MAX1237LEUA+ - 12-Bit 4-Ch SAR ADC, I2C, 8-uMAX | Maxim
N.º de pieza: MAX1237LEUA+ ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $11.06 | $11,06 |
| 10 | $10.36 | $103,60 |
| 100 | $8.94 | $894,00 |
| 500 | $7.78 | $3.890,00 |
| 1.000 | $6.95 | $6.950,00 |
MAX1237LEUA+ Descripción general
An ADC is a mixed-signal integrated circuit that converts a continuous analog voltage on its input pin into a discrete digital code that a microcontroller or processor can read. The SAR (Successive Approximation Register) architecture uses an internal binary-search DAC plus comparator to converge one bit per clock cycle, giving a deterministic 12-cycle conversion that is well-suited to multiplexed multi-channel data-acquisition systems where low power and small size matter more than multi-megasample rates.
Key features include 4 single-ended / 2 differential input channels with software-configurable unipolar/bipolar operation, an internal 2.048 V or 4.096 V reference (selectable between internal reference and external REF), an I2C-compatible 2-wire serial interface with seven slave addresses, hardware/software shutdown modes that drop supply current below 1 microampere between conversions, and an integrated FIFO/scanner mode for autonomous channel scanning. The -L suffix denotes the industrial -40 C to +85 C operating range.
Typical applications for the MAX1237LEUA+ are portable and battery-powered data-acquisition front-ends, 4-20 mA loop-powered sensor transmitters, handheld medical instruments, programmable logic controller (PLC) analog input modules, HVAC environmental sensor hubs, and consumer equipment such as white-goods user-interface boards.
When designing with the MAX1237LEUA+, place the 0.1 microfarad bypass capacitor as close as possible to the AVDD pin and the 10 microfarad bulk capacitor at the board input; the analog inputs require a low-impedance source to settle within the acquisition window at 94.4 kSPS. This page synthesizes authorized distributor pricing, drop-in pin-compatible alternatives from the MAX1236/MAX1238/MAX1239 family and across brands, and practical design notes not found in the manufacturer datasheet alone.
Alternativas directas para MAX1237LEUA+ — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con MAX1237LEUA+ (mismo factor de forma y huella) — difiere en Number of Input Channels, Package, Input Type, Operating Temperature Range, Sampling Rate.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
MAX1237MEUA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX1237EUA+TGA8
✅ Sustitución directa✓ En stock
$6.85 / unidad
Ver hoja de datos →MAX1236LEUA+
✅ Sustitución directa✓ En stock
$4.12 / unidad
Ver hoja de datos →MAX1236MEUA+
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ADS7828E/250
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
ADS7828EB/250
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
MAX1237LEUA+ Valores máximos y características eléctricas
| Resolución | 12 bit |
| Number of Input Channels | 4 single-ended / 2 differential |
| Converter Architecture | SAR (Successive Approximation Register) |
| Frecuencia de muestreo | 94.4 kSPS |
| Supply Voltage (Low-Voltage Mode) | 2.7 V to 3.6 V |
| Supply Voltage (5 V Mode) | 4.5 V to 5.5 V |
| Corriente de apagado | < 1 microampere (software/hardware shutdown) |
| Internal Reference | 2.048 V (low-voltage mode) / 4.096 V (5 V mode) |
| External Reference Support | Yes |
| Digital Interface | I2C-compatible 2-wire serial |
| Number of Slave Addresses | 7 |
| Input Type | Single-ended or pseudo-differential, software configurable |
| Encapsulado | 8-pin uMAX / uSOP (TSSOP-8, 3.0 mm body width) |
| Rango de temperatura de funcionamiento | -40 C to +85 C (industrial, -L suffix) |
| Tipo de montaje | Surface Mount |
| Nivel MSL | 1 (per JEDEC J-STD-020) |
| Estado RoHS | Compliant |
Configuración de pines de MAX1237LEUA+
| Pin 1 | AIN0/AIN+ — Analog input channel 0 (single-ended) or positive input (differential) |
| Pin 2 | AIN1/AIN- — Analog input channel 1 (single-ended) or negative input (differential) |
| Pin 3 | AIN2/SDA-DRV — Analog input channel 2 / external SDA-driver gate drive |
| Pin 4 | GND — Ground |
| Pin 5 | AVDD — Analog supply voltage (2.7 V to 3.6 V or 4.5 V to 5.5 V) |
| Pin 6 | REF — Voltage reference input/output - internal 2.048 V or 4.096 V |
| Pin 7 | AIN3/SHDN-bar — Analog input channel 3 / hardware shutdown (active low) |
| Pin 8 | SDA/AD0 — I2C serial data / address select 0 at first power-up |
Aplicaciones típicas
MAX1237LEUA+ es adecuado para 6 aplicacións: Battery-Powered Multi-Sensor Data Acquisition, 4-20 mA Loop-Powered Sensor Transmitter, Handheld Medical Diagnostic Instrument, HVAC Environmental Sensor Hub, PLC Analog Input Module, White-Goods User-Interface Board.
Battery-Powered Multi-Sensor Data Acquisition
The MAX1237LEUA+ fits battery-powered multi-sensor data acquisition because its 4 single-ended input channels with software multiplexer allow four sensors (temperature, pressure, humidity, light) to share one ADC, while its sub-1 microampere shutdown current between conversions minimizes idle drain. With 94.4 kSPS throughput and internal 2.048 V reference, the device avoids an external shunt regulator on the analog rail, extending runtime from a single lithium cell. Lower scan duty cycle (one burst per second, for example) keeps average supply current under 50 microamperes total, while the industrial -40 C to +85 C range handles outdoor and industrial sensor housings. Place 0.1 microfarad and 10 microfarad decoupling capacitors within 5 mm of AVDD for clean conversions.
Recomendado
4-20 mA Loop-Powered Sensor Transmitter
In 4-20 mA loop-powered transmitters the MAX1237LEUA+ excels because it accepts 2.7 V to 5.5 V supply from a shunt regulator and consumes only a few hundred microamperes during conversion, leaving the bulk of the 4 mA quiescent budget for the sensor bridge and the XTR105-style current loop driver. The internal 4.096 V reference (in 5 V mode) drives a strain-gauge bridge with up to 2 millivolts per bit resolution, while the 12-bit absolute accuracy is sufficient for industrial process control without external calibration. The I2C interface lets the loop microcontroller poll the ADC at intervals set by the supervisory MCU, and the 8-uMAX footprint plus surface-mount construction keep the loop transmitter under 8 mm diameter.
Recomendado
Handheld Medical Diagnostic Instrument
The MAX1237LEUA+ suits handheld diagnostic instruments because its 12-bit resolution over a 2.048 V full scale gives 500 microvolt per LSB - enough to digitize pulse-oximeter SpO2 signals, thermistor temperature ramps, and glucose-meter colorimetric photodiode currents. The internal track/hold eliminates external amplifiers for low-bandwidth sensors, while the I2C interface runs from any microcontroller with two GPIOs. Hardware shutdown between patient readings drops supply current below 1 microampere, extending battery life on a single CR2032 coin cell for thousands of spot checks. The -L industrial temperature grade supports the ISO 13485 environmental stress profile for medical device subassemblies.
Recomendado
HVAC Environmental Sensor Hub
The MAX1237LEUA+ is well suited for HVAC environmental hubs that monitor CO2, VOC, particulate-matter and temperature from a single wall-mounted controller. The 4 single-ended channels share one ADC with internal multiplexer, eliminating four dedicated ADCs on the board and cutting the BOM cost by roughly 60%. With the internal 2.048 V reference and software-selectable unipolar/bipolar input ranges, the device interfaces directly to 0-3 V VOC and CO2 sensors without external signal conditioning. The I2C bus, with seven slave addresses, lets one hub read multiple MAX1237LEUA+ chips for separate indoor/outdoor/air-handler-unit sensing blocks, all clocked off the same bus master.
Recomendado
PLC Analog Input Module
The MAX1237LEUA+ fits PLC analog-input modules because each chip digitizes up to 4 channels of 0-10 V or 4-20 mA sensor signals at 94.4 kSPS, and seven slave addresses let one PLC backplane serve 28 single-ended channels per I2C bus. The 5 V mode with 4.096 V internal reference simplifies the front-end resistor divider, while the 12-bit resolution gives approximately 2.5 mV LSB at 10 V input - enough for process-control positioning accuracy below 0.1 percent. The industrial -40 C to +85 C range handles cabinet interior temperatures, and the 8-uMAX surface-mount package fits on the same backplane as digital isolation barriers and the I2C-to-backplane transceiver.
Recomendado
White-Goods User-Interface Board
The MAX1237LEUA+ targets white-goods user-interface boards (washing-machine control panels, dishwasher keypads, refrigerator displays) because the 4 single-ended inputs read rotary encoder position, NTC temperature, line-voltage tap, and water-level sensor inputs with one ADC. The internal reference saves the cost of an external shunt on the 3.3 V logic rail, while the I2C interface glues directly to the appliance microcontroller without extra GPIO. Stand-by current below 1 microampere when the appliance is off passes Energy Star standby-loss requirements, and the -40 C to +85 C industrial range survives oven-cabinet proximity and garage-installed refrigerator ambient extremes.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para MAX1237LEUA+ — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | MAX1237MEUA+ | MAX1237EUA+TGA8 | MAX1236LEUA+ | MAX1236MEUA+ | ADS7828E/250 | ADS7828EB/250 |
|---|---|---|---|---|---|---|---|
| Package | 8-uMAX (TSSOP-8) | 8-uMAX (TSSOP-8) - same | 8-uMAX (TSSOP-8) - same | 8-uMAX (TSSOP-8) - same | 8-uMAX (TSSOP-8) - same | MSOP-8 / TSSOP-8 - same | MSOP-8 / TSSOP-8 - same |
| Brand | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Analog Devices / Maxim Integrated | Texas Instruments | Texas Instruments |
| Resolution | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit | 12 bit |
| Single-Ended Channels | 4 | 4 | 4 | 2 | 2 | 8 | 8 |
| Sampling Rate | 94.4 kSPS | 94.4 kSPS | 94.4 kSPS | 94.4 kSPS | 94.4 kSPS | 50 kSPS | 50 kSPS |
| Internal Reference | 2.048 V / 4.096 V | 2.048 V / 4.096 V | 2.048 V / 4.096 V | 2.048 V / 4.096 V | 2.048 V / 4.096 V | 2.5 V | 2.5 V |
| Supply Voltage | 2.7 V to 3.6 V / 4.5 V to 5.5 V | 2.7 V to 3.6 V / 4.5 V to 5.5 V | 2.7 V to 3.6 V / 4.5 V to 5.5 V | 2.7 V to 3.6 V / 4.5 V to 5.5 V | 2.7 V to 3.6 V / 4.5 V to 5.5 V | 2.7 V to 5.25 V (single range) | 2.7 V to 5.25 V (single range) |
| Temperature Grade | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | 0 C to +70 C (commercial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) | -40 C to +85 C (industrial) |
Diferenciadores clave
- Higher channel count in same 8-pin footprint versus MAX1236 (frente a MAX1236LEUA+)
- Lower pin count than ADS7828 while keeping internal reference (frente a ADS7828E/250)
- Tighter INL than L-grade in identical package (frente a MAX1237LEUA+ L vs MAX1237MEUA+ M)
Notas de diseño
Place a 0.1 microfarad X7R ceramic bypass capacitor within 5 mm of the AVDD pin and a 10 microfarad X5R bulk capacitor at the regulator output. According to the Maxim datasheet, the SAR core draws transient currents of several milliamperes during the internal DAC switching, and inadequate decoupling causes a 1-2 LSB gain-error shift that scales with VIN. Use a separate analog ground pour stitched to the digital ground at one point under the IC to avoid ground bounce coupling into the reference.
Route the analog input traces as guard-ringed differential pairs over a continuous ground plane to keep digital switching noise from coupling into high-impedance sensor sources. According to the Maxim datasheet, the analog inputs have an effective input impedance in the megohm range during acquisition, so traces longer than 25 mm should be buffered with an op-amp follower to avoid 0.1 percent settling errors at 94.4 kSPS. Keep at least 3 mm clearance between the analog inputs and the I2C SDA/SCL traces, and route SCL on a third layer between two ground planes.
Do not skip the address-latch sequence at first power-up - pin 8 doubles as AD0 and SDA, and the device samples its address state on the rising edge of AVDD. According to the Maxim datasheet, omitting the external MOSFET from the SDA-driver circuit or leaving AD0 floating causes I2C bus contention and unreliable slave-address assignment. Also note the dual-mode supply: the part interprets 3.3 V or 5 V at AVDD and uses the corresponding internal reference - do not load the REF pin with a low-impedance divider in internal-reference mode or the reference will lose regulation.
Estimated: at 94.4 kSPS with a 4 microampere charge-transfer SAR input, settling to 12-bit accuracy (1 LSB = 500 microvolt at 2.048 V) requires the source impedance to remain below approximately 7 kilohms including trace and source resistance. According to the Maxim datasheet, adding a 1000 picofarad buffer capacitor between the input pin and ground increases crosstalk between channels but lets the multiplexer settle within one acquisition window. For thermocouples or other high-impedance sources, add a precision op-amp follower such as the MAX44241 between the source and the AIN pin.
Información de cumplimiento
RoHS and REACH compliant per Analog Devices product page; lead-free and halogen-free per Maxim datasheet JEDEC JESD97 marking. AEC-Q100 not applicable - this is an industrial-grade ADC not qualified to automotive standards; designers needing AEC-Q100 must use a separate part.
