-compatible serial clock line, open-drain input; requires external pull-up resistor |
| Broche 15 | AIN10 / AD1 — Analog input channel 10 (single-ended) or I2C slave-address bit 1 |
| Broche 16 | AIN11 / AD0 — Analog input channel 11 (single-ended) or I2C slave-address bit 0 |
Applications typiques
MAX1238LEEE+T convient pour 6 applications: Battery-Powered Multi-Channel Data Logger, Industrial Process Control Sensor Multiplexing, Thermocouple and RTD Temperature Measurement, Portable Handheld Test Instruments, Medical Instrumentation Front-Ends, HVAC and Environmental Sensor Nodes.
Battery-Powered Multi-Channel Data Logger
The MAX1238LEEE+T's 670 µA at 94.4 ksps and 0.5 µA shutdown current make it a strong fit for battery-powered multi-channel data loggers that wake, sample all 12 channels, and return to sleep. With 12-bit resolution across 0 V to 4.096 V the 1 LSB size is 1 mV, sufficient for slow thermocouple and 4-20 mA shunt signals in industrial logging. Pairing the on-chip 50 ppm/°C reference eliminates external precision references; only bypass caps are required for full 12-bit performance. Estimated: at a 1 Hz aggregate sampling rate with shutdown between conversions, average supply current drops to roughly 5 µA, so a 1000 mAh Li-coin cell can run for >3 years.
Recommandé
Industrial Process Control Sensor Multiplexing
The MAX1238LEEE+T's 6/12-channel software-configurable mux aligns directly with industrial PLC analog input modules that aggregate multiple 4-20 mA or 0-10 V process signals. The internal 4.096 V reference is convenient when scaling 4-20 mA shunts (250 Ω gives 1-5 V), while ±1 LSB INL/DNL satisfies 0.1%-of-full-scale accuracy needed for level and pressure transmitters. Integrated temperature sensing can compensate cold junctions of remote thermocouples wired to the multiplexer inputs. The -40 °C to +85 °C operating range covers IEC 60068 industrial cabinet profiles; for hazardous-area approvals an additional galvanic isolation stage is required outside the IC.
Recommandé
Thermocouple and RTD Temperature Measurement
With its internal ±2 °C die temperature sensor and 12-bit resolution the MAX1238LEEE+T enables a single IC to handle both external thermocouple measurements and cold-junction compensation. Differential-mode operation lets two RTDs be read simultaneously via a ratiometric excitation. The 50 ppm/°C internal reference is suitable for an external RTD excitation buffer; for higher-accuracy thermocouple work, replace it with a MAX6325-class external reference on the REF pin. Pairing with a low-noise front-end analog input filter (10 Hz Sallen-Key 2nd-order) brings effective resolution near 14 bits after averaging.
Recommandé
Portable Handheld Test Instruments
The MAX1238LEEE+T's compact 16-QSOP footprint (0.0256 in²) and 670 µA at full speed suit handheld DMM and oscilloscope probes that need many input channels in a tight enclosure. Its 94.4 ksps throughput captures audio-band signals adequately for HVAC, vibration, and PQ measurements. The integrated reference removes two external components per ADC, BOM-count-critical in cost-sensitive consumer test gear. Pairing the part with a small Cortex-M0 MCU is common; I2C 7-bit addressing lets up to eight MAX1238s share a bus, expanding front-end channel count without extra MCUs.
Recommandé
Medical Instrumentation Front-Ends
The MAX1238LEEE+T's 12-bit resolution, low power consumption, and ±1 LSB linearity make it relevant to battery-powered patient-monitoring front-ends where leakage current and channel density both matter. Internal temperature sensing enables patient-side skin-temperature telemetry without extra thermistors. The 94.4 ksps throughput handles multi-lead ECG digitisation at 1 kHz per channel after downsampling. The IC is graded -40 °C to +85 °C, suitable for non-implantable medical designs; for IEC 60601 patient leakage requirements, design the chassis analog ground plane carefully with isolated DC-DC converters feeding AVDD/DVDD.
Recommandé
HVAC and Environmental Sensor Nodes
Wireless and wired HVAC sensor nodes use the MAX1238LEEE+T to digitize multiple analog humidity, CO2, VOC, and thermistor signals while reading the on-chip die temperature for self-calibration. The 0.5 µA shutdown current allows the node to wake every 30 s, sample all channels, then sleep, hitting multi-year coin-cell battery life targets. With 12-bit resolution over the 0-4.096 V input range the LSB size is approximately 1 mV, sufficient for thermistor-based humidity sensors whose output is roughly 1-3.5 V. The internal reference is precise enough for HVAC-grade calibration; for ashrae-rated building sensors an external REF becomes worthwhile.
Recommandé
Récapitulatif des produits recommandés
Données de référence d'ingénierie pour MAX1238LEEE+T — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | MAX1238EEE+T | MAX1139MEEE+T | MAX1239LEEE+ |
|---|---|---|---|---|
| Package | 16-QSOP | 16-QSOP - same | 16-QSOP - same | 16-QSOP - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Resolution | 12 bit | 12 bit | 10 bit | 12 bit |
| Analog Inputs | 6 or 12 channels | 6 or 12 channels | 6 or 12 channels | 6 or 12 channels |
| Max Sampling Rate | 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 | 2.7 V to 3.6 V |
| Internal Reference | 4.096 V, 50 ppm/°C | 4.096 V, 50 ppm/°C | 4.096 V | 4.096 V |
| Interface | I2C, 400 kHz | I2C, 400 kHz | I2C, 400 kHz + 1.7 MHz HS mode | I2C, 400 kHz + 1.7 MHz HS mode |
| Operating Temperature | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C |
Principaux différenciateurs
- 12-bit resolution with on-chip 4.096 V reference in 16-QSOP (vs MAX1139MEEE+T)
- Industrial temperature grade -40 °C to +85 °C with software configurable 6/12 channels (vs MAX1238EEE+)
- 0.5 µA software shutdown with internal temperature sensor (vs MAX1039LEEE)
- 94.4 ksps throughput with internal track/hold (vs Generic 12-bit I2C ADCs)
Notes de conception
The MAX1238LEEE+T draws 670 µA at full 94.4 ksps throughput but drops to 0.5 µA in software shutdown. For battery-powered designs sequence wake / sample / convert / shutdown in the I2C-driven setup register rather than gating the supply. Estimated: at one conversion every 30 s the average supply current is roughly 5 µA, dominated by the I2C pull-up leakage. Always drive both AVDD and DVDD from low-noise LDOs - the part shares an internal 4.096 V reference node and a noisy AVDD will manifest as amplified INL/DNL errors.
Place the 0.1 µF + 10 µF decoupling pair on AVDD and DVDD within 3 mm of the device pins, on the same board layer with short, wide traces. Use a single-point ground joining analog ground (AGND) and digital ground (DGND) only at pin 10; never use a ground-loop trace. Route AIN traces symmetrically for differential-pair operation and guard them with analog ground. The 16-QSOP exposed lead-frame is not a thermal pad; thermal performance in this package relies on minimizing AVDD-side copper losses rather than heatsinking.
The 12-bit ADC achieves best dynamic performance when input source impedance is below 1 kΩ. For higher-impedance sensors (e.g. pH probes, biased thermistors) add a low-noise op-amp buffer (OPA350-class) in front of the AIN pin. The internal track/hold settles in roughly 200 ns; let SCL frequency stay at 400 kHz max when using high source impedance to avoid coupling-induced non-linearity. The on-chip ADC has ±1 LSB INL/DNL; achieving 12 ENOB in production layouts requires attention to power-rail ferrite beads and slot-shield patterns on the analog ground plane.
Do not exceed 5.5 V on AVDD - the part has no internal clamp and overvoltage will damage the reference. Do not leave REF floating: even when overdriven externally, the REF pin should be decoupled with at least 0.1 µF + 4.7 µF to limit reference noise. Avoid burst-mode I2C transactions without proper setup-register sequencing - improper transitions can leave the ADC in a non-defined state. Always read the datasheet's setup-register bit definitions before adding new channel configurations.
Ground-plane stitching vias around AIN traces prevent cross-talk; for designs with multiplexer inputs that swing more than 4 V, allow guard traces driven by analog ground. The internal I2C pull-up resistors are NOT included - external 2.2 kΩ to 10 kΩ pull-ups must be sized per bus capacitance. Designed for 5 V AVDD/2.7-5 V DVDD; using it on a 3.3 V-only rail requires review against the 2.7-3.6 V MAX1237/MAX1239 datasheet instead.
Informations de conformité
RoHS compliant per the Analog Devices (formerly Maxim Integrated) MAX1238 product page. Not AEC-Q100 - choose an AEC-Q100 qualified variant from the MAX12xx automotive family for vehicle applications. Lead-free and halogen-free per the manufacturer datasheet.
